# 78 FR 53582: Endangered and Threatened Wildlife and Plants; Threatened Status for Oregon Spotted Frog

> Federal · Regulations · In force

URL: https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2013-20986

## Section

- **Citation:** 78 FR 53582
- **Heading:** Endangered and Threatened Wildlife and Plants; Threatened Status for Oregon Spotted Frog
- **Jurisdiction:** Federal
- **Kind:** Regulations
- **Status:** In force
- **Text as of:** August 14, 2026
- **Source:** Compiled text
- **Location:** Federal Register / Vol. 78 / 78 FR 53582

## Text

DEPARTMENT OF THE INTERIOR Fish and Wildlife Service 50 CFR Part 17 [FWS-R1-ES-2013-0013; 4500030113] RIN 1018-AZ04 Endangered and Threatened Wildlife and Plants; Threatened Status for Oregon Spotted Frog AGENCY:
Fish and Wildlife Service, Interior.

ACTION:
Proposed rule.

SUMMARY:
We, the U.S. Fish and Wildlife Service, propose to list the Oregon spotted frog ( Rana pretiosa ), as a threatened species under the Endangered Species Act. If we finalize this rule as proposed, it would extend the Act's protections to this species. The effect of this regulation is to add this species to the list of Endangered and Threatened wildlife under the Act.

DATES:
We will accept comments received or postmarked on or before October 28, 2013. Comments submitted electronically using the Federal eRulemaking Portal (see ADDRESSES section, below) must be received by 11:59 p.m. Eastern Time on the closing date. We must receive requests for public hearings, in writing, at the address shown in FOR FURTHER INFORMATION CONTACT by October 15, 2013.

ADDRESSES:
Written Comments: You may submit comments by one of the following methods:
(1) Electronically: Go to the Federal eRulemaking Portal: http://www.regulations.gov. In the Search box, enter FWS-R1-ES-2013-0013, which is the docket number for this rulemaking. You may submit a comment by clicking on “Comment Now!”
(2) By hard copy: Submit by U.S. mail or hand-delivery to: Public Comments Processing, Attn: FWS-R1-ES-2013-0013; Division of Policy and Directives Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax Drive, MS 2042-PDM; Arlington, VA 22203.
We request that you send comments only by the methods described above. We will post all comments on http://www.regulations.gov. This generally means that we will post any personal information you provide us (see the Public Comments section below for more information).
FOR FURTHER INFORMATION CONTACT:
Ken Berg, Manager, U.S
ife Service; 4401 N. Fairfax Drive, MS 2042-PDM; Arlington, VA 22203.
We request that you send comments only by the methods described above. We will post all comments on http://www.regulations.gov. This generally means that we will post any personal information you provide us (see the Public Comments section below for more information).
FOR FURTHER INFORMATION CONTACT:
Ken Berg, Manager, U.S. Fish and Wildlife Service, Washington Fish and Wildlife Office, 510 Desmond Drive SE., Suite 102, Lacey, WA 98503, by telephone 360-753-9440 or by facsimile 360-753-9445. Persons who use a telecommunications device for the deaf (TDD) may call the Federal Information Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Executive Summary
Why we need to publish a rule. Under the Act, if a species is determined to be an endangered or threatened species throughout all or a significant portion of its range, we are required to promptly publish a proposal in the Federal Register and make a determination on our proposal within 1 year. Listing a species as an endangered or threatened species can be completed only by issuing a rulemaking. The Oregon spotted frog is a candidate for listing and, by virtue of a settlement agreement with Wild Earth Guardians, we must make a final listing determination under the Act by the end of fiscal year 2014.
• This rule will propose to list the Oregon spotted frog as threatened.
The basis for our action. Under the Act, we can determine that a species is an endangered or threatened species based on any of five factors: (A) The present or threatened destruction, modification, or curtailment of its habitat or range; (B) Overutilization for commercial, recreational, scientific, or educational purposes; (C) Disease or predation; (D) The inadequacy of existing regulatory mechanisms; or (E) Other natural or manmade factors affecting its continued existence
endangered or threatened species based on any of five factors: (A) The present or threatened destruction, modification, or curtailment of its habitat or range; (B) Overutilization for commercial, recreational, scientific, or educational purposes; (C) Disease or predation; (D) The inadequacy of existing regulatory mechanisms; or (E) Other natural or manmade factors affecting its continued existence.
We have determined that the Oregon spotted frog is impacted by one or more of the following factors to the extent that the species meets the definition of a threatened species under the Act:
• Habitat necessary to support all life stages is continuing to be impacted and/or destroyed by human activities that result in the loss of wetlands to land conversions; hydrologic changes resulting from operation of existing water diversions/manipulation structures, new and existing residential and road developments, drought, and removal of beavers; changes in water temperature and vegetation structure resulting from reed canarygrass invasions, plant succession, and restoration plantings; and increased sedimentation, increased water temperatures, reduced water quality, and vegetation changes resulting from the timing and intensity of livestock grazing (or in some instances, removal of livestock grazing at locations where it maintains early seral stage habitat essential for breeding);
• Predation by nonnative species, including nonnative trout and bullfrogs;
• Inadequate existing regulatory mechanisms that result in significant negative impacts such as habitat loss and modification; and
• Other natural or manmade factors including small and isolated breeding locations, low connectivity, low genetic diversity within occupied sub-basins, and genetic differentiation between sub-basins.
We will seek peer review
cluding nonnative trout and bullfrogs;
• Inadequate existing regulatory mechanisms that result in significant negative impacts such as habitat loss and modification; and
• Other natural or manmade factors including small and isolated breeding locations, low connectivity, low genetic diversity within occupied sub-basins, and genetic differentiation between sub-basins.
We will seek peer review. We are seeking comments from knowledgeable individuals with scientific expertise to review our analysis of the best available science and application of that science and to provide any additional scientific information to improve this proposed rule. Because we will consider all comments and information received during the comment period, our final determination may differ from this proposal.
Information Requested
We intend that any final action resulting from this proposed rule will be based on the best scientific and commercial data available and be as accurate and as effective as possible. Therefore, we request comments or information from the public, other concerned governmental agencies, Native American tribes, the scientific community, industry, or any other interested parties concerning this proposed rule. We particularly seek comments concerning:
(1) The species' biology, range, and population trends, including:
(a) Habitat requirements for feeding, breeding, and sheltering;
(b) Genetics and taxonomy;
(c) Historical and current range including distribution patterns;
(d) Historical and current population levels, and current and projected trends; and
(e) Past and ongoing conservation measures for the species, its habitat or both.
(2) The factors that are the basis for making a listing determination for a species under section 4(a) of the Act (16 U.S.C. 1531 et seq. ), which are:
(a) The present or threatened destruction, modification, or curtailment of its habitat or range;
(b) Overutilization for commercial, recreational, scientific, or educational purposes;
(c) Disease or predation;
species, its habitat or both.
(2) The factors that are the basis for making a listing determination for a species under section 4(a) of the Act (16 U.S.C. 1531 et seq. ), which are:
(a) The present or threatened destruction, modification, or curtailment of its habitat or range;
(b) Overutilization for commercial, recreational, scientific, or educational purposes;
(c) Disease or predation;
(d) The inadequacy of existing regulatory mechanisms; or
(e) Other natural or manmade factors affecting its continued existence.
(3) Biological, commercial trade, or other relevant data concerning any threats (or lack thereof) to this species and existing regulations that may be addressing those threats.
(4) Additional information concerning the historical and current status, range, distribution, and population size of this species, including the locations of any additional populations of this species.
(5) Any information on the biological or ecological requirements of the species, and ongoing conservation measures for the species and its habitat.
(6) Land use designations and current or planned activities in the areas occupied by the species and possible impacts of these activities on this species.
(7) Information on the projected and reasonably likely impacts of climate change on the Oregon spotted frog.
(8) Information on the type, application of, and methods of monitoring chemical contaminants, in addition to the projected and reasonably likely impacts of chemical contaminants on the Oregon spotted frog.
ccupied by the species and possible impacts of these activities on this species.
(7) Information on the projected and reasonably likely impacts of climate change on the Oregon spotted frog.
(8) Information on the type, application of, and methods of monitoring chemical contaminants, in addition to the projected and reasonably likely impacts of chemical contaminants on the Oregon spotted frog.
(9) The development of a 4(d) special rule. We are also considering developing a special rule to exempt certain ongoing land and water management activities (e.g., grazing, mechanical vegetation management, water level manipulation) from take prohibitions of the Act if the Oregon spotted frog is listed, when those activities are conducted in a manner consistent with the conservation of the frog. Under section 4(d) of the Act, the Secretary may publish a special rule that modifies the standard protections for threatened species with special measures tailored to the conservation of the species that are determined to be necessary and advisable. Note that a 4(d) special rule will not remove or alter in any way the consultation requirements under section 7 of the Act.
We see meaningful opportunities to conserve the Oregon spotted frog by allowing and promoting ongoing, and possibly new, activities on non-Federal lands that contribute to the conservation of this now largely management-dependent species. The Service is continuing to evaluate the range and scope of activities that may be consistent with the conservation of the frog and the range of options for providing “take” coverage (e.g., special rules, Habitat Conservation Plans, Safe Harbor Agreements, and other types of conservation agreements) for non-Federal landowners conducting these activities that further Oregon spotted frog conservation. We are specifically seeking information and comments regarding:
ies that may be consistent with the conservation of the frog and the range of options for providing “take” coverage (e.g., special rules, Habitat Conservation Plans, Safe Harbor Agreements, and other types of conservation agreements) for non-Federal landowners conducting these activities that further Oregon spotted frog conservation. We are specifically seeking information and comments regarding:
(a) What measures are necessary and advisable for the conservation and management of the Oregon spotted frog that are appropriate for a proposed 4(d) special rule to encourage landowners to manage their lands for the benefit of the Oregon spotted frog.
(b) Information regarding the types of activities that occur within Oregon spotted frog habitat and how they are or can be implemented (e.g., timing, extent) consistent with maintaining or advancing conservation of the frog.
(c) Whether the Service should develop a 4(d) special rule to allow incidental take of Oregon spotted frog if the take results from implementation of a comprehensive State conservation program or regional or local conservation programs.
(d) Information concerning whether it would be appropriate to include in the 4(d) special rule a provision for take of Oregon spotted frog in accordance with applicable State law for educational or scientific purposes, the enhancement of propagation or survival of the species, zoological exhibition, and other conservation purposes consistent with the Act.
egional or local conservation programs.
(d) Information concerning whether it would be appropriate to include in the 4(d) special rule a provision for take of Oregon spotted frog in accordance with applicable State law for educational or scientific purposes, the enhancement of propagation or survival of the species, zoological exhibition, and other conservation purposes consistent with the Act.
(e) Additional provisions the Service may wish to consider for a 4(d) special rule in order to conserve, recover, and manage the Oregon spotted frog.
Please include sufficient information with your submission (such as scientific journal articles or other publications) to allow us to verify any scientific or commercial information you include.
Please note that submissions merely stating support for or opposition to the action under consideration without providing supporting information, although noted, will not be considered in making a determination, as section 4(b)(1)(A) of the Act directs that determinations as to whether any species is an endangered or threatened species must be made “solely on the basis of the best scientific and commercial data available.”
You may submit your comments and materials concerning this proposed rule by one of the methods listed in the ADDRESSES section. We request that you send comments only by the methods described in the ADDRESSES section.
If you submit information via http://www.regulations.gov, your entire submission—including any personal identifying information—will be posted on the Web site. If your submission is made via a hardcopy that includes personal identifying information, you may request at the top of your document that we withhold this information from public review. However, we cannot guarantee that we will be able to do so. We will post all hardcopy submissions on http://www.regulations.gov. Please include sufficient information with your comments to allow us to verify any scientific or commercial information you include
ncludes personal identifying information, you may request at the top of your document that we withhold this information from public review. However, we cannot guarantee that we will be able to do so. We will post all hardcopy submissions on http://www.regulations.gov. Please include sufficient information with your comments to allow us to verify any scientific or commercial information you include.
Comments and materials we receive, as well as supporting documentation we used in preparing this proposed rule, will be available for public inspection on http://www.regulations.gov, or by appointment, during normal business hours, at the U.S. Fish and Wildlife Service, Washington Fish and Wildlife Office (see FOR FURTHER INFORMATION CONTACT ).
Previous Federal Actions
We received a petition dated May 1, 1989, from the Board of Directors of the Utah Nature Study Society on May 4, 1989. The petition requested that the U.S. Fish and Wildlife Service (Service or USFWS) add the spotted frog ( Rana pretiosa ) to the Federal List of Endangered and Threatened Species. The Service published a notice of a 90-day finding in the Federal Register (54 FR 42529) on October 17, 1990, stating that substantial information indicates that the petitioned action may be warranted. On May 7, 1993, the Service published a 12-month finding in the Federal Register (58 FR 27260) indicating that the spotted frog ( Rana pretiosa ) warranted listing as threatened in some portions of its range, but was precluded by other higher priority listing actions. Subsequent genetic analyses separated the spotted frog into two separate species, Rana pretiosa (Oregon spotted frog) and Rana luteiventris (Columbia spotted frog)
ished a 12-month finding in the Federal Register (58 FR 27260) indicating that the spotted frog ( Rana pretiosa ) warranted listing as threatened in some portions of its range, but was precluded by other higher priority listing actions. Subsequent genetic analyses separated the spotted frog into two separate species, Rana pretiosa (Oregon spotted frog) and Rana luteiventris (Columbia spotted frog). The Service recognized these taxonomic changes in the Federal Register (62 FR 49398) on September 19, 1997, and assigned a listing priority number of “2” to the Oregon spotted frog and a listing priority number of “3” (Wasatch Front population), “6” (West Desert population), or “9” (Great Basin population) for the Columbia spotted frog. The candidate status for Oregon spotted frog was most recently reaffirmed in the October 26, 2011, Candidate Notice of Review (CNOR) (76 FR 66370).
In a settlement agreement with plaintiff WildEarth Guardians on May 10, 2011, the Service submitted a workplan to the U.S. District Court for the District of Columbia in re Endangered Species Act Section 4 Deadline Litigation, No. 10-377 (EGS), MDL Docket No. 2165 (D. DC May 10, 2011), and obtained the court's approval to systematically, over a period of 6 years, review and address the needs of more than 250 candidate species to determine if they should be added to the Federal Lists of Endangered and Threatened Wildlife and Plants. The Oregon spotted frog is one of the candidate species identified in the May 2011 workplan.
Status Assessment for Oregon Spotted Frog
Background
Species Description
The Oregon spotted frog is named for the characteristic black spots covering the head, back, sides, and legs. The dark spots have ragged edges and light centers, usually associated with a tubercle or raised area of skin. These spots become larger and darker, and the edges become more ragged with age (Hayes 1994, p. 14). Body color also varies with age
tted Frog
Background
Species Description
The Oregon spotted frog is named for the characteristic black spots covering the head, back, sides, and legs. The dark spots have ragged edges and light centers, usually associated with a tubercle or raised area of skin. These spots become larger and darker, and the edges become more ragged with age (Hayes 1994, p. 14). Body color also varies with age. Juveniles are usually brown or, occasionally, olive green on the back and white, cream, or flesh-colored with reddish pigments on the underlegs and abdomen (McAllister and Leonard 1997, pp. 1-2). Adults range from brown to reddish brown but tend to become redder with age. Large, presumably older, individuals may be brick red over most of the dorsal (back) surfaces (McAllister and Leonard 1997, pp. 1-2). Red surface pigments on the adult abdomen also increase with age, and the underlegs of adults are a vivid orange red. Tan to orange folds along the sides of the back (dorsolateral folds) extend from behind the eye to midway along the back (McAllister and Leonard 1997, p. 1). The eyes are upturned; there is a faint mask, and a light jaw stripe extends to the shoulder. Small bumps and tubercles usually cover the back and sides (Leonard et al. 1993, p. 130). The hind legs are short relative to body length, and the hind feet are fully webbed (Leonard et al. 1993, p. 130).
The Oregon spotted frog is a medium-sized frog that ranges from about 44 to 105 millimeters (mm) (1.7 to 4.1 inches (in)) in body length (McAllister and Leonard 1997, p. 1; Rombough et al. 2006, p. 210). Females are typically larger than males; females reach up to 105 mm (4 in) (Rombough et al. 2006, p. 210) and males to 75 mm (3 in) (Leonard et al. 1993, p. 130).
Morphological characters can be used to distinguish Oregon spotted frogs from other closely related spotted frogs
llimeters (mm) (1.7 to 4.1 inches (in)) in body length (McAllister and Leonard 1997, p. 1; Rombough et al. 2006, p. 210). Females are typically larger than males; females reach up to 105 mm (4 in) (Rombough et al. 2006, p. 210) and males to 75 mm (3 in) (Leonard et al. 1993, p. 130).
Morphological characters can be used to distinguish Oregon spotted frogs from other closely related spotted frogs. Mottling with dark pigments and fragmentation of the superficial red or orange-red wash on the abdomen can distinguish the Oregon spotted frog from some Columbia spotted frog populations (Hayes 1997, p. 3; Hayes et al. 1997, p. 1). Coloration of the underlegs and abdomen, size and shapes of spots, groin mottling, eye positions, relative length of hind legs to body size, degree of webbing, behaviors, and other characteristics can be used to distinguish among adults of closely related species. However, tadpoles are difficult to distinguish among species (Corkran and Thoms 1996, p. 150; McAllister and Leonard 1997, p. 6).
The Oregon spotted frog has a weak call consisting of a rapid series of six to nine low clucking notes described as sounding like a distant woodpecker's tapping. Males will call at any time, both day and night (McAllister and Leonard 1997, p. 12). Males have been documented to call from submerged sites that are physically distant (tens to hundreds of meters) from oviposition (egg-laying) sites (Bowerman 2010, p. 85). These submerged calls are inaudible at the surface and begin several days prior to breeding. Submerged calling is more frequent at night, although daytime calling has been recorded during overcast days (Bowerman 2010, pp. 85-86). It is unclear if mate selection takes place during this period of calling remotely from the breeding site, but it seems likely (Bowerman 2010, p. 86). This species rarely vocalizes except during the breeding season, which occurs in the spring (Leonard et al. 1993, p. 132); however, vocalizations have been heard during the fall (Leonard et al. 1997, pp
ring overcast days (Bowerman 2010, pp. 85-86). It is unclear if mate selection takes place during this period of calling remotely from the breeding site, but it seems likely (Bowerman 2010, p. 86). This species rarely vocalizes except during the breeding season, which occurs in the spring (Leonard et al. 1993, p. 132); however, vocalizations have been heard during the fall (Leonard et al. 1997, pp. 73-74; Pearl 2010, pers. comm.).
Taxonomy
The common name “spotted frog” and the scientific name Rana pretiosa (order Anura; family Ranidae) were first applied to a series of five specimens collected in 1841 by Baird and Girard (1853, p. 378) from the vicinity of Puget Sound. Two of these specimens were later determined to be northern red-legged frogs ( Rana aurora ) (Hayes 1994, p. 4; Green et al. 1997, p. 4). Dunlap (1955) demonstrated the morphological differences between northern red-legged frogs, Cascades frogs, and spotted frogs. Subsequently, the “spotted frog” was separated into two species, Rana pretiosa (Oregon spotted frog) and Rana luteiventris (Columbia spotted frog) based on genetic analyses (Green et al. 1996, 1997).
Phylogenetic analyses were conducted on samples of Oregon spotted frogs collected from 3 locations in Washington and 13 locations in Oregon (Funk et al. 2008). Results indicate two well-supported clades (a group of biological taxa (as species) that includes all descendants of one common ancestor) nested within the Oregon spotted frog: the Columbia clade (Trout Lake Natural Area Preserve (NAP) and Camas Prairie) and the southern Oregon clade (Wood River and Buck Lake in the Klamath Basin). The Columbia River does not appear to act as a barrier, as the two sites that comprise the Columbia clade occur in Washington (Trout Lake NAP) and in Oregon (Camas Prairie). Haplotype and nucleotide diversity was low for Oregon spotted frogs in general and was very low for each of the two nested clades, respectively (Funk et al. 2008, p. 203)
clade (Wood River and Buck Lake in the Klamath Basin). The Columbia River does not appear to act as a barrier, as the two sites that comprise the Columbia clade occur in Washington (Trout Lake NAP) and in Oregon (Camas Prairie). Haplotype and nucleotide diversity was low for Oregon spotted frogs in general and was very low for each of the two nested clades, respectively (Funk et al. 2008, p. 203). Only six haplotypes were found across the entire range of the Oregon spotted frog, indicating low genetic variation (Funk et al. 2008, p. 205). Recent genetic work conducted by Robertson and Funk (2012, p. 6) in the Deschutes and Klamath basins indicate the sampled Oregon spotted frog sites are characterized by very small effective population sizes and little genetic variation (i.e., measured as low heterozygosity and low allelic richness).
Blouin et al. (2010) performed genetic analyses on Oregon spotted frogs from 23 of the known sites in British Columbia, Washington, and Oregon for variation at 13 microsatellite loci and 298 base pairs of mitochondrial DNA. Their results indicate that Rana pretiosa comprised six major genetic groups: (1) British Columbia; (2) the Chehalis drainage in Washington, (3) the Columbia drainage in Washington, (4) Camas Prairie in northern Oregon, (5) the central Cascades of Oregon, and (6) the Klamath basin (Blouin et al. 2010, pp. 2184-2185). Within the northern genetic groups, the British Columbia (Lower Fraser River) and Chehalis (Black River) populations form the next natural grouping (Blouin et al. 2010, p. 2189). Recently discovered locales in the Sumas, South Fork Nooksack, and Samish Rivers occur in-between these two groups. While no genetic testing has been done on these newly found populations, it is reasonable to assume that they are likely to be closely related to either the British Columbia or Chehalis group, or both, given their proximity and use of similar lowland marsh habitats
l. 2010, p. 2189). Recently discovered locales in the Sumas, South Fork Nooksack, and Samish Rivers occur in-between these two groups. While no genetic testing has been done on these newly found populations, it is reasonable to assume that they are likely to be closely related to either the British Columbia or Chehalis group, or both, given their proximity and use of similar lowland marsh habitats.
Levels of genetic variation in the Oregon spotted frog groups are low compared to other ranid frogs, suggesting these populations are very small and/or very isolated (Blouin et al. 2010, p. 2184). Blouin et al. (2010) found a high frequency of mitochondrial DNA private alleles (i.e., an allele found in only one population or geographic location) in the central Cascades and Klamath Basin groups. This finding suggests an historical (rather than recent) isolation between individual groups (Blouin et al. 2010, p. 2189). This finding also reinforces microsatellite-based conclusions that gene flow among sites has been very low, even on small geographic scales (Blouin et al. 2010, p. 2188). Recent work by Robertson and Funk (2012) in the Deschutes and Klamath basins reinforces the Blouin et al. (2010) et al. 2010, pp. 2186, 2188) and most Oregon spotted frog populations are separated by more than 6.2 miles (mi) (10 kilometers (km). Therefore, Blouin et al. (2010, p. 2189), and Robertson and Funk (2012, p. 5) hypothesize that low aquatic connectivity and small isolated populations are important causes of the low genetic diversity within sites and the high genetic differentiation among sites.
Life-History
Male Oregon spotted frogs are not territorial and often gather in large groups of 25 or more individuals at specific locations (Leonard et al. 1993, p. 132). Breeding occurs in February or March at lower elevations and between early April and early June at higher elevations (Leonard et al. 1993, p. 132). Males and females separate soon after egg-laying with females returning to fairly solitary lives
le Oregon spotted frogs are not territorial and often gather in large groups of 25 or more individuals at specific locations (Leonard et al. 1993, p. 132). Breeding occurs in February or March at lower elevations and between early April and early June at higher elevations (Leonard et al. 1993, p. 132). Males and females separate soon after egg-laying with females returning to fairly solitary lives. Males often stay at the breeding site, possibly for several weeks, until egg-laying is completed (McAllister and Leonard 1997, p. 13) (The term egg-laying site or habitat is used interchangeably with breeding site or habitat throughout this rule).
Oregon spotted frogs' eggs are extremely vulnerable to desiccation and freezing as a result of the species' laying habits. Females may deposit their egg masses at the same locations in successive years, indicating the sites may have unique characteristics. For example, some marked males and females at Sunriver (Upper Deschutes River, OR) returned to the same breeding site for 3 or more years (Bowerman 2006, pers. comm.). Further, at several sites in Oregon and Washington, the same egg-laying locations have been used for more than a decade (Hayes 2008, pers. comm.). Although egg masses are occasionally laid singly, the majority of egg masses are laid communally in groups of a few to several hundred (Licht 1971, p. 119; Nussbaum et al. 1983, p. 186; Cooke 1984, p. 87; Hayes et al. 1997 p. 3; Engler and Friesz 1998, p. 3). They are laid in shallow, often temporary, pools of water; gradually receding shorelines; on benches of seasonal lakes and marshes; and in wet meadows. These sites are usually associated with the previous year's emergent vegetation, are generally no more than 14 in (35 centimeters (cm)) deep (Pearl and Hayes 2004, pp. 19-20), and most of these sites dry up later in the season (Joe Engler, FWS, pers. comm. 1999). Shallow water is easily warmed by the sun, and warmth hastens egg development (McAllister and Leonard 1997, p. 8)
s; and in wet meadows. These sites are usually associated with the previous year's emergent vegetation, are generally no more than 14 in (35 centimeters (cm)) deep (Pearl and Hayes 2004, pp. 19-20), and most of these sites dry up later in the season (Joe Engler, FWS, pers. comm. 1999). Shallow water is easily warmed by the sun, and warmth hastens egg development (McAllister and Leonard 1997, p. 8). However, laying eggs in shallow water can result in high mortality rates for eggs and hatchling larvae due to desiccation or freezing.
Licht (1974, pp. 617-625) documented the highly variable mortality rates for spotted frog life-history stages in marsh areas in the lower Fraser Valley, BC: embryos (30 percent), tadpoles (99 percent), and post-metamorphic (after the change from tadpole to adult, or “metamorphosis”) frogs (95 percent). Licht (1974, p. 625) estimated mortality of each life stage and predicted only a 1 percent chance of survival of eggs to metamorphosis, a 67 percent chance of juvenile survival for the first year, and a 64 percent adult annual survival with males having a higher mortality rate than females. An average adult between-year survival of 37 percent was estimated by a mark-recapture study at Dempsey Creek in Washington between 1997 and 1999 (Watson et al. 2000, p. 19).
Adult Oregon spotted frogs begin to breed by 1-3 years of age, depending on sex, elevation, and latitude. Males may breed at 1 year at lower elevations and latitudes but generally breed at 2 years of age. Females breed by 2 or 3 years of age, depending on elevation and latitude. Longevity of the species is not well understood; however, there are multiple examples of Oregon spotted frogs living beyond 7 years of age (Watson et al. 2000, p. 21; Kelly McAllister, WDOT 2008, pers. comm.; Jill Oertley, U.S. Forest Service 2005, pers. comm.; Pearl 2005, pers. comm.).
Egg-laying can begin as early as February in British Columbia and Washington and as late as early June in the higher elevations
species is not well understood; however, there are multiple examples of Oregon spotted frogs living beyond 7 years of age (Watson et al. 2000, p. 21; Kelly McAllister, WDOT 2008, pers. comm.; Jill Oertley, U.S. Forest Service 2005, pers. comm.; Pearl 2005, pers. comm.).
Egg-laying can begin as early as February in British Columbia and Washington and as late as early June in the higher elevations. Tadpoles metamorphose into froglets (tiny frogs) (about 16-43 mm (0.6-1.75 in) in length) during their first summer (Leonard et al. 1993, p. 132; Pearl and Bowerman 2005, pers. comm.). Tadpoles are grazers, having rough tooth rows for scraping plant surfaces and ingesting plant tissue and bacteria. They also consume algae, detritus, and probably carrion (Licht 1974, p. 624; McAllister and Leonard 1997, p. 13).
Post-metamorphic Oregon spotted frogs are opportunistic predators that prey on live animals, primarily insects, found in or near the water. Important prey groups of adult frogs include leaf beetles (Chrysomelidae), ground beetles (Carabidae), spiders (Arachnidae), rove beetles (Staphylinidae), syrphid flies (Syrphidae), long-legged flies (Dolichopodidae), ants (Formicidae), water striders (Gerridae), spittlebugs (Cercopidae), leaf hoppers (Cicadellidae), aphids (Aphididae), dragonflies and damsel flies (Odonates), and yellowjackets (Vespidae) (Licht 1986a, pp. 27-28). Oregon spotted frogs also eat adult Pacific tree frogs ( Pseudacris regilla ), small red-legged frogs, and newly metamorphosed red-legged frogs and western toad ( Bufo boreas ) juveniles (Licht 1986a, p. 28; Pearl and Hayes 2002, pp. 145-147; Pearl et al. 2005a, p. 37).
Similar to many North American pond-breeding anurans (belonging to the Order Anura, which contains all frogs), predators can strongly affect the abundance of larval and post-metamorphic Oregon spotted frogs. The heaviest losses to predation are thought to occur shortly after tadpoles emerge from eggs, when they are relatively exposed and poor swimmers (Licht 1974, p. 624)
l et al. 2005a, p. 37).
Similar to many North American pond-breeding anurans (belonging to the Order Anura, which contains all frogs), predators can strongly affect the abundance of larval and post-metamorphic Oregon spotted frogs. The heaviest losses to predation are thought to occur shortly after tadpoles emerge from eggs, when they are relatively exposed and poor swimmers (Licht 1974, p. 624). However, the odds of survival appear to increase as tadpoles grow in size and aquatic vegetation matures, thus affording cover (Licht 1974, p. 624). Adult Oregon spotted frogs have a number of documented and potential natural predators, including garter snakes ( Thamnophis species (spp.)), great blue herons ( Ardea herodias ), green-backed herons ( Butorides virescens ), American bitterns ( Botaurus lentiginosus ), belted kingfishers ( Ceryle alcyon ), sandhill cranes ( Grus canadensis ), raccoons ( Procyon lotor ), coyotes ( Canis latrans ), striped skunks ( Mephitis mephitis ), mink ( Mustela vison ), river otters (Lutra canadensis ), and feral cats ( Felis domesticus ) (McAllister and Leonard 1997, p. 13; Hayes et al. 2005, p. 307; Hayes et al. 2006, p. 209). Tadpoles may be preyed upon by numerous vertebrate predators including belted kingfishers, hooded mergansers ( Lophodytes cucullatus ), common garter snakes ( Thamnophis sirtalis ), western terrestrial garter snakes ( Thamnophis elegans ), larval and adult roughskin newts ( Taricha granulosa ), larval northwestern salamanders ( Ambystoma gracile ), cutthroat trout ( Oncorynchus clarki ), Olympic mudminnows ( Novumbra hubbsi ), and three-spined sticklebacks ( Gasterosteus aculeatus ) (McAllister and Leonard 1997, p. 14)
cullatus ), common garter snakes ( Thamnophis sirtalis ), western terrestrial garter snakes ( Thamnophis elegans ), larval and adult roughskin newts ( Taricha granulosa ), larval northwestern salamanders ( Ambystoma gracile ), cutthroat trout ( Oncorynchus clarki ), Olympic mudminnows ( Novumbra hubbsi ), and three-spined sticklebacks ( Gasterosteus aculeatus ) (McAllister and Leonard 1997, p. 14).
Subadult Oregon spotted frogs have been observed within dense aggregations of recently hatched Oregon spotted frog tadpoles, and stomach flushing verified that these subadult Oregon spotted frogs had consumed (cannibalized) recently hatched conspecific (belonging to the same Dytiscus spp.), giant water bugs ( Lethocerus americanus ), backswimmers ( Notonecta undulata and N. kirbyi ), water scorpions ( Ranatra sp.), dragonfly nymphs ( Odonata ), and worm-leeches ( Arhynchobdellida ) (McAllister and Leonard 1997, p. 14). Leeches and other invertebrates, roughskin newts, and northwestern salamanders are likely Oregon spotted frog egg predators (McAllister and Leonard 1997, p. 14).
The introduction of nonnative species into the historical range of the Oregon spotted frog is believed to have contributed to the decline of this and other species of frogs (Hayes and Jennings 1986, pp. 491-492, 494-496; Hayes 1994, p. 5; 61 FR 25813; McAllister and Leonard 1997, pp. 25-26; Pearl et al. 2004, pp. 17-18). Bullfrogs ( Lithobates catesbeiana ) are known predators of Oregon spotted frogs (R. Haycock and R.A. Woods, unpubl. data, 2001 cited in COSFRT 2012, p. 19), and introduced fish such as brook trout ( Salvelinus fontinalis ) and centrarchids ( Micropterus and Lepomis spp.) are also likely predators (Pearl et al. 2009a, p. 140).
Habitat
Watson et al. (2003, p
5-26; Pearl et al. 2004, pp. 17-18). Bullfrogs ( Lithobates catesbeiana ) are known predators of Oregon spotted frogs (R. Haycock and R.A. Woods, unpubl. data, 2001 cited in COSFRT 2012, p. 19), and introduced fish such as brook trout ( Salvelinus fontinalis ) and centrarchids ( Micropterus and Lepomis spp.) are also likely predators (Pearl et al. 2009a, p. 140).
Habitat
Watson et al. (2003, p. 298) summarized the conditions required for completion of the Oregon spotted frog life cycle as shallow water areas for egg and tadpole survival, perennially deep, moderately vegetated pools for adult and juvenile survival in the dry season, and perennial water for protecting all age classes during cold wet weather.
The Oregon spotted frog inhabits emergent wetland habitats in forested landscapes, although it is not typically found under forest canopy. Historically, this species was also associated with lakes in the prairie landscape of the Puget lowlands (McAllister and Leonard 1997, p. 16). This is the most aquatic native frog species in the Pacific Northwest, as all other species have a terrestrial life stage. It is almost always found in or near a perennial body of water, such as a spring, pond, lake, sluggish stream, irrigation canal, or roadside ditch (Engler 1999, pers. comm.). The observation that extant Oregon spotted frog populations tend to occur in larger wetlands led Hayes (1994, Part II pp. 5, 7) to hypothesize that a minimum size of 9 acres (ac) (4 hectares (ha)) may be necessary to reach suitably warm temperatures and support a large enough population to persist despite high predation rates. However, Oregon spotted frogs also occupy smaller sites and are known to occur at sites as small as 2.5 ac (1 ha) and as large as 4,915 ac (1,989 ha) (Pearl and Hayes 2004, p. 11). Oregon spotted frogs have been found at elevations ranging from near sea level in the Puget Trough lowlands in Washington to approximately 5,000 feet (ft) (1,500 meters (m)) in the Oregon Cascades in western Oregon (Dunlap 1955, p
egon spotted frogs also occupy smaller sites and are known to occur at sites as small as 2.5 ac (1 ha) and as large as 4,915 ac (1,989 ha) (Pearl and Hayes 2004, p. 11). Oregon spotted frogs have been found at elevations ranging from near sea level in the Puget Trough lowlands in Washington to approximately 5,000 feet (ft) (1,500 meters (m)) in the Oregon Cascades in western Oregon (Dunlap 1955, p. 316; Hayes 1997, p. 16; McAllister and Leonard 1997, pp. 8-10).
Oregon spotted frogs can make use of a variety of pond types as long as there is sufficient vegetation and seasonal habitat available for breeding, summer feeding, and overwintering (Pearl et al. 2009a, p. 144). Oregon spotted frogs at Dempsey Creek in Washington selected areas of relatively shallow water with less emergent vegetation but more submergent vegetation than adjacent habitats. They avoided dry, upland areas of pasture grass (Watson et al. 1998, p. 10; 2000, pp. 54-57; 2003, p. 297). Radio telemetry data indicates Oregon spotted frogs at Dempsey Creek also make extensive use of scrub-shrub wetland habitats adjacent to forested uplands (Risenhoover et al. 2001a, p. 13).
Oregon spotted frogs breed in shallow pools (2-12 in (5-30 cm) deep) that are near flowing water, or which may be connected to larger bodies of water during seasonally high water or at flood stage. Characteristic vegetation includes grasses, sedges, and rushes, although eggs are laid where the vegetation is low or sparse, such that vegetation structure does not shade the eggs (McAllister and Leonard 1997, p. 17). While native vegetation is the preferred substrate, the frog may also use short, manipulated canarygrass/native vegetation mix (J. Engler, pers. comm. 1999). Full solar exposure seems to be a significant factor in breeding habitat selection (McAllister and White 2001, p. 12; Pearl and Hayes 2004, p. 18). The availability of the unique characteristics of traditional egg-laying sites is limited, and adults may have limited flexibility to switch sites (Hayes 1994, p
so use short, manipulated canarygrass/native vegetation mix (J. Engler, pers. comm. 1999). Full solar exposure seems to be a significant factor in breeding habitat selection (McAllister and White 2001, p. 12; Pearl and Hayes 2004, p. 18). The availability of the unique characteristics of traditional egg-laying sites is limited, and adults may have limited flexibility to switch sites (Hayes 1994, p. 19). This may make the Oregon spotted frog particularly vulnerable to modification of egg-laying sites (Hayes 1994, p. 19).
After breeding, during the dry season, Oregon spotted frogs move to deeper, permanent pools or creeks (Watson et al. 2003, p. 295). They are often observed near the water surface basking and feeding in beds of floating and submerged vegetation (Watson et al. 2003, pp. 292-298; Pearl et al. 2005a, pp. 36-37).
Known overwintering sites are associated with flowing systems, such as springs and creeks, that provide well-oxygenated water (Hallock and Pearson 2001, p. 15; Hayes et al. 2001, pp. 20-23, Tattersall and Ultsch 2008, pp. 123, 129, 136) and sheltering locations protected from predators and freezing (Risenhoover et al. 2001b; Watson et al. 2003, p. 295). Oregon spotted frogs apparently burrow in mud, silty substrate, clumps of emergent vegetation, woody accumulations within the creek, and holes in creek banks when inactive during periods of prolonged or severe cold (Watson et al. 2003, p. 295; Hallock and Pearson 2001, p. 16; McAllister and Leonard 1997, p. 17); however, they are intolerant of anoxic (absence of dissolved oxygen) conditions and are unlikely to burrow into the mud for more than a day or two (Tattersall and Ultsch 2008, p. 136) because survival under anoxic conditions is only a matter of 4-7 days (Tattersall and Ultsch 2008, p. 126). This species remains active during the winter in order to select microhabitats that can support aerobic metabolism and allow it to evade predators (Hallock and Pearson 2001, p. 15; Hayes et al. 2001, pp. 20-23; Tattersall and Ultsch 2008, p
n a day or two (Tattersall and Ultsch 2008, p. 136) because survival under anoxic conditions is only a matter of 4-7 days (Tattersall and Ultsch 2008, p. 126). This species remains active during the winter in order to select microhabitats that can support aerobic metabolism and allow it to evade predators (Hallock and Pearson 2001, p. 15; Hayes et al. 2001, pp. 20-23; Tattersall and Ultsch 2008, p. 136). In central Oregon, where winters generally result in ice cover over ponds, Oregon spotted frogs follow a fairly reliable routine of considerable activity and movement beneath the ice during the first month following freeze-up. Little movement is observed under the ice in January and February, but activity steadily increases in mid-March, even when ice cover persists (Bowerman 2006, pers. comm.). Radio-tracked frogs remained active all winter, even under the ice at Trout Lake NAP (Hallock 2009, pers comm.) and Conboy National Wildlife Refuge (NWR) (Hayes et al. 2001, pp. 16-19).
Results of a habitat utilization and movement study at Dempsey Creek in Washington indicate that adult frogs made infrequent movements between widely separated pools and more frequent movements between pools in closer proximity (Watson et al. 2003, p. 294), but remained within the study area throughout the year. Home ranges averaged 5.4 ac (2.2 ha), and daily movement was 16-23 ft (5-7 m) throughout the year (Watson et al. 2003, p. 295). During the breeding season (February-May), frogs used about half the area used during the rest of the year. During the dry season (June-August), frogs moved to deeper, permanent pools, and occupied the smallest range of any season, then moved back toward their former breeding range during the wet season (September-January) (Watson et al. 2003, p. 295). Individuals equipped with radio transmitters stayed within 2,600 ft (800 m) of capture et al. 1998, p. 10) and within 1,312 ft (400 m) at the Trout Lake NAP (Hallock and Pearson 2001, p. 16)
frogs moved to deeper, permanent pools, and occupied the smallest range of any season, then moved back toward their former breeding range during the wet season (September-January) (Watson et al. 2003, p. 295). Individuals equipped with radio transmitters stayed within 2,600 ft (800 m) of capture et al. 1998, p. 10) and within 1,312 ft (400 m) at the Trout Lake NAP (Hallock and Pearson 2001, p. 16).
Recaptures of Oregon spotted frogs at breeding locations in the Buck Lake population in Oregon indicated that adults often move less than 300 ft (100 m) between years (Hayes 1998a, p. 9). However, longer travel distances, while infrequent, have been observed between years and within a single year between seasons. Three adult Oregon spotted frogs (one male and two females) marked in a study at Dempsey Creek and the Black River in Washington moved a distance of 1.5 mi (2.4 km) between seasons along lower Dempsey Creek to the creek's mouth from the point where they were marked (McAllister and Walker 2003, p. 6). Adult female Oregon spotted frogs traveled 1,434 ft (437 m) between seasons from their original capture location at the Trout Lake Wetland NAP (Hallock and Pearson 2001, p. 8). Two juvenile frogs at the Jack Creek site in Oregon were recaptured the next summer 4,084 ft (1,245 m) and 4,511 ft (1,375 m) downstream from where they were initially marked, and one adult female moved 9,183 ft (2,799 m) downstream (Cushman and Pearl 2007, p. 13). Oregon spotted frogs at the Sunriver site routinely make annual migrations of 1,640 to 4,265 ft (500 to 1,300 m) between the major egg-laying complex and an overwintering site (Bowerman 2006, pers. comm.).
While these movement studies are specific to Oregon spotted frogs, the number of studies and size of the study areas are limited and haven't been conducted over multiple seasons or years. In addition, the ability to detect frogs is challenging because of the difficult terrain in light of the need for the receiver and transmitter to be in close proximity
ntering site (Bowerman 2006, pers. comm.).
While these movement studies are specific to Oregon spotted frogs, the number of studies and size of the study areas are limited and haven't been conducted over multiple seasons or years. In addition, the ability to detect frogs is challenging because of the difficult terrain in light of the need for the receiver and transmitter to be in close proximity. Hammerson (2005) recommends that a 3.1-mile (5-km) dispersal distance be applied to all ranid frog species, because the movement data for ranids are consistent. The preponderance of data indicates that a separation distance of several kilometers may be appropriate and practical for delineation of occupancy, despite occasional movements that are longer or that may allow some genetic interchange between distant populations (for example, the 6.2-mi (10-km) distance noted by Blouin et al. 2010, pp. 2186, 2188). Accordingly, based on the best available scientific information, we presume that Oregon spotted frog habitats are connected for purposes of genetic exchange when occupied/suitable habitats fall within a maximum movement distance of 3.1 mi (5 km).
Historical Range/Distribution
Historically, the Oregon spotted frog ranged from British Columbia to the Pit River basin in northeastern California (Hayes 1997; p. 40; McAllister and Leonard 1997, p. 7). Oregon spotted frogs have been documented at 61 historical localities in 48 watersheds (3 in British Columbia, 13 in Washington, 29 in Oregon, and 3 in California) in 31 sub-basins (McAllister et al. 1993, pp. 11-12; Hayes 1997, p. 41; McAllister and Leonard 1997, pp. 18-20; COSEWIC 2011, pp. 12-13) (See Table 1). We are assuming the watersheds that have recently been documented to be occupied were also occupied historically based on their complete disconnect from known-occupied watersheds and the limited dispersal ability of Oregon spotted frog
California) in 31 sub-basins (McAllister et al. 1993, pp. 11-12; Hayes 1997, p. 41; McAllister and Leonard 1997, pp. 18-20; COSEWIC 2011, pp. 12-13) (See Table 1). We are assuming the watersheds that have recently been documented to be occupied were also occupied historically based on their complete disconnect from known-occupied watersheds and the limited dispersal ability of Oregon spotted frog. For the rest of the document, we will describe historical and current range or distribution based on river sub-basins/watersheds. A river sub-basin is equivalent to a 4th field watershed and a hydrologic unit code of 8. A watershed is equivalent to a 5th field watershed and a hydrologic unit code of 10.
Table 1—Oregon Spotted Frog Historical and Extant Distribution Throughout Range Location Sub-basins *: Watersheds British Columbia • Lower Fraser River sub-basin near Sumas Prairie in Abbotsford, Nicomen Island in Matsqui, and in Langley Township. Recently (1996/1997 and 2008) discovered at MD Aldergrove, Maria Slough, Mountain Slough, and Morris Valley. Washington Counties: Clark, King, Klickitat, Pierce, Skagit, Snohomish, and Thurston • Fraser River sub-basin: recently discovered (2012) in the Sumas River, a tributary to the Lower Chilliwack River watershed; • Nooksack River sub-basin: South Fork Nooksack River (recently discovered (2011 and 2012) in the Black Slough); • Straits of Georgia sub-basin: recently discovered (2011 and 2012) along the mainstem of the Samish River; • Lower Skagit River sub-basin: Skagit River-Frontal Skagit Bay and Finney Creek-Skagit River; • Skykomish River sub-basin: Woods Creek-Skykomish River at Monroe; • Duwamish River sub-basin: Lower Green River at Kent; • Lake Washington sub-basin: Lake Washington at Seattle; • Puget Sound (no sub-basin): Chambers Creek-Frontal Puget Sound (Spanaway Lake) and McLane Creek-Frontal Puget Sound (Patterson/Pattison Lake); • Nisqually River sub-basin: Lower Nisqually River-Frontal Puget Sound (Kapowsin); • Upper Chehalis River sub-basin: Black River (
r at Monroe; • Duwamish River sub-basin: Lower Green River at Kent; • Lake Washington sub-basin: Lake Washington at Seattle; • Puget Sound (no sub-basin): Chambers Creek-Frontal Puget Sound (Spanaway Lake) and McLane Creek-Frontal Puget Sound (Patterson/Pattison Lake); • Nisqually River sub-basin: Lower Nisqually River-Frontal Puget Sound (Kapowsin); • Upper Chehalis River sub-basin: Black River (Demspey Creek, Beaver Creek, Blooms Ditch, and recently discovered in Salmon and Fish Pond Creeks); • Lower Willamette River sub-basin: Salmon Creek-Frontal Columbia River at Brush Prairie, Vancouver, and possibly Burnt Bridge Creek at Orchards; • Middle Columbia-Hood River sub-basin: White Salmon River (Trout Lake Creek at Gular and Trout Lake); • Klickitat River sub-basin: Middle Klickitat River (Conboy Lake on Outlet, Fraiser, and Chapman Creeks). Oregon Counties: Multnomah, Clackamas, Marion, Linn, Benton, Jackson, Lane, Wasco, Deschutes, and Klamath • Lower Willamette River sub-basin: Johnson Creek; • Lower Deschutes River sub-basin: Tygh Creek and White River; • Clackamas River sub-basin: Oak Grove Fork Clackamas River; • Middle Willamette River sub-basin: Mill Creek-Willamette River and Oak Creek; • South Santiam River sub-basin: South Santiam River-Hamilton Creek; • Upper Willamette River sub-basin: Muddy Creek; • McKenzie River sub-basin: Upper McKenzie River and South Fork McKenzie River; • Middle Fork Willamette River sub-basin: Salt Creek-Willamette River; • Upper Deschutes River sub-basin: Deschutes River-McKenzie Canyon, Deschutes River-Pilot Butte, Deschutes River-Fall River, and Deschutes River-Browns Creek; • Little Deschutes River sub-basin: Upper Little Deschutes River, Middle Little Deschutes River, Lower Little Deschutes River, Long Prairie, and Crescent Creek; • Williamson River sub-basin: Klamath Marsh-Jack Creek, West of Klamath Marsh, and Williamson River above Klamath Marsh
hutes River-McKenzie Canyon, Deschutes River-Pilot Butte, Deschutes River-Fall River, and Deschutes River-Browns Creek; • Little Deschutes River sub-basin: Upper Little Deschutes River, Middle Little Deschutes River, Lower Little Deschutes River, Long Prairie, and Crescent Creek; • Williamson River sub-basin: Klamath Marsh-Jack Creek, West of Klamath Marsh, and Williamson River above Klamath Marsh. • Sprague River sub-basin: North Fork Sprague River and Sprague River above Williamson; • Upper Klamath Lake sub-basin: Wood River and Klamath Lake watersheds; • Upper Klamath sub-basin: Spencer Creek and Jenny Creek; • Lost River sub-basin: Lake Ewauna-Upper Klamath River. California Counties: Modoc, Shasta, and Siskiyou • Lost River sub-basin: Lower Klamath Lake. • Upper Pit River sub-basin: Pine Creek-South Pit River (near Alturas). • Lower Pit River sub-basin: Town of Pittville-Pit River (near Fall River Mills). * Bolded sub-basins represent the sub-basins with extant locales. Oregon spotted frogs may not be extant in all of the historic watersheds within these sub-basins. Current Range/Distribution
Currently, the Oregon spotted frog is found from extreme southwestern British Columbia south through the Puget Trough, and in the Cascades Range from south-central Washington at least to the Klamath Basin in southern Oregon. Oregon spotted frogs occur in lower elevations in British Columbia and Washington and are restricted to high elevations in Oregon (Pearl et al. 2010 p. 7). In addition, Oregon spotted frogs currently have a very limited distribution west of the Cascade crest in Oregon, are considered to be extirpated from the Willamette Valley in Oregon (Cushman et al. 2007, p. 14), and may be extirpated in the Klamath and Pit River basins of California (Hayes 1997, p. 1)
olumbia and Washington and are restricted to high elevations in Oregon (Pearl et al. 2010 p. 7). In addition, Oregon spotted frogs currently have a very limited distribution west of the Cascade crest in Oregon, are considered to be extirpated from the Willamette Valley in Oregon (Cushman et al. 2007, p. 14), and may be extirpated in the Klamath and Pit River basins of California (Hayes 1997, p. 1).
In British Columbia, Oregon spotted frogs no longer occupy the locations documented historically, but they currently are known to occupy four disjunct locations in a single sub-basin, the Lower Fraser River (Canadian Oregon Spotted Frog Recovery Team 2012, p. 6).
In Washington, Oregon spotted frogs are known to occur only within six sub-basins/watersheds: the Sumas River, a tributary to the Lower Fraser River; the Black Slough in the lower South Fork Nooksack River, a tributary of the Nooksack River; Samish River; Black River, a tributary of the Chehalis River; Outlet Creek (Conboy Lake), a tributary to the Middle Klickitat River; and Trout Lake Creek, a tributary of the White Salmon River. The Klickitat and White Salmon Rivers are tributaries to the Columbia River. The Oregon spotted frogs in each of these sub-basins/watersheds are isolated from frogs in other sub-basins.
A reintroduction project was initiated in 2008 at Dailman Lake in Pierce County on Joint Base Lewis-McChord Military Reservation. This sub-basin (Nisqually River) was historically occupied by Oregon spotted frogs with documented occurrences at Spanaway Lake, Spanaway Pond, Little Spanaway Lake and Kapowsin (McAllister and Leonard 1997, pp. 18-19). Eggs were collected from the Black River and the Conboy Lake Oregon spotted frog breeding locations, captive reared until metamorphosis, and released in the fall or subsequent spring. Through 2011, researchers collected 7,870 eggs and released 3,355 frogs (Tirhi and Schmidt 2011, pp. 51-53). Surveys in April 2011 found 3 verified Oregon spotted frog egg masses and 11 suspected egg masses
. 18-19). Eggs were collected from the Black River and the Conboy Lake Oregon spotted frog breeding locations, captive reared until metamorphosis, and released in the fall or subsequent spring. Through 2011, researchers collected 7,870 eggs and released 3,355 frogs (Tirhi and Schmidt 2011, pp. 51-53). Surveys in April 2011 found 3 verified Oregon spotted frog egg masses and 11 suspected egg masses. However, breeding was not detected in 2012. This effort is ongoing and the efficacy and viability of a breeding Oregon spotted frog population being established in this area is undetermined. The reintroduction efforts at this location are not likely to facilitate Oregon spotted frog recovery in this extirpated sub-basin because of the extent of development at the historical locales and lack of suitable habitat; therefore, this location will not be discussed further.
In Oregon, Oregon spotted frogs are known to occur only within eight sub-basins: Lower Deschutes River, Upper Deschutes River, Little Deschutes River, McKenzie River, Middle Fork Willamette, Upper Klamath, Upper Klamath Lake, and the Williamson River. The Oregon spotted frogs in most of these sub-basins are isolated from frogs in other sub-basins, although Oregon spotted frogs in the lower Little Deschutes River are aquatically connected with those below Wickiup Reservoir in the Upper Deschutes River sub-basin. Oregon spotted frog distribution west of the Cascade Mountains in Oregon is restricted to a few lakes in the upper watersheds of the McKenzie River and Middle Fork Willamette River sub-basins, which represent the remaining 2 out of 12 historically occupied sub-basins.
In California, this species has not been detected since 1918 (California Academy of Science Museum Record 44291) at historical sites and may be extirpated (Hayes 1997 pp. 1, 35). However, there has been little survey effort of potential habitat since 1996, so this species may still occur in California
e River sub-basins, which represent the remaining 2 out of 12 historically occupied sub-basins.
In California, this species has not been detected since 1918 (California Academy of Science Museum Record 44291) at historical sites and may be extirpated (Hayes 1997 pp. 1, 35). However, there has been little survey effort of potential habitat since 1996, so this species may still occur in California.
Population Estimates and Status
Of the 61 historical localities where the species' previous existence can be verified (e. g., museum specimens, photographs, reliable published records), only 13 were confirmed as being occupied in studies conducted in the 1990s (Hayes 1997, p. 1; McAllister and Leonard 1997, p. 20). Hayes visited historical localities one to four times, with a minimum of 2 hours devoted to site visits for localities that could be identified precisely. For sites where the location was imprecisely known, he searched three to six points in the area that possessed favorable habitat, for 20 minutes to 3 hours, depending on site size. He also visited sites that were judged to have a potentially high likelihood of having Oregon spotted frogs (i.e., within the historical range, consistent with elevations documented for verifiable specimens, and within suitable habitat) (Hayes 1997, p. 6). Based on those studies, Hayes (1997, p. 1) estimated the species may no longer occur in 76 to 90 percent of its historical range. Although this estimated loss of historical localities does not take into account the localities found since 2000, the current range of the Oregon spotted frog is significantly smaller than the historical range, based on the best available scientific and commercial information.
Egg mass counts are believed to be a good metric of adult population size and are the most time-efficient way to estimate population size (Phillipsen et al. 2009, p. 7). Adult females lay one egg mass per year, and the breeding period occurs within a reliable and predictable timeframe each year (McAllister 2006, pers
rical range, based on the best available scientific and commercial information.
Egg mass counts are believed to be a good metric of adult population size and are the most time-efficient way to estimate population size (Phillipsen et al. 2009, p. 7). Adult females lay one egg mass per year, and the breeding period occurs within a reliable and predictable timeframe each year (McAllister 2006, pers. comm.). Egg mass numbers are collected in a single survey timed to coincide with the end of the breeding season, when egg laying should be et al. 2009, p. 7). Using egg mass counts to estimate population size has some weaknesses. For example, researchers have uncertainties about whether adult females breed every year and find difficulty in distinguishing individual egg masses in large communal clusters. However, a minimum population estimate can be derived from the total egg mass count multiplied by two (one egg mass equals two adult frogs). While there are weaknesses in these estimates, as discussed above, they are the best estimates available for Oregon spotted frog numbers.
Egg mass counts, as currently conducted at most sites, do not allow for evaluation of trends within a site nor between sites because surveys are not standardized. Survey effort, area coverage, and timing can differ between years at individual sites. In addition, method of survey can differ between years at individual sites and differs between sites. Because of the weaknesses associated with the egg mass counts, site estimates derived from egg mass counts are considered to be a minimum estimate and generally should not be compared across years or with other sites. However, some breeding locations have been surveyed in a consistent manner (in some cases by the same researcher) and for enough years that trend data are available and considered to be reliable. Trend information is provided in the following sub-basin summaries for the locations where the information is available
imum estimate and generally should not be compared across years or with other sites. However, some breeding locations have been surveyed in a consistent manner (in some cases by the same researcher) and for enough years that trend data are available and considered to be reliable. Trend information is provided in the following sub-basin summaries for the locations where the information is available.
For the purposes of this document, the terms `location' and `site' simply refer to the general locations where breeding has been observed. In some cases, a site may be equivalent to an Oregon spotted frog population (for example, Penn Lake). In other cases, a site may include multiple breeding locations within wetland complexes where hydrological connections may facilitate movement between breeding areas, but where movement patterns and genetic conditions are undetermined within the complexes (for example, Klamath Marsh NWR. Accordingly, a site should not be interpreted to be a population. Because of the lack of complete information between breeding locations, populations were not specifically identified for this status review, and the focus of our analysis regarding the status of Oregon spotted frogs was within the individual river sub-basins.
The following summarizes the best available scientific and commercial information available regarding populations within the currently occupied river sub-basins in British Columbia, Washington, and Oregon. We used multiple data sources, including various unpublished reports, databases, and spreadsheets provided by our partner agencies. These sources are identified in the following sections as “multiple data sources” and are included in our literature cited list, which is included as supplementary information on http://www.regulations.gov for this proposed rule. These sources are available upon request from the Washington Fish and Wildlife Office (see ADDRESSES )
orts, databases, and spreadsheets provided by our partner agencies. These sources are identified in the following sections as “multiple data sources” and are included in our literature cited list, which is included as supplementary information on http://www.regulations.gov for this proposed rule. These sources are available upon request from the Washington Fish and Wildlife Office (see ADDRESSES ). In most sub-basins, trend information regarding the collective status of the populations within the sub-basin is limited or not available, though it is presented below where available. The status of a sub-basin may be undetermined because the Oregon spotted frog presence has only recently been identified, the trend information is uncertain, or sufficient survey information is not available to indicate a trend. However, when viewed at the range-wide scale, the Oregon spotted frog has been extirpated from most of its historical range, and the threat of current and future impacts to the Oregon spotted frog occurs over the entire range of the species. Ongoing threats have significantly reduced the overall extent and distribution of suitable habitat for the Oregon spotted frog, as discussed in “Summary of Factors Affecting the Species” below.
British Columbia
Currently, Oregon spotted frogs are known to occur only within four sites in the Lower Fraser River Basin. Of the four sites, Maintenance Detachment Aldergrove (MD Aldergrove) is nearing, or may have reached extirpation, as no egg masses have been discovered at the site since 2006; Mountain Slough appears to be stable; Maria Slough may be declining; and there is limited data for the recently discovered Morris Valley site (COSEWIC 2011, p. v). Estimates from the three most well-studied populations (MD Aldergrove, Maria Slough, Mountain Slough) indicate a population decline of 35 percent during the period 2000-2010 (COSEWIC 2011, p
have been discovered at the site since 2006; Mountain Slough appears to be stable; Maria Slough may be declining; and there is limited data for the recently discovered Morris Valley site (COSEWIC 2011, p. v). Estimates from the three most well-studied populations (MD Aldergrove, Maria Slough, Mountain Slough) indicate a population decline of 35 percent during the period 2000-2010 (COSEWIC 2011, p. 32), and the most recent egg mass counts indicate the minimum population size for all of British Columbia is fewer than 350 adults (COSEWIC 2011, pp. 27-30). One extant population is near extinction, and the remaining populations are small and vulnerable to disturbance and stochastic events. Extirpation of the MD Aldergrove population would result in a reduction of 76 percent of the extent of Oregon spotted frog in the Lower Fraser River (COSEWIC 2011, pp. vii-ix). Therefore, populations of Oregon spotted frogs in the Lower Fraser River are declining.
Washington
In Washington, the Oregon spotted frog was historically found in the Puget Trough from the Canadian border to the Columbia River, and east to the Washington Cascades (McAllister et al. 1997, p. vii). Current distribution is limited to four watersheds in the Puget Trough, three that drain to Puget Sound and one that drains to the Pacific Ocean, and two watersheds in the southeast Cascades that drain to the Columbia River. In 1997, the locations for 11 historical populations in Washington were verified using museum specimen and published records, and only 1 historically known population and 2 recently discovered populations were known to remain in Washington in 1997 (McAllister et al. 1997, p. vii). The authors also stated that past populations of the Oregon spotted frog in Washington are largely undocumented (McAllister et al. 1997, p. 18). Current population estimates are based on the 2012 census of egg masses at all known extant breeding areas. Based on these estimates, the minimum population in Washington was at least 7,368 breeding adults in 2012
in 1997 (McAllister et al. 1997, p. vii). The authors also stated that past populations of the Oregon spotted frog in Washington are largely undocumented (McAllister et al. 1997, p. 18). Current population estimates are based on the 2012 census of egg masses at all known extant breeding areas. Based on these estimates, the minimum population in Washington was at least 7,368 breeding adults in 2012.
Trend data are limited; however, the Oregon spotted frog population in the Middle Klickitat River (Conboy Lake) appears to be declining (see below for further information). The population trend within the rest of the occupied sub-basins is unknown, although some individual breeding areas may be stable or extirpated (for example, 110th Ave in the Black River). More detailed discussions of Washington's occupied sub-basins/watersheds are provided below.
Lower Chilliwack River (Sumas River)— In 2012, one Oregon spotted frog breeding area was found on a privately owned dairy farm on a small tributary to the Sumas River (Bohannon et al. 2012). The Sumas River is a tributary to the Lower Fraser River, along which the British Columbia breeding areas occur. However, the breeding area on the Sumas River is more than 20 mi (35 km) upstream of the confluence with the Fraser River, and separated by unsuitable aquatic habitat. Therefore, an aquatic connection to the British Columbia et al. 2012) and the full extent of Oregon spotted frog distribution and abundance has not been determined.
South Fork Nooksack River— In 2011 and 2012, Oregon spotted frog breeding areas were found on privately owned parcels in the Black Slough, a tributary of the South Fork Nooksack River. On one parcel, the egg-laying habitat was in off-channel wetlands dominated by reed canarygrass ( Phalaris arundinacea ) and recent shrub plantings
spotted frog distribution and abundance has not been determined.
South Fork Nooksack River— In 2011 and 2012, Oregon spotted frog breeding areas were found on privately owned parcels in the Black Slough, a tributary of the South Fork Nooksack River. On one parcel, the egg-laying habitat was in off-channel wetlands dominated by reed canarygrass ( Phalaris arundinacea ) and recent shrub plantings. Egg-laying areas on other parcels were located within former pasture lands that had been planted with trees and fenced within the last 2 or 3 years under the Conservation Reserve Enhancement Program (CREP) to eliminate grazing and improve water quality (Bohannon et al. 2012). At least 230 adults (based on 2012 surveys) are associated with the known breeding areas along the Black Slough; however, this area has not been surveyed extensively (Bohannon et al. 2012), and the full extent of Oregon spotted frog distribution and abundance has not been determined.
Samish River— In 2011 and 2012, Oregon spotted frog breeding areas were found on privately owned parcels along the upper reaches of the Samish River. All of the breeding areas are seasonally flooded grazed or formerly grazed pasture lands that are predominantly reed canarygrass (Bohannon et al. 2012). At least 1,220 adults (based on 2012 surveys) are associated with the known breeding areas along the Samish River; however, this area has not been surveyed extensively, and the full extent of Oregon spotted frog distribution and abundance has not been determined.
Black River— Oregon spotted frogs occupy wetlands in the floodplain and tributaries of the upper Black River drainage between Black Lake and the town of Littlerock. They are currently known to occur at two locations within the Black River floodplain (Blooms Ditch near 110th Avenue Bridge and near 123rd Avenue) and in four tributaries: Dempsey Creek, Salmon Creek, Allen Creek, and Beaver Creek (Hallock 2013; WDFW and USFWS multiple data sources)
s in the floodplain and tributaries of the upper Black River drainage between Black Lake and the town of Littlerock. They are currently known to occur at two locations within the Black River floodplain (Blooms Ditch near 110th Avenue Bridge and near 123rd Avenue) and in four tributaries: Dempsey Creek, Salmon Creek, Allen Creek, and Beaver Creek (Hallock 2013; WDFW and USFWS multiple data sources). In 2012, a new breeding location was detected along Fish Pond Creek, which flows directly into Black Lake, not Black River. Oregon spotted frog egg-laying areas in the Black River may be isolated from each other and the frogs associated with the Fish Pond Creek may not be hydrologically connected to frogs in the Black River due to the human alteration of the Black Lake drainage pattern. Further investigation of this new location is needed.
The full extent of the population's distribution, abundance, and status in the Black River has not been determined. As of 2012, the Black River adult breeding population comprised at least 1,748 breeding adults (Hallock 2013, p. 27). Oregon spotted frogs in Dempsey Creek have been monitored relatively consistently since the late 1990s. Other breeding areas in the Black River have been monitored inconsistently or are newly found, and surveys to identify additional breeding locations continue. The Dempsey Creek breeding area may be declining, but the trend for the remainder of the occupied areas is undetermined.
White Salmon River ( Trout Lake Creek )—Oregon spotted frogs occupy approximately 1,285 ac (520 ha) of the lower Trout Lake Creek watershed, ranging in elevation 1,960-2,080 ft (597-633 m). In total, as of 2012, a minimum population estimate of 2,124 breeding adults (Hallock 2012) associated with 12 breeding areas have been identified. Two of the breeding areas have been monitored since they were found by Leonard (1997). The other locations have been monitored sporadically since they were discovered
he lower Trout Lake Creek watershed, ranging in elevation 1,960-2,080 ft (597-633 m). In total, as of 2012, a minimum population estimate of 2,124 breeding adults (Hallock 2012) associated with 12 breeding areas have been identified. Two of the breeding areas have been monitored since they were found by Leonard (1997). The other locations have been monitored sporadically since they were discovered. Monitoring of egg mass numbers at two breeding areas within the Trout Lake NAP revealed considerable population volatility and a general pattern of decline from 2001 through 2007 (Hallock 2011, p. 8). During the period of egg mass declines, three events of note occurred that could have influenced frogs at the NAP: Annual precipitation was unusually low, cattle grazing was reduced and then eliminated, and frogs infected with chytrid fungus ( Batrachochytrium dendrobatids ( Bd )) were present (Pearl et al. 2009b, Hayes et al. 2009). While the 2009 and 2010 egg mass counts indicate that Oregon spotted frog numbers may be rebounding within the eastern portions of the NAP, the numbers in the western portion continue to be less than half of the estimates from the 1990s.
Middle Klickitat River ( Conboy Lake )—The extent of Conboy Lake wetland complex habitat occupied by Oregon spotted frogs at high water is approximately 7,462 ac (3,020 ha), ranging in elevation 1,804-1,896 ft (550-576 m). This wetland complex comprises two lakebeds that are entirely seasonal (except in wet years) and are joined by Camas Ditch, which flows into Outlet Creek, the main drainage for the system that flows northeast into the Klickitat River. As of 2012, there were a minimum of 1,954 breeding adults in the Conboy Lake wetland complex (Hallock 2013, p. 27). This used to be the largest Oregon spotted frog population throughout the entire range (highest egg mass count 7,018 in year 1998). However, Oregon spotted frog egg mass surveys suggest a continued long-term decline (approximately 86 percent) since 1998 (Hayes and Hicks 2011; Hallock 2013, p
12, there were a minimum of 1,954 breeding adults in the Conboy Lake wetland complex (Hallock 2013, p. 27). This used to be the largest Oregon spotted frog population throughout the entire range (highest egg mass count 7,018 in year 1998). However, Oregon spotted frog egg mass surveys suggest a continued long-term decline (approximately 86 percent) since 1998 (Hayes and Hicks 2011; Hallock 2013, p. 36). At present, the population trend of Oregon spotted frogs in the Middle Klickitat River is considered to be declining.
Oregon
Population estimates of Oregon spotted frogs in Oregon are primarily based on egg mass surveys conducted in 2011 and 2012 at all known extant sites, and newly discovered occupied areas that had been unsurveyed prior to 2012. Population estimates for the Middle Fork Willamette River sub-basin are based on mark-recapture studies conducted by USGS in 2011, rather than egg mass surveys. Based on these survey data, the minimum population estimate in Oregon consists of approximately 12,847 breeding adults. More detailed discussions of Oregon's occupied sub-basins are provided below and are available in our files.
Lower Deschutes River —Within the Lower Deschutes River sub-basin, a single extant population of Oregon spotted frog occurs at Camas Prairie, an 82-ac (33-ha) marsh located along Camas Creek in the White River watershed. The Camas Prairie Oregon spotted frogs are the most geographically isolated, carry several alleles that are absent or rare in other sites, and have the lowest genetic diversity of Oregon spotted frogs rangewide (Blouin et al. 2010, p. 2185). The frogs at this location appear to be the only remaining representatives of a major genetic group that is now almost extinct (Blouin et al. 2010, p. 2190). Since 2004, egg mass surveys have been conducted annually, and the population trend has been positive. Based on the 2012 egg mass count, the minimum population size of breeding adults is 152 (Corkran 2012, pers. comm.)
et al. 2010, p. 2185). The frogs at this location appear to be the only remaining representatives of a major genetic group that is now almost extinct (Blouin et al. 2010, p. 2190). Since 2004, egg mass surveys have been conducted annually, and the population trend has been positive. Based on the 2012 egg mass count, the minimum population size of breeding adults is 152 (Corkran 2012, pers. comm.). Although the population trend has been positive at the single known location, the number of individuals in the population remains low.
Upper Deschutes River —Oregon spotted frogs in the Upper Deschutes River sub-basin occur in high-elevation lakes up to 5,000 ft (1,524 m), wetland ponds, and riverine wetlands and oxbows along the Deschutes River. Approximately 13 known breeding locations are within four watersheds in
The consistency of population surveys varies by breeding site, and population trend information is limited. Only two sites within the sub-basin have been monitored consistently since the early 2000s and show an increasing population trend: Dilman Meadow and Sunriver (USGS and J. Bowerman 2000 through 2012 datasets). Trend data are not available for the remainder of populations within the Upper Deschutes River sub-basin. Sunriver, located downstream of Wickiup Reservoir, is the largest population of Oregon spotted frogs within the Deschutes River sub-basin with a population of at least 1,454 breeding adults based on 2012 egg mass surveys (J. Bowerman dataset 2012). A minimum population estimate for the Upper Deschutes River sub-basin (including Sunriver) is approximately 3,530 breeding adults based on surveys since 2006 (USGS 2006 to 2012 and J. Bowerman 2012 datasets)
e largest population of Oregon spotted frogs within the Deschutes River sub-basin with a population of at least 1,454 breeding adults based on 2012 egg mass surveys (J. Bowerman dataset 2012). A minimum population estimate for the Upper Deschutes River sub-basin (including Sunriver) is approximately 3,530 breeding adults based on surveys since 2006 (USGS 2006 to 2012 and J. Bowerman 2012 datasets).
Little Deschutes River —Oregon spotted frogs are distributed throughout wetland, pond, and riverine habitats in the Little Deschutes River sub-basin, which drains an area of approximately 1,020 square miles (2,600 km 2 ) and flows north from its headwaters in northern Klamath County to its convergence with the Deschutes River 1 mi (1.2 km) south of Sunriver and approximately 20 mi (32 km) south of Bend, Oregon. The Little Deschutes River is approximately 92 mi (148 km) long. Approximately 23 known breeding locations (as of 2012) are within five watersheds in the sub-basin: Upper, Middle, and Lower Little Deschutes River; Crescent Creek; and Long Prairie. Big Marsh, a 2,000-ac (809 ha) wetland located within headwaters at 4,760 ft (1,451 m) elevation on the Deschutes National Forest, has the largest monitored population of Oregon spotted frogs in the Little Deschutes River sub-basin and possibly rangewide. The estimated population size of Big Marsh based on a 2012 U.S. Forest Service (USFS) egg mass survey is 5,324 breeding adults (male and female) (USFS data 2012).
Because 70 percent of the sub-basin is privately owned and mostly unsurveyed, a population estimate for the entire Little Deschutes River sub-basin is difficult to determine. A minimum population estimate of Oregon spotted frogs based on limited survey data from public and private lands in 2012 is approximately 6,628 breeding adults (including Big Marsh above)
(male and female) (USFS data 2012).
Because 70 percent of the sub-basin is privately owned and mostly unsurveyed, a population estimate for the entire Little Deschutes River sub-basin is difficult to determine. A minimum population estimate of Oregon spotted frogs based on limited survey data from public and private lands in 2012 is approximately 6,628 breeding adults (including Big Marsh above). However, the vast acreage of wetland complexes and suitable habitat for Oregon spotted frogs along the mainstem Little Deschutes River and Crescent Creek indicate that the frog population within the unsurveyed areas may be well above this estimate. Although the trend of the frog population at Big Marsh appears to be increasing based on USFS surveys from 2002 to 2012 (USFS 2002-2012), the population trend of the remainder of frogs within the sub-basin is undetermined.
McKenzie River —Oregon spotted frogs in the McKenzie River sub-basin are located within the South Fork McKenzie River watershed in an area referred to as the Mink Lake Basin in the wilderness of the Willamette National Forest. There are two known breeding populations: one at Penn Lake and one at an unnamed marsh 0.28 mi (0.45 km) north of Mink Lake. The Penn Lake and Unnamed Marsh populations are about 0.93 mi (1.5 km) apart and are not hydrologically connected via surface water. Mark-recapture monitoring of these populations has been conducted by USGS from 2007 through 2011 (Adams et al. 2007, 2008 p. 13, 2009 p. 14, 2010 p. 14 and 2011 p. 14). A population estimate for breeding adults in the McKenzie River sub-basin, based on mark-recapture efforts by USGS in 2011 is 217 (i.e., 179 at Penn Lake and 38 at Unnamed Marsh) (Adams et al. 2011). However, trend has not been estimated for these populations
these populations has been conducted by USGS from 2007 through 2011 (Adams et al. 2007, 2008 p. 13, 2009 p. 14, 2010 p. 14 and 2011 p. 14). A population estimate for breeding adults in the McKenzie River sub-basin, based on mark-recapture efforts by USGS in 2011 is 217 (i.e., 179 at Penn Lake and 38 at Unnamed Marsh) (Adams et al. 2011). However, trend has not been estimated for these populations.
Middle Fork Willamette River —Oregon spotted frogs in the Middle Fork Willamette River sub-basin are limited to a single population at Gold Lake and bog, located in the 465-ac (188-ha) Gold Lake Bog Research Natural Area on the Willamette National Forest within the Salt Creek watershed. This population is one of three remaining populations of Oregon spotted frogs west of the Cascade mountain crest in Oregon. The Gold Lake Bog site consists of three small ponds over an area of approximately 3.7 ac (1.5 ha) within a larger bog where three major streams converge. Breeding surveys are periodically conducted by USGS and the Willamette National Forest. However, long-term trend data are lacking for this site. Based on USGS egg mass surveys in 2007, the estimated population size is approximately 1,458 breeding adults (USGS datasets).
Williamson River —Oregon spotted frogs in the Williamson River sub-basin occur in two watersheds: Klamath Marsh/Jack Creek and Williamson River above Klamath Marsh and consist of three populations: Jack Creek, Klamath Marsh NWR, and the Upper Williamson River. Data from 1996 through the present suggests the Jack Creek population is declining, and the survey data from 2000 through the present suggests that the Klamath Marsh population is stable. These watersheds are a mixture of both private and public (BLM, USFS, and NWR) lands and consist of both wetland and riverine potential habitats from 4,500 to 5,200 ft (1,371-1,585 m) in elevation
lliamson River. Data from 1996 through the present suggests the Jack Creek population is declining, and the survey data from 2000 through the present suggests that the Klamath Marsh population is stable. These watersheds are a mixture of both private and public (BLM, USFS, and NWR) lands and consist of both wetland and riverine potential habitats from 4,500 to 5,200 ft (1,371-1,585 m) in elevation. As of 2011, the minimum population estimate for the sub-basin is approximately 376 breeding individuals (male and female) (KMNWR 2011, USFS 2012, USGS multiple datasets). Permission to survey adjacent private lands has not been obtained, however, the private lands surrounding the public lands appear to have suitable habitat and likely contain additional breeding complexes and individuals.
Upper Klamath Lake —Oregon spotted frogs in the Upper Klamath Lake sub-basin occupy two watersheds that flow into Upper Klamath Lake: Klamath Lake and Wood River. There are four populations in this sub-basin: Crane Creek, Fourmile Creek, Sevenmile Creek, the Wood River channel and the adjacent but separate BLM Wood River canal. These populations occur in both riverine and wetland habitats. Historically, these two watersheds were hydrologically connected. Survey efforts on Fourmile Creek, Sevenmile Creek, and the Wood River channel have been sporadic while Crane Creek and the BLM Wood River canal have been surveyed annually. These data suggest that there is still insufficient information to obtain population trends for all but the BLM Wood River canal population, which is declining. As of 2011, the minimum population estimate for the sub-basin is approximately 374 breeding individuals (male and female) (USGS multiple datasets, BLM multiple datasets). Permission to survey adjacent private lands has not been obtained, however, the private lands surrounding the known populations appear to have suitable habitat and likely contain additional breeding complexes and individuals
ing. As of 2011, the minimum population estimate for the sub-basin is approximately 374 breeding individuals (male and female) (USGS multiple datasets, BLM multiple datasets). Permission to survey adjacent private lands has not been obtained, however, the private lands surrounding the known populations appear to have suitable habitat and likely contain additional breeding complexes and individuals. Trend data are lacking for three out of four populations in the Upper Klamath Lake.
Upper Klamath —Oregon spotted frogs in the Upper Klamath sub-basin occupy two lacustrine habitats: Parsnip Lakes in Jackson County and Buck Lake in Klamath County. Both of these sites are
Summary of Current Population Range and Trend
Oregon spotted frogs may no longer occur in as much as 90 percent of their historically documented range, including all of the historical localities in California (i.e., 90 percent of the historical areas are no longer occupied). Currently, the Oregon spotted frog is found in 15 sub-basins ranging from extreme southwestern British Columbia south through the Puget Trough, and in the Cascades Range from south-central Washington at least to the Klamath Basin in Oregon. Oregon spotted frogs occur in lower elevations in British Columbia and Washington and are restricted to higher elevations (i.e., 4,000 to 5,200 ft (1,219 to 1,585 m) in Oregon. In addition, Oregon spotted frogs currently have a very limited distribution west of the Cascade crest in Oregon and are considered to be extirpated from the Willamette Valley.
In most sub-basins, trend information regarding the collective status of the populations within the sub-basin is limited or not available. The best available scientific and commercial information available indicates the trend is undetermined for Oregon spotted frog populations in 13 of the sub-basins and is declining in the Lower Fraser River and Middle Klickitat sub-basins. Threats to the remaining populations are ongoing or increasing, however, as described below
of the populations within the sub-basin is limited or not available. The best available scientific and commercial information available indicates the trend is undetermined for Oregon spotted frog populations in 13 of the sub-basins and is declining in the Lower Fraser River and Middle Klickitat sub-basins. Threats to the remaining populations are ongoing or increasing, however, as described below.
Summary of Factors Affecting the Species
Section 4 of the Act (16 U.S.C. 1533), and its implementing regulations at 50 CFR part 424, set forth the procedures for adding species to the Federal Lists of Endangered and Threatened Wildlife and Plants. Under section 4(a)(1) of the Act, we may list a species based on any of the following five factors: (A) The present or threatened destruction, modification, or curtailment of its habitat or range; (B) overutilization for commercial, recreational, scientific, or educational purposes; (C) disease or predation; (D) the inadequacy of existing regulatory mechanisms; and (E) other natural or manmade factors affecting its continued existence. Listing actions may be warranted based on any of the above threat factors, singly or in combination. Each of these threats/factors is discussed below.
Threats for the Oregon spotted frog were assessed by breeding locations and occupied watersheds, then summarized by occupied sub-basin. Each of the five threat categories were summarized by sub-basin using the unified threats classification system (loosely based on the IUCN-CMP (World Conservation Union-Conservation Measures Partnership)), best available data, and best professional judgment. We summarized each occupied sub-basin for scope, severity, impact, timing, and stress, to ensure our determination would be based on the best scientific and commercial data available, as required under section 4(b)(1)(A). Scope is the proportion of the occupied area within the sub-basin that can reasonably be expected to be affected
rtnership)), best available data, and best professional judgment. We summarized each occupied sub-basin for scope, severity, impact, timing, and stress, to ensure our determination would be based on the best scientific and commercial data available, as required under section 4(b)(1)(A). Scope is the proportion of the occupied area within the sub-basin that can reasonably be expected to be affected. Severity is the level of damage to the species from the threat that can reasonably be expected. Impact summarizes the degree to which a species is observed, inferred, or suspected to be directly or indirectly affected and is based on the combination of the severity and scope rating (for example, if the severity and scope ratings were both high, then the impact rating was high). Timing is the immediacy of the threat (i.e., is the threat ongoing, could happen in the short term, or is only in the past). Stress is the key ecological, demographic, or individual attribute that may be impaired or reduced by a threat. The completed analysis (Threats Synthesis Rangewide Analysis) is available at http://www.regulations.gov and http://www.fws.gov/wafwo. The syntheses by threat categories are included in the following threat factor discussions.
Large historical losses of wetland habitat have occurred across the range of the Oregon spotted frog. Wetland losses are estimated from between 30 to 85 percent across the species range with the greatest percentage lost having occurred in British Columbia. These wetland losses have directly influenced the current fragmentation and isolation of remaining Oregon spotted frog populations.
Loss of natural wetland and riverine disturbance processes as a result of human activities has and continues to result in degradation of Oregon spotted frog habitat
rcent across the species range with the greatest percentage lost having occurred in British Columbia. These wetland losses have directly influenced the current fragmentation and isolation of remaining Oregon spotted frog populations.
Loss of natural wetland and riverine disturbance processes as a result of human activities has and continues to result in degradation of Oregon spotted frog habitat. Historically, a number of disturbance processes created early successional wetlands favorable to Oregon spotted frogs throughout the Pacific Northwest: (1) Rivers freely meandered over their floodplains, removing trees and shrubs and baring patches of mineral soil; (2) beavers created a complex mosaic of aquatic habitat types for year-round use; and (3) summer fires burned areas that would be shallow water wetlands during the Oregon spotted frog breeding season the following spring. Today, all of these natural processes are greatly reduced, impaired, or have been permanently altered as a result of human activities, including stream bank, channel, and wetland modifications; operation of water control structures (e.g., dams and diversions); beaver removal; and fire suppression.
The historical loss of Oregon spotted frog habitats and lasting anthropogenic changes in natural disturbance processes are exacerbated by the introduction of reed canarygrass, nonnative predators, and potentially climate change. In addition, current regulatory mechanisms and voluntary incentive programs designed to benefit fish species have inadvertently led to the continuing decline in quality of Oregon spotted frog habitats in some locations. The current wetland and stream vegetation management paradigm is generally a no-management or restoration approach that often results in succession to a tree- and shrub-dominated community that unintentionally degrades or eliminates remaining or potential suitable habitat for Oregon spotted frog breeding
ly led to the continuing decline in quality of Oregon spotted frog habitats in some locations. The current wetland and stream vegetation management paradigm is generally a no-management or restoration approach that often results in succession to a tree- and shrub-dominated community that unintentionally degrades or eliminates remaining or potential suitable habitat for Oregon spotted frog breeding. Furthermore, incremental wetland loss or degradation continues under the current regulatory mechanisms. If left unmanaged, these factors are anticipated to result in the eventual elimination of remaining suitable Oregon spotted frog habitats or populations. The persistence of habitats required by the species is now largely management dependent.
Factor A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range
Threats to the species' habitat include changes in hydrology due to construction of dams and human-related alterations to seasonal flooding, introduction of nonnative plant and animal species, vegetation succession and encroachment, poor water quality, livestock grazing (in some circumstances), and residential and commercial development.
Habitat losses and alterations affect amphibian species in a variety of ways, including reducing or eliminating immigration through losses of adjacent populations (see “Factor E”) and effects on critical aspects of the habitat (Hayes and Jennings 1986, pp. 492-494). These critical aspects include suitable egg-laying and nursery sites, refuges from predation or unfavorable environmental conditions, and suitable temperatures necessary for egg laying, growth, and development (Hayes and Jennings 1986, pp. 492-494)
igration through losses of adjacent populations (see “Factor E”) and effects on critical aspects of the habitat (Hayes and Jennings 1986, pp. 492-494). These critical aspects include suitable egg-laying and nursery sites, refuges from predation or unfavorable environmental conditions, and suitable temperatures necessary for egg laying, growth, and development (Hayes and Jennings 1986, pp. 492-494).
Because Oregon spotted frogs have specific habitat requirements, they are particularly vulnerable to habitat alterations: (1) A restricted number of communal egg-laying locations are used year after year; (2) the species' warm water microhabitat requirement results in habitat overlap with introduced warm water fish species and other warm water fauna that prey on Oregon spotted frogs (for example, bullfrogs); (3) the availability of suitable warm water habitat, a requirement in the active season, is generally limited in the cool climate of the Pacific Northwest; (4) the species is vulnerable to the loss or alteration of springs used for overwintering; and (5) their habitat requirements (for example, spatial structure) for overwintering, active season, and breeding habitats are more complex than for other frog species (Hayes et al. 1997, p. 4). In addition, breeding habitat is arguably the single most important habitat component for many aquatic-breeding amphibians because amphibian embryos and larvae depend on aquatic habitats for survival (Leonard 1997, p. 1).
Loss of Wetlands
British Columbia— Extensive diking of river ways and draining of Sumas Lake for conversion to agriculture significantly modified drainage patterns and resulted in loss of associated wetlands in the Fraser River lowlands of British Columbia (COSEWIC 2011, p. 20). Boyle et al. (1997, p. 190) estimated an 85 percent loss of habitat types preferred by Oregon spotted frogs (fen, swamp/bog/marsh) between 1820 and 1990. Moore et al
diking of river ways and draining of Sumas Lake for conversion to agriculture significantly modified drainage patterns and resulted in loss of associated wetlands in the Fraser River lowlands of British Columbia (COSEWIC 2011, p. 20). Boyle et al. (1997, p. 190) estimated an 85 percent loss of habitat types preferred by Oregon spotted frogs (fen, swamp/bog/marsh) between 1820 and 1990. Moore et al. (2003 cited in COSEWIC 2011) found wetland loss continued between 1989 and 1999 as a result of urban and agricultural encroachment. Agricultural land use changes, such as the conversion of field habitat to blueberry and cranberry production, has led to impacts through drain tile installation and riparian area encroachment/erosion. Sediment deposition into streams and wetlands by runoff from adjacent agricultural fields can impact Oregon spotted frog breeding habitat by changing the channel/wetland shape and depth (Lynch and Corbett 1990). Land conversion for agriculture is ongoing at Mountain Slough and to some extent at Maria Slough and Morris Valley (COSFRT 2012, p. 24), within Oregon spotted frog habitat.
Washington— Estimates for Washington indicate that over 33 percent of wetlands were drained, diked, and filled between pre-settlement times and the 1980s (Canning and Stevens 1990, p. 23); losses in the historical range of the Oregon spotted frog are even higher because of the high degree of development in the low elevations of the Puget Trough (McAllister and Leonard 1997, p. 22).
Major alterations to Conboy Lake wetland complex in Washington began when settlers started moving to Glenwood Valley in the late 1800s. Wet meadows were drained through a series of canals, ditches, and dikes largely developed between 1911 and 1914, and remain today. The five creeks that flow into this wetland complex and the Cold Springs ditch are entirely channelized within the wetland complex
Major alterations to Conboy Lake wetland complex in Washington began when settlers started moving to Glenwood Valley in the late 1800s. Wet meadows were drained through a series of canals, ditches, and dikes largely developed between 1911 and 1914, and remain today. The five creeks that flow into this wetland complex and the Cold Springs ditch are entirely channelized within the wetland complex. Ditching, filling, and other habitat alterations have resulted in little or no retention of surface water in the late-season lakebeds (Conboy Lake and Camas Prairie), reducing the amount of aquatic habitat available for the Oregon spotted frog. The historical Conboy lakebed is believed to have retained water for 10 to 12 months in most years. Currently, it retains water only during wet years and is purposefully drained annually to control bullfrogs (Ludwig 2012, pers. comm.). The Camas Prairie portion of Glenwood Valley retains water year-round over a small area and only in wet years. Typically, aquatic habitat is reduced to about 1,000 ac (400 ha) during the late summer and early fall (Hayes et al. 2000), and once the seasonal lakebeds dry, the network of ditches and channels provide the only aquatic habitat for Oregon spotted frogs. In order to maintain sufficient flow through the system, a small area of Bird Creek must be excavated every 2 to 3 years to remove the high level of sand and gravel that is deposited annually from upstream. Most of the other ditches have been cleaned on a much less frequent basis (intervals of up to 20 years), although in the future, the Conboy Lake NWR plans to clean select reaches on a 5-10 year cycle (Ludwig 2012, pers. comm.).
Oregon— Historical losses of wetland in Oregon are estimated at 38 percent between pre-settlement times and the 1980s with 57 and 91 percent of these losses concentrated in the Willamette Valley and Klamath Basin, respectively (Dahl 1990). Wetland loss continues in the Willamette Valley (Daggett et al. 1998; Morlan et al. 2005)
lean select reaches on a 5-10 year cycle (Ludwig 2012, pers. comm.).
Oregon— Historical losses of wetland in Oregon are estimated at 38 percent between pre-settlement times and the 1980s with 57 and 91 percent of these losses concentrated in the Willamette Valley and Klamath Basin, respectively (Dahl 1990). Wetland loss continues in the Willamette Valley (Daggett et al. 1998; Morlan et al. 2005). Between 1982 and 1994, a net loss of 6,877 ac (2783 ha) of wetlands (2.5 percent of the 1982 wetland area) occurred, primarily due to conversion to agriculture (Daggett et al. 1998 p. 23), and between 1994 and 2005, an estimated additional net loss of 3,932 ac (1591 ha) (1.25 percent of the 1994 wetland area) took place, primarily due to development (Morlan et. al. 2010. pp. 26-27). Oregon spotted frogs are believed to be extirpated from the Willamette Valley.
Human alteration of wetlands in the central Oregon Cascades has been a less severe threat since many of the sites inhabited by the Oregon spotted frog are located at high elevation and within lakes and wetlands located on Federal lands managed by the USFS. However, damming and diverting water for irrigation needs has resulted in the loss of wetlands within the Upper Deschutes sub-basin beginning in the early 1900s (see hydrology section below). Wetland loss is also an ongoing threat to Oregon spotted frogs within the Little Deschutes River sub-basin in south Deschutes County, where land development has increased since the 1960s.
A substantial amount of wetland habitat in the Klamath Basin has been drained and converted to other uses, primarily for grazing and row-crop production, although the extent of this loss is difficult to estimate due to a lack of accurate historical data (Larson and Brush 2010). The majority of wetland degradation and alteration took place in the southern part of the upper basin, where extensive drainage occurred at Tule and Lower Klamath Lakes in the early 20th Century (Larson and Brush 2010, p. 4)
es, primarily for grazing and row-crop production, although the extent of this loss is difficult to estimate due to a lack of accurate historical data (Larson and Brush 2010). The majority of wetland degradation and alteration took place in the southern part of the upper basin, where extensive drainage occurred at Tule and Lower Klamath Lakes in the early 20th Century (Larson and Brush 2010, p. 4). Wetlands at the north end of the basin, including Sycan Marsh, Klamath Marsh, Upper Klamath Lake, and in the Wood River Valley, have also suffered extensive hydrologic alteration. Ongoing losses are currently minimized due to strict regulations governing wetlands, and there are no known ongoing losses of wetlands in the
Loss of Wetlands Conclusion— Historical loss of wetlands has been extensive throughout the range of the species, and is the primary reason for the absence of the species from as much as, or more than, 90 percent of its former range (also see Historical Distribution). Land conversions that result in loss of wetlands are continuing throughout the range. Wetlands continue to be lost or degraded in at least 10 of the 15 occupied sub-basins. Even though these losses are occurring at much lower rates than in the past because of Federal and State regulations that pertain to wetlands (see Factor D), the ongoing loss of wetlands continues to pose a threat to the Oregon spotted frog.
Hydrological Changes
Changing water levels at critical periods in the Oregon spotted frog's life cycle, whether natural or human-induced, has negatively affected the species. Lowered water levels have exposed individuals to predation by reducing cover and confining them to smaller areas where they are more vulnerable to predators (see also Factor C). Water level reduction during the breeding season, due to both natural and anthropogenic causes, has resulted in the loss of the entire reproductive effort for the year due to stranding and desiccation of the egg masses in British Columbia (Licht 1971, p. 122; COSFRT 2012, p
dation by reducing cover and confining them to smaller areas where they are more vulnerable to predators (see also Factor C). Water level reduction during the breeding season, due to both natural and anthropogenic causes, has resulted in the loss of the entire reproductive effort for the year due to stranding and desiccation of the egg masses in British Columbia (Licht 1971, p. 122; COSFRT 2012, p. 18), Washington (Lewis et al. 2001, p. 8; Hayes et al. 2000, pp. 6-7), and Oregon (Pearl and Hayes 2004, p. 24). Excessive seasonal flooding at critical periods has also resulted in the loss of shallow wetlands needed for egg-laying and development.
Most of the currently occupied Oregon spotted frog sites are threatened by changes in hydrology. Twenty-one of twenty-eight (75 percent) sites surveyed in Washington and Oregon have had some human-related hydrological alterations, ranging from minor changes (for example, local ditching around springs) to substantial changes, including major modifications of historical flow patterns (Hayes 1997, p. 43; Hayes et al. 1997, p. 6). Oregon spotted frogs in four of the occupied sub-basins (Lower Fraser River, Middle Klickitat River, Little Deschutes River, and Upper Klamath) are experiencing high to very high impacts due to ongoing hydrological changes based on the unified threats classification system ranking, described above. The altered hydrology has affected both breeding and wintering habitat, as discussed below.
Water Diversions/Manipulations— Dams in the upper watersheds of the Puget Trough, Willamette Valley, and the Deschutes River have significantly reduced the amount of shallow overflow wetland habitat that was historically created by natural flooding (Cushman and Pearl 2007, pp. 16-17). The inundation of large marsh complexes, and habitat fragmentation by the construction of reservoirs in the Cascades, has also eliminated and degraded Oregon spotted frog habitat
the Puget Trough, Willamette Valley, and the Deschutes River have significantly reduced the amount of shallow overflow wetland habitat that was historically created by natural flooding (Cushman and Pearl 2007, pp. 16-17). The inundation of large marsh complexes, and habitat fragmentation by the construction of reservoirs in the Cascades, has also eliminated and degraded Oregon spotted frog habitat. We are not aware of proposals for construction of new dams or reservoirs that would pose a threat to the existing Oregon spotted frog populations in British Columbia, Washington, or Oregon. However, the operation of existing dams/diversions/water control structures in Washington and Oregon continues to affect populations of Oregon spotted frogs due to extreme water fluctuations between and within years. These operations inundate and desiccate Oregon spotted frog habitat, while creating and maintaining habitat suitable for nonnative predaceous species.
Water management in the Glenwood Valley, Washington (Middle Klickitat River sub-basin), appears to be playing a significant role in the decline of the Oregon spotted frog in this sub-basin. Water management in this area is complex due to the juxtaposition of landowners and water diversion structures. The need to retain water on the Conboy Lake NWR for resources, including the Oregon spotted frog, conflicts with needs of the intermingled and adjacent private landowners who want water drawn down in order to grow reed canarygrass for haying or to graze cattle. In addition, water management on the NWR is constrained by failing dikes, plugged ditches, undersized culverts, and lack of water control structures (USFWS 2012, p. 27). Dewatering by Conboy Lake NWR generally begins June 1, but begins as early as April on privately held lands, which also results in the dewatering of some refuge lands (USFWS 2012, p. 28). The Camas Prairie area of the valley is drained annually to facilitate production of hay and grazing opportunities (USFWS 2012, p. 28)
ndersized culverts, and lack of water control structures (USFWS 2012, p. 27). Dewatering by Conboy Lake NWR generally begins June 1, but begins as early as April on privately held lands, which also results in the dewatering of some refuge lands (USFWS 2012, p. 28). The Camas Prairie area of the valley is drained annually to facilitate production of hay and grazing opportunities (USFWS 2012, p. 28).
Dewatering breeding areas during the egg stage results in desiccation of Oregon spotted frog egg masses. Dewatering during the rearing stage results in tadpole mortality if water is not retained through metamorphosis. Physical barriers created by the dike system hinders young frogs (recently metamorphed) from moving into permanent waters, especially when water is drawn down too quickly or a surface water connection to permanent water is not retained. Disconnection from permanent water occurs in some places in the valley, which results in young frogs becoming stranded and dying. In the areas where a connection to permanent water is retained and frogs are able to move with the water, the frogs become concentrated in smaller areas with predators such as fish and bullfrogs or become easy targets for terrestrial predators (Engler 2003; 2006, pers. comm.). This issue is complex, because the nonnative bullfrog is fairly common on the refuge, and studies indicate they can prey heavily on native frog species, including Oregon spotted frog.
Water management can be used as a method to reduce bullfrog tadpole survival by drying up seasonal wetlands completely by early fall. However, widespread drawdowns for bullfrog tadpole control can conflict with the need to provide rearing, movement, and summertime water for Oregon spotted frogs (USFWS 2010b, pp. 36, 63, 67)
can prey heavily on native frog species, including Oregon spotted frog.
Water management can be used as a method to reduce bullfrog tadpole survival by drying up seasonal wetlands completely by early fall. However, widespread drawdowns for bullfrog tadpole control can conflict with the need to provide rearing, movement, and summertime water for Oregon spotted frogs (USFWS 2010b, pp. 36, 63, 67). Surveys since 1998 have documented extensive annual declines in Oregon spotted frog egg mass numbers due to early water drawdowns and perennially low water; therefore, inadequate water or poorly timed water management activities continue to be a threat to Oregon spotted frog that has a significant negative impact on recruitment (the addition of young individuals to the adult population) and survival in the Middle Klickitat River sub-basin.
In the Upper Deschutes River sub-basin in Oregon, regulated water releases from Crane Prairie and Wickiup Reservoirs result in extreme seasonal fluctuations in stream flows that have affected the amount of overwintering and breeding habitat available for Oregon spotted frogs. Prior to the construction of Wickiup Dam in 1947, the Deschutes River below the current dam site exhibited stable flows averaging approximately 730 cubic feet per second (cfs) (20.7 cubic meters per second (cms)) and 660 cfs (18.7 cms) during summer and winter, respectively (Hardin-Davis 1991). Water storage in
Currently, Oregon spotted frog breeding is known to occur in only three areas downstream of Wickiup Reservoir: Sunriver, Slough Camp, and Old Mill Pond (including adjacent Les Schwab Amphitheater marsh on the Deschutes River). Oregon spotted frog habitat at Sunriver Resort has been managed and maintained by Sunriver Nature Center by using weirs to stabilize the water levels from the beginning of the breeding season through metamorphosis, which has resulted in a large and fairly stable population of Oregon spotted frogs, despite the low river flows during the breeding season
ab Amphitheater marsh on the Deschutes River). Oregon spotted frog habitat at Sunriver Resort has been managed and maintained by Sunriver Nature Center by using weirs to stabilize the water levels from the beginning of the breeding season through metamorphosis, which has resulted in a large and fairly stable population of Oregon spotted frogs, despite the low river flows during the breeding season. Breeding and dispersal of metamorphosing frogs at the Slough Camp site is likely affected by the seasonal timing of storage and release of water from the reservoir each year. Adults have been observed at the inlet to Slough Camp (east side) prior to the flow releases from the reservoir in early April, indicating that frogs may be staging to access breeding habitat that becomes accessible when flows are released for the irrigation season (Higgins 2012, pers. comm.). At the onset of the storage season in October, the east side of Slough Camp drains rapidly of water, which could result in stranding of frogs that have bred and reared in this location. In August 2012, Oregon spotted frogs were discovered in a water retention pond at The Old Mill District shops in downtown Bend, Oregon. The shallow pond holds water year round and is approximately 20 ft (6 m) from the Deschutes River channel. The hydrological relationship between the pond and flow manipulation within the river has not been determined. However, there is an outflow from the pond, and the detection of numerous juvenile Oregon spotted frogs in a large marsh on the Deschutes River across from the pond at The Old Mill (Bowerman 2012, pers. comm.) indicates there is a connection to the river. The impacts of regulated river flows to Oregon spotted frogs within the large marsh area remain to be evaluated.
Oregon spotted frog habitat in the Little Deschutes River sub-basin in Oregon may also be affected by regulated water management downstream of Crescent Lake Dam in Crescent Creek and the Little Deschutes River below the confluence with Crescent Creek
here is a connection to the river. The impacts of regulated river flows to Oregon spotted frogs within the large marsh area remain to be evaluated.
Oregon spotted frog habitat in the Little Deschutes River sub-basin in Oregon may also be affected by regulated water management downstream of Crescent Lake Dam in Crescent Creek and the Little Deschutes River below the confluence with Crescent Creek. Regulated water releases from Crescent Lake typically occur in June, just after the breeding season. Egg mass stranding has been observed on three separate occasions along the Little Deschutes River, downstream of the confluence with Crescent Creek, prior to the release of irrigation water (Demmer 2012, pers. comm.). Overwintering habitats may be limited when flows from Crescent Lake typically cease in October at the onset of the storage season. Groundwater may be ameliorating the impacts from the regulated water management in Crescent Creek in locations where groundwater discharges to the stream (Gannett et al. 2001), but a full analysis has not yet been conducted.
In the Klamath Basin, the Upper Klamath sub-basin populations are particularly vulnerable to water diversion and manipulation. Water from Hyatt (30 cfs; 0.8 cms) and Howard Prairie Reservoirs (50 cfs; 1.4 cms) are diverted to Keene Creek Reservoir (Ferrari 2000, p. 1; Bear Creek Watershed Council 2001, p. 139) upstream of Parsnip Lakes (Jackson County), known occupied habitat for the Oregon spotted frog. Approximately 190 cfs (5.4 cms) of water is diverted from Keene Creek Reservoir and used for municipal consumptive and hydroelectric energy purposes (BOR 2009 Web site; BOR 2011 Web site). In addition, water from Buck Lake (Klamath County) can be manipulated, depending on water needs, in such a way that water is moved quickly across the landscape
known occupied habitat for the Oregon spotted frog. Approximately 190 cfs (5.4 cms) of water is diverted from Keene Creek Reservoir and used for municipal consumptive and hydroelectric energy purposes (BOR 2009 Web site; BOR 2011 Web site). In addition, water from Buck Lake (Klamath County) can be manipulated, depending on water needs, in such a way that water is moved quickly across the landscape. Water flow in the Upper Klamath Lake and Williamson River sub-basins is highly manipulated (modified) to improve forage production for cattle grazing (see Livestock Grazing Klamath Basin discussion) (NRCS 2010, p. 60). The water is diverted (removed) after egg masses have been laid, but prior to their hatching, thus resulting in both stranding and desiccation of upstream egg masses while, at the same time, inundating do

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Source: Frix Law Library, https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2013-20986. Check the current official text before relying on it. Not legal advice.