# Endangered and Threatened Wildlife and Plants; Removing Oenothera avita ssp. eurekensis From the Federal List of Endangered and Threatened Plants, and Reclassification of Swallenia alexandrae From Endangered to Threatened

> Briefs, arguments, decisions, and more.

URL: https://www.frixlaw.com/law-library/documents/fr%3A2018-03769

## Record

- **Collection:** Federal Register
- **Document type:** Rule
- **Published:** February 27, 2018
- **Citation:** 83 FR 8576

## Text

DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R8-ES-2013-0131; FXES11130900000-145-FF09E42000]
RIN 1018-AW04
Endangered and Threatened Wildlife and Plants; Removing Oenothera avita ssp. eurekensis From the Federal List of Endangered and Threatened Plants, and Reclassification of Swallenia alexandrae From Endangered to Threatened

AGENCY:

Fish and Wildlife Service, Interior.

ACTION:

Final rule and availability of post-delisting monitoring plan.

SUMMARY:

We, the U.S. Fish and Wildlife Service (Service), are removing
Oenothera avita
ssp. e
urekensis,
which is now recognized as
Oenothera californica
ssp.
eurekensis
(with a common name of Eureka Valley evening-primrose, Eureka evening-primrose, or Eureka Dunes evening-primrose) from the Federal List of Endangered and Threatened Plants. We are also reclassifying
Swallenia alexandrae
(with a common name of Eureka dune grass, Eureka dunegrass, or Eureka Valley dune grass) from an endangered to a threatened species. For Eureka Valley evening-primrose, this action is based on our evaluation of the best available scientific and commercial information, including comments received, which indicates that the threats have been eliminated or reduced to the point that the subspecies no longer meets the definition of an endangered species or a threatened species under the Endangered Species Act of 1973, as amended (Act).

For Eureka dune grass, this reclassification is based on our evaluation of the best available scientific and commercial information, including comments received. We conclude that the stressors acting upon Eureka dune grass are of sufficient imminence, scope, or magnitude to indicate that they are continuing to result in impacts at either the population or rangewide scales, albeit to a lesser degree than at the time of listing, and we find that Eureka dune grass meets the statutory definition of a threatened species (
i.e.,
the stressors impacting the species or its habitat are of sufficient magnitude, scope, or imminence to indicate that the species is likely to become an endangered species in the foreseeable future throughout all or a significant portion of its range).

DATES:

This final rule becomes effective March 29, 2018.

ADDRESSES:

Comments, materials received, and supporting documentation used in preparation of this final rule are available on the internet at
http://www.regulations.gov
under Docket No. FWS-R8-ES-2013-0131. Additionally, comments, materials, and supporting documentation are available for public inspection by appointment (see
FOR FURTHER INFORMATION CONTACT
below). The post-delisting monitoring plan for
Oenothera californica
ssp.
eurekensis
is available on our Endangered Species Program's national website (
http://endangered.fws.gov
) and on the internet at
http://www.regulations.gov
at Docket No. FWS-R8-ES-2013-0131.

FOR FURTHER INFORMATION CONTACT:

Mendel Stewart, Field Supervisor, Carlsbad Fish and Wildlife Office, 2177 Salk Avenue, Suite 250, Carlsbad, CA 92008; telephone 760-431-9440; facsimile 760-431-5901. If you use a telecommunications device for the deaf (TDD), call the Federal Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Executive Summary

Species addressed. Oenothera californica
ssp.
eurekensis
(Eureka Valley evening-primrose) and
Swallenia alexandrae
(Eureka dune grass) are endemic to three dune systems in the Eureka Valley, Inyo County, California. Eureka Valley falls within federally designated wilderness within Death Valley National Park and is managed accordingly by the National Park Service (Park Service).

Why we need to publish this document.
A species that is in danger of extinction or likely to become so in the foreseeable future throughout all or a significant portion of its range warrants protection under the Endangered Species Act. If a species is determined to no longer to be a threatened species or an endangered species, we may reclassify the species or remove it from the Federal List of Endangered and Threatened Wildlife and Plants. Removing a species from the List or changing its status on the List can only be completed by issuing a rule. We proposed to delist Eureka Valley evening-primrose and Eureka dune grass in 2014.

• This document finalizes the delisting of Eureka Valley evening-primrose. Our evaluation took into consideration information and comments submitted during the public comment period, as well as subsequent information that became available. At this time, the best available information continues to indicate that there are no longer population- or rangewide-level threats impacting Eureka Valley evening-primrose such that it is in danger of extinction now or is likely to become endangered in the foreseeable future. Thus, we conclude that Eureka Valley evening-primrose no longer meets the definition of an endangered species or threatened species, and we are removing it from the Federal List of Endangered and Threatened Plants in title 50 of the Code of Federal Regulations at 50 CFR 17.12(h).

• This document finalizes the reclassification of Eureka dune grass from an endangered species to a threatened species. Based on our evaluation of the best scientific and commercial information available, including information and comments submitted during the public comment period, we now determine that the stressors identified in the proposed rule are more significant than previously thought. Although threats identified at the time of listing have been substantially removed, Eureka dune grass is currently responding negatively to the stressors to which it is exposed. The best available scientific and commercial data lead us to conclude that Eureka dune grass no longer meets the definition of an endangered species under the Act, but it is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range. Therefore, we are reclassifying the species from an endangered species to a threatened species.

The basis for our action.
Under the Endangered Species Act of 1973, a species may be determined to be an endangered species or threatened species because of 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 must consider the same factors in delisting a species. We may delist a species if the best scientific and commercial data indicate the species is neither a threatened species nor an endangered species for one or more of the following reasons: (1) The species is extinct, (2) the species has recovered and is no longer endangered or threatened, or (3) the original scientific data used at the time the species was classified were in error.

We have determined that stressors to one or more populations of Eureka Valley evening-primrose no longer exist, or they are not causing significant impacts at either the population or rangewide scales such that the species is currently in danger of extinction or is likely to become endangered within the foreseeable future throughout all or a significant portion of its range. Additionally, we have determined that stressors to one or more populations of Eureka dune grass are of sufficient imminence, intensity, or magnitude to cause significant impacts at either the population or rangewide scales such that the species is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range.

Peer review and public comment.
We sought comments from independent specialists to ensure that our consideration of the status of Eureka Valley evening-primrose and Eureka dune grass is based on scientifically sound data, assumptions, and analyses. We invited these peer reviewers to comment on our proposed delisting rule. We also considered all public comments and information received during the comment period, and other new information available since publication of the proposed rule. The final decisions do not substantially rely on information received after the close of the comment period, as this new information was supportive of or consistent with information already in the record. Comments are addressed at the end of this
Federal Register
document.

Previous Federal Actions

Please refer to the proposed delisting rule for Eureka Valley evening-primrose and Eureka dune grass (79 FR 11053, February, 27, 2014) or the species' profiles available on the internet at
www.ecos.fws.gov
for a detailed description of the previous Federal actions concerning these species prior to the publication of the proposed delisting rule. The proposed delisting rule established a 60-day comment period that closed on April 28, 2014, and we did not receive any requests to extend the comment period or hold a public hearing.

Background

For the proposed delisting rule, we conducted a scientific analysis as presented in this document and supplemented with additional information presented in the Background Information document (Service 2014, entire; available at
http://www.regulations.gov,
Docket No. FWS-R8-ES-2013-0131). The Background Information document was prepared by Service biologists to provide additional discussion of the environmental setting for the Eureka Valley, and other information on the life history, taxonomy, genetics, seed bank ecology, survivorship and demography, rangewide distribution, and abundance surveys, as well as additional information on the stressors that may be impacting Eureka Valley evening-primrose and Eureka dune grass. Also, see the Final Species Analysis available under Docket No. FWS-R8-ES-2013-0131 at
http://www.regulations.gov
(Service 2017).

Eureka Dune Ecosystem

Eureka Valley evening-primrose and Eureka dune grass are endemic (unique to a geographic area) to the sand dunes of Eureka Valley (Figure 1), which occur within Death Valley National Park, Inyo County, California. Three dune systems (collectively referred to as “the Eureka Dunes”) occur in Eureka Valley and are located between the Last Chance Mountains to the east, the Saline Mountains to the south, and the Inyo Mountains to the west and north (Rowlands 1982, p. 2). The Main Dunes (sometimes referred to in literature as “Eureka Dunes”) system parallel the Last Chance Mountains (Service 1982, p. 12) and are the largest of the three dunes, covering a total area of about 2,003 acres (ac) (811 hectares (ha)) (Service 2013 based on Shovik 2010). The Saline Spur and Marble Canyon Dunes, two smaller dune systems, cover an area of about 238 ac (96 ha) and 610 ac (247 ha), respectively (Service 2013 based on Shovik 2010). Saline Spur Dunes and Marble Canyon Dunes, including a southern extension of Marble Canyon Dunes known as the unnamed site, are located approximately 4 miles (mi) (6.4 kilometers (km)) and 9 mi (14.4 km) west of the Main Dunes (Bagley 1986, p. 4). The southern extension of Marble Canyon Dunes (the unnamed site) was previously treated as a separate dune system, but we refer to this area and the rest of the dune system as the Marble Canyon Dunes. See additional discussion in Service 2014 (pp. 4-7). Temperature regime, wind speeds, and precipitation patterns vary among the three dunes likely due to their relative position within Eureka Valley. For instance, the Main Dunes (labeled as “Eureka Dunes” in Figure 1, below) has lower daily temperatures than the other two dunes, while other patterns, such as rainfall, vary among the three dunes on both a temporal and spatial scale (Scoles-Sciulla and DeFalco 2017).

ER27FE18.000

Eureka Valley Evening-Primrose

See the proposed delisting rule (79 FR 11053) and the Background Information document (Service 2014) for a detailed discussion of Eureka Valley evening-primrose's description, taxonomy, life history, rangewide distribution, abundance surveys, and population estimates, which are available under Docket No. FWS-R8-ES-2013-0131 at
http://www.regulations.gov.

Eureka Valley evening-primrose is a short-lived perennial in the evening-primrose family (Onagraceae). It forms leaf rosettes for the first 1 or 2 years, then develops decumbent or ascending stems to 31.5 inches (in) (8 decimeters) high. Large individuals have the potential to produce tens of thousands of seeds (Pavlik and Barbour 1985, pp. 15, 21). Eureka Valley evening-primrose has mechanisms for both short- and long-distance seed dispersal (Pavlik 1979a, p. 59; 1979b, p. 71; Pavlik and Barbour 1985, pp. 27, 41; 1986, pp. 31, 81).
Oenothera californica
ssp.
eurekensis
is currently the accepted scientific name (Wagner 1993, p. 803; Wagner 2002, p. 395; Wagner
et al.
2007, p. 180; Wagner 2012, p. 952; California Native Plant Society (CNPS) 2013). We have no specific information for Eureka Valley evening-primrose indicating the level of genetic diversity within or among the populations.

In general, Eureka Valley evening-primrose individuals spend most of the year as a small rosette of leaves (Pavlik 1979a, pp. 47-49, 52; 1979b, pp. 87-88). However, observations indicate that, under optimal conditions, recruits (first-year plants) can bloom in the year in which they germinate (Pavlik 1979a, p. 66). In April and May, mature plants undergo rapid stem elongation and bloom between April and July. Plants sometimes bloom again in the fall with additional summer or fall rains (Pavlik 1979a, p. 53; 1979b, p. 89). However, abundance and timing of rainfall appear to be important not only for germination, but for successful recruitment of individuals into the population; sufficient rainfall for germination in the fall months needs to be followed by additional rainfall events during the winter months for recruitment to occur (Pavlik and Barbour 1986, p. 10).

In addition to the production of seed through sexual reproduction, Eureka Valley evening-primrose reproduces vegetatively through the production of clonal rosettes that arise from a branched rootstock (Pavlik 1979a, p. 68; Pavlik and Barbour 1986, p. 84; Pavlik and Barbour 1988, p. 240). If conditions are favorable, a large individual can produce both rosettes and flower in the same year. In years with unfavorable climatic conditions, established plants may remain dormant and persist underground by their fleshy roots. Therefore, the number of above-ground plants observed in any year represents only a portion of the population and may consist of multiple individuals of the same genetic identity.

In general, evening-primrose taxa are pollinated by hawkmoths, butterflies, and bees (Gregory 1964, pp. 387, 398, 403, 407; Moldenke 1976, pp. 322, 346, 358). In particular, a hawkmoth known as the white-lined sphinx moth (
Hyles lineata
), bees (
Haprobroda
spp. (no common name),
Hesperapis
spp. (no common name)), and sweat bees (
Lasioglossum lusoria
) have been

observed on Eureka Valley evening-primrose (Griswold
in litt.
2012).

New information made available during the comment period or since publication of the proposed rule is summarized in the next three sections below.

Species Description, Taxonomy, and Life History

New information comprises the following: Over two growing seasons (2014, 2015), rooting depth for Eureka Valley evening-primrose was observed to be within the top 11.8 in (30 centimeters (cm)) of substrate (Scoles-Sciulla and DeFalco 2016, p. 9); compared to Eureka dune grass, which roots at a deeper level, Eureka Valley evening-primrose accesses water that is closer to the surface of the sand. Additionally, Eureka Valley evening-primrose seeds buried in all three dunes in July of 2014 and retrieved after 3, 6, 9, and 14 months had high germination rates, regardless of burial depth or which dune they were buried at. By comparison, seeds that were stored indoors starting July 2014 had lower total germination after 3 and 6 months, but had similar total germination after 14 months (Scoles-Sciulla and DeFalco 2016, p. 8). Overall, this information suggests that exposure to high temperatures during the summer months facilitates after-ripening (the period of internal change that is necessary in some apparently mature seeds before germination can occur) in this species (Scoles-Sciulla and DeFalco 2016, p. 8).

Rangewide Distribution

New information comprises the following: Continued monitoring for visible presence/absence within the rangewide 1-ha grid system resulted in documentation of the largest expanse of Eureka Valley evening-primrose ever recorded at all three dune systems since this monitoring effort began in 2007 (Park Service 2015). While the taxon remains tied to the sandy soils associated with the three dune systems, in “good” years such as 2014, individuals may be found farther away from the three dunes (Park Service 2014); however, the areas closer to the dunes continue to be the “core” areas where the taxon is found, even in years of lower abundance and productivity (Park Service 2013a, 2014, 2015). This information indicates that Eureka Valley evening-primrose has the ability to withstand years of less-than-favorable climatic conditions, and take advantage of years with more favorable climatic conditions.

Abundance Surveys and Population Estimates

New information comprises the following: Based on two additional years (2014, 2015) of monitoring Eureka Valley evening-primrose beyond the 2008-2013 monitoring period described in the proposed rule, the Park Service has continued to observe great annual variability in the abundance of the taxon, with 2014 being a “superbloom” year with the number of individuals estimated at well over 1 million (Park Service 2014, p. 6). In 2015, the abundance was not as large as in 2014, but larger than it had been other years previous to 2014; based on Park Service data, we estimated the visible abundance to be in the tens of thousands (see Park Service 2015, Figure 12 on p. 16). Overall, this information suggests that the visible abundance is only a portion of the total number of individuals that are present from year to year (with other individuals remaining dormant if climatic conditions are less than optimal), and that this characteristic contributes to the resiliency of the species.

Eureka Dune Grass

See the proposed delisting rule (79 FR 11053) and the Background Information document (Service 2014) for a detailed discussion of Eureka dune grass's description, taxonomy, life history, rangewide distribution, abundance surveys, and population estimates, which are available under Docket No. FWS-R8-ES-2013-0131 at
http://www.regulations.gov.

Eureka dune grass is a perennial, hummock-forming (development of mounds of windblown soil at the base of plants on dune landscapes) grass comprising a monotypic genus (genus containing only one single species) of the grass family (Poaceae). The coarse, stiff stems reach 20 in (50 cm) in height, and the lanceolate leaves are tipped with a sharp point (DeDecker 1987, p. 2). Flowers are clustered in spike-like panicles and produce seeds that are 0.16 in (4 millimeter (mm)) long and 0.08 in (2 mm) wide (Bell and Smith 2012, p. 1,496). The root system becomes fibrous and extensive over time and can give rise to adventitious stems. Based on its morphological characteristics and taxonomic affinities, the species is thought to be a relictual species, which exists as a remnant of a formerly widely distributed group in an environment that is now different from where it originated.

Eureka dune grass is dormant during the winter and begins to produce new shoot growth around February. Growth accelerates in May, with flowering from April to June and seed dispersal between May and July (Pavlik 1979a, pp. 47-49; Pavlik 1979b, p. 87; Service 1982, pp. 4-6). Like all grass taxa, the flowers of Eureka dune grass are wind-pollinated and, therefore, do not rely on insect pollinators. Eureka dune grass does not appear to propagate asexually (Pavlik and Barbour 1985, p. 4); therefore, sexual reproduction is considered to be the dominant form of reproduction for this species.

Individuals have been observed to continue growing for at least 12 years with no signs of senescence (Henry n.d., pers. comm.
in
Pavlik and Barbour 1986, p. 11), and likely can grow for decades; older individuals form large hummocks that can reach on the order of 2,500 cubic decimeters (88 cubic feet; extrapolated from Pavlik and Barbour (1988, p. 229)). Germination of new individuals appears to occur infrequently, typically in response to rainfall during the summer months (Pavlik and Barbour 1986, pp. 47-59).

The amount of Eureka dune grass seed produced per individual increases with canopy size, which means that larger individuals may contribute more seed to the seed bank (Pavlik and Barbour 1985, p. 14). Compared to other perennial grass species, Eureka dune grass produces low numbers of seeds per individual (Pavlik and Barbour 1986, p. 30); this low seed production could be due to the inefficiency of wind pollination and the low density of individuals across the dunes (Pavlik and Barbour 1985, p. 17).

New information made available during the comment period or since publication of the proposed rule is summarized in the next three sections below.

Species Description, Taxonomy, and Life History

New information comprises the following: Over two growing seasons (2014, 2015), rooting depth for Eureka dune grass was observed to be 35.4 in (90 cm) (Scoles-Sciulla and DeFalco 2016, p. 9).

Rangewide Distribution

New information comprises the following:

(1) In 2014 and 2015, the Park Service continued to monitor presence/absence of Eureka dune grass across all three dunes. Comparing the area (
i.e.,
number of acres/hectares) that contained Eureka dune grass in 2015 with the area that contained Eureka dune grass in 2011, they found: On the Main Dunes, there was a 20 percent loss (from 1,102 to 885

ac (446 to 358 ha)); on Marble Canyon Dunes, there was a 1 percent loss (from 195 to 193 ac (79 to 78 ha)); and on Saline Spur Dunes, there was a 7 percent gain (from 215 to 230 ac (87 to 93 ha)) (Park Service 2015 p. 5).

(2) Since 2012, the Park Service has continued to map individual clumps of Eureka dune grass on the Main Dunes with Global Positioning System (GPS) (National Park Service 2015). Due to inconsistent application of mapping protocols in earlier years, the Park Service considers data from 2014 and 2015 to be the most accurate. From 2014 to 2015, the area covered with dune grass declined by 19.2 percent (from 69.39 to 56.05 ac (280,799 square meter (m
2
) to 226,846 m
2
)) (Park Service 2015). The greatest losses appear to be in the central and south-central portions of the Main Dunes.

(3) Photopoints continued to be monitored by the Park Service in 2014 and 2015. These photopoints, including some that were established in 1974, provide a qualitative assessment of the changes in coverage of Eureka dune grass within the viewsheds they include. For the Main Dunes, the combined viewshed of all photopoints represents 33.4 percent of the dune; for Marble Canyon Dunes, the combined viewshed represents 21 percent of the dune; all photopoints from these two dunes document a substantial loss of Eureka dune grass coverage since the time they were established (Park Service 2014). The Park Service also noted that between 2014 and 2015, no substantial change was observed (Park Service 2015), suggesting that the losses occurred prior to 2014. Photopoints were not established on the Saline Spur Dunes until 2008 and 2010 (Park Service 2014); therefore, data is not available for a long-term qualitative evaluation of dune grass coverage in this population.

While a reduction in visible Eureka dune grass individuals is clearly noticeable from a visual inspection, it is difficult to quantify this reduction in terms of estimating changes in population distribution, densities, or abundance. Without other quantitative data to assist in interpretation, it would be difficult to distinguish whether visual changes represent local shifts in distribution and density or rangewide changes in the population. The additional information provided by the presence/absence monitoring, as well as the GPS mapping of clumps on the Main Dunes corroborates the observations of the loss of Eureka dune grass that has occurred over the last 35 years.

The most robust analysis can be made for the Main Dunes, for which there are all three sets of data (photopoints, presence/absence surveys, and GPS mapping), and all of which show a loss of individuals over time. The Main Dunes also represents over half of all the Eureka dune grass in Eureka Valley, so the loss from this dune is significant for the entire range of the species. Three sets of data (photopoints, presence/absence surveys, and GPS mapping), are also available for Marble Canyon Dunes, though presence/absence surveys and GPS mapping were initiated in both cases a year later than at the Main Dunes. Photopoints taken in the northern and northeastern portion of the dune show a loss of individuals between 1985 and 2013; presence/absence surveys indicate slight gains and losses between 2008 and 2015; and GPS mapping was not considered accurate by the Park Service until 2015, and therefore comparisons with earlier years cannot be made. Photopoint monitoring from the Main Dunes and from Marble Canyon Dunes both qualitatively indicate that extensive losses of dune grass occurred during the earlier portion of the 28-year monitoring period. More frequent photopoint monitoring was not initiated until 2007; by this time, most of the loss had already occurred, and more recent photos show less change.

Only presence/absence surveys (initiated in 2008) and GPS mapping of individuals (initiated in 2012 but not considered accurate until 2015) is available for Saline Spur Dunes. These two data sets have established that the western edge of Saline Spur Dunes contains the largest continuous population of Eureka dune grass at all three dunes (Park Service 2015 p. 2). Photopoint monitoring at this dune was only established in 2008 and 2010, and as of 2014 did not indicate any visible change (Park Service 2014, p. 6).

On a small scale, the usefulness of comparing recent maps with historical maps is limited because of the higher precision that was possible in the 2007 to 2015 surveys. Overall and on a large scale, the most recent maps indicate that Eureka dune grass populations are still present in the same general locations from which they were known at the time of our 2007 5-year status review. The precision that has been available with the hectare grid surveys and the GPS mapping has provided more useful examination of the distribution of Eureka dune grass on a smaller scale and a means by which to compare changes in distribution over time. The total extent of Eureka dune grass on all three dunes as of 2015 (Park Service 2015) is presented in the “
Swallenia
Maps” document available on the internet at
http://www.regulations.gov
under Docket No. FWS-R8-ES-2013-0131.

Abundance Surveys and Population Estimates

For a detailed discussion of the abundance and population estimates for Eureka dune grass, see the Background Information Document (Service 2014), which is available under Docket No. FWS-R8-ES-2013-0131 at
http://www.regulations.gov.
In that previous discussion, we stated that developing population estimates for Eureka dune grass is challenging because of: Lack of historical information regarding population sizes at the time of listing (to establish baseline for comparison), the site-specific transects that were done in 1976 and 1986 (
e.g.,
see Henry (1976) and Bagley (1986)), and followup surveys conducted by the Park Service (Park Service 2008a, pp. 5-6 and 17-18), were too spatially limited to be useful for population estimates, and estimating numbers of individuals is inherently difficult because of their clumping growth form. The Park Service previously attempted estimating population size based on the monitoring of the hectare grid at all three dunes: For the year 2011, the estimate was 8,014 individuals, and for 2013, it was 8,176 individuals (Park Service 2013a, p. 7). The Park Service cautions that the true population size could vary greatly due to a variety of limitations and assumptions. Even so, we know that, based on this information, thousands of Eureka dune grass individuals exist, and the number was relatively stable across the 2 years compared.

New information comprises the following: The Park Service has not attempted a revised method for estimating population size due to the inherent difficulty of doing so. However, because the estimates were based on the area occupied by Eureka dune grass in the monitoring of the hectare grid, we refer back to that metric (see section on
Rangewide Distribution
for Eureka dune grass, above) as a surrogate.

The best available data indicate the species continues to occur within Eureka Valley at all three dunes within its range (and as stated above, we have no information regarding population size at the time of listing for comparison, with population surveys prior to listing being limited to the northern end of the Main Dunes). Based on the combination of all data available (photopoints monitoring, presence/absence surveys based on the hectare grid, and GPS mapping of individual clumps), indications are that, between

2011 and 2015, the amount of Eureka dune grass has declined at the Main Dunes by 20 percent; the changes at Marble Canyon Dunes and Saline Spur Dunes have been of a smaller magnitude, with Marble Canyon Dunes showing a one percent loss, and with Saline Spur Dunes showing a seven percent increase (Park Service 2015, p. 5).

History of Threats Analyses for Eureka Valley Evening-Primrose and Eureka Dune Grass

For a brief history of the threats analyses that we conducted since the time Eureka Valley evening-primrose and Eureka dune grass were listed in 1978, see our proposed delisting rule (79 FR 11053, February 27, 2014). For a detailed discussion of the status review initiated with our 2011 90-day finding (76 FR 3069, January 19, 2011), see the Background Information document (Service 2014, pp. 38-65). Both the proposed listing rule and Background Information document are available on the internet at
http://www.regulations.gov
at Docket No. FWS-R8-ES-2013-0131.

Summary of Changes From the Proposed Rule

(1) We updated information on annual survey results based on monitoring for abundance and distribution undertaken by the Park Service in 2014 and 2015 (Park Service 2014, 2015). Also included is the Park Service's new subsampling methodology (Park Service 2017).

(2) We updated information on abiotic characteristics of the dune habitat (temperature, wind, and precipitation patterns) within the description of the Eureka Dunes Ecosystem in the Background section based on observations made by the United States Geological Survey (USGS) (Scoles-Sciulla and DeFalco 2017).

(3) We updated information on life-history characteristics, specifically rooting depth, for both species, and seed longevity for Eureka Valley evening-primrose, based on observations made by USGS (Scoles-Sciulla and DeFalco 2017).

(4) We added new information to the section on potential competition between
Salsola
spp. (Russian thistle) and Eureka Valley evening-primrose, based on research conducted by Chow (2016).

(5) On July 1, 2014, we published a final policy interpreting the phrase “significant portion of its range” (79 FR 37578). We have revised our discussion of “significant portion of its range” as it relates to both Eureka Valley evening-primrose and Eureka dune grass in the Determinations section below to be consistent with our policy. Although the final policy's approach differed slightly from that discussed in the proposed rule, applying the policy did not affect the outcome of the final status determinations.

(6) We have revised our determination regarding Eureka dune grass based on new information and analyses, and now conclude it best fits the definition of a threatened species.

Recovery and Recovery Plan Implementation

Section 4(f) of the Act directs us to develop and implement recovery plans for the conservation and survival of endangered and threatened species unless we determine that such a plan will not promote the conservation of the species. Under section 4(f)(1)(B)(ii), recovery plans must, to the maximum extent practicable, include: “Objective, measurable criteria which, when met, would result in a determination, in accordance with the provisions of [section 4 of the Act], that the species be removed from the list.” However, revisions to the list (adding, removing, or reclassifying a species) must reflect determinations made in accordance with sections 4(a)(1) and 4(b) of the Act. Section 4(a)(1) requires that the Secretary determine whether a species is an endangered species or threatened species (or not) because of one or more of five threat factors. Section 4(b) of the Act requires that the determination be made “solely on the basis of the best scientific and commercial data available.” Therefore, recovery criteria should help indicate when we would anticipate that an analysis of the species' status under section 4(a)(1) would result in a determination that the species is no longer an endangered species or threatened species.

Thus, while recovery plans provide important guidance to the Service, States, and other partners on methods of minimizing threats to listed species and measurable objectives against which to measure progress towards recovery, they are not regulatory documents and cannot substitute for the determinations and promulgation of regulations required under section 4(a)(1) of the Act. A decision to revise the status of or remove a species from the Federal List of Endangered and Threatened Plants (50 CFR 17.12) is ultimately based on an analysis of the best scientific and commercial data then available to determine whether a species is no longer an endangered species or a threatened species, regardless of whether that information differs from the recovery plan. Below, we summarize the recovery plan goals and discuss progress toward meeting the recovery objectives and how they inform our analyses of the species' status and the stressors affecting them.

In 1982, we finalized the Eureka Valley Dunes Recovery Plan, which included recovery objectives for both Eureka Valley evening-primrose and Eureka dune grass (Recovery Plan; Service 1982). While the Recovery Plan did not include recovery criteria, the plan followed guidance in effect at the time it was finalized and we consider its recovery objectives to be similar to what are considered to be recovery criteria under current recovery planning guidance. The Recovery Plan identified two objectives, each with specific recovery tasks, to consider Eureka Valley evening-primrose and Eureka dune grass for downlisting to threatened status, and eventually, delisting (Service 1982, pp. 26-41). These two objectives are:

(1) Restore the Eureka dune grass and the Eureka Valley evening-primrose to threatened status by protecting extant populations from existing (
i.e.,
in 1982) and potential human threats.

(2) Determine the number of individuals, populations, and acres of habitat necessary for each species to maintain itself without intensive management, in a vigorous, self-sustaining manner within their natural historical dune habitat (estimated 6,000 ac (2,428 ha)) and implement recovery tasks to attain these objectives.

Objective 1: Restore the Eureka dune grass and the Eureka Valley evening-primrose to threatened status by protecting extant populations from existing (i.e., in 1982) and potential human threats.

Objective 1 is intended to remove existing human threats to populations of Eureka Valley evening-primrose and Eureka dune grass through enforcement of existing laws and regulations, and management of human access to Eureka Valley (Service 1982, p. 26). At the time of listing, the primary threat to both species was off-highway vehicle (OHV) activity, and a lesser threat was camping on and around the dunes (43 FR 17910, April 26, 1978). Since listing, potential human threats have included other recreational activities such as sandboarding and horseback riding.

Various land management decisions and activities have been implemented by the Bureau of Land Management (BLM; prior to Park Service acquisition of the Eureka Valley area in 1994) and the Park Service (since 1994). All of the dune systems within Eureka Valley have also been designated as Federal

wilderness areas. A number of land use decisions and management activities have been implemented to support the long-term protection of Eureka Valley evening-primrose and Eureka dune grass within the Federal wilderness area, including (but not limited to): Making OHV activity illegal; conducting patrols to enforce laws, regulations, and restrictions; closing and restoring unauthorized roads; installing interpretative signs, barriers, and wilderness boundary signs; and delineating and maintaining campsites (Park Service 2008a, 2009, 2010).

Additionally, various education and public outreach (
e.g.,
public awareness program, interpretive displays) have been conducted to reduce overall impacts to both species. Because all three populations occur within Federal wilderness areas that are now protected against the threats identified as imminent at the time of listing and in the Recovery Plan, we conclude that the condition of the habitat for Eureka Valley evening-primrose and Eureka dune grass has improved due to management activities that have been implemented by BLM and the Park Service, and that this recovery objective has been met.

Objective 2: Determine the number of individuals, populations, and acres of habitat necessary for each species to maintain itself without intensive management, in a vigorous, self-sustaining manner within their natural historical dune habitat (estimated 6,000 ac (2,428 ha)) and implement recovery tasks to attain these objectives.

At the time the recovery plan was developed, our knowledge of the demographic characteristics of the two species was limited. The intent of this objective was to gather and develop information necessary to evaluate the status of both species with regards to demographic characteristics to determine at what point they could be considered recovered, and more importantly to attain the desired demographic levels necessary for recovery. While we have not yet developed precise values for all of the various demographic characteristics that help us determine whether actions to remove threats have the desired effect (
e.g.,
stable populations, positive growth), both species still occupy all three dune systems, and the best available monitoring data indicate thousands of plants are present at each dune system. Additionally, the best available information indicates that the BLM and Park Service have sufficiently minimized OHV and other recreation activities that were previously impacting the populations and their habitat. Even though the precise values of all demographic characteristics are not known, we note that many research and monitoring efforts have occurred for both species since the time of listing (unless otherwise noted), which have provided information on the life-history needs of both Eureka Valley evening-primrose and Eureka dune grass, as well as potential impacts to both species, including (but not limited to) the following studies:

(1) Conducting a series of studies on both species to investigate effects of pollination on seed set, seed ecology, species' demography, and plant and animal interactions (herbivory, seed predation, and dispersal) (Pavlik and Barbour 1985, 1986).

(2) Establishing baseline conditions for monitoring trends of both species across all three dune systems (Bagley 1986).

(3) Studying the genetic diversity of all Eureka dune grass populations (Bell 2003).

(4) Conducting partial distribution surveys of both species on portions of various dunes (Beymer
in litt.
1997; Peterson
in litt.
1998), as well as documenting the distribution and abundance of Russian thistle, a potential competitor, across all three dune systems (Park Service 2011a).

(5) Documenting distribution, abundance, and demography of both species (Park Service 2008b, 2008c, 2010a, 2011a, 2011b, 2012, 2013a, 2014, 2015, 2017).

(6) Determining if vegetation succession at the northern end of the Main Dunes (Eureka dune grass habitat) is associated with changes in subsurface hydrology (Park Service 2008c, p. 4).

(7) Investigating potential competition between Russian thistle and Eureka Valley evening-primrose, and the effects of herbivory on Eureka Valley evening-primrose (Chow and Klinger 2013a; Chow
in litt.
2011; Chow 2016).

(8) Monitoring photopoint stations over time, starting in 1985, and retaken at various intervals (Park Service 2008c, 2011b, 2014).

(9) Investigating the correlations between abiotic factors (temperature, wind, and precipitation patterns) and growth response in Eureka Valley evening-primrose and Eureka dune grass (Scoles-Sciulla and DeFalco 2017).

As a result of the considerable work that has been undertaken to understand the population dynamics and life histories of these two species, we have: (1) Established detailed baseline information regarding the abundance and distribution of both species with which to compare their status in future years, including the documentation of a population estimate for over a million individuals of Eureka Valley evening-primrose in the “superbloom” year of 2014; (2) investigated potential stressors more closely and determined that some potential stressors are of more concern than others; (3) clarified how the life-history strategies of the two species are different and lead to resiliency for Eureka Valley evening-primrose but not Eureka dune grass; and (4) suggested other potential stressors for the two species that should be monitored into the future. Overall, we consider the intent of Objective 2 has been partially met.

In summary, based on our review of the Recovery Plan and the information obtained from the various management activities, surveys, and research that have occurred to date, we conclude that the habitat for Eureka Valley evening-primrose and Eureka dune grass has been protected and its status improved due to land use decisions and management activities that have been implemented by BLM and the Park Service to reduce human-caused threats (Objective 1). Further, we conclude, as detailed below, that the status of Eureka Valley evening-primrose has improved substantially as documented by its resiliency and elucidated by the surveys and research undertaken since the time of listing (Objective 2). Therefore, the intent of both objectives has been met for the Eureka Valley evening-primrose. However, Objective 2 has not been met for the Eureka dune grass because monitoring data indicate declining trends at the Main Dunes and Marble Canyon Dunes.

Summary of Factors Affecting the Species

Section 4 of the Act and its implementing regulations (50 CFR part 424) set forth the procedures for listing species, reclassifying species, or removing species from listed status. “Species” is defined by the Act as including any species or subspecies of fish or wildlife or plants, and any distinct population segment of any species of vertebrate fish or wildlife which interbreeds when mature (16 U.S.C. 1532(16)). A species may be determined to be an endangered or threatened species because of any one or a combination of the five factors described in section 4(a)(1) of the Act: (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

human made factors affecting its continued existence. A species may be reclassified or removed from the Federal List of Endangered and Threatened Plants (50 CFR 17.12) on the same basis.

Determining whether the status of a species has improved to the point that it can be downlisted or delisted requires consideration of whether the species is an endangered species or threatened species because of the same five categories of threats specified in section 4(a)(1) of the Act. For species that are already listed as endangered species or threatened species, this analysis of threats is an evaluation of both the threats currently facing the species and the threats that are reasonably likely to affect the species in the foreseeable future following the delisting or downlisting and the removal or reduction of the Act's protections.

A species is an “endangered species” for purposes of the Act if it is in danger of extinction throughout all or a significant portion of its range and is a “threatened species” if it is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range. The word “range” in the significant portion of its range phrase refers to the range in which the species currently exists, and the word “significant” refers to the value of that portion of the range being considered to the conservation of the species. The “foreseeable future” is the period of time over which events or effects reasonably can or should be anticipated, or trends extrapolated. For the purposes of this analysis, we first evaluate the status of the species throughout all its range, then consider whether the species is in danger of extinction or likely to become so in a significant portion of its range.

Summary of Factors Affecting Eureka Valley Evening-Primrose

A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range

OHV Activity

For a detailed discussion of the types and amount of OHV activity, both at the time of listing and since then, see the proposed delisting rule (79 FR 11053, February 27, 2014) and the Background Information document (Service 2014), which are available under Docket No. FWS-R8-ES-2013-0131 at
http://www.regulations.gov.
OHV activity has not been authorized on the dunes in Eureka Valley since 1976, and not anywhere off established roads since 1994, when all the lands in Eureka Valley were included in a wilderness area designation.

OHV activity could affect Eureka Valley evening-primrose habitat in multiple ways, as evidenced from many studies that have occurred within dune ecosystems (such as Wilshire and Nakata 1976, Webb and Wilshire 1983). Physical impacts on dunes can include compaction or erosion of sandy substrates, acceleration of wind erosion (Gillette and Adams 1983, pp. 97-109), and acceleration of dune drift (Gilberston 1983, pp. 362-365). OHV activity can also change the unique hydrologic conditions of dunes. Because dunes have the capacity to hold moisture for long periods of time, disturbance of the surface sands resulting in exposure of moist sands underneath can increase moisture loss from the dunes (Geological Society of America 1977, p. 4). Changes in physical and hydrologic properties of the dunes from heavy OHV activity could in turn affect the suitability of the dune habitat for germination and recruitment of seedlings, clonal expansion of existing individuals, and dispersal of seeds to favorable microsites.

The same potential OHV impacts that affect dune habitat can also affect Eureka Valley evening-primrose individual plants. Normally, these types of impacts would be discussed under Factor E (Other Natural or Manmade Factors Affecting Its Continued Existence), but are included here in the Factor A discussion for ease of analysis. OHV impacts to individual plants within dune systems and other desert ecosystems have been extensively studied (such as Bury and Luckenbach 1983, Gilbertson 1983, and Lathrop 1983). Within dunes systems, for instance, while OHV activity alters the physical structure and hydrology of the dunes (rendering the dune habitat less suitable for supporting individuals and populations of the two species), it also affects individuals directly by shredding plants or damaging root systems, thereby killing or injuring (
e.g.,
reducing the reproduction or survival of individuals) the plants.

Although unauthorized OHV activity has occasionally occurred on the Eureka Dunes, it has not approached the levels seen prior to listing Eureka Valley evening-primrose as an endangered species. Existing regulatory mechanisms (such as through the Park Service's Organic Act and other laws guiding management of Park Service lands) in place since listing have resulted in beneficial effects to the species (
e.g.,
management measures to control OHV and recreational activities) (see additional discussion under Factor D, below). The management of OHV activity through land use designations (
i.e.,
Area of Critical Environmental Concern, Federal wilderness areas) has resulted in the near elimination of OHV activity on Eureka Dunes at the current time. We anticipate this situation will continue into the future because we expect Federal wilderness areas to remain in place indefinitely, and we expect the Park Service's current management to be implemented over the next 20 years, as well as modified periodically into the future with adaptive management strategies (as demonstrated by the Park Service's natural resource management strategies to date and anticipated in the future per Park Service policies and regulations (see Factor D)). Additionally, the remote location, inaccessibility, and wilderness status of the Saline Spur and Marble Canyon Dunes appear to be providing sufficient protection for dune habitats and plants at these locations both currently and in the future. Although the Park Service has documented sporadic occurrences of unauthorized OHV activity, these occurrences are almost entirely localized to areas on and adjacent to the northern end of the Main Dunes (Park Service 2013a, p. 3).

In response to the publication of the proposed delisting rule, Park Service stated that OHV trespass on the dunes still occurs and is documented at least annually, and that current staffing and funding levels do not allow for a constant park presence at the dunes, which would be required to completely prevent OHV trespass (Park Service 2014, p. 5). Regardless, the best available information indicates that OHV trespass activity is no longer causing significant population- or rangewide-level impacts to Eureka Valley evening-primrose.

Other Recreational Activities

In addition to unauthorized OHV activity that may occur currently (as described above), other recreational activities have been known historically and currently occur (occasionally) within the Eureka Dunes, including horseback riding, sandboarding, camping outside of designated areas, and creation of access routes. For a detailed discussion regarding these recreational activities, both at the time of listing and since then, see the proposed delisting rule (79 FR 11053, February 27, 2014) and the Background Information document (Service 2014), which are available under Docket No. FWS-R8-ES-2013-0131 at
http://www.regulations.gov.
Camping and associated access routes were identified as a minor threat in the Recovery Plan because their proximity to Eureka Dunes

facilitated unauthorized OHV activity (Service 1982, pp. 22-23). Horseback riding and sandboarding were potential threats to Eureka Valley evening-primrose and Eureka dune grass identified after listing, and were discussed in the 5-year status reviews published in 2007 (Service 2007a, p. 10; Service 2007b, pp. 7-8). All of these activities were discussed in our 5-year review under Factor A because, like OHV activity, they have the ability to have physical impacts on the dune habitat (such as destabilization and displacement of sands); however, these same activities have the potential for damaging individual plants through crushing, trampling, and uprooting. Although impacts to individual plants are more appropriately discussed under Factor E, for ease of analysis we also discuss impacts to individual plants here.

New information regarding impacts specifically to Eureka Valley evening-primrose individual plants (as opposed to habitat) comprises the following: In response to the publication of the proposed delisting rule, the Park Service referred back to a study conducted by Pavlik (1979a), which found that seedlings of both Eureka dune grass and Eureka Valley evening-primrose are extremely fragile and cannot tolerate even the lightest disturbance by foot traffic. Although the Park Service has not been able to measure the amount of foot traffic, the potential impacts from such traffic can be qualitatively observed on stabilized sand following rain events (Park Service 2014, p. 5). In addition, one peer reviewer observed evidence (
i.e.,
tracks) of unauthorized OHV activity at the base of the Main Dunes, as well as increased visitor use, specifically camping, at the dunes since the 1980s (McLaughlin
in litt.
2014).

Our current assessment is that, while the Park Service has documented some unauthorized activity (
e.g.,
sandboarding, OHV activity in closed areas) that may result in minor or occasional impact to individual plants, these are infrequent occurrences and affect very small areas and are not spread throughout the range of the species. Additionally, existing regulatory mechanisms (such as through the Park Service's Organic Act and other laws guiding management of Park Service lands) in place since listing have resulted in beneficial effects to the species (including management measures to control recreational activities) (see additional discussion under Factor D, below). Therefore, the best available information at this time indicates that other recreational activities, if they occur, are not causing population-level effects (as compared to pre-listing levels) to Eureka Valley evening-primrose currently, nor are they expected to do so in the future, in large part due to the extensive protections and management provided by the Park Service.

As discussed in the proposed rule (79 FR 11053, February 27, 2014), regulatory provisions of the Wilderness Act, the Park Service Organic Act, and the other laws guiding management of Park Service lands are adequate to minimize threats to populations of Eureka Valley evening-primrose from OHV activity, sandboarding, and horseback riding.

B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes

Utilization for commercial, recreational, scientific, or educational purposes was not identified as a threat to Eureka Valley evening-primrose in the listing rule. There is no known commercial or recreational value that we consider consumptive (that is, based on physical use or removal of the plants). Educational groups frequently visit Eureka Dunes, but we are unaware of any activities that would be considered consumptive use. Since listing, there have been three section 10(a)(1)(A) permits issued for studies involving the removal of plants, seeds, or plant parts; only two of these permits included Eureka Valley evening-primrose. These studies usually involve collection of seeds or leaves for laboratory experiments or collection of voucher specimens for herbaria; in each case we analyzed potential impacts during the permitting process and determined that the collection activities would not jeopardize the continued existence of the species. We do not consider this level of research and collection to pose any potential threat of overutilization for the species. Furthermore, the State of California and the Park Service have regulatory mechanisms in place to control any potential utilization in the future (see also Factor D below). Any collection of plants would require permits from the State of California and the Park Service. We do not have any new information regarding this factor, and we conclude that overutilization for commercial, recreational, scientific, or educational purposes are not a short-term or long-term threat to the continued existence of Eureka Valley evening-primrose.

C. Disease or Predation

At the time of listing, disease and predation were not identified as a potential threat to Eureka Valley evening-primrose. Since then, studies (Pavlik and Barbour 1985, 1986; Scoles-Sciulla and DeFalco 2013) and observations (Chow
in litt.
2011, 2012b) imply that herbivory and seed predation may be a potential stressor for the species. For a detailed discussion regarding disease and predation, both at the time of listing and since then, see the proposed delisting rule (79 FR 11053, February 27, 2014) and the Background Information document (Service 2014), which are available under Docket No. FWS-R8-ES-2013-0131 at
http://www.regulations.gov.

New information comprises updated results from two studies that were ongoing at the time the proposed rule published.

(1) Chow and Klinger (2014) evaluated the effects of lagomorph (taxonomic order of mammals comprising rabbits, hares, and pikas) herbivory on Eureka Valley evening-primrose competition, both with itself, and with Russian thistle (see discussion of the latter under Factor E) in an ex situ setting. While herbivory can result in the removal of aboveground vegetative material, it was not found to exacerbate intraspecific competition in Eureka Valley evening-primrose (Chow and Klinger (2013b, p. 21). However, herbivory can result in mortality of plants if individuals are repeatedly consumed or the roots are eaten, and it could also impact flower and fruit production (Chow and Klinger 2014, pp. 19, 21).

(2) USGS (Scoles-Sciulla and DeFalco 2013) observed that up to 99 percent of the surface area of Eureka Valley evening-primrose individuals were consumed over the growing season in 2012, contributing to low survival rates at all dune sites that year. In subsequent years, USGS reported on survival rates over the course of the growing season (
e.g.,
100 percent in 2013 (Scoles-Sciulla and DeFalco 2014, pp. 8-9), and between 20 and 70 percent at various dunes in 2014 (Scoles-Sciulla and DeFalco 2015, pp. 8-9); however, no other herbivory effects were discussed with the findings for these years.

Seed predation and herbivory are naturally occurring processes. We expect that Eureka Valley evening-primrose has adapted to withstand some level of herbivory and seed predation. Given that Eureka Valley evening-primrose continues to occupy the same general distribution identified at the time of listing, it does not appear that herbivory and seed predation by themselves are occurring at such a level to cause population-level declines or other adverse effects to the species as a whole. Based on the best available

information at this time (including the research observations provided by Chow and Klinger (2013b) and USGS (Scoles-Sciulla and DeFalco 2014, 2015); the expectation that this species has evolved with some level of herbivory/seed predation; and the fact that herbivory/seed predation is naturally occurring and some level of herbivory/seed predation is expected, we conclude that the observed impacts are not causing population-level effects for Eureka Valley evening-primrose currently, nor are they expected to do so in the future.

D. The Inadequacy of Existing Regulatory Mechanisms

Under this factor, we evaluate whether the stressors identified within the other factors may be ameliorated or exacerbated by any existing regulatory mechanisms or conservation efforts. Section 4(b)(1)(A) of the Act requires that the Service take into account “those efforts, if any, being made by any State or foreign nation, or any political subdivision of a State or foreign nation, to protect such species. . . .” In relation to Factor D under the Act, we interpret this language to require the Service to consider relevant Federal, State, and Tribal laws, regulations, and other such binding legal mechanisms that may ameliorate or exacerbate any of the threats we describe in threat analyses under the other four factors or otherwise enhance the species' conservation. Our consideration of these mechanisms is described in detail within each of the threats or stressors to the species (see discussion under each of the other factors).

The following existing regulatory mechanisms and conservation actions were specifically considered and discussed as they relate to the stressors, under the applicable factors, affecting Eureka Valley evening-primrose: The Wilderness Act, the Park Service Organic Act, and the other laws guiding management of Park Service lands are adequate to minimize threats to populations of Eureka Valley evening-primrose from OHV activity, sandboarding, and horseback riding. Beneficial effects for Eureka dune grass include: (1) Management measures to control illegal OHV activity (see Factor A discussion, above), including the Park Service's management policies (Park Service 2006); (2) the Organic Act; (3) the legal and stewardship mandates outlined in the Park Service's General Management Plan (Park Service 2002, entire); and (4) the Wilderness and Backcountry Stewardship Plan (Park Service 2013b, pp. 4, 5, 10, 16), given all areas containing populations of the species are within congressionally designated wilderness. The best available information indicates that these existing regulatory mechanisms have reduced the previously identified significant adverse effects to individual plants and populations, especially impacts associated with OHV activity (Factors A and E) and other recreational activities (
i.e.,
sandboarding, camping, and associated access routes) (Factors A and E). There are no existing regulatory mechanisms to address other potential stressors, including herbivory, seed predation, competition with Russian thistle, effects of climate change, and stochastic events.

While most of these laws, regulations, and policies are not specifically directed toward protection of Eureka Valley evening-primrose, they mandate consideration, management, and protection of resources that benefit the species. We expect these laws, regulatory mechanisms, and management plans to remain in place into the future.

For a detailed discussion regarding inadequacy of existing regulatory mechanisms, both at the time of listing and since then, see the proposed delisting rule (79 FR 11053, February 27, 2014) and the Background Information document (Service 2014), which are available under Docket No. FWS-R8-ES-2013-0131 at
http://www.regulations.gov.
There is no new information concerning these regulatory mechanisms.

E. Other Natural or Manmade Factors Affecting Its Continued Existence

OHV Activity and Other Recreational Activities

See the “OHV Activity” and “Other Recreational Activities” sections, above under Factor A, for a complete discussion of realized and potential impacts since the time of listing. As stated there, we included a complete discussion of potential impacts to both habitat and individual plants under Factor A for ease of analysis. We conclude, based on the best available information, that the Wilderness Area designation, coupled with Park Service management of OHV activity and other recreational activity, has significantly reduced potential impacts to Eureka Valley evening-primrose individuals, currently and into the future. See additional discussion above under Factors A and D.

Competition With Russian Thistle

Invasive, nonnative plants can potentially affect the long-term persistence of endemic species.
Salsola
spp. (Russian thistle) is the only invasive, nonnative species that has spread onto the dunes in the Eureka Valley. Previous information (available at the time of our 2007 5-year reviews) was generally limited to personal observations and collections with no specific information regarding the density or distribution of Russian thistle. However, due to continuing concerns expressed by the Park Service and other parties since 2007, we conducted a more thorough review of the life-history characteristics of Russian thistle and the potential impacts it could have on Eureka Valley evening-primrose, particularly the potential for Russian thistle to compete with Eureka Valley evening-primrose for resources such as water and nutrients, which would potentially result in fewer or smaller individuals of Eureka Valley evening-primrose. We also reviewed information provided by the Park Service concerning the distribution of Russian thistle on and around the dunes in Eureka Valley and preliminary results of an
ex situ
competition study (Chow and Klinger 2013b). For a detailed discussion regarding the potential for competition between Eureka Valley evening-primrose and Russian thistle, both at the time of listing and since then, see the proposed delisting rule (79 FR 11053, February 27, 2014) and the Background Information document (Service 2014), which are available under Docket No. FWS-R8-ES-2013-0131 at
http://www.regulations.gov.

New Information comprises the following: A preliminary study regarding interspecific competition (competition between individuals of different species) and intraspecific competition (competition between individuals of the same species) initiated in 2012 was updated by Chow and Klinger (2016) and Chow (2016). They found that competition (interspecific and intraspecific) reduced the relativized biomass of target individuals for both Eureka Valley evening-primrose and Russian thistle (Chow and Klinger 2014, p. 16). They were unable to determine if competition (inter- and intraspecific) affected the reproductive potential of either taxa, although they did observe that Eureka Valley evening-primrose produced more vegetative material, whereas Russian thistle produced more reproductive material (Chow and Klinger 2014, p. 20). This is likely the result of the different reproductive strategies (annual versus perennial) employed by these two taxa (Chow and Klinger 2014, p. 20). As in their preliminary study, Chow and Klinger (2013b, p. 16) found that Eureka

Valley evening-primrose tolerated interspecific competition better than Russian thistle. However, the effect of intraspecific competition between Eureka Valley evening-primrose individuals was less clear. For example, the highest number of neighbors (
i.e.,
six individuals) in one of the treatments did not result in the greatest impact to the target individual (Chow and Klinger 2014, p. 16). This may be because of competition occurring below ground.

Rooting depth of Eureka Valley evening-primrose was observed during the course of two different studies. Most of the Eureka Valley evening-primrose roots examined from a laboratory experiment were located at the bottom of pots as opposed to Russian thistle roots, which were more concentrated in the mid-section of the pot (Chow and Klinger 2014, pp. 17-18). This finding suggests the possibility that the spatial separation of the roots of Eureka Valley evening-primrose and Russian thistle is why the effects of intraspecific competition examined on the dunes was greater for Eureka Valley evening-primrose than interspecific competition. Rooting depth relative to soil moisture was also observed by USGS (Scoles-Sciulla and DeFalco 2015, p. 10); they concluded that Eureka Valley evening-primrose likely uses soil moisture within the top 11.8 in (30 cm) of soil because soil moisture at greater depths varied little over the spring and early summer, when primrose individuals were actively growing.

The growing phenologies (timing) of Eureka Valley evening-primrose and Russian thistle are likely sufficiently different that competition for water resources is minimal. The Park Service (Park Service 2014) observed the “phenological asynchrony” between these two species and noted that, although they share habitat in semi-stabilized sand, they do not appear to be stimulated by the same precipitation events and so do not reproduce at the same time or compete for the same resources. Overall at the present time, the best available information presented by Chow and Klinger (2013b) and Chow (2016) suggest that Russian thistle does not outcompete the Eureka Valley evening-primrose. Additionally, recent reports from the Park Service (2013, 2014) indicate that Eureka Valley evening-primrose continues to occupy areas where it was known to occur around the time of listing. Therefore, we do not consider impacts from Russian thistle to be a threat to the continued existence of the Eureka Valley evening-primrose both now and in the future.

Climate Change

For a detailed discussion regarding the potential effects of climate change on Eureka Valley evening-primrose, both at the time of listing and since then, see the proposed delisting rule (79 FR 11053, February 27, 2014) and the Background Information document (Service 2014), which are available under Docket No. FWS-R8-ES-2013-0131 at
http://www.regulations.gov.

Potential effects of climate change may include a variety of potential changes, such as the following:

(1) A decrease in the level of soil moisture that could increase evaporation and transpiration rates and thus impact the growth or performance of individual plants (Weltzin
et al.
2003, p. 943).

(2) Altered timing and amount of rainfall could influence germination and possibly establishment of Eureka dune grass (Pavlik and Barbour 1986, p. 47).

(3) The timing of phenological phases, such as flowering, leafing out, and seed release in both Eureka Valley evening-primrose and Eureka dune grass, could change, which has been noted in many other plant species (Bertin 2008, pp. 130-131). Additionally, pollinator availability could become limited (Hegland
et al.
2009) during the time Eureka Valley evening-primrose is flowering, which in turn could affect pollination effectiveness, and consequently the amount of seed it produces.

(4) Lower rainfall could affect survival of individual plants (
e.g.,
reproductive adults, seedlings) and result in less frequent germination events, both of which could affect recruitment. Alternatively, increased rainfall could increase germination and survival, but could also increase competition with invasive, nonnative plants or increase the population size of herbivores. With respect to herbivores, a subsequent decrease in rainfall could result in increased herbivory of certain plants due to a decreased availability in the variety of vegetation.

New information comprises the following: The most recent global climate models from the Intergovernmental Panel on Climate Change (IPCC) fifth assessment (IPCC 2013) do not resolve how two important weather patterns (
i.e.,
the El Niño Southern Oscilliation (ENSO) phenomenon and North American monsoon) will change over the next century (Cook and Seager 2013). These two weather patterns may be important drivers of the Eureka Valley evening-primrose population dynamics (Evans
in litt.
2014); climate envelope forecasts indicate that suitable climate for Eureka Valley evening-primrose will shift to the northwest of Eureka Valley dunes by 2050 (Evans
in litt.
2014).

In 2016, USGS completed 3 years of field study at all three dune systems to evaluate the influence of rainfall and temperature patterns on germination and growth of Eureka Valley evening-primrose and Eureka dune grass (Scoles-Sciulla and DeFalco 2017); final analysis will not be complete until 2018. Preliminary results indicate that: (1) Temperature regime, wind speeds, and precipitation patterns at the three dunes show some differences that likely are due to their relative position within Eureka Valley (for instance, the Main Dunes has lower daily temperatures than the other two dunes, while other patterns, such as rainfall, vary among the three dunes on both a temporal and spatial scale); (2) soil moisture probes installed near Eureka Valley evening-primrose individuals suggest that moisture at depths greater than 11.8 in (30 cm) varied little over the spring and early summer when the species was actively growing; and (3) rooting depth for Eureka Valley evening-primrose was within the top 11.8 in (30 cm) of substrate (Scoles-Sciulla and DeFalco 2017). Although the study is incomplete, this information indicates that the extent of the annual expression of Eureka Valley evening-primrose may vary between dunes in part due to the variation in precipitation between the dunes and that the species is accessing soil moisture at a deeper level than Russian thistle, which may reduce potential competition.

In summary, effects of climate change on Eureka Valley evening-primrose may occur in the future, although we cannot predict what the effects will be. Regardless, climate change will be affecting the climatic norms with which this species has previously persisted, and it is probable that this shift could cause stress to the species. We note that, as a short-lived perennial, the ability of this species to shift geographically over time in accordance with shifting climatic norms is greater than would be for a long-lived perennial plant species. However, because of the uncertainty regarding the magnitude and the imminence of such a shift, we are unable to determine the extent that this may become a stressor in the future. Additionally, while uncertainty exists, we expect the Park Service will continue to manage and monitor the species so that corrective actions may occur in the future.

Stochastic Events

For a detailed discussion regarding the potential effects of stochastic events on Eureka Valley evening-primrose, both at the time of listing and since then, see the proposed delisting rule (79 FR 11053, February 27, 2014) and the Background Information document (Service 2014), which are available under Docket No. FWS-R8-ES-2013-0131 at
http://www.regulations.gov.
In those documents, we discussed that environmental stochasticity (variation in recruitment and mortality rates in response to weather, disease, competition, predation, or other factors external to the population) could result from such events as drought, windstorms, and timing and amount of rainfall. There is no new information regarding the potential effects of stochastic events on Eureka Valley evening-primrose.

Overall, it is possible that environmental stochasticity (in the form of extreme weather events) could cause stress to Eureka Valley evening-primrose. However, the best available information at this time does not indicate the impacts associated with the observed and predicted range of stochastic events would affect the long-term persistence of Eureka Valley evening-primrose.

In our proposed rule and supporting documents, we also discussed that low genetic diversity theoretically could affect the ability of plant species to adjust to novel or fluctuating environments, survive stochastic events, or maintain high levels of reproductive performance (Huenneke 1991, p. 40). The species-rich genus
Oenothera
has been used as a model for the study of plant evolution, particularly regarding reproductive systems (Theiss
et al.
2010). DNA analysis has been used to clarify phylogenetic relationships; evidence indicates that the genus
Oenothera
is polyphyletic (relating to a taxonomic group that does not include the common ancestor of the members of the group, and whose members have two or more separate origins) (Levin
et al.
2003, 2004). Despite the number of studies, however, we have no specific information for
O. californica
ssp.
eurekensis
indicating the level of genetic diversity within or among the populations. However, given the resiliency exhibited by the species, at this time, the best available information does not indicate the species is experiencing any potential negative effects of low genetic diversity within and among the Eureka Valley evening-primrose populations.

Combination of Factors

For a detailed discussion regarding the potential effects of a combination of factors on Eureka Valley evening-primrose, both at the time of listing and since then, see the proposed delisting rule (79 FR 11053, February 27, 2014) and the Background Information document (Service 2014), which are available under Docket No. FWS-R8-ES-2013-0131 at
http://www.regulations.gov.
In those documents, we discussed that a combination of favorable climatic conditions could lead to an increase in food sources for small mammal populations, which could then cause additional stress on Eureka Valley evening-primrose through seed predation and herbivory. During the comment period, one peer reviewer commented that, although boom and bust population cycles of small mammals and their impacts on native vegetation are well known, in the case of Eureka Valley, there may be another confounding factor: Prior to the introduction of Russian thistle to the Valley in the last century, lagomorph populations were likely smaller. The spread of Russian thistle around the dunes may have increased the size of lagomorph populations above historical levels, and thus could potentially result in increased herbivory on Eureka Valley evening-primrose (Thomas
in litt.
2014).

During field studies since the proposed delisting rule was published, researchers (Chow and Klinger 2014, pp. 19-20, 46) observed evidence of small mammal predation and lagomorph predation on Eureka Valley evening-primrose during their field studies. However, no quantitative data are available regarding the extent of herbivory on Eureka Valley evening-primrose throughout its range, the size of the lagomorph population (or other small mammal populations), nor how their numbers fluctuate with the presence of Russian thistle. In addition, the “superbloom” year of 2014 provided a qualitative confirmation that, despite the large expression of Russian thistle that occurred in 2010 and the observations of small mammal herbivory in the intervening years, Eureka Valley evening-primrose was sufficiently resilient to have an aboveground expression of more than 1 million individuals.

While the combination of factors could potentially affect Eureka Valley evening-primrose, the best available information does not indicate that cumulative or synergistic effects are of sufficient magnitude or extent that they are affecting the viability of the species at this time or into the future.

Summary of Factors Affecting the Species—Eureka Dune Grass

A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range

OHV Activity

OHV activity may impact Eureka dune grass and its habitat in the same fashion and magnitude as that described above for Eureka Valley evening-primrose (see the OHV Activity section under Factor A for Eureka Valley evening-primrose, above). This includes 4-wheel drive vehicular use of roads and trails, predominantly on public lands, for the purpose of touring, hunting, fishing, or other public land use. Existing regulatory mechanisms (such as through the Park Service's Organic Act and other laws guiding management of Park Service lands) in place since listing have resulted in beneficial effects to the species, including management measures to control OHV and recreational activities) (see additional discussion under Factor D, below). As a result, OHV-related impacts to Eureka dune grass have essentially been ameliorated, in large part due to the designation of Federal wilderness areas throughout the species' range, with the exception of some minor unauthorized OHV activity that the Park Service acknowledges, also noting that the remote location of the dunes and limited resources make enforcing restrictions difficult (Park Service 2011b, p. 17).

Additional discussion regarding potential impacts and the Park Service's management of OHV activity, land use designations, and the potential for future adaptive management strategies regarding OHV activities that are established to benefit Eureka dune grass and other Eureka Dunes ecosystem species are described in detail under the OHV Activity section under Factor A for the Eureka Valley evening-primrose, above, and in the proposed delisting rule (79 FR 11053, February 27, 2014).

Overall, the current level of unauthorized OHV use is sporadic and does not occur across the range of the species, and there does not appear to be any correlation between OHV recreation and the status of the species. Given the management of OHV activity through land use designations has resulted in the near elimination of OHV activity on Eureka Dunes at the current time, and given the likelihood that these protections and adaptive management strategies will continue into the future at the remote locations where Eureka

dune grass occurs, we conclude that OHV activity no longer impacts the species or its habitat at the population or rangewide levels currently and into the future.

Other Recreational Activities

In addition to unauthorized OHV activity that may occur currently (as described above), other recreational activities have historically and currently occur (occasionally) within the Eureka Dunes, including horseback riding, sandboarding, camping outside of designated areas, and creation of access routes. Potential impacts from these recreational activities are described in detail either above in the Other Recreational Activities section under Factor A for Eureka Valley evening-primrose, or in the associated Other Recreational Activities section of the proposed delisting rule. Existing regulatory mechanisms (such as through the Park Service's Organic Act and other laws guiding management of Park Service lands) in place since listing have resulted in beneficial effects to the species (including management measures to control recreational activities) (see additional discussion above for Eureka Valley evening-primrose, as well as under Factor D, below).

New information is the same as that presented above for Eureka Valley evening-primrose: In response to publication of the proposed delisting rule, the Park Service referred back to a study conducted by Pavlik (1979a), which found that seedlings of Eureka dune grass are extremely fragile and cannot tolerate even the lightest disturbance by foot traffic. Although the Park Service has not been able to measure the amount of foot traffic, the potential impacts from such traffic can be qualitatively observed on stabilized sand following rain events (Park Service 2014, p. 5). In addition, one peer reviewer observed evidence (
i.e.,
tracks) of unauthorized OHV activity at the base of the Main Dunes, as well as increased visitor use, specifically camping, at the dunes since the 1980s (McLaughlin
in litt.
2014).

Our current assessment is that, while the Park Service has documented some unauthorized activity (
e.g.,
sandboarding, OHV activity in closed areas) that may result in minor or occasional impact to individual plants, these are infrequent occurrences and affect very small areas and are not spread throughout the range of the species. The Park Service is aware of the potential for impacts to Eureka dune grass from hikers accessing the north end of the Main Dunes and considers this a priority area for rangers to patrol and to have visitor contact.

Given the existing conservation measures in place across the Eureka Dunes (
i.e.,
reduction or elimination of impacts associated with horseback riding, sandboarding, camping, and establishment of access points via implementation of patrols, illegal road closures, interpretative signs, barriers, etc.), the best available information at this time indicates that unauthorized OHV and other recreational activities, if they occur, are not causing population-level effects (as compared to pre-listing levels) for Eureka dune grass habitat currently, nor are they expected to do so in the future.

B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes

Given the same scenario and discussion applies, please see the Factor B section for Eureka Valley evening-primrose, above, regarding collection of seeds or leaves for laboratory experiments or collection of voucher specimens for herbaria as a potential stressor to Eureka dune grass. Of the three section 10(a)(1)(A) permits issued for studies involving the removal of plants, seeds, or plant parts, only two of these were for Eureka dune grass. We do not consider this level of research and collection to pose any potential threat of overutilization for the species. We also do not have any new information regarding this factor, and we conclude that collection of seeds or leaves is not a short-term or long-term threat to the continued existence of Eureka dune grass.

C. Disease or Predation

At the time of listing, disease and predation were not identified as potential threats to Eureka dune grass. Since then, studies imply that herbivory and seed predation are a potential stressor to the species. For a detailed discussion regarding disease and predation, both at the time of listing and since then, see the proposed delisting rule (79 FR 11053, February 27, 2014) and the Background Information document (Service 2014), which are available under Docket No. FWS-R8-ES-2013-0131 at
http://www.regulations.gov.

New information comprises the following: Updated results from one study on plant growth and reproduction (Scoles-Sciulla and DeFalco 2015) that was ongoing at the time of the proposed delisting rule. Results indicate that in 2014, out of 90 Eureka dune grass individuals tagged in 2013, 16 did not grow due to severe herbivore damage in 2013; and an additional 4 plants grew but did not reproduce (Scoles-Sciulla and DeFalco 2015, p. 8). In 2015, the same 16 individuals still did not grow, and 3 of the additional 4 plants grew but did not reproduce (Scoles-Sciulla and DeFalco 2016, p. 8). No herbivory effects were discussed with the findings for the year 2016 (Scoles-Sciulla and DeFalco 2017).

In their 2015 monitoring report, the Park Service made note of rodent herbivory on leaves and stems of Eureka dune grass, most likely from kangaroo rats (
Dipodomys
sp.) that underwent a population surge in the previous year (Park Service 2015, pp. 18-19). Additionally, abundant rodent tracks were found in the central and southern portions of the Main Dunes (Park Service 2015, pp. 18-19). No studies have been done to quantify the extent of herbivore damage to the species. However, because Eureka dune grass produces seed in low abundance, the loss of any of this seed to herbivores could affect the ability of the species to bank seed and germinate in abundance when suitable conditions arise in the future.

New information is also noted with regards to potential herbivory from lagomorphs. Thomas (
in litt.
2014) cited two references that were inadvertently excluded in the proposed rule or Background Information document (Service 2014, entire). This information indicates that Russian thistle is consumed by black-tailed jackrabbits and cottontail rabbits (Daniel
et al.
1993, p. 5; Fagerstone
et al.
1980, pp. 230-231) and may be a preferred food source (Fagerstone
et al.
1980, p. 230). Thomas (
in litt.
2014) suggests that it is possible that Russian thistle may have increased lagomorph populations above historical levels, and thus, increased herbivory on Eureka dune grass. Although anecdotal in nature, we also note that the Park Service staff has made observations of herbivory by small mammals on Eureka dune grass (Park Service 2015, pp. 18-20).

Seed predation and herbivory are naturally occurring processes. We expect that Eureka dune grass can adapt to withstand some level of herbivory and seed predation. Given that the species continues to occupy the same range as identified at the time of listing, it does not appear that herbivory and seed predation by themselves are occurring at such a level to cause population-level declines or other adverse effects to the species as a whole. Based on the best available information at this time (
i.e.,
observations by USGS and the Park Service between 2013 and 2015, the expectation that this species

has evolved with some level of herbivory/seed predation, that herbivory/seed predation is naturally occurring, and some level of herbivory/seed predation is expected for the species), we conclude that the observed impacts in and of themselves are not likely causing population-level effects for Eureka dune grass currently. However, given that Eureka dune grass is already experiencing low to no reproduction, any additional loss of biomass due to herbivory will likely place additional stress on individual plants and limit their ability to expend resources on reproduction. Therefore, we acknowledge that herbivory or seed predation could be a concern for this species into the future, and recommend that observations of this stressor should continue.

D. The Inadequacy of Existing Regulatory Mechanisms

Under this factor, we evaluate whether the stressors identified within the other factors may be ameliorated or exacerbated by any existing regulatory mechanisms or conservation efforts. Section 4(b)(1)(A) of the Act requires that the Service take into account “those efforts, if any, being made by any State or foreign nation, or any political subdivision of a State or foreign nation, to protect such species. . . .” In relation to Factor D under the Act, we interpret this language to require the Service to consider relevant Federal, State, and Tribal laws, regulations, and other such binding legal mechanisms that may ameliorate or exacerbate any of the threats we describe in threat analyses under the other four factors or otherwise enhance the species' conservation. Our consideration of these mechanisms is described in detail within each of the threats or stressors to the species (see discussion under each of the other factors).

As similarly described above under the Factor D section for Eureka Valley evening-primrose, the following existing regulatory mechanisms and conservation actions were specifically considered and discussed as they relate to the stressors, under the applicable factors, affecting Eureka dune grass: The Wilderness Act, the Park Service Organic Act, and the other laws guiding management of Park Service lands. We concluded they are adequate to minimize and control threats to populations of Eureka dune grass from OHV activity, sandboarding, and horseback riding. Eureka dune grass and its habitat benefit from existing regulatory mechanisms and conservation actions, including: (1) Management measures to control illegal OHV activity (see Factor A discussion, above), including the Park Service's management policies (Park Service 2006); (2) the Organic Act; (3) the legal and stewardship mandates outlined in the Park Service's General Management Plan (Park Service 2002, entire); and (4) the Wilderness and Backcountry Stewardship Plan (Park Service 2013b, pp. 4, 5, 10, 16), given all areas containing populations of the species are within congressionally designated wilderness. The best available information indicates that these existing regulatory mechanisms have reduced the previously identified significant adverse effects to individual plants and populations, especially impacts associated with OHV activity (Factors A and E) and other recreational activities (
i.e.,
sandboarding, camping, and associated access routes) (Factors A and E). We also expect the Park Service to continue using these mechanisms to assist in reducing impacts into the future. At this time, there are no existing regulatory mechanisms to address herbivory, seed predation, effects of climate change, and stochastic events under Factor E (see below).

Downlisting Eureka dune grass from an endangered species to a threatened species on the Federal List of Endangered or Threatened Plants would not significantly change the protections afforded this species under the Act. Additionally, while most of the other laws, regulations, and policies considered are not specifically directed toward protection of Eureka dune grass, they mandate consideration, management, and protection of resources that benefit the species. We expect these laws, regulatory mechanisms, and management plans to remain in place into the future.

For a more detailed discussion of the various existing regulatory mechanisms, both at the time of listing and since then, see the proposed delisting rule (79 FR 11053, February 27, 2014) and the Background Information document (Service 2014), which are available under Docket No. FWS-R8-ES-2013-0131 at
http://www.regulations.gov.
There is no new information concerning these regulatory mechanisms.

E. Other Natural or Manmade Factors Affecting Its Continued Existence

OHV Activity and Other Recreational Activities

See the OHV Activity and Other Recreational Activities sections, above, under Factor A for Eureka dune grass and Eureka Valley evening-primrose for a complete discussion of realized and potential impacts since the time of listing. As stated there, we conclude, based on the best available information, that the Wilderness Area designation, coupled with Park Service management of OHV activity and other recreational activity, has significantly reduced potential impacts to Eureka dune grass individuals currently and into the future. Even so, there is one portion of the range of this species (and not affecting Eureka Valley evening-primrose)—the Main Dunes adjacent to the campground area—that is subject to the most impact from recreational hiking. The National Park Service has anecdotally documented foot traffic in this area when it is most observable,
i.e.,
after a rain event (Park Service 2014, p. 5). If the area being trampled overlaps with an area where there has been a localized germination event of Eureka dune grass, it could result in the loss of those individuals as well as potentially prevent the species from recovering (
e.g.,
limiting the species' ability to expend resources on growth and establishment that would increase abundance of individuals) in the area. We expect the Park Service to continue to manage OHV and other recreational activities to assist in reducing impacts to Eureka dune grass into the future.

Competition With Russian Thistle

Invasive, nonnative plants can potentially impact the long-term persistence of endemic species. Russian thistle is the only invasive, nonnative species that has spread onto the dunes in the Eureka Valley. Potential impacts associated with Russian thistle are described under the Competition with Russian Thistle section under Factor E for Eureka Valley evening-primrose, above, and in the associated section of the proposed delisting rule (79 FR 11053, February 27, 2014) and the Background Information document (Service 2014), which are available under Docket No. FWS-R8-ES-2013-0131 at
http://www.regulations.gov.

The potential for Russian thistle to impact Eureka dune grass is unlikely because: (1) Eureka dune grass typically occurs on the steeper, unstable slopes of the dunes, which appears to limit the establishment of Russian thistle; and (2) Russian thistle roots are shallower than those of Eureka dune grass, which reduces the likelihood of potential competition between the two species.

New information comprises the following: The Park Service continued to note the presence/absence of Russian thistle during the hectare grid monitoring in 2014 and 2015; at the Main Dunes, the number of hectares in the monitoring grid where Russian thistle and Eureka dune grass both occur

was 19 percent in 2013 (Park Service 2014, pp. 4, 12, 15; 2015, p. 3), and 4 percent in 2015 (Hoines
in litt.
2017). Due to the steeper terrain occupied by Eureka dune grass on the Main Dunes, the percentage of hectares of Russian thistle that overlap with dune grass is less than that for overlap between Russian thistle and Eureka Valley evening-primrose. At the two smaller dunes, there is a greater percentage of hectares of Russian thistle that overlap with Eureka dune grass than at the Main Dunes (in 2013, 91 percent at Saline Spur Dunes, and 76 percent at Marble Canyon Dunes). However, on a finer spatial scale, the cover of each of these species (Eureka dune grass and Russian thistle) is so low that the opportunity for competition is limited. In addition, in their ecological study of Eureka dune grass, USGS measured the rooting depth, and found it to be approximately 35 in (90 cm) (Scoles-Sciulla and DeFalco 2016, p. 9). The rooting depth for annual species of Russian thistle is shallower (in one study, the average was 24 in (60 cm) (Padilla and Pugnare 2007)). There are also phenological differences in the growing season between Eureka dune grass and Russian thistle: During the growing season for Russian thistle (summer), adult dune grass individuals are extracting water from lower depths (Scoles-Sciulla and DeFalco 2016). Therefore, based on the best available information, although competition between individuals of Russian thistle and individuals of Eureka dune grass may occasionally occur, because of their separation in space and time, we conclude that competition with Russian thistle does not pose a population-level impact to Eureka dune grass at this time.

Climate Change

For a detailed discussion of climate change in the Eureka Valley and its potential effects to Eureka dune grass and its habitat, please see the proposed delisting rule (79 FR 11053, February 27, 2014) and the Background Information document (Service 2014), which are available under Docket No. FWS-R8-ES-2013-0131 at
http://www.regulations.gov.
At the time we published the proposed rule, we concluded that there is considerable uncertainty in local climate projections, and we expected Eureka dune grass is adapted to withstand drier climate conditions. We also stated that impacts from climate change on Eureka dune grass may occur in the future, although we cannot predict what the effects will be.

New information comprises the following: In 2016, USGS completed a field study at all three dune systems to evaluate the influence of rainfall and temperature patterns on germination and growth of Eureka dune grass and Eureka Valley evening-primrose; the results of this study are not yet available (Scoles-Sciulla and DeFalco 2017, p. 9). To date, they note the following:

(1) Temperature regime, wind speeds, and precipitation patterns at the three dunes show some differences that likely are due to their relative position with Eureka Valley. For instance, the Main Dunes has lower daily temperatures than the other two sites, while other patterns, such as rainfall, vary among the three dunes on both a temporal and spatial scale.

(2) Soil moisture probes installed near dune grass individuals suggest that moisture from a summer storm event (11 in (29 cm)) may infiltrate the soil near plants more deeply than away from plants. Also, soil moisture down to 35 in (90 cm) declined more rapidly near the dune grass than in the interspaces during this time when Eureka dune grass is actively growing.

(3) Rooting depth for Eureka dune grass was 35 in (90 cm) during the 2014 and 2015 growth seasons, as compared to a “within top [11 in] 30 cm” rooting depth for Eureka Valley evening-primrose (Scoles-Sciulla and DeFalco 2017, pp. 5-8).

There are two primary ways in which a shift in local climatic conditions could affect the long-term persistence of Eureka dune grass. First, because the species taps into water at deeper soil levels in the dune sands, a reduction in the availability of this water could affect the persistence of mature, established individuals; a loss of these mature individuals from the population is significant, because most of the seed production for the future of the population is contributed by these older individuals. Second, a shift in precipitation patterns during the summer and fall season could affect the ability of Eureka dune grass to have successful germination events. Water year precipitation (
i.e.,
the total annual rainfall between October 1 of one year until September 30 of the following year) has been on a declining trend between 1896 and 2013 (Willoughby
in litt.
2014); summer precipitation (April through September) has also been on a declining trend between 1896 and 2013 (Willoughby
in litt.
2014). It is reasonable to assume the lack of summer precipitation is one of the parameters affecting the ability of Eureka dune grass to experience germination events. Park Service staff had documented a germination event in 2014, but none had been observed prior to that since 1984 (Park Service 2014; Pavlik and Barbour 1986, p. 50). At this time, we have no further information regarding the extent to which the 2014 germinants may have survived or become established within the population.

In summary, impacts from climate change on Eureka dune grass may occur in the future. Although we cannot predict what the effects will be, they could impact various aspects of the life history of the species, including altering germination and establishment success, as well as growth, reproduction, and longevity. Regardless, climate change will be affecting the climatic norms with which this species has previously persisted, and it is probable that this shift could cause stress to the species. We note that, as a long-lived perennial, the ability of this species to shift geographically over time in accordance with shifting climatic norms is less than would be for a short-lived perennial (for example, Eureka Valley evening-primrose) or annual plant species. The conditions for germination (specifically, late summer/early fall precipitation) occur less frequently than the typical winter precipitation to which most annual and perennial Mojave desert species respond. Although several patches of germination were observed by the Park Service in 2014, that was the only year since rangewide monitoring began in 2008 that they observed such germination. Because of the uncertainty regarding the magnitude and the imminence of such a shift in climatic norms, we are unable to determine the extent to which this will become a stressor in the foreseeable future, and particularly how it will affect the interval between successful germination and establishment events that the species needs to replace the loss of senescent individuals.

Stochastic Events

For a detailed discussion of the potential impacts of stochastic events on Eureka dune grass and its habitat, see the “Stochastic Events” section of the proposed delisting rule (79 FR 11053, February 27, 2014) and the Background Information document (Service 2014, pp. 62-64). At the time we published the proposed rule, we concluded that neither windstorms nor a variation in rainfall represent a substantial threat to Eureka dune grass. We have no new information regarding the potential threat posed by stochastic events.

With regard to genetic stochasticity, we stated in the proposed delisting rule that low genetic diversity may affect the ability of plant species to adjust to novel or fluctuating environments, survive

stochastic events, or maintain high levels of reproductive performance (Huenneke 1991, p. 40). Although Bell (2003, p. 6) concluded that there was low genetic diversity within and among the three populations of Eureka dune grass, there is no past information available regarding the level of genetic diversity within and among the three populations of Eureka dune grass that would allow us to determine if genetic diversity has changed over time or the extent to which low genetic diversity may affect the species' fitness or its ability to adapt to changing conditions over time. Overall, we concluded in the proposed delisting rule that genetic stochasticity does not pose a threat to Eureka dune grass currently or in the future.

Currently, we have no additional information on whether genetic diversity has changed over time, or whether genetic stochasticity poses a threat to Eureka dune grass in the future.

Combination of Factors

For a detailed discussion of the combination of various factors and potential impacts on Eureka dune grass and its habitat, see the “Combination of Factors” section of the proposed delisting rule (79 FR 11053, February 27, 2014), and the Background Information document (Service 2014), which are available under Docket No. FWS-R8-ES-2013-0131 at
http://www.regulations.gov.
We concluded that while the combination of factors could potentially impact Eureka dune grass, the best available information did not indicate that the magnitude or extent of cumulative or synergistic effects was impacting the species to the point that they are affecting the viability of the species at this time or into the future (although the available information indicates some uncertainty about how synergistic effects could impact the species in the future).

The best available information for Eureka dune grass indicates that the rangewide distribution (as represented by presence in the grid monitoring), as well as the number of large individuals of the dune grass, is in decline at two (the Main Dunes and Marble Canyon Dunes) out of three of the dune systems. In addition, since most of Eureka dune grass occurs at the Main Dunes, the decline in abundance and distribution at the Main Dunes represents a larger proportion of the decline rangewide for the species. Although we do not know specifically what the combination of factors may be contributing to the decline of Eureka dune grass, the combination of rangewide distribution monitoring, 30 years of photopoints, and trends analysis by three different parties (Kendall
in litt.
2014; Park Service 2014; and Willoughby
in litt.
2014) indicate that the status of this species is not yet stable or improving. This species exhibits life-history characteristics (intrinsic factors) that include low seed production, low frequency of germination, and low frequency of establishment of new individuals that reach reproductive age. These characteristics contribute to the difficultly of maintaining robust populations of individuals over time. Any additional external (extrinsic) factors, such as trampling, herbivory, or drought, that impact these critical life-history stages in Eureka dune grass will reduce its reproductive potential, and its ability to persist, in the future.

Please see the Climate Change section under Factor E, above, for a discussion of its potential effect as a stressor to Eureka dune grass. At this time, our evaluation of the best available information indicates that the combination of stress caused by changing climatic norms with other stressors, such as herbivory, are likely exacerbating the species' ability to exhibit a stable or increasing population size across its range into the future. We also note that the best available information suggests this species is physiologically adapted to the specific hydrologic and soil conditions on the dunes. However, both water year precipitation and summer precipitation have declined in the region between 1896 and 2013; these declines could affect the species by reducing successful germination events and recruitment in the summer-fall months and also by reducing the health and longevity of established adults due to lower annual rainfall.

With respect to herbivory (please see the Factor C section above), it is possible that the abundance of lagomorphs (due to presence of Russian thistle that it feeds on) has increased greater than historical levels, and thus may contribute to elevated levels of herbivory on Eureka dune grass (Thomas
in litt.
2014). Although anecdotal in nature, we also note that the Park Service staff has made observations of herbivory by small mammals on Eureka dune grass (Park Service 2015, pp. 18-20).

Determinations

Introduction

Under section 4(a)(1) of the Act, we determine whether a species is an endangered species or threatened species because of any of the following: (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.

The fundamental question before the Service is whether the species meets the definition of “endangered species” or “threatened species” under the Act. To make this determination, we evaluated the projections of extinction risk, described in terms of the condition of current and future populations and their distribution (taking into account the risk factors and their effects on those populations). For any species, as population condition declines and distribution shrinks, the species' extinction risk increases and overall viability declines.

The Act defines an endangered species as any species that is “in danger of extinction throughout all or a significant portion of its range” and a threatened species as any species “which is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range.” On July 1, 2014, we published a final policy interpreting the phrase “significant portion of its range” (SPR) (79 FR 37578). In our policy, we interpret the phrase “significant portion of its range” in the Act's definitions of “endangered species” and “threatened species” to provide an independent basis for listing a species in its entirety; thus there are two situations (or factual bases) under which a species would qualify for listing: A species may be in danger of extinction or likely to become so in the foreseeable future throughout all of its range; or a species may be in danger of extinction or likely to become so throughout a significant portion of its range. If a species is in danger of extinction throughout an SPR, it, the species, is an “endangered species.” The same analysis applies to “threatened species.”

Our final policy addresses the consequences of finding a species is in danger of extinction in an SPR, and what would constitute an SPR. The final policy states that (1) if a species is found to be endangered or threatened throughout a significant portion of its range, the entire species is listed as an endangered species or a threatened species, respectively, and the Act's protections apply to all individuals of the species wherever found; (2) a portion of the range of a species is

“significant” if the species is not currently endangered or threatened throughout all of its range, but the portion's contribution to the viability of the species is so important that, without the members in that portion, the species would be in danger of extinction, or likely to become so in the foreseeable future, throughout all of its range; (3) the range of a species is considered to be the general geographical area within which that species can be found at the time the Service or the National Marine Fisheries Service makes any particular status determination; and (4) if a vertebrate species is endangered or threatened throughout an SPR, and the population in that significant portion is a valid DPS, we will list the DPS rather than the entire taxonomic species or subspecies.

The SPR policy is applied to all status determinations, including analyses for the purposes of making listing, delisting, and reclassification determinations. The procedure for analyzing whether any portion is an SPR is similar, regardless of the type of status determination we are making. The first step in our assessment of the status of a species is to determine its status throughout all of its range. Depending on the status throughout all of its range, we will subsequently examine whether it is necessary to determine its status throughout a significant portion of its range. If we determine that the species is in danger of extinction, or likely to become so in the foreseeable future, throughout all of its range, we list the species as an endangered (or threatened) species and no SPR analysis will be required. The same factors apply whether we are analyzing the species' status throughout all of its range or throughout a significant portion of its range.

As described in our policy, once the Service determines that a “species”—which can include a species, subspecies, or distinct population segment (DPS)—meets the definition of “endangered species” or “threatened species,” the species must be listed in its entirety and the Act's protections applied consistently to all individuals of the species wherever found (subject to modification of protections through special rules under sections 4(d) and 10(j) of the Act).

For the purpose of these determinations, we note that the implementation timeline of Death Valley National Park's Wilderness and Backcountry Stewardship Plan (Park Service 2013b) is 20 years. We think this is an appropriate timeframe over which events or effects reasonably can or should be anticipated, or trends extrapolated, because it is the length of time that the Park has planned for managing the habitat of Eureka Valley evening-primrose and Eureka dune grass, and during which time the Park will be monitoring the status of the populations. Although we expect this beneficial management to occur for at least the length of this timeframe, we expect management of the Eureka Dunes to continue well into the future beyond 20 years. Based on the Park Service's track record for natural resource management and revisions to management plans, we can reasonably expect such revisions to incorporate protective management consistent with the needs of the species well into the future and beyond the existing 20-year stewardship plan timeframe described above. We expect future revisions to be consistent with laws, regulations, and policies governing Federal land management planning; however, we cannot predict the exact contents of future plans. For additional information used to determine foreseeable future for these species, see the discussion of the Park Service's responsibilities and a description of Death Valley National Park's Wilderness and Backcountry Stewardship Plan in the “Recovery” and “Factor D” sections of the Background Information document (Service 2014, pp. 32-38, 48-51).

In considering what factors might constitute threats to the species, we must look beyond the mere exposure of the species to the factor to determine whether the exposure causes actual impacts to the species. If there is exposure to a factor, but no response, or only a positive response, that factor is not a threat. If there is exposure and the species responds negatively, the factor may be a threat and we then attempt to determine how significant the threat is. If the threat is significant, it may drive, or contribute to, the risk of extinction of the species such that the species warrants listing as an endangered species or a threatened species as those terms are defined by the Act. This does not necessarily require empirical proof of a threat. The combination of exposure and some corroborating evidence of how the species is likely impacted could suffice. The mere identification of factors that could impact a species negatively is not sufficient to compel a finding that listing is appropriate; we require evidence that these factors individually or cumulatively are operative threats that act on the species to the point that the species meets the definition of an endangered species or threatened species under the Act.

Eureka Valley Evening-Primrose—Determination of Status Throughout All of Its Range

As required by section 4(a)(1) of the Act, we conducted a review of the status of this plant and assessed the five factors to evaluate whether Eureka Valley evening-primrose is in danger of extinction currently or likely to become so in the foreseeable future throughout all of its range. We examined the best scientific and commercial information available regarding the past, present, and future threats faced by the species. We reviewed information presented in the 2010 petition, information available in our files and gathered through the status review initiated with our 90-day finding in response to this petition, additional information that became available since the time our 2007 5-year status reviews were completed, and other available published and unpublished information, including public comments and information available after publication of the proposed rule. We also consulted with species experts and land management staff with Death Valley National Park who are actively managing for the conservation of Eureka Valley evening-primrose.

We examined the following stressors that may be affecting Eureka Valley evening-primrose: Unauthorized OHV activity, and other unauthorized recreational activities (specifically, horseback riding, sandboarding, camping, and access routes) (Factor A); collection for scientific research (Factor B); herbivory and seed predation (Factor C); the inadequacy of existing regulatory mechanisms (Factor D); and other unauthorized recreational activities (
i.e.,
horseback riding, sandboarding, camping, and access routes), competition with Russian thistle, effects of climate change, and stochastic events (Factor E). Our analysis indicates that measures have been put in place since the time of listing that have resulted in management and the elimination or reduction of the significant impacts to Eureka Valley evening-primrose populations identified at the time of listing (
i.e.,
OHV activity, and to a lesser extent camping and unauthorized OHV activity) that could have resulted in the extirpation of all or parts of populations. These impacts have been eliminated or reduced to the extent that they are considered negligible currently, and are expected to continue to be negligible into the future.

It is important to acknowledge the significant commitment made initially by BLM and subsequently by the Park Service in their efforts to provide

permanent protection to Eureka Valley evening-primrose and its habitat, as well as ongoing management, research, and public outreach opportunities. Since the publication of the proposed delisting rule in 2014, the Park Service continued to monitor the species for presence/absence throughout its range in 2014 and 2015 and developed a new subsampling method that was initiated in 2017. In addition, the Park Service coordinated with researchers to promote additional studies on monitoring methodologies (Chow and Klinger 2016), examine competition with Russian thistle (Chow and Klinger 2016), and investigate how growth and reproduction are influenced by changes in local climate (Scoles-Sciulla and DeFalco 2017). The Park Service worked with us to develop a post-delisting monitoring plan for Eureka Valley evening-primrose, which commits the Park Service to continued monitoring of this species for a period of 10 years.

The recovery criteria in the recovery plan have been achieved and the recovery objectives identified in the recovery plan have been met for Eureka Valley evening-primrose, based on the information presented in this final rule, the proposed rule (79 FR 11053, February 27, 2014), and the Background Information document (Service 2014), which are available under Docket No. FWS-R8-ES-2013-0131 at
http://www.regulations.gov.

In conclusion, as discussed in the
Summary of Factors Affecting the Species—Eureka Valley Evening-primrose
section above, herbivory, seed predation, stochastic events, climate change, and competition with Russian thistle during years the thistl

[Text truncated at 120,000 characters. The full text is on the page linked above.]

---

Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A2018-03769. Public record. Not legal advice.