Endangered and Threatened Wildlife and Plants; 12-Month Petition Finding to list Silene verecunda ssp. verecunda (Mission Dolores Campion)

DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

Endangered and Threatened Wildlife and Plants; 12-Month Petition

Finding to list Silene verecunda ssp. verecunda (Mission Dolores

Campion)

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 12-month petition finding.

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SUMMARY: The U.S. Fish and Wildlife Service (Service) announces a 12-

month finding on a petition to list Silene verecunda ssp. verecunda

(Mission Dolores Campion) pursuant to the Endangered Species Act of

1973, as amended (Act). After review of all available scientific and

commercial data, the Service finds that listing this species is not

warranted at this time. The known populations of S. verecunda ssp.

verecunda are unlikely to be affected by toxic waste site studies and

clean-up related to military base closure actions. The population

status and vulnerability of S. verecunda ssp. verecunda to threats is

unknown for the central part of its range including Montara Mountain in

San Mateo County to Rancho del Oso in Santa Cruz County, California.

The recent discovery of S. verecunda ssp. verecunda in chaparral and

mixed evergreen plant communities indicates that this species may be

more widely distributed and have broader habitat affinities than

previously believed.

DATES: The finding announced in this document was made on July 24,

1995. Comments and materials regarding this petition finding may be

submitted to the Field Supervisor at the address listed below until

further notice.

ADDRESSES: Data, information, comments, or questions concerning this

finding may be sent to the Field Supervisor, Sacramento Field Office,

U.S. Fish and Wildlife Service, 2800 Cottage Way, Room E-1803,

Sacramento, California 95825-1846. The petition finding, supporting

data, comments, and materials received will be available for public

inspection, by appointment, during normal business hours at the above

address.

FOR FURTHER INFORMATION CONTACT: Kirsten Tarp, staff biologist, at the

above address or telephone 916/979-2120.

SUPPLEMENTARY INFORMATION:

Background

Section 4(b)(3)(B) of the Endangered Species Act of 1973, as

amended (16 U.S.C. 1531 et seq.), requires that after receiving a

petition that is found to present substantial information indicating

that the petitioned action may be warranted, the Service make a finding

within 12 months of the date of the receipt of the petition on whether

the petitioned action is (a) not warranted, (b) warranted, or (c)

warranted but precluded from immediate proposal by other pending

proposals of higher priority. Such 12-month findings are to be

published promptly in the Federal Register.

On May 29, 1991, the Service received a petition dated May 28,

1991, from Mr. Brian O'Neill, General Superintendent of the Golden Gate

National Recreation Area (GGNRA), National Park Service, San Francisco,

California, to emergency list five candidate plants including Silene

verecunda ssp. verecunda (Mission Dolores Campion). The petition cited

threats to this species that would result from military base closure

activities on the Presidio in San Francisco, California. These

activities included hazardous or toxic waste site studies and clean-up,

and increased traffic and recreational activities. A 90-day finding was

made by the Service that the petition presented substantial information

indicating that the

[[Page 46569]]

requested action may be warranted. The 90-day finding was published in

the Federal Register on August 19, 1992 (57 FR 37513). A status review

was continued for this category 2 candidate species (58 FR 51186;

September 30, 1993).

Silene verecunda ssp. verecunda is a perennial herb in the pink

family (Caryophyllaceae) that grows from 10 to 70 centimeters (4 to 28

inches) tall. Each flower has five pink to rose colored notched petals,

and the purplish sepals are united into a tube, making the flower look

bell-shaped.

Silene verecunda ssp. verecunda previously was reported to occupy

open grassy areas in sandy to rocky soils in coastal strand, coastal

prairie, and coastal scrub plant communities ranging from San Francisco

south to Santa Cruz County (Young 1979). Recently, S. verecunda ssp.

verecunda has been reported to occur in chaparral and mixed evergreen

forest plant communities (Skinner and Pavlik 1994; Lion Baumgartner,

Thomas Reid Associates, in litt. 1994). Historical populations from

Lake Merced and Mission Dolores in San Francisco have been extirpated

due to commercial and residential development. Currently there are

about 2,000 known individuals of S. verecunda ssp. verecunda found

primarily on private or non-Federal land, including about 700 plants on

San Bruno Mountain (Lion Baumgartner, in litt. 1994). Three

populations, totaling seven hundred plants according to a 1993 census,

occur on the Presidio in San Francisco. It is not known how much

potential habitat, or numbers of individuals may occur from Montara

Mountain in San Mateo County to Rancho Del Oso in Santa Cruz County.

The northern range of Silene verecunda ssp. verecunda overlaps a

rapidly urbanizing portion of the San Francisco Bay area. Most of the

habitat within the northern part of the range of S. verecunda ssp.

verecunda has been disturbed or eliminated except for areas on San

Bruno Mountain that are protected for the conservation of the

endangered mission blue butterfly (Icaricia icarioides missionensis).

Implementation of the San Bruno Mountain Habitat Conservation Plan

(HCP) developed under sections 10(a)(1)(B) and 10(a)(2)(A) of the Act

has conserved habitat for the butterfly, and indirectly benefits S.

verecunda ssp. verecunda by maintaining the habitat in which both

species occur. On federally owned land on the Presidio in San

Francisco, increased human access and activities potentially threatened

three populations of S. verecunda ssp. verecunda. One of these

populations has been fenced to restrict access, and the other two

populations are expected to be protected by fencing when ownership of

the Presidio is transferred from the Department of Army to the National

Park Service. Invasive non-native vegetation is encroaching on some

populations of S. verecunda ssp. verecunda. On the Presidio, however,

there are ongoing efforts to remove the invasive species. There is no

quantitative trend data to assess the extent to which S. verecunda ssp.

verecunda has or will be impacted by non-native plants. Therefore, such

threat to this species is not known to be immediate or imminent. The

known populations of S. verecunda ssp. verecunda that occur on the

Presidio are unlikely to be affected by toxic waste site studies and

clean-up. This species does not occur near the area where these

activities most likely would occur (Peter Lacivita, U.S. Army Corps of

Engineers, pers. comm. 1993). Neither disease, predation, or

overutilization are known to be a threat to S. verecunda ssp.

verecunda.

Stochastic (random) and natural events can cause population

fluctuations or even population extirpations but are not usually a

concern until the number of individuals or geographic distribution

become vulnerably small. A combination of remnant small populations, a

narrow range, and restricted habitat, could make all or a significant

part of any population susceptible to destruction from stochastic

natural events, such as flood, drought, disease, or other natural

occurrences (Shaffer 1981, Primack 1993) such as genetics and

reproductive success.

No demographic studies exist to indicate that the reproductive

success of Silene verecunda ssp. verecunda is threatened, or is

vulnerable to adverse impacts from random events. There is no evidence

at this time to suggest that reproductive capacity is a factor posing a

threat to the survival of the species. Low seed production in perennial

plants is not necessarily a trait that makes a species vulnerable to

extinction. Huenneke (1986) indicates that low genetic diversity in

plants is rarely seen as a threat to their survival. Intrinsically,

most rare plants are likely to have genetic systems enabling them to

cope with the genetic consequences of rarity.

The population status of S. verecunda ssp. verecunda and its

vulnerability to threats in the central part of its range (i.e.,

Montara Mountain in San Mateo County to Rancho del Oso in Santa Cruz

County) are not known at this time. Moreover, the discovery of S.

verecunda ssp. verecunda in chaparral and mixed evergreen plant

communities is an indication that this taxon may be more widely

distributed and have broader habitat affinities than previously

believed. Chaparral covers an extensive portion of the Coast Ranges in

the San Francisco Bay area. Consequently, the unknown overall status of

the taxon makes any assumptions about vulnerability of S. verecunda

ssp. verecunda to current threats unsupportable at this time.

The Service has reviewed the petition, other available literature

and information, and consulted with biologists and researchers familiar

with Silene verecunda ssp. verecunda. On the basis of the best

scientific and commercial information available regarding S. verecunda

ssp. verecunda, the Service finds that the petitioned action is not

warranted at this time because there is insufficient information about

the taxon's status and its vulnerability to threats. The Service will

continue to maintain S. verecunda ssp. verecunda as a species of

concern. The Service encourages all interested parties to investigate

the population status of S. verecunda ssp. verecunda and its

vulnerability to threats, with particular reference to the southern and

central portions of its range and populations occurring in chaparral

and mixed evergreen plant communities. If additional data becomes

available in the future, the Service may reassess the listing priority

for this species or the need for listing.

Author

The primary author of this document is Kirsten Tarp (see ADDRESSES

section).

Authority

The authority for this action is the Endangered Species Act of

1973, as amended (16 U.S.C. 1531 et seq.)

Dated: July 24, 1995.

John G. Rogers,

Acting Director, Fish and Wildlife Service.

[FR Doc. 95-22172 Filed 9-6-95; 8:45 am]

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