Endangered and Threatened Wildlife and Plants; 12-Month Finding for a Petition To List the Plant Botrychium lineare

AGENCY:

Fish and Wildlife Service, Interior.

ACTION:

Notice of 12-month petition finding.

SUMMARY:

We, the U.S. Fish and Wildlife Service (Service), announce a 12-month finding for a petition to list Botrychium lineare (slender moonwort) as threatened under the Endangered Species Act of 1973, as amended (Act). After reviewing all available scientific and commercial information, we have determined that listing this species is warranted but precluded by other higher priority actions.

This decision is based on the number, variety, and significance of threats affecting the species. Botrychium lineare is currently known from a total of nine populations in Colorado, Montana, Oregon, and Washington. Various populations of this taxon are threatened by a variety of factors including: habitat destruction and fragmentation from road construction and maintenance, including herbicide spraying, recreational activities, grazing and trampling by wildlife and livestock, development, timber harvest, and competition from non-native plant species. Upon publication of this notice of 12-month petition finding, Botrychium lineare will be added to our candidate species list.

DATES:

The finding announced in this document was made on March 9, 2001. Comments and information may be submitted until further notice.

ADDRESSES:

You may submit data, information, comments, or questions concerning this finding to the Supervisor, U.S. Fish and Wildlife Service, Snake River Basin Office, 1387 S. Vinnell Way, Room 368, Boise, Idaho 83709. You may inspect the petition finding, supporting data, and comments by appointment during normal business hours at the Snake River Basin Office.

FOR FURTHER INFORMATION CONTACT:

Robert Ruesink, Supervisor (see ADDRESSES section) (telephone 208/378-5243; facsimile 208/378-5262).

SUPPLEMENTARY INFORMATION:

Background

Section 4(b)(3)(A) of the Endangered Species Act of 1973, as amended (Act) (16 U.S.C. 1531 et seq.), requires that, for any petition to revise the List of Threatened and Endangered Species containing substantial scientific and commercial information that listing may be warranted, we make a finding within 12 months of the date of the receipt of the petition on whether the petitioned actions is—(i) not warranted, (ii) warranted, or (iii) warranted but precluded from immediate proposal by other higher priority efforts to revise the List of Threatened and Endangered Species. Section 4(b)(3)(C) requires that petitions for which requested action is found to be warranted but precluded should be treated as though resubmitted on the date of such finding, i.e., requiring a subsequent finding to be made within 12 months. Such 12-month findings are to be published promptly in the Federal Register.

On July 28, 1999, we received a petition dated July 26, 1999, from the Biodiversity Legal Foundation. The petitioner requested us to list Botrychium lineare as endangered or threatened and to designate critical habitat within a reasonable period of time following the listing. The petitioner submitted biological, distributional, historical, and other information and scientific references in support of the petition.

On May 10, 2000 (65 FR 30048), we published a 90-day petition finding concluding that the petition presented substantial information indicating that the requested action may be warranted. Accordingly, we initiated a status review pursuant to section 4(b)(3)(B) on the petitioned action.

We have reviewed the petition, and based on the best scientific and commercial information available, we believe that sufficient information is currently available to support a finding that listing Botrychium lineare as threatened is warranted, but that a proposed rule at this time is precluded by work on other higher priority listing actions.

Section 4(b) of the Act states that we may make warranted but precluded findings only if we find that (1) an immediate proposed rule is precluded by other pending actions, and (2) expeditious progress is being made on other listing actions. Due to the large amount of litigation we face, primarily over critical habitat, we are working on numerous listing actions mandated by court orders and settlement agreements. Complying with these orders and settlement agreements will consume nearly all or all of our listing budget for FY 2001. Any funding we may have available for discretionary listing actions will likely be allocated for emergency listings only. However, we can continue to place species on the candidate species list (Jamie Clark, Service, in litt. 2000).

Biology and Ecology

A member of the adder's-tongue family (Ophioglossaceae), Botrychium lineare is a small perennial fern with a pale green leaf (trophophore) from 6 to 18 centimeters (2 to 7 inches) long. Leaf segments are typically linear and divided or forked at the ends. The sporophore (spore-bearing structure) is 1 to 2 times the length of the trophophore with a single main axis. Both the sporophore and the trophophore arise from an erect subterranean stem. Spores mature primarily in late June and July. Similar to other Botrychium species, the tiny, lightweight spores may be disseminated by wind, water, or possibly by animal vectors (Zika et al. 1995).

Surveys and field identification of moonworts are complicated by their biology. The plants are small, difficult to find, and are usually scarce. They cannot be positively identified in their immature states. Fronds may appear above ground during some growing seasons, or may not appear at all during unfavorable seasons (Vanderhorst 1997). Botrychium lineare was initially described in 1994 and is considered to be one of the more distinctive of the moonworts (Wagner and Wagner 1994). The nearest relative of B. lineare is thought to be B. campestre, a widespread species that is typically found at lower elevations (Wagner and Wagner 1994). Recent genetic studies have shown that although B. lineare is closely related to B. campestre, it is a distinct taxon (Farrar 2000). The B. lineare populations in Colorado, Oregon, Montana, and Washington are all genetically distinct from one another, which suggests a long period of isolation that is consistent with truly rare species (Donald Farrar, Iowa State University, in litt. 2000).

In the United States, Botrychium lineare is currently known from a total of nine populations: three in Colorado (El Paso and Lake counties), two in Oregon (Wallowa County), three in Montana (Glacier County), and one in Washington (Ferry County). In addition to the nine currently known B. lineare populations, there are four historic B. lineare population sites in the United States and two in Canada. Populations previously known from Idaho (Boundary County), Montana (Lake County), California (Fresno County), Colorado (Boulder County), and Canada (Quebec and New Brunswick), have not been seen for at least 20 years and may be extirpated (Wagner and Wagner 1994). The 90-day petition finding for this species (65 FR 30048) mentions a population previously known from Inyo County, California. However, we believe that the information regarding the location of this population (as published in Wagner and Wagner 1994) is incorrect, and that this site is probably in Fresno, not Inyo, County (Tim Thomas, Service, pers. comm. 1999).

The total number of individuals for all 9 occupied sites is about 190 (Edna Rey-Vizgirdas, Service, in litt. 2000). However, this number should be viewed as an estimate since Botrychium species do not always come up every year and exist below ground for most of their life cycle. Populations range in size from 2 to 100 individuals (E. Rey-Vizgirdas, in litt. 2000). Only 3 populations contain more than 15 individuals. Of the three largest populations, two are found in Montana (Glacier National Park and Blackfeet Indian Reservation) and one occurs in Colorado (Pikes-San Isabel National Forest). Of the remaining six B. lineare populations, four occur on Federal land, including the Pike-San Isabel National Forest (Colorado), Glacier National Park (Montana), Wallowa-Whitman National Forest (Oregon), and Colville National Forest (Washington). One population occurs on private land in Lostine Canyon, Oregon, which is a private inholding within the Wallowa-Whitman National Forest. The B. lineare site in Lake County, Colorado, is currently only known from a herbarium specimen consisting of two B. lineare plants collected in 1992 at approximately 3,243 meters (m) (10,640 feet (ft)) near Leadville, Colorado. This specimen was previously misidentified as B. minganense (Toby Spribille, Kootenai National Forest, in litt. 2000). No B. lineare plants were found at this site when it was surveyed in August 2000 (T. Spribille, in litt. 2000).

All Botrychium species are believed to be obligately dependent on mycorrhizal fungi (the symbiotic association of a fungus with the roots of a vascular plant) throughout their life cycle. A fungal associate is present within the plant at the earliest stages of development, and there are no reports of successful completion of the Botrychium's life cycle without mycorrhizal fungi. Very little information exists regarding the specificity or habitat requirements of the mycorrhizal fungi that are associated with moonworts (Vanderhorst 1997). Similar to orchids, Botrychium species can remain dormant for 1 or more years, and cannot be identified with certainty in their immature stages. The ecology of moonworts and their vulnerability to management activities such as prescribed fire are not well understood (Zika et al. 1995; Vanderhorst 1997).

The habitat for Botrychium lineare has been described as “deep grass and forbs of meadows, under trees in woods, and on shelves on limestone cliffs, mainly at higher elevations' (Wagner and Wagner 1994), but they also state that to describe a typical habitat for this species would be problematic since the known sites are so different. A specific habitat description for the species is difficult because of its current and historically disjunct distribution ranging from sea level in Quebec to nearly 3,000 m (9,840 ft) in Boulder County, Colorado. Botrychium spores are small and lightweight enough to be carried by air currents. This dispersal mechanism may explain the broad and often disjunct distribution patterns exhibited by moonworts (Vanderhorst 1997).

This species is found in a variety of montane forest or meadow habitats. Three of the known Montana Botrychium lineare populations occur on roadsides in early seral habitat (i.e., open habitat dominated by low-growing forbs (herbs) rather than shrubs or trees) (T. Spribille, in litt. 2000). Other B. lineare sites occur in grass-to forb-dominated openings in forests characterized by cone-bearing trees such as pine, spruce, and fir species (Paula Brooks, Wallowa-Whitman National Forest, in litt. 2000). At these occupied sites, B. lineare occurs with numerous associated species including Fragaria virginiana (strawberry), Antennaria spp. (pussy-toes), Galium boreale (northern bedstraw), Potentilla spp. (cinquefoil), Symphoricarpos albus (snowberry), Vaccinium spp. (huckleberry), Calamagrostis spp. (reedgrass), Festuca spp. (fescue), Picea engelmannii (Engelmann spruce), Thuja plicata (western red cedar), Pseudotsuga menziesii (Douglas-fir), Pinus ponderosa (ponderosa pine), Pinus contorta (lodgepole pine), and Populus tremuloides (aspen) (Steve Tapia, Pike-San Isabel National Forest, in litt. 2000; Kathleen Ahlenslager, Colville National Forest, in litt. 2000; E. Rey-Vizgirdas, pers. obs., 2000). Other Botrychium species, including B. ascendens (upward-lobed moonwort), B. crenulatum (wavy moonwort), B. minganense (Mingan Island moonwort), B. lunaria (common moonwort), and B. montanum (mountain moonwort), may also occur within or near habitat occupied by B. lineare. It is common for several Botrychium species to occur together in what has been called “genus communities” by researchers, a sympatric pattern of distribution which is unexplained (Vanderhorst 1997).

Summary of Factors Affecting the Species

Section 4 of the Act and regulations (50 CFR part 424) promulgated to implement the listing provisions of the Act set forth the procedures for adding species to the Federal lists. A species may be determined to be an endangered or threatened species due to one or more of the five factors described in section 4(a)(1). These factors and their application to Botrychium lineare are as follows:

A. The present or threatened destruction, modification, or curtailment of its habitat or range. Botrychium lineare is threatened by impacts associated with recreational activities. For example, since the Hurricane Creek B. lineare site (Wallowa-Whitman National Forest) is adjacent to a popular hiking and pack trail, it may be affected by recreational impacts such as trampling or campfires. This site has been used for camping since it is relatively flat and close to the trailhead, and campfire rings were observed in the area (P. Brooks, pers. comm. 2000). The Hurricane Creek B. lineare population may also be threatened by livestock trampling (i.e., by pack animals), erosion, and exotic weeds (Oregon Natural Heritage Program 1999). The Lostine Canyon site, which occurs on a private inholding within the Wallowa-Whitman National Forest, is potentially threatened by development, timber harvest, and recreational activities (P. Brooks, pers. comm. 2000).

Two Botrychium lineare sites, one in Glacier National Park and one on the Blackfeet Indian Reservation in Montana, are located on roadsides where they may be affected by road maintenance activities, herbicide spraying, mowing, or by vehicles that pull off the road to look at wildlife (T. Spribille, in litt. 2000; Tara Williams, Glacier National Park, in litt. 2000). Although such activities are ongoing and have likely affected these sites in the past, the degree of disturbance and the timing of these activities may affect the survival and reproduction of this species. For example, road maintenance activities that occur prior to spore maturation and dispersal could adversely affect the reproduction of B. lineare. Herbicide spraying recently conducted along the road where B. lineare occurs on the Blackfeet Indian Reservation killed much of the roadside vegetation (Mary Weatherwax, Blackfeet Environmental Office, pers. comm. 2000). This site is the largest known B. lineare population and contains 100 plants (T. Spribille, in litt. 2000). The effects of this spraying on B. lineare are currently unknown. Future surveys should provide more information on the status of this population. The residual effect of herbicide spraying on B. lineare is unknown. Some herbicides are known to be resident in the soil for long periods of time, affecting the plants that persist there (65 FR 7339).

The Botrychium lineare site in Lake County, Colorado (near Leadville) is apparently located within a Superfund site (T. Spribille, in litt. 2000). This site is currently threatened by activities and associated disturbance related to the construction of a concrete conduit. An asphalt bike path through the upper portion of the site was completed in July 2000, and major construction and excavation to install the concrete conduit was observed in August 2000. Although other Botrychium species, including B. lunaria and B. minganense, were found at this site, no B. lineare plants were observed despite intensive surveys conducted in August 2000 (T. Spribille, in litt. 2000).

Of the two Botrychium lineare populations on the Pike-San Isabel National Forest (Colorado), the larger population (based on number of individuals) occurs in a meadow with a utility pole (power line) approximately 30 m (100 ft) from the Pikes Peak toll road. Maintenance of this power line could potentially threaten the B. lineare population, but such maintenance would have to be coordinated with Forest staff (S. Tapia, in litt. 2000). Although the toll road itself is heavily used, the B. lineare site is located along the lower half of the road and receives little recreational use (S. Tapia, pers. comm. 1999).

Habitat succession and fire suppression may threaten Botrychium lineare. However, the relationship of habitat succession and fire suppression to the persistence of B. lineare is unclear. For example, in a biological assessment for sensitive plants in the Lostine River canyon, a U.S. Forest Service (Forest Service) botanist notes that “Botrychium species seem to be found in areas that receive natural disturbances such as fire and landslides but we are not yet able to predict what disturbance interval or successional stage best suits them” (Hustafa 1999). Controlled (prescribed) fires or wildfires could also affect habitat for B. lineare, but the response of this species to fire is not currently known. In some cases, wildfires or controlled fires create high ground temperatures which may sterilize the soil and eliminate fungal species that are necessary for the survival of moonworts (Zika 1992). We are not aware of any plans to implement controlled burning programs in B. lineare habitat at this time.

B. Overutilization for commercial, recreational, scientific, or educational purposes. The plant is not a source for human food, nor is it currently of commercial horticulture interest. Therefore, overutilization is not considered to be a threat to this species at the present time.

C. Disease or predation. While disease is not currently known to be a threat to Botrychium lineare, populations may be affected by grazing by livestock or wildlife. The specific effects of grazing on the species are unknown, although if grazing by livestock or wildlife species occurs prior to the maturation and release of spores, the capacity for sexual reproduction of affected plants may be compromised. For example, the proximity of both B. lineare populations in Oregon to trails and developed recreation sites could result in grazing by horses or other domestic animals. One B. lineare site (on the Colville National Forest) occurs within a grazing allotment but is fenced to exclude livestock (K. Ahlenslager, in litt. 2000). Although open range grazing is common on the Blackfeet Indian Reservation, the B. lineare population on the Reservation appeared to be ungrazed when it was discovered in July 2000 by a Forest Service botanist (T. Spribille, in litt. 2000). Botrychium lineare has not been observed in areas with obvious disturbance by livestock (K. Ahlenslager, in litt. 2000; T. Spribille, in litt. 2000).

D. The inadequacy of existing regulatory mechanisms. Botrychium lineare is considered a sensitive species in Regions 2, 5, and 6 of the Forest Service, which include extant and historical B. lineare sites found in Colorado, Oregon, Washington, and California (Forest Service 1999, 2000; Joanna Clines, Sierra National Forest, in litt. 2000). The Forest Service has regulations that address the need to protect these sensitive species, as well as candidate, and federally listed species (e.g., the National Forest Management Act). Forest Service Regions 1 and 4, which include extant and historical sites found in Montana and Idaho, do not have B. lineare on their regional sensitive species lists (Teresa Prendusi, Forest Service, in litt. 2000; Steve Shelly, Forest Service, in litt. 2000); the species in these regions, therefore, is not given any special consideration. However, the Forest Service does prohibit the collection of any native plants without a permit on Forest Service lands. Botrychium lineare is not on Canada's list of threatened or vulnerable species, so there is no special protection for this species in Canada (Canadian Wildlife Service 2000).

Monitoring of some (but not all) Botrychium lineare populations on Federal lands has been initiated. Monitoring helps to identify threats and management actions that may be necessary to control habitat degradation and protect the species. Only one site, which occurs on the Colville National Forest, has been fenced to protect the species from livestock grazing. However, some of the B. lineare sites on Federal lands are threatened by exotic weeds, herbicide spraying, trampling, and road construction and maintenance (see Factors A and E for additional information).

The National Park Service (Park Service) has policies to promote the conservation of federally listed or candidate species and other rare or sensitive species within park boundaries (T. Williams, in litt. 2000). However, as discussed previously, the two Botrychium lineare sites in Glacier National Park are located on roadsides where they may be subject to road maintenance activities or potential damage from vehicles. Therefore, long-term protection of these sites may be difficult due to their location (i.e., adjacent to roads, which are potentially a source of recurring disturbance).

Although Botrychium lineare is considered to be rare and imperiled by the State natural heritage programs in Colorado, Montana, Oregon, and Washington, the State heritage program rankings are not legal designations and do not confer State regulatory protection to this species.

E. Other natural or manmade factors affecting its continued existence. Non-native plant species may threaten habitat occupied by Botrychium lineare. Exotic species have been observed in the vicinity of B. lineare populations in Colorado (S. Tapia, in litt. 2000), Montana (T. Spribille, in litt. 2000), Oregon (Oregon Natural Heritage Program 1999), and Washington (K. Ahlenslager, in litt. 2000). Non-native plant species can compete with native plant species for resources such as space, nutrients, and water, and can replace them. As a result, the effects of non-native species may be especially serious for native taxa that have extremely small population sizes, such as B. lineare.

The amount of habitat occupied by Botrychium lineare is extremely small. Total habitat size for all extant sites, except for the Leadville and one Pikes Peak, Colorado, site, is approximately 1.15 hectares (ha) (2.85 acres (ac)), and nearly all of the sites are smaller than 465 square meters (5000 square feet). The B. lineare plants at the smaller Pikes Peak site have not been located in the last few years, and only two plants were previously known, so the actual amount of occupied habitat is likely to be extremely small. No B. lineare plants were found at the Leadville site in 2000, so it is not possible to estimate the amount of occupied habitat. Of the two B. lineare sites in Oregon, the Lostine Canyon site occupies an area of approximately 10 × 10 m (30 × 30 ft) (Wagner and Wagner 1994), and the Hurricane Creek site is found in an area up to 1 ha (2.5 ac) in size (Oregon Natural Heritage Program 1999). The site in Washington (on the Colville National Forest) occupies an area of approximately 15 × 30 m (50 × 100 ft) (K. Ahlenslager, in litt. 2000). The larger of the two B. lineare populations on the Pike-San Isabel National Forest occupies an area of approximately 35 × 10 m (115 × 30 ft) (Carpenter 1996a, 1996b; Colorado Natural Heritage Program 1999). Botrychium lineare populations range in size from 2 to 100 plants, with only 3 populations supporting more than 15 individuals.

The small size of existing Botrychium lineare populations makes this species vulnerable to extirpation due to random naturally occurring events. A single random event could extirpate a substantial portion or all of the individuals at a given site. Also, changes in gene frequencies within small, isolated populations can lead to a loss of genetic variability and a reduced likelihood of long-term viability (Franklin 1980; Soulé 1980; Lande and Barrowclough 1987).

We have carefully assessed the best scientific and commercial information available regarding the past, present, and future threats faced by the species. Only nine populations of Botrychium lineare are known to exist, and the small amount of occupied habitat and few individuals, combined with ongoing threats, make this species vulnerable to extinction. All of the remaining sites that support B. lineare are small and fragmented, and the various sites are vulnerable to impacts from factors including herbicide use, recreational activities, competition from non-native vegetation, road construction and maintenance, development, timber harvest, and incidental loss from trampling or grazing by wildlife or livestock. Also, all of these populations are particularly susceptible to extinction from random events because of their extremely small size. Existing regulatory mechanisms are inadequate to protect this taxon.

We conclude that the overall magnitude of threats to Botrychium lineare throughout its range is moderate and the overall immediacy of these threats is non-imminent. Botrychium lineare is considered a species without subspecies classification. Pursuant to our Listing Priority Guidance (48 FR 43098), a species for which threats are moderate and non-imminent is assigned a Listing Priority Number of 11. While we conclude that listing of Botrychium lineare is warranted, an immediate proposal to list is precluded by other higher priority listing actions. During fiscal year 2001, we must spend nearly all of our Listing Program funding to comply with court orders and judicially approved settlement agreements, which are now our highest priority actions. Botrychium lineare will be added to the list of candidate species upon publication of this notice of 12-month finding. We will continue to monitor the status of the slender moonwort and other candidate species. Should an emergency situation develop with one or more of these species, we will act to provide immediate protection, if warranted.

References Cited

A complete list of all references cited herein, as well as others, is available upon request from the Snake River Basin Office (see ADDRESSES section).

Author(s)

The primary authors of this document are Edna Rey-Vizgirdas, U.S. Fish and Wildlife Service, Snake River Basin Office (see ADDRESSES section), and Barbara Behan, U.S. Fish and Wildlife Service, Regional Office, 911 N.E. 11th Avenue, Portland, Oregon 97232.

Authority

The authority for this action is the Endangered Species Act of 1973, as amended (16 U.S.C. 1531 et seq.).