V. Botrychium montanum W. H. Wagner (mountain grape-fern)

Area of Application: Throughout the area covered by the Northwest Forest Plan.

A. Introduction

Botrychium montanum is a tiny, herbaceous, perennial fern in the Ophioglossaceae plant family. Common names used for the species include mountain grape-fern and western goblin.

Botrychium montanum is classified as a Survey and Manage Strategy 1 and 2 species under the FSEIS/ROD (USDA Forest Service and USDI Bureau of Land Management 1994a). B. montanum is on the R6 Regional Forester's Sensitive Species List (USDA Forest Service 1991) and BLM's Bureau Assessment List for Oregon and Bureau Tracking List for Washington. The Washington Natural Heritage Program previously listed this species as Sensitive but it has been demoted to their "Watch" list, which are those taxa more abundant and/or less threatened in Washington than previously thought (Washington Natural Heritage Program 1997). In Oregon, it is on List 2, which means "threatened, endangered, or possibly extirpated from Oregon but more common or stable elsewhere" (Oregon Natural Heritage Program 1998).

B. Unique Characteristics, Biology, and Ecology

Botrychium montanum is a tiny herbaceous, perennial fern. It is most notable for its small size, the rudimentary, irregularly shaped lobes of the sterile leaf blade, and dull color. Adult plants are generally about 4-8 cm (1.6-3.1 inches) tall, but can be as small as 1.5 cm (0.6 in.).

The above-ground or visible parts of this species consist of a single upright stem arising from the ground and terminating in a cluster of tiny ball-like structures, which resemble a bunch of grapes; hence, the common name for the genus of "grape-fern". These globular structures (the sporangia) contain the spores necessary for sexual reproduction. Branching off from the main stem is the sterile, fern-like leaf blade (trophophore), which has a very short petiole. In Botrychium, the portion of the stem below this juncture of the sterile blade with the main stem is referred to as the common stalk, and the portion with the sporangia is called the fertile stalk (sporophore). In Botrychium montanum, the common stalk comprises about 60 (40-90) percent of the total height of the plant. At the base of the common stalk but just below the ground, Botrychium has several layers of leaf primordia, which are the preformed buds of plants that will emerge in future years. The roots are rather fleshy and cylindrical, as is typical of mycorrhizal plants (Potash 1998).

The sterile blade is generally linear, usually about 2-3 cm (1.2 inches) up to about 6 cm (2.4 inches) long by 0.7 cm (0.2 in.) wide, somewhat succulent, and a dull, glaucous, grey-green color. The segments (pinnae or lobes) of the sterile blade are extremely variable in outline but are always small relative to the pinnae of other Botrychium. They range from 1 to 6 pairs that are ascending, mostly widely separated, short rhombic, with entire to coarsely dentate margins. The pinnae have venation like the ribs of a fan and do not have a midrib. The sterile blade only has a few segments, which are often squared-off at the tips. The blade is often malformed or misshapen due to the development of supernumerary sporangia on the margins of segments or on abnormal stalks arising from the blade (Potash 1998).

Botrychium are terrestrial ferns that reproduce by means of microscopic spores (Lellinger 1985). The growth rate is very slow and ordinarily only a single leaf is produced per year - primordia are contained within the bud for several years, and only one primordium matures each season. In some species of Botrychium, asexual reproduction is accomplished via gemmae, which are spherical units that are produced on the underground stem and are capable of developing into sporophytes (Farrar and Johnson-Groh 1990; Camacho 1996). The existence of gemmae in Botrychium montanum has not yet been studied. Several species of Botrychium apparently undergo periods of dormancy, where the plant will not emerge for one to several years and then reemerge in the exact same location (Montgomery 1990, Gehring and Potash 1998). The existence of dormancy in Botrychium montanum has not yet been studied.

There is evidence to suggest that there may be a facultative mycorrhizal association between western redcedar (Thuja plicata) and Botrychium montanum (USDA Forest Service and Bureau of Land Management. 1994b). Underground associations between the fern roots and fungi are apparently fragile but essential, and presumably are established during the gametophyte phase (Zika 1992). It may be the fungal symbiont that is most affected by changes in canopy coverage, summer temperature, and soil moisture (Zika 1992). Gehring and Potash (1994) found that the distribution of Botrychium was independent of the distribution of western redcedar in a monitoring study near Mt. Baker in Washington; however, B. montanum was not one of the 6 Botrychium species present at this study site. Dr. Warren Wagner (Potash 1998) suggests that spore ingestion by animals may be important as a dispersal mechanism and has observed many Botrychium species grazed by deer. On the Mt. Baker-Snoqualmie NF, botanists have observed evidence of grazing by slugs on Botrychium.

C. Specific Habitat Associations

USDA Forest Service and USDI Bureau of Land Management (1994b) note that "of all the grapeferns considered, Botrychium montanum is most closely associated with old growth". In general it occurs in dark coniferous forests, usually near swamps and streams from 1000-3000m (3300-9800 ft.) in elevation (Morin 1993). Within the range of the northern spotted owl, the typical habitat for Botrychium montanum has been characterized as Thuja plicata swamps in the Cascades of Oregon and Washington (Wagner 1992), and is thought to be dependent on Thuja plicata through a mycorrhizal relationship.

In contrast, in the eastern portion of the species' range, Botrychium montanum occurs in mesic, open Picea engelmanii or Abies grandis woods, along grassy trails, and on Columbia River basalts, and spring-fed sunny peat lands dominated by Deschampsia and forbs (Wagner and Wagner 1981; Zika 1992). This portion of the range is outside the analysis area and only included here as a point of information.

Habitat on the Mt. Hood National Forest has been summarized by Zika (1992) as follows: "All populations are found between 1066-1366 m (3500-4500 ft.) elevation, in deep shade under old-growth stands of Thuja plicata. The plants tend to grow among sparse low vascular plants in alluvium covered by dense duff, on narrow or broad floodplains, where the soil is fertile and mesic. Slopes are usually gentle. None of the sites are along large waterways but tend to be near the upper ends of small tributaries and along headwater springs". The dominant or most common species associated with Botrychium montanum on the Mt. Hood National Forest are: Thuja plicata, Anemone deltoidea, and Viola glabella. Both sightings on Okanogan National Forest are by a spring or seep in a draw dominated by Thuja plicata.

On the Mt. Baker-Snoqualmie National Forest, sites ranged from 475-1866 m (1560-6100 ft.) in elevation. The majority (60% ) of sites were in the Western Hemlock Zone under 833 m (2700 ft.) elevation on flat to gentle slopes. The sites are rocky, characterized as having a very shallow soil or dense moss covering bedrock or gravel. The plants grow in duff or moss, with a depauperate understory. The most commonly associated vascular plants are: Thuja plicata, Tsuga heterophylla, Acer circinatum, Polystichum munitum, and Tiarella trifoliata. Notable exceptions are a population on a rocky alpine ridge at 1866 m (6100 ft.), dominated by Epilobium angustifolium, and a population growing under dense herbaceous cover in a shrub thicket dominated by Acer circinatum and Alnus sinuata.

On the Willamette National Forest, Botrychium montanum has been documented in two dissimilar habitat types. One population is in a habitat similar to the northern areas with Thuja plicata (western redcedar) and Tsuga heterophylla (western hemlock) in the overstory, and

Tiarella trifoliata (foamflower), Cornus canadensis (bunchberry), Linnaea borealis (twinflower), and Trillium ovatum (trillium) as understory components. The second population is in a much drier habitat, dominated by Pseudotsuga menziesii (Doulgas-fir) and Calocedrus decurrens (incense cedar). Understory shrubs include Berberis nervosa (dwarf Oregon grape), Chimaphila umbellata (prince's pine), and Whipplea modesta (whipple vine).

The Wenatchee National Forest appears to be a population center for this species within the range of the northern spotted owl, both in terms of the number of different populations, and the fact that some populations have numerous (e.g., several hundred) individuals. The majority of sightings could be characterized as occurring between 666-1000 m (2200-3200 ft.) elevation, on stream terraces or alluvial floodplains, in coniferous forests, with silt or organic muck overlain by coniferous duff. The most common plant association is Tsuga heterophylla/Asarum caudatum (Williams and Smith 1991). Other very large populations are in the Tsuga heterophylla/Oplopanax horridum plant association. A notable exception is a population in a moist subalpine meadow at 1900m (6200 ft.) elevation.

D. Range of Botrychium montanum

1. Known Range

Botrychium montanum is endemic to western North America and considered rare throughout its range. The type specimen was located in Lake County, Montana (Wagner and Wagner 1981). The Flora of North America (Morin 1993) shows it occurring in British Columbia, Washington, Oregon, California, and Montana. Botrychium montanum was also documented in Idaho as of 1993 (Idaho Conservation Data Center 1994).

2. Suspected Range

Sites of Botrychium montanum could be located on federal land in southern Oregon and in the high Cascades of northern California (Jepson 1993).

E. Timing of Surveys

Surveys should be conducted May through September when the above ground sporophyte of Botrychium montanum is likely to be present.

F. Threats

Threats to the species are those actions that would change the canopy coverage, summer temperature, and soil moisture (Zika 1992). Management Recommendations (Potash 1998) identified the major threats to B. montanum as follows:

• Timber harvest may have direct physical impacts from harvest activities, and indirect impacts from significant changes in light regime, hydrology, temperature, and microclimate.
• Changes to hydrologic regime resulting from road construction, culvert placement, etc.
• Habitat degradation of native plant communities resulting from exotic weed invasion.
• Trampling by recreational users.
• Soil compaction would presumably have an adverse effect on the underground primordial buds of this species.
• Botrychium montanum may respond poorly to fire - however the reaction is unknown at the current time.
• Livestock grazing may have several adverse impacts on Botrychium montanum including direct consumption, trampling, soil compaction, and introduction of exotic weeds.
• Burial by surface deposition (resulting from erosion after or during construction, flooding, or other events) could directly impact Botrychium montanum because of the small size of this species.

REFERENCES

Camacho, P. 1996. Gemmae in Pacific Northwest Botrychium. American Fern Journal 86:27.

Farrar, D. R., and C. L. Johnson-Groh. 1990. Subterranean sporophytic gemmae in moonwort ferns, Botrychium subgenus Botrychium. American Journal of Botany 77: 1168-1175.

Gehring, J. and L. Potash. 1994. 1993 Survey of Nooksack Botrychium . Unpublished monitoring results. Mt. Baker-Snoqualmie National Forest, Mountlake Terrace, WA

Gehring, J. and L. Potash. 1996. 1995 Survey of Nooksack Botrychium . Unpublished monitoring results. Mt. Baker-Snoqualmie National Forest, Mountlake Terrace, WA

Hickman, J. (Ed.). 1993. The Jepson manual: Higher plants of California. University of California Press, Berkeley, California.

Idaho Conservation Data Center. 1994. Unpublished database records, Idaho Conservation Data Center, Idaho Dept. of Fish and Game, Boise.

Lellinger, David B. 1985. A field manual of the ferns and fern-allies of the United States and Canada. Smithsonian Institution Press. Washington, D.C.

Montgomery, J. D. 1990. Survivorship and predation changes in five populations of Botrychium dissectum in eastern Pennsylvania. American Fern Journal 80: 173-182.

Morin, N. (Ed.). 1993. Flora of North America North of Mexico. Volume 2, Pteridophytes and Gymnosperms. Oxford University Press, New York.

Oregon Natural Heritage Program. 1998. Rare, Threatened and Endangered Species of Oregon. Oregon Natural Heritage Program, Portland, Oregon. 92 pp.

Potash, L. 1998. Management Recommendations for mountain grape-fern (Botrychium montanum W.H. Wagner). Unpublished manuscript.

USDA Forest Service. 1991. Regional Forester's Sensitive Species List, for Region 6 (Pacific Northwest).

USDA Forest Service and USDI Bureau of Land Management. 1994a. Final supplemental environmental impact statement on managing of habitat for late successional and old-growth species within the range of the northern spotted owl. Portland, Oregon.

USDA Forest Service and USDI Bureau of Land Management. 1994b. Final supplemental environmental impact statement on managing of habitat for late successional and old-growth species within the range of the northern spotted owl. Appendix J2, Results of Additional Species Analysis. Portland, Oregon.

Washington Natural Heritage Program. 1997. Endangered, threatened, and sensitive vascular plants of Washington - with working lists of rare non-vascular species. Department of Natural Resources. Olympia. 62p.

Wagner, David H. 1992. Guide to the species of Botrychium in Oregon. USDA Forest Service report for the Mt. Hood National Forest.

Wagner, W. H. Jr. and F. S. Wagner. 1981. New species of moonworts, Botrychium subg. Botrychium (Ophioglossaceae), from North America. American Fern Journal: Vol. 71:1. p. 20-30.

Williams, C. and B. Smith. 1991. Forested Plant Associations of the Wenatchee National Forest. In Draft. Wenatchee National Forest, Leavenworth, WA

Zika, Peter F. 1992. Draft management guide for rare Botrychium species (moonworts and grapeferns) for the Mt. Hood National Forest. Oregon Natural Heritage Program unpublished report for the USDA Forest Service, Portland.