The following Participating Institutions are custodians for this species in the CPC National Collection:
New England Wild Flower Society
The conservation of Adiantum viridimontanum is fully sponsored.
Elizabeth J. Farnsworth contributed to this Plant Profile.
Adiantum viridimontanum is a slender fern that grows up to 75 cm (2.5 feet) tall. This species can be found in Vermont and Quebec in habitats that have exposed rock, some of which is mined for asbestos. These rocky areas (called serpentine habitat) typically support only sparse vegetation comprised of the few species (some rare) that can tolerate the very mineral-rich but shallow soil found here. Recent botanical inventories have turned up 7 populations in Vermont and 14 in Quebec. In Vermont, most populations appear stable and are restricted to relatively isolated sites, one of which is protected. However, this species faces a number of threats to its long-term survival, including mining of the rocky habitat where it occurs, road widening activities in areas where the plant occurs in road cuts, and the negative impacts of invasive species.
Research and Management Summary:
A handful of individuals/organizations are conducting research on this species. Conservation organizations on both sides of the border are beginning to take steps to protect these unique serpentine areas, which harbor many rare and specialized plant species.
The leaves of this fern are slender, 30 - 75 cm (1 - 2.5 ft) long, with shiny, water-resistant surfaces and dark, glabrous petioles (Ruesink 2001). In high light, the leaves are held upright, while in shadier conditions, they spread horizontally, resembling horseshoes. The more triangular, fertile frond extends beyond the leaves and bears sori (reproductive structures) on dark brown, false indusia on its margins during late summer and fall.
Distribution & Occurrence
Adiantum viridimontanum has been described from a variety of habitats where serpentine rock (composed of dunnite or serpentinite) is exposed, including asbestos quarries, road cuts, talus slopes, and cliffs. These outcrops typically support only sparse vegetation comprised of the few species (some rare) that can tolerate the excessively mineral-rich chemistry of the shallow soil that weathers from cracks in the rock (Thomspon and Sorenson 2000).
Like other plant species that occur in these habitats, Adiantum viridimontanum appears to thrive best in direct sunlight, where cover of other plant species is low. In this sense, the fern behaves like a typical disturbance colonizer and may even require disturbances to recruit and establish at new sites (Ruesink 2001).
According to Ruesink (2001), grasses and herbaceous species associated with the fern in Vermont include: harebell (Campanula rotundifolia), field chickweed (Cerastium arvense), hairgrass (Deschampsia flexuosa), rock sandwort (Arenaria stricta), and poverty grass (Danthonia spicata). Common juniper (Juniperus communis var. depressa) dominates the shrub layer, while red spruce (Picea rubra) and gray birch (Betula populifolia) make up a canopy of usually stunted trees.
|21 occurrences of Adiantum viridimontanum are recorded from Vermont and Quebec. Vermont occurrences are estimated to contain a total of approximately 2000 plants.|
Conservation, Ecology & Research
Because populations are widely isolated from each other, gene flow is likely to be small, and genetic diversity of populations may be low. Spore dispersal is thought to be quite local, within a few meters of the parent plant (Ruesink 2001).
Herbivory has not been observed on the fern. This is most likely attributed to the fact that fern leaves often contain high levels of secondary compounds, including tannins and phenolics, which (Ruesink 2001).
Dr. Geoffrey Hall, Botanist with the Quebec office of The Nature Conservancy - Canada, is leading an effort to document and evaluate populations of Adiantum viridimontanum in Quebec in order to prioritize protection and management efforts (Hall 1998).
Spores have been collected from several Vermont populations for spore banking by the New England Plant Conservation Program (New England Wild Flower Society, Framingham, Massachusetts). Plants were successfully grown from some of these spores, but most plants died following transplantation. However, there is at least one nursery in New England that is successfully propagating the plant. Several plants and a small amount of seed (from one population) in cold storage are currently in the New England Wild Flower Society's rare plant collection.
The Vermont Nongame and Natural Heritage Program, as well as volunteer task forces of the New England Plant Conservation program, have monitored several populations of the fern throughout Vermont for several years, but no assessment of population viability or trends has been performed to date.
Only one serpentine site in Quebec is currently protected (Tremblay 1994). According to Ruesink (2001), the Quebec Ministry of the Environment and The Nature Conservancy Canada recently purchased a large serpentine area with a large maidenhair fern population, at Mont Caribou, which will be designated an ecological reserve.
International cooperation between Canadian and U. S. conservation organizations to protect the fern
Regular monitoring for the presence of invasive species that can outcompete the fern
Standardized techniques for quantifying population size
Population viability analysis
Genetic studies to determine homozygosity levels and effects of inbreeding on populations and to assess interactions among members of the Adiantum pedatum complex
Studies of factors limiting sporophyte establishment, including light, moisture, soil chemistry, microclimate, and pathogens
Dann, K.T. 1988. Traces on the Appalachians: A natural history of serpentine in eastern North America. New Brunswick, New Jersey: Rutgers University Press.
Thompson, E.H.; Sorenson, E.R. 2000. Wetland, Woodland, Wildland: A guide to the natural communities of Vermont. Waterbury, Vermont: The Nature Conservancy and the Vermont Department of Fish and Wildlife.