\ \ J{\' ' t::·t,:. z l V..., _\ \ I Target Plant Species and Potential Plant Conservation Sites In the Wyoming Portion Of the Black Hills Ecoregion Prepared for The Nature Conservancy Midwest Science Division By Walter Fe1iig Wyoming Natural Diversity Database University of Wyoming PO Box 3381 Laramie, WY 82071 2 June 2000 Table of Contents Page --, I Introduction ..................................................... 3 ' ·.-3 Methods ••••••••••••••••••••• • ••••••••••••••••••••••••••••••••• Results/Discussion .... ·. 5 Primary Vascular Plant Targets from the Wyoming Black Hills . 7 Secondary Vascular Plant Targets from the Wyoming Black Hills . 11 Acknowledgements . 20 Literature Cited .................................................·. 20 Tables and Appendices Tables I. Vascular Plant Target Species in the Wyoming Pmiion of the Black Hills Ecoregion . 4 2. Potential Plant Conservation Sites in the Wyoming Portion of the Black Hills Ecoregion . 6 Appendix A. Range maps of Target Vascular Plant Species in the Wyoming Portion Of the Black Hills Ecoregion . 22 B. Element Occurrence Ranks . 40 2 INTRODUCTION The Black Hills ecoregion is located in northeastern Wyoming and northwestern South Dakota and consists of an isolated Laramide-age uplift (the Black Hills and Bear Lodge Mountains) and adjacent hogback rims and foothills. Although small in area, the Black Hills has an unusually rich and diverse flora that contains elements of five of the ten-- - .· major floristic provinces in N01ih America (Marriott 1985). The Black Hills flora has its· strongest affinity with the Cordilleran Forest Province (Rocky Mountains), but also has species in common with the Northern Conifer (boreal forest), Eastern Deciduous Forest, Grassland, and Great Basin provinces (McIntosh 1931 ). The origin of this unique : floristic assemblage has been attributed to large shifts in the distribution of the provinces following changes in climate since the Pleistocene. Many species adapted to cool or wet conditions have been able to persist in shady, mesic draws within the Black Hills, while more dry-adapted species have moved into the area. The rich flora and unusual vegetation patterns of the Hills have in turn contributed to the region's diverse fauna. As a result of its history, the Black Hills contain a large concentration of disjunct plant and animal species which are widespread rangewide, but often uncommon within the Hills themselves. These isolated populations may be genetically distinct and have the potential to evolve into new taxa through allopatric speciation. Several unique species and subspecies have already evolved in the Black Hills fauna (including Cooper's Rocky Mountain snail, White-winged junco, and Black Hills redbelly snake), although similar speciation patterns have yet to be detected among the region's flora. The Nature Conservancy (TNC) has identified the Black Hills as an important conservation area and TNC's Midwest Science Division is currently developing a comprehensive, region-wide conservation blueprint for the region. TNC has contracted with the Wyoming Natural Diversity Database (WYNDD) and South Dakota Natural Heritage Program to identify target plant and animal species and natural plant community types in need of conservation attention and determine potential conservation goals for these targets. This report summarizes the goals for selected vascular plant species and describes potential plant conservation sites in the Wyoming portion of the Black Hills ecoreg10n. METHODS Target vascular plant species for the ecoregion were chosen based on their limited or isolated geographic ranges, high habitat specificity, or strong evidence of decline in the Black Hills (Fertig and Beauvais 1999; South Dakota Department of Game, Fish, and Parks 1998). All Sensitive species on Black Hills National Forest were also selected (Marriott et al. 1990; USDA Black Hills National Forest 1996). The final targets list was prioritized by degree of threat and overall rarity into a primary and secondary list (Table 1). For each target species, information was assembled on distribution, abundance, and protection status from heritage databases, consultation with regional experts, recent rare species surveys, and the literature (USDA Black Hills National Forest 1996; Fe1iig 1993; i I 3 r '1 Table 1. Vascular Plant Target Species / In the Wyoming Portion of the Black Hills Ecoregion Primary Targets* Global State Rank Species Rank Range WY SD· Botrychium campestre 3 Peripheral 1 u Carex alopecoidea 5 Disjunct 1 2 Equisetum scirpoides 5 Disjunct 1 2 Lycopodium complanatum 5 Disjunct 1 1 Platanthera orbiculata 57 Disjunct 1 1 *Other primary vascular plant targets m the ecoreg1on (Ad,antum cap1llus-venens, Carex tnbu/o1des, Corallorrhiza odontorhiza, Drypoteris carthusiana, Epipactis gigantea, Salix serissima, and Viola selkirkii) do not occur in the Wyoming portion of the Black Hills) ' Secondary Targets** Global State Rank Species Rank Range WY SD Adenocaulon bicolor 57 Disjunct 1 2 r Adoxa moschatellina 5 Sparse 1 u : Carex rosea 5 Disjunct 1 Not tracked Cryptantha cana 5 Reg. End. 3 (not tracked) 2 Cypripedium calceolus var. 5 Disjunct 1-2 u pubescens r Equisetum sylvaticum 5 Disjunct 1 Not tracked ) Lycopodium annotinum 5 Sparse 2 (not tracked) 1 Lycopodium dendroideum 5 Disjunct 1 2 Muhlenbergia glomerata 5 Sparse 1 Not tracked Polystichum lonchitis 5 Sparse 2 1 Scirpus atrocinctus 5 Disjunct 1 Not tracked Selaginella rupestris 5 Disjunct 1 Not tracked Vaccinium membranaceum 5 Sparse 2 (not tracked) 2 ** Other secondary vascular plant targets m the ecoreg10n (Asplenium tnchomanes, Asplenium trichomanes-ramosum, Carex be/la, Carex lepta/ea, Carex pedzmculata, Cryptogramma acrostichoides, Eleocharis rostellata, Equisetum variegatum, Eustoma russellianum, Listera convallarioides, Pedicularis procera, Petasites sagittatus, Pinusflexilis,Salix candida, Salix lucida, and Sanguinaria canadensis) do not occur in the Wyoming portion of the Black Hills. Codes: Global Rank: A measure of the relative rangewide abundance ofa full species, variety or subspecies on a scale of 1 (rarest) to 5 (very common). "?" indicates uncertainty in the numerical score. "Q" indicates a question about the validity of a taxon. Range: the geographic distribution pattern of each \ I• taxon. Reg End= regional endemics (found in a limited geographic area, usually 200-500 square miles, in 1 or more states), Disjunct= species that are widely isolated from the main contiguous portion of their range. Sparse = species which are always found in small patches of specialized habitat and sporadically distributed over a large geographic area. Peripheral= species at the edge of their contiguous distribution. State Rank: based on the same 1-5 scale as Global ranks, but are applied to a species' abundance within a single state. "U" indicates a species is present in the state, but its status is not known. 4 r Fertig et al. 1994; Marriott 1985, 1989a, 1989b, 1991, 1993; Ode and Marriott 1990). These data were used to develop conservation goals for each target element that address the minimum number and distribution of populations needed to ensure long-term survival. Point location data were also used to identify important biological areas that could be considered part of a "portfolio" of potential conservation sites (The Nature Conservancy 1997) (Table 2). Location maps for each species are in Appendix A. RESULTS/DISCUSSION Thirteen vascular plant species have been selected as primary targets for conservation: attention in the ecoregion, of which six are presently known from the Wyoming portion of the Black Hills. An additional 29 taxa are recognized as secondary targets, 13 of which occur in the Wyoming segment (Table 1). Only one of these targets (Botrychium campestre) is found exclusively in the Wyoming part of the ecoregion. The development of finite conservation goals for rare plant taxa is hampered by the lack of detailed knowledge about their life history, demographic structure, genetic composition, and metapopulation dynamics (Given 1994, Primack 1993). In addition, the ability of many plants to produce long-lived seed banks and reproduce asexually confounds our abilities to determine the minimum population size needed for long-term survival (Menges 1991 ). While a universal "magic number" for the minimum viable population size of plants is probably unattainable (Givens 1994), theoreticians have suggested that minimum population sizes of 500 individuals may be sufficient for large­ bodied, long-lived perennial plants of stable environments, while a minimum of 10,000 individuals might be needed for the survival of annual plants in unstable environments (Primack 1996). The number of individuals in a single population may be less important than the total number and spatial extent of all populations for ensuring the long term survival of a plant species (Given 1994 ). A conservation strategy that protects a suite of populations scattered across the full range of a species is likely to capture greater genetic variability than single populations and reduces the risk of a species being extirpated due to localized, stochastic environmental disturbances. The number of sites needed to ensure adequate representation will vary depending on a species' life history, growth form, population size, pollination biology, and genetic variability (Given 1994, Primack 1993). In the absence of concrete demographic and genetic data for most target species in the Black Hills ecoregion, the planning team for the