Eriogonum visheri A. Nelson (Visher’s buckwheat): A Technical Conservation Assessment Prepared for the USDA Forest Service, Rocky Mountain Region, Species Conservation Project December 18, 2006 Juanita A. R. Ladyman, Ph.D. JnJ Associates LLC 6760 S. Kit Carson Cir E. Centennial, CO 80122 Peer Review Administered by Center for Plant Conservation Ladyman, J.A.R. (2006, December 18). Eriogonum visheri A. Nelson (Visher’s buckwheat): a technical conservation assessment. [Online]. USDA Forest Service, Rocky Mountain Region. Available: http://www.fs.fed.us/r2/ projects/scp/assessments/eriogonumvisheri.pdf [date of access]. ACKNOWLEDGMENTS The time spent and help given by all the people and institutions listed in the reference section are gratefully acknowledged. I would also like to thank the North Dakota Parks and Recreation Department, in particular Christine Dirk, and the South Dakota Natural Heritage Program, in particular David Ode, for their generosity in making their records, reports, and photographs available. I thank the Montana Natural Heritage Program, particularly Martin Miller, Mark Gabel of the Black Hills University Herbarium, Robert Tatina of the Dakota Wesleyan University, Christine Niezgoda of the Field Museum of Natural History, Carrie Kiel Academy of Natural Sciences, Dave Dyer of the University of Montana Herbarium, Caleb Morse of the R.L. McGregor Herbarium, Robert Kaul of the C. E. Bessey Herbarium, John La Duke of the University of North Dakota Herbarium, Joe Washington of the Dakota National Grasslands, and Doug Sargent of the Buffalo Gap National Grasslands - Region 2, for the information they provided. I also appreciate the access to files and assistance given to me by Andrew Kratz, Region 2 USDA Forest Service, and Chuck Davis, U.S. Fish and Wildlife Service in Denver. The information provided by Prof. James Reveal was very valuable, and I appreciate the time he spent answering my questions. In addition, I would like to thank Deb Golanty at the Helen Fowler Library, Denver Botanic Gardens, for her persistence in retrieving some rather obscure articles. I also would like to acknowledge the generosity of D.L. Gustafson and Martin Wefald, of Montana State University, for making their Graphical Locator available on the Internet. I appreciate the reviews of Kathy Carsey, Prof. Richard Spellenberg, and an anonymous reviewer and thank them for their time and consideration of the assessment. AUTHOR’S BIOGRAPHY Juanita A. R. Ladyman received her B.Sc. degree (with First-class honors) in Biochemistry from London University, England. Her first professional position was as plant pathology laboratory technician and, later, as Greenhouse research supervisor with the Arid Lands Research Center on Sadiyat Island in the United Arab Emirates. She obtained her Ph.D. degree in Botany and Plant Pathology from Michigan State University where she was also a research assistant with the D.O.E. Plant Research Laboratory. She worked as a plant physiological ecologist and plant scientist for Shell Development Company conducting research on the physiology, ecology, and reproductive biology of economically important plant species and their wild relatives. She then worked for a plant biotechnology company in their Genetic Transformation and Plant Tissue Culture Division. For the last 15 years she has worked in the area of conservation, particularly on rare, endemic, and sensitive plant species in the southwest United States. For three years of that time, she was the botanist with the New Mexico Natural Heritage Program. She has conducted research and monitoring programs on both non-vascular and vascular species. She currently is a partner in JnJ Associates LLC, an environmental consulting company in Colorado. COVER PHOTO CREDIT Eriogonum visheri (Visher’s buckwheat). Cover photograph courtesy of David Ode, South Dakota Game, Fish, and Parks Department, used with permission. LIST OF ERRATA 2 3 SUMMARY OF KEY COMPONENTS FOR CONSERVATION OF ERIOGONUM VISHERI Status Eriogonum visheri (Visher’s buckwheat) is a small, inconspicuous summer annual plant endemic to the badlands of North Dakota, South Dakota, and Montana. The Northern Region (Region 1) and the Rocky Mountain Region (Region 2) of the USDA Forest Service (USFS) have designated E. visheri a sensitive species. The taxon is also on the watch list of the Bureau of Land Management in Montana. Eriogonum visheri was designated a Category 2 candidate for listing as endangered or threatened under the federal Endangered Species Act (16 U.S.C. 1531 et seq.). It lost that status in 1996 when the U.S. Fish and Wildlife Service (USFWS) eliminated the Category 2 designation, but it still remains a species of management concern for the USFWS. NatureServe assigns E. visheri the global rank of vulnerable (G3). The species is designated critically imperiled (S1) by the Montana Natural Heritage Program, between imperiled and vulnerable (S2S3) by the North Dakota Natural Heritage Inventory, and vulnerable (S3) by the South Dakota Natural Heritage Program. These state and global ranks indicate the rarity and vulnerability of a taxon, but they have no regulatory weight. Primary Threats Eriogonum visheri is vulnerable to habitat loss and degradation because it is restricted to a limited suite of edaphic conditions derived from geological formations within a limited geographic range. Much of the range of E. visheri is within the Williston Basin of western North Dakota, eastern Montana, and northwestern South Dakota. This basin is rich in extractable minerals and oil and gas, and so it has been and continues to be affected by activities associated with resource extraction. While future levels of resource extraction activity are likely to be substantial in many parts of the taxon’s range, they are not likely to impact E. visheri occurrences in the Buffalo Gap National Grassland of Region 2 because of a dearth of oil, natural gas, or locatable minerals there. All activities that lead to significant soil disturbance (e.g., mechanized vehicle traffic, livestock grazing) are likely to present a significant threat to the long-term persistence ofEriogonum visheri occurrences. While disturbance may open areas to initial colonization by E. visheri, it also increases the probability of colonization by invasive non-native plants. Eriogonum visheri evolved in habitats where interspecies competitive pressures are very low, and evidence suggests that infestations of aggressive plant species are a significant threat to sustainable populations of this species over the long term. Disturbance can also reduce or eliminate the seed bank, which appears to be the primary long-term survival strategy of the species. Eriogonum visheri is likely to be palatable to non-selective herbivores, such as livestock, some species of wildlife, and arthropods, but the potential magnitude of the effect of browsing is not known. Primary Conservation Elements, Management Implications, and Considerations Eriogonum visheri is an annual, edaphic endemic restricted to the badlands of western South Dakota, southwestern North Dakota, and eastern Montana. Over the last century, approximately 119 occurrences have been reported, and 22 of these are on Region 2 National Forest System land. Eriogonum visheri occurrence sizes are highly variable both spatially and temporally. Because occurrences undergo local extirpations and other areas may experience only temporary colonization, it is difficult to evaluate trends in abundance and occurrence extent without systematic monitoring. Estimating changes in range and abundance that might have occurred prior to 1980 is not possible because of a lack of information. The seed bank appears to be very important in maintaining populations of Eriogonum visheri over the long term. However, this facet of its life history and biology makes E. visheri vulnerable to disturbance. Occupied habitat is very difficult to determine for a species where a large proportion of its population may reside in the seed bank. Biological evaluations that concentrate on areas occupied by aboveground plant stems may miss areas occupied by dormant seeds. This situation is not unique to E. visheri and poses a problem in achieving adequate habitat conservation for any plant species with similar life history characteristics. 2 3 Relatively little is known about this taxon’s biology or ecological requirements. Its precise habitat requirements, the role of disturbance in its life history, and seed dispersal mechanisms of Eriogonum visheri are not known. Colonies are widely distributed and typically occupy less than 1 percent of the ostensibly suitable (“potential”) habitat that is surveyed. The role of disturbance in the species’ life history is unknown. Eriogonum visheri is adapted to soils that crack and swell and experience erosion from precipitation and wind. Apparently the seeds are primarily dispersed by surface run-off; plants tend to grow in microdrainages and places where water would accumulate, even if only fleetingly, during a storm. Maintaining Eriogonum visheri as a USFS sensitive species in Region 2 ensures that it is considered during management planning. Sensitive species status encourages periodic evaluation of its condition on National Forest System land. Three occurrences on the Buffalo Gap National Grassland (Region 2) exist within an area that is open only to non-motorized recreation. This area’s management prescription affords the species some protection from disturbance. It would be desirable to have additional areas