U.S. Fish and Wildlife Service Species Status Assessment Report Eriogonum tiehmii (Tiehm’s buckwheat) (Photo: James Morefield/Nevada Division of Natural Heritage) Version 1.0 April 2021 Region 10 1 ACKNOWLEDGEMENTS Writers and Contributors This document was prepared by Sarah Kulpa, Restoration Ecologist/Botanist, Reno Fish and Wildlife Office with assistance from members of the Eriogonum tiehmii SSA Core Team including Sophia Heston, Justin Barrett, and Deborah Giglio. Peer Reviewers We appreciate the helpful comments provided by peer and partner reviewers on an earlier draft. Peer reviews were received from Arnold Tiehm, Herbarium Curator, University of Nevada, Reno; Ben Grady, Assistant Professor of Biology, Ripon College and President, Eriogonum Society; and Joyce Maschinski, President and CEO, Center for Plant Conservation. Partner reviews were received from the Bureau of Land Management and Nevada Division of Natural Heritage. Funding The U.S. Fish and Wildlife Service provided funding to Dr. Jacqualine Grant of Southern Utah University to do an eDNA study on Eriogonum tiehmii. We thank her for providing expedited research to help inform this Species Status Assessment Report. SUGGESTED CITATION: U.S. Fish and Wildlife Service. 2021. Species status assessment report for Eriogonum tiehmii (Tiehm’s buckwheat), Version 1.0. Department of the Interior California-Great Basin Region. Sacramento, California. April, 2021. 2 TABLE OF CONTENTS LIST OF FIGURES .................................................................................................................................... 5 LIST OF TABLES ...................................................................................................................................... 5 LIST OF ACRONYMS .............................................................................................................................. 5 EXECUTIVE SUMMARY ........................................................................................................................ 6 1.0 INTRODUCTION ................................................................................................................................. 8 1.1 Purpose of the SSA ............................................................................................................................ 8 1.2 Petition History ................................................................................................................................. 8 1.3 State Listing Status ........................................................................................................................... 9 1.4 Methodology ...................................................................................................................................... 9 1.4.1. Analytical Framework .............................................................................................................. 9 1.4.2. Legal Framework .................................................................................................................... 11 2.0 SPECIES BACKGROUND ................................................................................................................ 13 2.1 Species Description ......................................................................................................................... 13 2.2 Taxonomy and Genetics ................................................................................................................. 14 2.3 Phenology and Life History ............................................................................................................ 15 2.4 Habitat and Ecological Needs ........................................................................................................ 16 2.5 Range and Geographic Distribution ............................................................................................. 18 2.6 Abundance, Population Trend, and Population Demographics ................................................. 22 3.0 CURRENT CONDITIONS AND STATUS ...................................................................................... 23 3.1 Threats Affecting Eriogonum tiehmii and Habitat ....................................................................... 24 3.1.1 Habitat Modification................................................................................................................ 25 Mineral Exploration and Development ..................................................................................................... 25 Road Development and Off-Highway Vehicle Use ................................................................................... 26 Livestock Grazing ....................................................................................................................................... 27 Nonnative, Invasive Plant Species .............................................................................................................. 28 3.1.2 Herbivory .................................................................................................................................. 29 3.1.3 Climate Change ........................................................................................................................ 33 3.1.4 Small Population Size .............................................................................................................. 34 3.1.5 Disease ....................................................................................................................................... 35 3.1.6 Overutilization (unauthorized collecting) .............................................................................. 35 3.2 Conservation Measures and Regulatory Mechanisms ................................................................. 35 3.3 Summary of Current Condition .................................................................................................... 36 4.0 FUTURE CONDITIONS AND STATUS ......................................................................................... 37 4.1 Threats Affecting Eriogonum tiehmii and Habitat ....................................................................... 37 3 4.1.1 Habitat Modification................................................................................................................ 38 Mineral Exploration and Development ..................................................................................................... 38 Road Development and Off-Highway Vehicle Use ................................................................................... 40 Livestock Grazing ....................................................................................................................................... 41 Nonnative, Invasive Plant Species .............................................................................................................. 41 4.1.2 Herbivory .................................................................................................................................. 42 4.1.3 Climate Change ........................................................................................................................ 42 4.1.4 Small Population Size .............................................................................................................. 45 4.1.5 Disease ....................................................................................................................................... 45 4.1.6 Overutilization (over collecting) ............................................................................................. 45 4.2 Conservation Measures and Regulatory Mechanisms ................................................................. 45 4.3 Summary of Future Conditions ..................................................................................................... 46 5.0 FUTURE SCENARIO CONSIDERATIONS ................................................................................... 48 5.1 Scenario 1 ......................................................................................................................................... 48 5.2 Scenario 2 ......................................................................................................................................... 49 5.3 Scenario 3 ......................................................................................................................................... 50 5.4 Scenario 4 ......................................................................................................................................... 52 5.5 Uncertainties Relating to Future Conditions ................................................................................ 53 5.6 Summary of Future Condition Scenarios ..................................................................................... 53 6.0 OVERALL SYNTHESIS ................................................................................................................... 55 7.0 LITERATUE CITED ......................................................................................................................... 58 4 LIST OF FIGURES Figure 1. The stepwise process for assessing a species’ status (Service 2016, entire)…………………….9 Figure 2. A. Eriogonum tiehmii flowers and B. Eriogonum tiehmii stems and leaves (photo credit: James Morefield/Nevada Division of Natural Heritage)………………………….……... 13 Figure 3. Multidimensional scaling of biallelic, single-nucleotide