Wallace, Sara Helm2016-04-182016-04-182015http://udspace.udel.edu/handle/19716/17644Plant taxa that are threatened toward extinction are often a priority for conservation research. While many threatened, vascular, seed-bearing taxa can be conserved ex situ in seed banks, others cannot be seed-banked. These non seedbankable taxa are known as "exceptional." There is currently no comprehensive resource available to plant conservation researchers that identifies threatened, exceptional plant taxa and their storage needs. This research refined the definition of "exceptional," and then compiled and analyzed data about the seed storage behavior of threatened, vascular plant taxa in the U.S. and Canada. Researchers in the field of plant conservation were surveyed to obtain their opinion of the best parameters for the definition of "exceptional" as it pertains to threatened, vascular, seed-bearing plant taxa. A list of 5,923 threatened plant taxa of the U.S. and Canada was then sent to many of the survey's respondents requesting information regarding the seed storage behavior of the taxa. The information contributed by the researchers was compiled and standardized for analysis. Based on the responses from researchers representing 147 institutions, the definition of exceptional is: An exceptional plant taxon is a species, subspecies, or variety of vascular, seed-bearing plant which cannot be seed-banked because the seed biology or availability satisfies one or more of the following conditions: produces recalcitrant seeds, produces few or no seeds, cannot be easily propagated by seed, produces poor-quality or non-viable seeds, seeds are not easily accessible for collection when mature (or at all), or produces seeds infrequently. Information provided by 22 researchers resulted in further knowledge of the seed storage behavior of 2,090 threatened, vascular seed-bearing plant taxa of the U.S. and Canada. Of the 156 exceptional taxa, 53% are trees and 27% are shrubs. Hawaii and Florida account for 90% of the exceptional taxa. In addition, those with seed storage behaviors of exceptional tend to be from the more evolutionarily advanced orders. The list and corresponding seed storage behavior information generated from this study will help researchers identify priorities for effective and efficient conservation of threatened, exceptional plants and their ecosystems. Furthermore, the list will facilitate communication, target conservation efforts, and support funding for the research of these taxa. Lastly, this list can serve as a model for the generation of a global list. Six Supplemental Spreadsheet Files Included in Electronic Version: Appendix G Known Status, Appendix H Unknown Status, Appendix J Suggested Additions, Appendix K Pteridophytes, Appendix M Seed Storage Behavior List, Appendix N Threatened ListPlant species -- United States.Plant species -- Canada.Endangered plants -- United States -- Information resources.Endangered plants -- Canada -- Information resources.Seeds -- Storage -- United States -- Information resources.Seeds -- Storage -- Canada -- Information resources.Thesis946877976