Preparing plant collections for biological invasions: a study of the effects of emerald ash borer (Agrilus planipennis Fairmaire) through case study analysis

Lyons, Robert E.United States history has documented the tremendous environmental and economic destruction that biological invasions like chestnut blight and Dutch elm disease have caused. In more recent years the exotic, Asian-introduced emerald ash borer (EAB; Agrilus planipennis Fairmaire) has decimated North American ash populations. If public horticulture institutions are to ensure the long-term survival of core collections from such threats, the vulnerability of these holdings, and the institution in general, must be recognized and actions taken to protect and preserve these valuable resources. This research investigated the destructive impact of EAB on plant collections and natural areas at public gardens in the U.S. Great Lakes region, to articulate and publicize the lessons learned from this exotic pest. Furthermore, this research reports the management strategies utilized by affected institutions, the preparation initiatives of institutions that reside in EAB’s impending range, and the involvement of institutions in additional activities pertaining to EAB. This study also documents analogous cases of biological invasion, such as hemlock woolly adelgid (Adelges tsugae Annand), sudden oak death (Phytophthora ramorum Werres et al.), and Asian cycad scale (Aulacaspis yasumatsui Takagi) that are affecting institutions in other regions of the United States. To aid in research initiatives, such as resistance breeding pertaining to the EAB invasion, this study also sought to investigate the current state of ex situ Fraxinus collections globally. Research methodology primarily included qualitative, semi-structured, onsite interviews with staff at four public garden case study sites. Secondary phone interviews were conducted with staff at additional institutions affected by EAB, with institutions dealing with analogous cases of biological invasion, and with professionals involved in collaborative initiatives. Furthermore, the current state of wild origin Fraxinus holdings was explored through the utilization of on-line survey tools and submission of collection inventories by participating institutions. Beyond the decimation of collection and natural area specimens and the resulting effects on aesthetics, reported impacts included shifts in resource allocation, extensive secondary environmental implications, mandated operational changes, financial losses due to unrealized revenue, stress on donor relations, and effects on visitor morale and experience. The collective analysis of the reported preparation and management strategies, involvement in additional initiatives, and lessons learned revealed 13 critically important recommendations in three overarching categories including: Institutional Planning, Collections and Natural Areas Stewardship, and Collaborative Efforts by the Public Garden Community and Beyond. Recommendations include: greater prioritization of collections, secondary storage of vitally important holdings, the fundamental value of documentation and mapping, the essential need for explicit monitoring, the clear benefits of collaborative efforts, and the imperative merits of advocacy and education. These recommendations are to be considered by institutions to better prepare for future threats. A preliminary account of Fraxinus collections globally yielded 37 institutions submitting Fraxinus inventories. Over 800 wild origin Fraxinus accessions, representing over 50 reported species are recorded in these findings.University of Delaware, Department of Plant and Soil SciencesM.S