Managing Metapopulations of Threatened Species Across Jurisdictional Boundaries: Quantifying Effects of Climate Change, Environmental Synchrony, Dispersal, and Corridors
William Morris | Duke University
The primary objective of this project is to provide quantitative tools to improve cross-jurisdictional management of three at-risk species on and off Department of Defense (DoD) lands in the southeastern US. These tools will be widely applicable to other species and regions. Firmly grounded in the concept of a metapopulation (a population of populations), the tools will allow managers from multiple jurisdictions to determine the optimal, concerted strategy for managing species with multiple populations in the face of synchronous environmental variability, climate change, and encroachment, taking into account the dispersal ability of the species and the spatial distribution of populations. In addition, the tools will help to identify the optimal frequency and spatial arrangement of habitat restoration and management (i.e., enhancement of wetlands for a rare butterfly, and controlled burning for a fire-adapted plant) that maintains asynchronous populations at a spatial scale appropriate to the species’ dispersal ability and thus minimizes metapopulation extinction risk. The tools will also help to guide the construction and management of conservation corridors to link disjunct populations in such a way as to enhance metapopulation persistence.
The project will add value to existing data collected with previous Strategic Environmental Research and Development Program (SERDP) support, supplemented by the targeted collection of new data. These data will support the identification of the spatial scale at which neighboring populations are synchronized by shared climatic factors, which is essential for determining if multiple populations enhance metapopulation safety or are merely redundant. Existing and new data will also be incorporated into Spatially Explicit Individual-Based Models (SEIMBs) tailored to the life histories and dispersal abilities of the three focal species. When appropriate, the SEIBMs will allow habitat quality to change dynamically as a function of time since disturbance or restoration due to successional processes, an essential feature for determining optimal restoration frequency. Because they will be spatially explicit, they will allow data on demography and dispersal to be translated into specific assessments of which land parcels in the landscape would be particularly valuable to add to a conservation corridor, as well as whether dispersal between populations in the face of synchronous environmental variation will allow metapopulations to persist.
The deliverables from this project (both quantitative tools and direct interactions with managers from multiple jurisdictions) will help to relieve the DoD burden for managing rare species by improving and coordinating off-base management, by identifying key populations for species persistence, and by aiding the creation of viable metapopultions off-base through habitat restoration and the use of corridors. Moreover, the project will enhance the basic knowledge of metapopulation dynamics, by illuminating the mechanisms producing population synchrony and how differences in life history and dispersal ability govern the metapopulation persistence of diverse taxa inhabiting the same landscape.