Population modeling in conservation planning of the Lower Keys marsh rabbit

Date

2006-10-30

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Publisher

Texas A&M University

Abstract

Rapid development and urbanization of the Lower Florida Keys in the last 30 years has fragmented the habitat of the Lower Keys marsh rabbit (Sylvilagus palustris hefneri) and threatened it with extinction. Current threats exist at multiple spatiotemporal scales and include threats due to development, invasive species, and global climate change. On Boca Chica Key, the Lower Keys marsh rabbit (LKMR) exists as a metapopulation on Naval Air Station-Key West (NASKW). I conducted a population viability analysis to determine the metapopulation's risk of extinction under multiple management scenarios by developing a spatially-explicit, stage-structured, stochastic matrix model using the programs RAMAS Metapop and ArcGIS. These management scenarios include clearance of airfield vegetation, habitat conversion, and control of feral cats as an invasive species. Model results provided the Navy with relative risk estimates under these different scenarios. Airfield clearance with habitat conversion increased extinction risk, but when coupled with feral cat control, risk was decreased. Because of the potential of sea-level rise due to human-induced global climate change, and its projected impact on the biodiversity of the Florida Keys, I estimated the impacts of rising sea levels on LKMR across its geographic distribution under scenarios of no, low (0.3m), medium (0.6m), and high (0.9m) sea-level rise. I also investigated impacts due to 2 treatments (allowing vegetation to migrate upslope and not allowing migration), and 2 land-use planning decisions (protection and abandonment of humandominated areas). Not surprisingly, under both treatments and both land-use planning decisions, I found a general trend of decreasing total potential LKMR habitat with increasing sea-level rise. Not allowing migration and protecting human-dominated areas both tended to decrease potential LKMR habitat as compared with allowing migration and abandoning human-dominated areas. In conclusion, conservation strategies at multiple scales need to be implemented in order to reduce threats to LKMR, such as development, invasive species, and global climate change.

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