An evaluation of New England cottontail habitat restoration

Several state, federal and non-profit agencies have developed collaborative goals for restoring habitat in New England and New York for a declining rabbit species, the New England cottontail (Sylvilagus transitionalis, NEC). My goal was to evaluate habitat restorations at both the local, or site, scale, and the landscape scale. In order to objectively quantify the suitability of the sites being managed, I developed a Habitat Suitability Index, based on the HSI models designed the U.S. Fish and Wildlife Service. I identified candidate habitat variables for NEC, including types of cover and refuges, and food, and then asked a panel of NEC experts to rank the importance of the candidate variables. I collected data on the most important habitat variables at 60 sites managed for NEC across New England and eastern New York. The NEC experts also ranked the same 60 sites from 1 (unsuitable) to 5 (optimal). The model was optimized to improve agreement with expert opinions for the 60 sites. Specific applications may include determining when a site is suitable for releasing translocated or captive breed rabbits, and identifying habitat features that need modification as forest succession progresses. To evaluate habitat restoration efforts at a larger landscape scale, I created metapopulation models for two management focus areas (Cape Elizabeth and Kittery-Berwick) in Maine for population viability analyses. I ran simulations to compare the relative effects of the two focus areas as well as five management scenarios. I conducted a sensitivity analysis to determine the importance of various model parameters on extinction risk. The Cape Elizabeth focus area, which has more habitat patches that are closer together, had lower extinction risks than Kittery-Berwick. Reintroductions and creating additional habitat appeared especially important in the Kittery-Berwick focus area. The simulation results were sensitive to changes in the standard deviations of the survival and recruitment rates, and the probability of catastrophic mortality, indicating that variation is detrimental to NEC metapopulation growth. Variation in weather caused by climate change may need to be mitigated by monitoring and managing NEC habitat and populations