Scientific Investigations Report 2012–5149
Most national parks interact with adjacent lands because their boundaries fail to encompass all regional habitats, species pools, and migration routes. Activities planned for adjacent lands can have adverse effects on park resources and visitor experiences. For example, fragmentation of adjacent habitat into smaller and more isolated remnants may influence the suitability of park habitat for a wide range of species and limit animal dispersal pathways, which may influence visitor experiences and park resources as well as the energy balance and population dynamics of the animals themselves.
In this study, we examined habitat fragmentation consequences owing to a planned 1,295 hectare development by Winter Harbor Holding Company (WHHC) adjacent to the Schoodic District of Acadia National Park (ANP), Maine. Specifically, we examined the effects of development on (a) core natural habitat area (a cross-habitat indicator of fragmentation), (b) the suitability of habitat for bobcat, fisher, mink, and moose, and (c) the movement of these four species between ANP and other nearby protected areas (species specific indicators of fragmentation). Our intention was to assist ANP staff in forecasting both the general and specific effects of development on natural habitat area, habitat suitability, and animal movement, which would allow them to develop suitable management alternatives.
Our cross-habitat analysis of core natural areas identified locations within the entire Schoodic Peninsula that are made up of only natural land cover (forest, grassland, shrubland, wetland, and other water bodies) for both the current land-use conditions and after development of the WHHC parcel. This general indicator of fragmentation revealed that development of the WHHC parcel would result in 1.6 to 8.7 times more loss in habitat meeting the “core” criterion as compared to overall habitat loss. The ratio increased with the spatial scale of analysis, indicating that species requiring large blocks of unfragmented natural habitat are likely to be disproportionately affected by the development. Reductions in core-habitat area represent a shift in the remaining habitat away from large contiguous habitat blocks toward smaller, more isolated remnants, which may experience edge effects including higher rates of atmospheric deposition, more exotic species, and poorer habitat quality for interior species.
We further examined the suitability of the WHHC parcel for bobcat, fisher, mink, and moose. As of 2006, the WHHC parcel was highly suitable for moose (98 on a 100 scale), bobcat (85), mink (70), and fisher (65). Furthermore, 36 percent of moose highly suitable habitat and 20 percent of bobcat highly suitable habitat across the entire AOI lies within the planned development.
Lastly, we examined potential effects on animal movement between the Schoodic District of ANP in the south to and from other undeveloped lands to the north using a combination of least-cost path analysis and electrical circuit theory. Least-cost path analysis revealed that (as of 2006) the percentage of area of most efficient travel route for moose (62 percent), bobcat (43 percent), fisher (16 percent), and mink (10 percent), lies within the WHHC parcel. Reclassifying the WHHC parcel as developed substantially altered the most efficient travel route for all species. Moose experienced the greatest change in the most efficient travel route (97 percent change), followed by fisher (95 percent change), bobcat (92 percent change), and mink (40 percent change). Furthermore, development of the WHHC parcel resulted in increases in effective resistance (potential barriers to movement) among high-quality patches for bobcat (74 percent), moose (41 percent), fisher (19 percent), and mink (5 percent). These results indicate that movement of all four species among high-quality habitat patches and between the ANP and undeveloped lands to the north would be impacted by development of the WHHC parcel, likely resulting in increased energy expenditure by animals in these areas, effects on population density, and a reduction in animal viewings within the ANP boundary.
Posted August 28, 2012
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Rohweder, J.J., De Jager, N.R., and Guntenspergen, G.R., 2012, Anticipated effects of development on habitat fragmentation and movement of mammals into and out of the Schoodic District, Acadia National Park, Maine: U.S. Geological Survey Scientific Investigations Report 2012–5149, 30 p.
Results and Discussion