Weaving the conservation landscape: habitat connectivity and the future of the National Wildlife Refuge System

Maintaining habitat connectivity is one of the keys to conserve biodiversity in the face of global change. Chris' research integrates graph theory with future land use scenarios to evaluate connectivity and isolation of National Wildlife Refuges, one of the cornerstones for biodiversity conservation in the United States.

While protected areas are set aside to conserve biodiversity, land use pressure in the surrounding areas is rapidly isolating them, disconnecting them from surrounding habitats and other reserves, and ultimately threatening their capacity to sustain species. Maintaining landscape connectivity is therefore critical to conserve biodiversity. This is especially true in the face of climate change, where species are shifting distributions in response to climate.

Chris Hamilton, a PhD student at the SILVIS lab, is evaluating the impacts of land use change on biodiversity conservation. Specifically, Chris' research tries to understand the impacts that projected housing and land use change could have on the connectivity and isolation of National Wildlife Refuges, one of the most emblematic reserve systems in the United States. Recent studies have shown that housing density and land use pressures will increase significantly over the next 50 years, likely affecting species, biodiversity, and connectivity.

The center of Chris' research resides in the integration of habitat connectivity models with future land use scenarios. He is currently identifying a variety of species (i.e., amphibians, birds, mammals) that will be the targets for his novel applications. He will use graph theory, cost surface approaches, and species species distribution data to develop models of habitat connectivity, which will be integrated with geospatial scenarios of future housing and land use distributions. In doing so, he will be able to identify and map critical corridors, identify potential threatened areas, point out corridors to conserve, and highlight areas that should be restored. In addition, he will gain a better understanding of the ecological role of low density housing areas, which are the most common feature around National Wildlife Refuges. This information will be of immense value for managers and land use planners, as well as for any conservation efforts aimed to balance human activities and biodiversity in the face of global change.

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Preliminary analysis was conducted for about 500 National Wildlife Refuges. The graphics demonstrate how buffer analysis and census data (Buffers graphic) were used to quantify housing density (Housing densities graphic) and to identify areas with low housing density (< 6.2 houses/km2 ~ 1 house/ 40 acres), which could potentially provide, or be managed to provide, wildlife corridors (Corridors graphic). An example incorporating wildland vegetation distribution within a low housing density corrid

Preliminary analysis was conducted for about ~500 National Wildlife Refuges. The graphics demonstrate how buffer analysis and census data (Buffers graphic) were used to quantify housing density (Housing densities graphic) and to identify areas with low housing density (< 6.2 houses/km2 ~ 1 house/ 40 acres), which could potentially provide, or be managed to provide, wildlife corridors (Corridors graphic). An example incorporating wildland vegetation distribution within a low housing density corridor in also included (Application graphic).

 

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Percent housing growth from 1940 to 2000 at 4 distances around National Wildlife Refuges, compared with the United States national average housing growth. Areas close to wildlife refuges had the highest growth rates.

The research is being conducted in the Upper Midwest region of the United States, with collaboration and support from other intuitions (i.e., US Fish and Wildlife Service and US Geological Survey). The approaches developed here, however, should be seen as templates that can be applied anywhere else.