Estimating the cumulative effects of development on wildlife habitat

The cumulative effects problem in natural resource management and land use planning stems from the difficulty of demonstrating that while each single land use change results in a negligible impact, the accumulation of these individual changes over time and within a landscape or region may constitute a major impact. This paper details a general approach to estimate the cumulative effects of land use change on wildlife habitat using Summit County, CO, USA as a case study. Our approach is based on a functional relationship between effect on habitat and distance from development. Within this building-effect distance, habitat is assumed to be degraded, producing a disturbance zone. We sum the total area within the disturbance zone and track how it changes over time and in response to different land use planning actions. This method is sensitive to both housing density and spatial pattern, so that the relative effects of clustered development can be evaluated. Two factors are important in understanding how development potentially degrades habitat: alteration of habitat near buildings and roads and landscape fragmentation. Our results show clustered development reduces the negative impacts on wildlife habitat. For large building-effect distances, spatial pattern was found to be a stronger indicator of disturbance than density. Efforts to decrease habitat disturbance by lowering development density should include the regulation of subdivision pattern in addition to decreasing density. (C) 1997 Elsevier Science B.V.