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 ea ch single land use change results in a negligible impact, the accumula tion of these individual changes over time and within a landscape or r egion may constitute a major impact. This paper details a general appr oach 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 dist ance from development. Within this building-effect distance, habitat i s assumed to be degraded, producing a disturbance zone. We sum the tot al area within the disturbance zone and track how it changes over time and in response to different land use planning actions. This method i s sensitive to both housing density and spatial pattern, so that the r elative effects of clustered development can be evaluated. Two factors are important in understanding how development potentially degrades h abitat: alteration of habitat near buildings and roads and landscape f ragmentation. Our results show clustered development reduces the negat ive impacts on wildlife habitat. For large building-effect distances, spatial pattern was found to be a stronger indicator of disturbance th an density. Efforts to decrease habitat disturbance by lowering develo pment density should include the regulation of subdivision pattern in addition to decreasing density. (C) 1997 Elsevier Science B.V.