Development of a Shoreline Environmental Impact Index (SEII): An analysis of landscape pattern and structure metrics.

摘要

The goal of this study was to develop a Shoreline Environmental Impact Index (SEII) based upon landscape ecology pattern and structure metrics calculated from high resolution remotely sensed imagery This SEII would provide a tool for monitoring freshwater lakes and reservoirs in areas of rapid development. The land use/land cover information for the study was derived from National Aerial Photography Program (NAPP) imagery of a portion of Lake Murray, South Carolina shoreline scanned to simulate high resolution remotely sensed imagery. The shoreline in the study area was divided into 400 landscape units. Common landscape ecology metrics were calculated for these landscape units. They were also rated on a scale from 1 to 10 by expert visual interpretation with a rating of 1 indicating no environmental impact and 10 meaning the shoreline had been severely impacted and was in need of in situ monitoring.; Factor analysis of the landscape metrics calculated support previous work indicating a small number of independent, orthogonal factors are being measured by the landscape metrics (Riitters et al., 1995, Cain et al., 1997). Methods of combining landscape ecology metrics to create a meaningful Shoreline Environmental Impact Index (SEII) included multiple linear regression, multiple discriminant analysis, genetic neural networks, standard feed forward back propagation neural networks and manual combination. The ratings produced by the SEII's generated using these methods were then compared to the ratings by the experts. There was very little difference in the performance of several SEII's generated despite some differences in metrics and weighting chosen by the different methods. The ratings from all methods showed their ability to reflect the expert ratings in general. Conclusions indicate that the ability of the landscape metrics to discriminate between levels of shoreline degradation is contained within a relatively few metrics. In any of the current forms the SEII is suitable only for general indication of shoreline health.