Habitat Edge Contrast as an Indicator to Prioritize Sites for Ecological Restoration at the Landscape Scale

Abstract

Forest restoration at the landscape level has required the development of criteria and methods to prioritize sites of restoration. In this study, we analyzed the spatial patterns of habitat contrast edge to prioritize sites for restoration in a protected area in southern Chile. The edge contrast index (ECON) was estimated and mapped for each pairwise combination of habitat type, based on community composition and structure ecological variables. Correlation length, as a measure of landscape connectivity, was calculated to analyze the effect of restoring high-contrast edge zones on focal habitat continuity. Approximately, 20% of the landscape area was composed of patches of high-contrast habitat edge (ECON ≥50%). Out of the total edge length, 91% corresponded to high-contrast edges between the focal habitat and forest plantations of Eucalyptus globulus and Pinus radiata and stands invaded by Acacia spp. Only 9% corresponded to low-contrast edges (< 0.5) with natural forests. The highest ECON corresponded to patches both invaded by alien species (80-90%) and planted with exotic tree species (60-70%) that were adjacent to the focal habitat patches. Zones of high contrast that were dissecting the focal habitat patches were prioritized for restoration. The correlation length increased from 1,822 to 2,211 m for the current and the restoration scenario, respectively. Landscape planning should strive to reduce edges between suitable and unsuitable habitats, taking into account edge sensitivity of forest-dependent species and the spread of invasive species.