Edge effects in fragmented landscapes: A generic model for delineating area of edge influences (D-AEI)

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We developed a generic model for delineating area of edge influences D-AEI for quantifying edge effects within a landscape by combining remote sensing, geographic information systems (GIS), moving window (3 x 3), and computer programming techniques. Our model provided a more realistic assessment of edge effects than those based on traditional methods. Unique characteristics of the D-AEI model included: (1) preservation of the spatial characteristics of the landscape structure; (2) incorporation of the most critical parameters controlling edge effects, such as edge orientation, edge contrast, prevailing direction of edge effects, decay value, and interior approximation; and (3) ability to quantify edge effects for various variables at multiple scales. The model is flexible so that the users can define key parameters and generate ecologically relevant output based on environmental and spatial characteristics of the study area and the study purpose. Our results demonstrated that: (a) edge effects were not symmetrically distributed in all directions around clearcuts; (b) AEI was not necessarily continuous around patches; and (c) boundary dynamics and multiple edge effects were clearly reflected across the landscape. Results from this research are important for current and future resource assessments, biological conservation and wildlife habitat management, biodiversity studies of flora and fauna, microclimatic research, future studies on edges and their importance in landscape design and analysis. The model has potential for broader applications in other research areas where human and natural disturbances are evident, at multiple scales from watershed, forest management district, to region. (C) 2000 Elsevier Science B.V.

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Ecological Modelling