Application of DEI and MEI indices to evaluate the effect of fragmentation in oak ‎habitats on species diversity and soil chemical characteristics

Abstract

In order to introduce and application of DEI (Distance of Edge Influence) and MEI (Magnitude of Edge Influence) indices to determine the distance of edge effect and intensity of the edge effect on herbaceous species and soil chemical properties, Three forest fragments (under 10 hectares) from oak forests of Kermanshah province were selected with similar conditions in terms of slope, direction and altitude. In each fragment three transects were established from the edge to the forest interior. Measurements of vegetation and soil variables were collected at 0 (edge), 25, 50, 100, 150 m along each transect. The results showed that MEI index values ​​were positive for soil variables (except nitrogen, organic carbon and pH). The values ​​of this index were also positive for species richness, Shannon-Wiener diversity and Evenness. DEI index value ​​was 25 m for soil variables except pH and 50 m for diversity indices. The influence of edge on species richness, Shannon-Wiener diversity and Evenness was significant. Soil variables (except phosphorus) did not show significant differences at different distances from edge. Also, changes in species richness and soil chemical properties were observed in 0-50 m from edge. Totally, in sparse oak forests, fragmentation and edge effect had influence on species richness and soil chemical properties.