بررسی رابطه میان تراکم پوشش‌گیاهی و جانوران خاکزی در جنگل های حاشیه رودخانه کرخه به‌منظور تعیین حاشیه امن یا ضربه گیر رودخانه

The spatial distribution of soil organisms is influenced by the plant cover, thus resulting in a horizontal mosaic of areas subjected to gradients of nutrient availability and microclimatic conditions.This study was conducted to investigate the spatial variability of soil macrofauna in relation to vegetation density in the riparian forest landscape of Karkhe. The vegetation density was determined by calculating the NDVI index. Soil macrofauna were sampled using 200 sampling points along parallel transects (perpendicular to the river). The maximum distance between samples was 0.5 km. Soil macrofauna were extracted from 50 cm×50 cm×25 cm soil monolith by the hand-sorting procedure. Abundance, diversity (Shannon H’ index), richness (Menhinick index) and evenness (Sheldon index) were calculated. Soil macrofauna and NDVI data were analyzed using geostatistics (variogram) in order to describe and quantify the spatial continuity. The variograms were spherical, revealing the presence of spatial autocorrelation. The range of influence was 1724 m for abundance, 1326 m for diversity, 1825 m for richness, 1450 for evenness and 1977 m for NDVI. The kriging maps showed that the NDVI Index and soil macrofauna had spatial variability. The spatial pattern of soil macrofauna abundance and biodiversity were similar to the spatial pattern of vegetation density as shown in the correlation.