Analysis of Spatial Variability of Soil Macrofauna in RipariaForest of Karkhe, Irann

Document Type : Research Article

Authors

1 Department of Forestry, Faculty of Natural Resource and Marine Science, Tarbiat Modares University

2 Faculty of Agriculture, Shahekord University

3 Faculty of Environmental Science, Gorgan University

Abstract

Abstract
Information about the spatial patterns of soil biodiversity is limited though required, e.g. for understanding effects of biodiversity on ecosystem processes. This study was conducted to determine whether soil macrofauna biodiversity parameters display spatial patterns in the riparian forest landscape of Karkhe. Soil macrofauna were sampled using 200 sampling point along parallel transects (perpendicular to the river). The sampling procedure was hierarchically, maximum distance between samples was 0.5 km, but the samples were taken at shorter distance at different location of sampling. Soil macrofauna were extracted from 50 cm×50 cm×25 cm soil monolith by hand-sorting procedure. Abundance (Number of animals), diversity (Shannon H’ index), richness (Menhinick index) and evenness (Sheldon index) were analyzed using geostatistics (variogram) in order to describe and quantify the spatial continuity. The variograms of indices were spherical and revealed the presence of spatial autocorrelation. The range of influence was 1724 m for abundance, 1326 m for diversity, 1825 m for richness and 1450 for evenness. The variograms featured high ratio of nugget variance to sill (abundance (52%), diversity (55%), richness (53%) and evenness (35%)). This showed that there was the small-scale variability and proportion of unexplained variance. The kriging maps showed that the soil macrofauna have spatial variability.

Key words: Spatial pattern, Soil macrofauna, Geostatistics, Variogram, Kriging

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