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S. Gholami et al. 2010. Spatial pattern of soil macrofauna biodiversity in wildlife refugee of Karkhe in Southwestern Iran
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spatial pattern of soil biodiversity at the regional scale is limited though required, e.g. for
understanding regional scale effects of biodiversity on ecosystem processes (Joschko et.al.
2006). The practical consequences of these findings are useful for sustainable management of
soils and in monitoring soil quality. Soil macrofauna play significant, but largely ignored, roles
in the delivery of ecosystem services by soils at plot and landscape Scales (Lavelle et.al. 2006).
One main reason responsible for the absence of information about biodiversity at regional scale,
is the lack of adequate methods for sampling and analyzing data at this dimension. An adequate
approach for the analysis of spatial patterns is a transect study in which samples are taken in a
certain order and with a certain distance between samples (Joschko et.al. 2006). Geostatistics
provide descriptive tools such as variogram to characterize the spatial pattern of continuous and
categorical soil attributes (Goovaerts 1999; Gringarten and Deutsch 2001; Mohammadi 2006).
This method allows assessment of consistency of spatial patterns as well as the scale at which
they are expressed (Jimenez et al. 2001).
The aim of this study is to analyze spatial patterns of soil macrofauna (= invertebrates visible at
the naked eye) in Wildlife Refugee of Karkhe in the riparian forest of the southwestern Iran.
Parameters of soil macrofauna biodiversity comprise: abundance (total abundance of
macrofauna), and diversity.
2. Methodology
The study was carried out in Wildlife Refugee of Karkhe in the riparian forest of the
southwestern Iran (31 o 57 / - 32 o 05 / N and 48 o 13 / - 48 o 16 / E). The climate of the study area is
semi-arid. Average yearly rainfall is about 325.5 mm with a mean temperature of 24 oc . Plant
cover, mainly comprises Populus euphratica and Tamarix sp.
The both sides of river are similar, so we sampled on one of the two sides. Soil macrofauna
were sampled in 2009 using 200 sampling point along parallel transects (perpendicular to the
river). The distance between transects were 0.5 km. The sampling procedure was hierarchically,
we considered maximum distance between samples as 0.5 km, but the samples was taken at
250m, 100m, 50m, 20m, 15m, 10m, 5m, 2m and 1m at different location of sampling.
soil macrofauna (= invertebrates visible at the naked eye) was extracted from 50 cm×50 cm×25
cm soil monolith by hand-sorting procedure at the last winter (because at this time moisture and
temperature are suitable and soil macrofauna reach their highest abundance). All soil
macrofauna were identified to family level.
Number of animals (abundance) and diversity (Shannon H’ index) by using PAST version 1.39,
were determined in each sample. Classical statistical parameters, i.e. mean, standard deviation,
coefficient of variation, minimum and maximum, were calculated using SPSS17 software.
Diversity and abundance data were analyzed using geostatistics (variogram) in order to describe
and quantify the spatial continuity. Geostatistical analysis was performed using the software
Variowin 2.2 (variograms). Spatial distribution maps were made by block kriging using the
software Geoease and Surfer 8.0.
3. Result
Soil macrofauna communities were dominated by earthworm, diplopods, coleoptera, gastropoda,
araneae, and insect larvae, reaching an abundance of 43.1 individuals / m 2 .
Table 1 shows the mean, standard deviation, coefficient of variation, minimum and maximum
values for soil macrofauna abundance and diversity.
The variograms revealed the presence of spatial autocorrelation Fig. 1. The parameters of the
theoretical models fitted to experimental variograms are given in Table 2. The variograms of
two indices were spherical and showed positive nugget, which can be explained by sampling
error, short range variability, random and inherent variability. The nugget-to-sill ratio can be
Forest Landscapes and Global Change-New Frontiers in Management, Conservation and Restoration. Proceedings of the IUFRO Landscape Ecology
Working Group International Conference, September 21-27, 2010, Bragança, Portugal. J.C. Azevedo, M. Feliciano, J. Castro & M.A. Pinto (eds.)
2010, Instituto Politécnico de Bragança, Bragança, Portugal.