Spatio-temporal Dynamic Heterogeneity of Nematode Abundance in a Desert Ecosystem.

The abundance and distribution of natural populations of soil organisms can be influenced greatly by the types and arrangement of habitat patchiness within a landscape. Most animal populations inhabit a variety of different habitats, even within a relatively small geographic region. The aim of our research was to determine how abiotic and biotic environmental factors, including small shrub canopy, influence patchiness and the alteration of nematode populations inhabiting a small plot in a desert ecosystem. The results of our investigation showed that the aggregation of total number of nematodes, trophic groups, and nematode species in an arid region with low soil moisture content may be significantly different (P < 0.01), even in 10-m-square areas. Ecological indices such as lambda, H', J', and SR were defined as useful for detecting changes in spatial patterns of nematodes. Only the H' index identified a difference in temporal and spatial patterns (P < 0.01). We conclude that the influence of different factors such as temperature, organic content, and vegetation on small plots with extreme habitat conditions was not dominant. Factors such as inter- and intra-species competition appear to play the main role in the creation of the mosaic of small plots.