Abstract

The study was conducted to explore the influence of over-grazing and ungrazing on nematode biodiversity in a semi-arid region pasture, in Adıyaman, Turkey, in 2008.  Soil samples were taken in mid spring from a pasture that was previously divided into two sites, one is protected by fencing and the second is open to grazing, freely. Nematodes were extracted and allocated to trophic groups and both sites were compared regarding their abundance and diversity. A total of 19 nematode taxa were found in the study area. Plant parasitic nematodes 9 genera, bacterivores 6 genera, fungivores 3 genera, and predators and omnivores were represented by 1 order.  Rotylenchus, Tylenchus, Pratylenchus and Paratylenchus were the abundant genera in plant parasitic group; Acrobeloides and Cervidellus were the abundant genera in bacterivore group; Aphelenchoides and Ditylenchus were the abundant genera in fungivore group. Nematode diversity and abundance were greatly affected by the vegetation status depending on the grazing pattern. Diversity and abundance parameters were lower under the over-grazed site. The study suggested that there was a tight connection between vegetation cover of the ecosystem and soil biodiversity beneath it.    

Key words: Nematode biodiversity, pasture, trophic groups, grazing.