Multivariate analysis of correlations among vegetation, soil properties, and free-living nematodes for determining ecological sites in arid-zone forests of Lal Suhanra Biosphere Reserve (Pakistan)

The vegetation and soil chemical characteristics have a strong effect on the soil nematode community and the contribution to the soil fertility. This experiment examined the plant species composition, soil chemical factors and the free-living soil nematodes of the five biosphere ecotypes in Lal Suhanra National Park, namely, RD-25 (grassland), RD-50 (mixed vegetation stand), RD-50 (Eucalyptus stand), RD-65 (sodic), and RD-65 (saline). Multivariate methods (principal component analysis (PCA), detrended correspondence analysis (DCA) and canonical correspondence analysis (CCA) were used to evaluate the relationship between vegetation, nematode assemblage and soil properties, assess nematode community structure and diversity indices. PCA showed that the most significant variables that discriminated the distribution of nematodes across the five ecotypes were soil saturation percentage, and phosphorus. Microelements were positively correlated with Steinernema, Rhabditida and Oschius in RD-25 and RD-50 sites respectively. The Acrobeloides population dominated the saline RD-65 site, and it was closely correlated with the soil electrical conductivity and pH. Conversely, the sodic site was described as fungal-feeding nematodes and was highly associated to organic carbon and soil organic matter. The findings indicate that, the chemical properties of soil, especially salinity, sodicity, nutrients availability, and organic matter status, have a strong influence on the composition of free-living nematode communities in ecotypes. This research determines the most important soil parameters that arrange nematode assemblage and their ecological importance as the soil fertility predictors in the opposite biosphere environments