Linkages between spatial variations in riparian vegetation and floristic quality to the environmental heterogeneity: a case study of river Soan and its associated streams, Pakistan

摘要

This study attempts to develop Floristic Quality Index (FQI) as a biological indicator of human influence to evaluate ecological conditions of the River Soan and its feeding tributaries and establish the link between spatial distribution of plant communities to natural and anthropogenic gradients using classification and ordination methods. Plant species abundance data, water quality parameters, physical habitat, land-use types and climatic parameters were collected from 63 sites. Cluster Analysis (CA) identified five spatial groups of sites based on the floristic composition. Correspondence Analysis revealed the impact of urbanization, habitat degradation, and water quality as environmental predictors of anthropogenic stress. Floristic Quality Index (FQI) showed negative correlation with parameter associated with anthropogenic activities. Canonical Correspondence Analysis (CCA) axes were strongly related with FQI scores (r=0.9) and showed sites with least impact from man-made activities had higher FQI values. FQI values were lower for sites surrounded by agricultural or urban land-use types, with hydrologic modification and habitat deterioration. The results can provide a means of using an integrated approach of FQI, vegetation classification and ordination methods to evaluate riparian conditions, suggest continuous monitoring framework for biological indicators over time and assist to evaluate future conservation efforts.