Exploring the dynamic correlation of landscape composition and habitat fragmentation with surface water quality in the Shenzhen river and deep bay cross-border watershed, China

Abstract

The dynamics of land cover and landscape structure are important variables that influence the environmental and ecological quality of a watershed. In this study, a complex hypothesis was proposed that assumed water quality was closely correlated with landscape composition and habitat fragmentation and that this relationship varied at different spatial scales, namely, in riparian buffers with different widths. This hypothesis was tested using a case study in the Shenzhen River and Deep Bay watershed, which is the border region between the Hong Kong Special Administrative Region and Shenzhen in China. To effectively explore the correlation of habitat fragmentation with surface water quality, a compound indicator was proposed that can be used to disentangle the effect of habitat fragmentation from that of habitat loss alone. The results of the redundant analysis suggested that the surface water quality in our study area was strongly correlated with landscape composition and habitat fragmentation, and the correlations varied with riparian buffer widths. Compared to habitat fragmentation, landscape composition seemed to be the dominant contributor to the variation in water quality. The cross-border comparison between Hong Kong and Shenzhen suggested the riparian buffers with the strongest linkages were different for the two sides of the watershed, likely due to their special combinations of landscape characteristics and other socio-economic contexts. Whether habitat loss and fragmentation had negative effects on water quality depended on the habitat types and water quality variables that were examined. These findings can be helpful in offering useful information for future watershed management and landscape planning.