Land use outweighs other stressors in declining fish biodiversity in lakes of Eastern China during the 1980s-2010s

Understanding patterns and driving factors of freshwater fish biodiversity in metacommunities is essential for biological conservation but rarely studied in regions experiencing rapid land use changes. We examined changes of both alpha and beta fish diversities in taxonomic, functional, and phylogenetic facets during the 1980 s to 2010 s, and quantified contributions from natural and human drivers in lakes located in China's fastest economic development region. Results showed that almost all indices of alpha and beta diversity decreased through time. For alpha diversity, taxonomic and functional richness declined by 13 to 15%. Rheophilic and piscivorous fish species declined by 50 and 36%, respectively. For beta diversity, the decline of overall functional (-31%) diversity was greater than taxonomic (-17%) and phylogenetic (-19%) diversity. The decline of multiple facets of beta diversity indicated that fish communities in these lakes have homogenized through time. Land use (i.e., increased urban land and aquaculture ponds), hydrology (i.e., increased water level), climate (i.e., increased air temperature), and fishing (i.e., increased lake fishery catch) factors all made significant contributions to both alpha and beta fish diversity decline in multiple facets. The overall contribution from land use to the decline of multidimensional fish diversity was greater than those of other stressors. While attention should be given to both local human disturbance and regional climate factors, in regions experiencing rapid economic development and land use changes, local disturbances should be considered as a priority in biodiversity management plans.

Automated summary

This study examined the changes in freshwater fish diversity and the contributions of natural and human factors in lakes located in China's fastest economic development region. The results showed a decrease in both alpha and beta diversity indices. Alpha diversity, including taxonomic and functional richness, declined by 13-15%. Beta diversity, including overall functional, taxonomic, and phylogenetic diversity, also decreased. Land use, hydrology, climate, and fishing activities all significantly contributed to the decline in fish diversity. The impact of land use was found to be the greatest. In regions experiencing rapid economic development and land use changes, local disturbances should be prioritized in biodiversity management plans.