Six decades of changes in vascular hydrophyte and fish species in three plateau lakes in Yunnan, China.

摘要

Biodiversity in the plateau lakes of Yunnan, China has decreased significantly over the past decades. To better understand this degradation, we analyzed the processes and characteristics of changes in vascular hydrophytes and fish species in three of Yunnan's largest lakes (Dianchi, Erhai, and Fuxian). We reviewed primary literature reporting the occurrence of such species between the 1950s and 2000s. During this period, 46.3% of native hydrophytes and 84.0% of native fish species in Dianchi Lake had gone locally extinct, compared to 21.4 and 58.8% in Erhai, and 11.8 and 41.7% in Fuxian, respectively. In Dianchi alien species comprised 15.4% of total hydrophytes and 87.5% of total fish species, compared to 5.7 and 70.8% in Erhai, and 11.8 and 65.0% in Fuxian, respectively. The extinction of endemic fish species was particularly serious. The proportion of endemic fish species extinct was 90.0% in Dianchi, 75.0% in Erhai and 63.6% in Fuxian. Homogenization of fish assemblages (calculated Jaccard indices) across the lakes increased during the study period in parallel with the extinction of endemics and introduction of alien species. Results showed that lacustrine conditions determined the observed changes of hydrophytes and fish species, likely reflecting anthropogenic disturbances associated with rapid economic development around the lakes. In a developing region like the plateau of Yunnan, which is rich in endemic freshwater species, the challenge is how to balance economic growth with habitat protection.