网围拆除后东太湖鱼类功能群时空变化及影响因子

通过2019年4、7、10月对网围拆除后东太湖原网围养殖区和非养殖区鱼类资源的调查监测,构建"营养—运动"复合功能群,分析探讨鱼类功能群的时空分布特征及其与环境因子的关系.结果 表明:网围拆除后东太湖鱼类群落监测到39种,鲤科鱼类占比66.67％,与太湖相当(66％).采集到的鱼类可构建为4个营养功能群和5个运动功能群...

Spatio-temporal variation with influencing factors for fish functional groups in East Lake Taihu after the net removal

Based on the investigation and monitoring of fish resources in the original net enclosure (ONE) and no net enclosure (NNE) areas of East Lake Taihu after the removal of net enclosure (RNE) in April, July and October 2019, the "trophic-locomotion" combined functional group was constructed, and their spatio-temporal distribution characteristics and their relationship with environmental factors were analyzed. The results showed that 39 species of fish were detected in East Lake Taihu after the RNE, and the proportion of Cyprinidae fish was 66.67%, which was similar to that in Lake Taihu (66%). The collected fish could be divided into 4 trophic and 5 locomotion groups, with a total of 11 combined groups, among which the group "omnivorous, spindle body type with the strong locomotor ability" accounted for the largest proportion (41.34%). The followed functional groups were "primary carnivorous-spindle body type and strong locomotor ability", "plant carnivorous-spindle body type and strong locomotor ability", "secondary carnivorous-spindle body type and strong locomotor ability", accounting for 28.70%, 13.46% and 13.40%, respectively. In terms of seasonal change, the "omnivorous, spindle body type with strong locomotor ability" group was dominant in the ONE, while in the NNE, the dominant functional group evolved from "omnivorous-spindle body type with strong locomotor ability" + "herbivores-spindle body type with the strong athletic ability" to "primary carnivorous-spindle body type with the strong locomotor ability". Spatially, the density of omnivorous, secondary carnivorous and herbivorous fish in the ONE was higher than that in the NNE, while the functional group density of primary carnivorous fish was lower than that in the NNE. Among the environmental factors, ammonia nitrogen was the significant factor affecting the distribution of functional groups of fish in the ONE and was negatively correlated with the distribution of all functional groups. pH, total phosphorus, total nitrogen and dissolved oxygen were also the main environmental factors, but not significantly affecting the distribution of fish functional groups. The RNE has a positive effect on the restoration of the fish community and ecosystem remediation in East Lake Taihu. However, the evolution of the fish community and the natural environment after the RNE still needs to be further assessed.