季节性水位波动下鄱阳湖鱼类物种多样性动态模拟与预测

Exploring the mechanism of biodiversity maintenance has already become a fundamental issue in ecology. Poyang Lake, as the largest freshwater lake in China, has undergone dramatically seasonal fluctuations in water level, which severely influence the dynamic succession of aquatic ecological communities. Nevertheless, fish species diversity in Poyang Lake has always been maintained at relatively high levels compared to other lakes. Yet, little is known about the mechanism of fish diversity maintenance in Poyang Lake and the role of the periodic water-level fluctuation in the fish community succession. Taking fish diversity in Poyang Lake as an example, we are planning to construct a dynamic model for fish communities based on the neutral theory, so as to answer the following questions: (i) how the water-level fluctuation in Poyang Lake influences the distribution of fish species relative abundances in neutral communities; (ii) how interspecific differences in functional traits (e.g., species fecundity and immigration) affect fish community pattern in a nearly neutral model; (iii) using both the census data on fish diversity and the water-level monitoring data in Poyang Lake to validate the accuracy of both neutral and nearly neutral models. In summary, we anticipate that our modelling predictions would offer new insights into the mechanism of community maintenance in watershed ecosystems, thereby providing the decision support for aquatic biodiversity conservation and management.

生物多样性维持机制是生态学研究的核心议题。鄱阳湖作为中国第一大淡水湖，其水位变化一直呈现剧烈的季节性波动，严重影响了水生生态群落的动态演替。尽管如此，鄱阳湖的鱼类多样性相对其它湖泊却一直处于较高水平。那么，鄱阳湖鱼类物种多样性的维持机理是什么，以及水位周期性波动在鱼类群落动态演替过程中扮演着何种角色至今还不甚清楚。本项目以鄱阳湖鱼类多样性为研究对象，基于中性理论构建鱼类群落动态预测模型，从而探讨以下几个问题：（i）在中性条件下，鄱阳湖水位波动如何影响鱼类物种相对多度的分布格局；（ii）利用近中性模型研究种间特性差异(如繁殖率和迁移率等)对鱼类群落格局的影响；（iii）利用收集和调查的鄱阳湖鱼类数据以及相关水位监测数据比较中性和近中性模型的预测精确性。通过该项目研究，以期为流域生态系统群落维持机制提供新的理论视角，从而为淡水生物多样性保护和管理提供相应的决策支持。

探索生物多样性维持机制是生态学研究的核心议题。鄱阳湖作为我国第一大淡水湖，其水位变化一直呈现剧烈的季节性波动，极大地影响了水生生态群落的稳定性。本项目从野外鱼类调查与理论建模分析两方面入手，探讨了水位季节性波动对鱼类群落多样性的影响。在执行期间，每年对鄱阳湖及其周边区域进行鱼类群落调查，同时收集并整理以往的鱼类多样性数据。统计分析表明，鄱阳湖鱼类多样性（包括种、科、目等）呈现一定程度的波动，与鄱阳湖最高水位高度相关。另外，通过构建具有持续性干扰的新型竞争-占据权衡理论框架，模拟发现干扰-多样性关系呈现稳健的多峰特性，与中度干扰假说认为的单峰关系截然不同。其原因在于持续干扰与竞争-占据权衡相互作用可以促进剩余物种共存。因此，该理论可为季节性水位波动干扰条件下鄱阳湖鱼类多样性振荡提供极其简洁的机理性解释，从而为流域生态系统稳定性提供新的理论视角。