Abstract:
Phytoplankton communities are crucial components of aquatic ecosystems, and since they are highly interactive, they always form complex networks. Yet, our understanding of how interactive phytoplankton networks vary through time under changing environmental conditions is limited. Using a 29-year (339 months) long-term dataset on Lake Taihu, China, we constructed a temporal network comprising monthly sub-networks using \"extended Local Similarity Analysis\" and assessed how eutrophication, climate change, and restoration efforts influenced the temporal dynamics of network complexity and stability. The network architecture of phytoplankton showed strong dynamic changes with varying environments. Our results revealed cascading effects of eutrophication and climate change on phytoplankton network stability via changes in network complexity. The network stability of phytoplankton increased with average degree, modularity, and nestedness and decreased with connectance. Eutrophication (increasing nitrogen) stabilized the phytoplankton network, mainly by increasing its average degree, while climate change, i.e., warming and decreasing wind speed enhanced its stability by increasing the cohesion of phytoplankton communities directly and by decreasing the connectance of network indirectly. A remarkable shift and a major decrease in the temporal dynamics of phytoplankton network complexity (average degree, nestedness) and stability (robustness, persistence) were detected after 2007 when numerous eutrophication mitigation efforts (not all successful) were implemented, leading to simplified phytoplankton networks and reduced stability. Our findings provide new insights into the organization of phytoplankton networks under eutrophication (or re-oligotrophication) and climate change in subtropical shallow lakes.
摘要:
浮游植物群落是水生生态系统的重要组成部分,因为它们是高度互动的,它们总是形成复杂的网络。然而,我们对交互式浮游植物网络在不断变化的环境条件下如何随时间变化的理解是有限的。使用太湖29年(339个月)的长期数据集,中国,我们使用“扩展局部相似性分析”构建了一个包含月度子网络的时间网络,并评估了富营养化气候变化,恢复工作影响了网络复杂性和稳定性的时间动态。浮游植物的网络结构随着环境的变化而表现出强烈的动态变化。我们的研究结果揭示了富营养化和气候变化通过网络复杂性的变化对浮游植物网络稳定性的级联影响。浮游植物的网络稳定性随平均程度而增加,模块性,和嵌套性,并随着连通性而减少。富营养化(增加氮)稳定了浮游植物网络,主要是通过提高其平均程度,而气候变化,即,变暖和风速降低通过直接增加浮游植物群落的凝聚力和间接减少网络的连通性来增强其稳定性。浮游植物网络复杂性的时间动态的显著转变和大幅下降(平均程度,嵌套)和稳定性(鲁棒性,持久性)是在2007年实施了许多富营养化缓解努力(并非全部成功)后检测到的,导致浮游植物网络简化,稳定性降低。我们的发现为亚热带浅水湖泊在富营养化(或再营养)和气候变化下的浮游植物网络组织提供了新的见解。