Stoichiometric mechanisms of regime shifts in freshwater ecosystem

Haojie Su; Yao Wu; Wulai Xia; Lei Yang; Jianfeng Chen; Wenxuan Han; Jingyun Fang; Ping Xie

doi:10.1016/j.watres.2018.11.024

Stoichiometric mechanisms of regime shifts in freshwater ecosystem

Water Res. 2019 Feb 1:149:302-310. doi: 10.1016/j.watres.2018.11.024. Epub 2018 Nov 12.

Authors

Haojie Su¹, Yao Wu², Wulai Xia², Lei Yang³, Jianfeng Chen⁴, Wenxuan Han⁵, Jingyun Fang⁶, Ping Xie⁷

Affiliations

¹ Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan 430072, China; Department of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
² Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China.
³ College of Life Sciences, Wuhan University, Wuhan 430072, China.
⁴ Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan 430072, China.
⁵ College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
⁶ Department of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
⁷ Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan 430072, China; State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining 810016, China. Electronic address: xieping@ihb.ac.cn.

PMID: 30465988
DOI: 10.1016/j.watres.2018.11.024

Abstract

Catastrophic regime shifts in shallow lakes are hard to predict due to a lack of clear understanding of the associate mechanisms. Theory of alternative stable states suggests that eutrophication has profound negative effects on the structure, function and stability of freshwater ecosystems. However, it is still unclear how eutrophication destabilizes ecosystems stoichiometrically before a tipping point is reached. The stoichiometric homeostasis (H), which links fine-scale process to broad-scale patterns, is a key parameter in ecological stoichiometry. Based on investigation of 97 shallow lakes on the Yangtze Plain, China, we measured nitrogen (N) and phosphorus (P) concentrations of the aboveground tissues of common submerged macrophyte species and their corresponding sediments. We found submerged macrophytes showed significant stoichiometric homeostasis for P (H_P) but not for N (H_N). Furthermore, H_P was positively correlated with dominance and stability at the species level, and community production and stability at the community level. Identifying where macrophyte community collapse is a fundamental way to quantify their resilience. Threshold detection showed that macrophyte community dominated by high-H_P species had a higher value of tipping point (0.08 vs. 0.06 mg P L^-1 in lake water), indicating their strong resilience to eutrophication. In addition, macrophytes with high H_P were predominant in relative oligotrophic sediments and have higher ability in stabilizing the water environment compared to those low-H_P ones. Our results suggested that ecosystem dominated by homeostatic macrophyte communities was more productive, stable and resilient to eutrophication. Eutrophication-induced stoichiometric imbalance may destabilize the ecosystem by altering the community structure from high-to low-H_P species. Efforts should be focused on maintaining and restoration of high homeostatic communities to make ecosystem more resilient, which can significantly improve our understanding of the critical transition mechanisms.

Keywords: Ecological resilience; Eutrophication; Stoichiometric homeostasis; Submerged macrophyte.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

China
Ecosystem*
Eutrophication*
Lakes
Phosphorus

Substances

Phosphorus