Eutrophication decreases ecological resilience by reducing species diversity and altering functional traits of submerged macrophytes

Positive feedback is key to producing alternative stable states and
largely determines ecological resilience in response to external
perturbations. Understanding the positive feedback mechanisms in
macrophyte-dominated lakes is crucial for resilience-based management and
restoration. Based on the field investigation of submerged macrophyte
communities in 35 lakes in China, we found that morphological complexity
(MC) and morphological plasticity (MP) are correlated with the
stoichiometric homeostasis of phosphorus (HP) and are related to ecosystem
structure, functioning, and stability. We also found that the positive
feedback strength of lakes dominated by macrophytes is biomass- and
diversity-dependent. Eutrophication can decrease the community biomass by
decreasing community MC, MP, and HP and the species diversity through
low-light availability, ultimately decreasing the positive feedback
strength and resilience of clear-water states. We argue that functional
traits and species diversity should be considered to build more resilient
ecosystems in future changing environment scenarios.