Linking macrophyte species diversity and community stoichiometric homeostasis with multidimensional stability under algal bloom disturbances

Biodiversity and community functional traits are critical to preserving the lake ecosystem stability under global environmental changes, which is essential for sustaining the vital ecosystem services we depend on. However, how species diversity and the key functional trait affect the multiple dimensions (temporal stability, resistance, resilience and recovery) and facets (function, composition, diversity and functional trait) of stability of macrophyte communities to algal bloom disturbances in freshwater lakes remains unclear. Here, based on sediment nutrient gradient experiments and three-year seasonal monitoring of macrophyte communities in Erhai Lake before and after the occurrence of algal blooms, we found that species diversity and stoichiometric homeostasis of phosphorus (HP) have positive relationships with functional and compositional temporal stability, resistance, and recovery, indicating that ecosystems with high species diversity and community HP are more resistant and stable in response to external algal bloom disturbances. However, species diversity and community HP have no positive or even negative relationships with resilience, suggesting that high biodiversity with high-HP species-dominated ecosystems is not beneficial for the rapid recovery from disturbances, probably due to the slow growth and reproduction rate of high-HP species. In addition, we found strong positive correlations between functional and compositional stability across the four dimensions of stability, while stability of species diversity and the key functional trait (HP) exhibit complex relationships, implying the difficulty of optimizing multiple dimensions and facets of stability simultaneously. Our results highlight the importance of macrophyte species diversity and community HP in determining the multiple dimensions and facets of stability in response to disturbances, which provides new insights for predicting the responses of macrophyte-dominated lake ecosystems to the current increasing frequency of algal blooms.