Haemmig, T. | Search bioRxiv

bioRxiv2026

Community performance curves predict community stability despite interaction effects

Predicting whether aggregate community properties remain stable as environments fluctuate is a central challenge in ecology. We asked how well species' fundamental niches predict this aspect of community stability. We developed community performance (CP) curves by aggregating species-specific performance across environmental conditions and tested whether their variability explains temporal variability in communities. In Lotka-Volterra and mechanistic consumer-resource simulations, CP variability explained, on average, 89% of variation in total abundance variability, and explanatory power remained above 75% across gradients of interaction strength and coexistence conditions. In a purpose-designed microcosm experiment, CP variability explained 67% of variation in total biomass variability. CP curves thus retain substantial predictive information even in strongly interacting systems, providing a tractable basis for forecasting community stability when species interactions are unknown.

ecology↗

bioRxiv2025

The imbalance of nature: The Role of Species Environmental Responses for Ecosystem Stability

Understanding the mechanisms underlying ecosystem stability is crucial in predicting ecological responses to environmental fluctuations. While the diversity-stability relationship has been widely studied, the role of species fundamental responses to the environment remains underexplored. Here, we investigate how the distribution of fundamental responses, captured by a novel metric--imbalance--drives ecosystem stability through asynchrony and population stability. Using a microcosm experiment with protist communities, we manipulated species richness and response distributions (defined as interspecific variation in species performance curves) under fluctuating temperature and different nutrient concentrations. Our results show that lower imbalance, achieved through asynchrony or high population stability, causes higher temporal stability, while richness has no effect on stability. Structural equation modelling revealed that imbalance decreases stability indirectly via increasing synchrony and decreasing population stability, explaining 90% of observed variation. Comparing imbalance derived from single versus multispecies communities demonstrates that fundamental species responses are primary drivers of stability, challenging traditional paradigms emphasizing interspecific interactions. This study provides mechanistic links between species responses, environmental variability, and ecosystem stability, offering new insights into the responses of ecological systems to environmental change.

ecology↗