Warming-Induced Changes in the Stability of Rocky Intertidal Microbial CommunitiesResistance, Resilience and Phase Shifts

Luca Rindi¹, Lisandro Benedetti-Cecchi¹

¹University of Pisa, Italy

Identifying the properties that enable ecosystems to persist and remain stable under climate change is a central goal of modern ecology. Environmental warming may indeed reshape the composition and functional traits of ecological communities, potentially diminishing their capacity to withstand perturbations and sustain key functions. By integrating field-based warming experiments (pulse and press), community-level genomic profiling, and mathematical modeling, we investigated how different warming regimes influence the stability of rocky intertidal microbial biofilm communities.
Contrary to expectations, repeated pulses at a fixed temperature enhanced biofilm resistance to extreme temperatures by fostering greater diversity and functional redundancy in stress-tolerance traits. In contrast, highly fluctuating warming (repeated pulses of varying temperatures) increased recovery rates by favoring fast-growing taxa but at the expense of functional redundancy. This selection intensified the trade-off between stress-tolerance and growth traits, ultimately limiting the biofilm’s ability to buffer the impact of climate extremes.
Press-warming experiments, supported by model simulations, revealed that while warming increased spatial synchrony, it stabilized biofilm biomass by reducing fluctuations at both local and landscape scales. Notably, the stabilization at local scales was sufficient to counterbalance the destabilizing effects of higher spatial synchrony, resulting in a net stabilizing effect at the landscape scale.
These findings altogether offer a forward-looking perspective, on the stability and adaptability of microbial communities in the face of ongoing climatic warming.