Extreme warming restructures habitat distribution and productivity along
local gradients in stress and biodiversity
Abstract
Significant questions remain about how ecosystems that are structured by
abiotic stress will be affected by climate warming. A well-supported
hypothesis states that warming will cause species to shift along abiotic
gradients, such that distributions track changing local conditions.
Here, we investigated the impacts of a multi-year heatwave on community
dynamics and zonation in one such ecosystem: rocky intertidal
communities. We demonstrate that, while populations generally shifted
downslope towards reduced abiotic stress, species were impacted to
varying degrees, leading to complex changes in community and ecosystem
dynamics. Warming generally shifted primary production away from upper
elevations through synchronized seaweed declines and replacement by
invertebrates, while high producer biomass was maintained at lower
elevations through compensatory dynamics that resulted in novel
community composition. Our results illustrate that, rather than shifting
community zonation uniformly along local gradients, warming will
restructure habitat archetypes and redirect pathways for energy transfer
in stress-structured systems.