Micro-refuges or ecological traps: context-dependent effects of rock pools on intertidal biodiversity across latitudes

Biodiversity is unevenly distributed across the Earth. At very large
spatial scales, the decline in species richness from the tropics to the
poles, the Latitudinal Diversity Gradient (LDG), remains one of the most
widely recognized patterns in ecology. We investigated how
local-scale environmental heterogeneity influences biodiversity patterns
across broad biogeographic gradients, using intertidal
microhabitats (rock pools and adjacent emergent rock) as a model
system within one of the most environmentally stressful ecosystems on
Earth. This Dryad dataset compiles standardized biodiversity and
microclimate observations from rocky intertidal habitats at 26 locations
in 21 countries across six continents, spanning 38°S to 60°N
(2019–2022). Across the survey, 675 taxonomic entities were
recorded (505 identified to species level), with rock pools containing 618
taxa (274 unique) and emergent rock 401 taxa (57 unique). Data show that
microhabitat differences can strongly modify latitudinal biodiversity
patterns, with pools generally supporting higher taxonomic and functional
diversity than emergent rock, but with context-dependent outcomes under
extreme conditions. By mediating exposure to environmental
stress, intertidal microhabitats provide insight into how fine-scale
variability interacts with latitudinal stress gradients to shape
biodiversity distributions. Incorporating microhabitat variability into
biogeographic frameworks is important for understanding global
biodiversity patterns and predicting ecological responses to climate
change.