Global gradients in intertidal species richness and functional groups

Area of Science:

• Marine Ecology
• Biodiversity Research
• Latitudinal Gradients

Background:

• The existence of global latitudinal diversity gradients in rocky intertidal zones remains uninvestigated.
• Understanding the drivers of biodiversity patterns is crucial for conservation and ecological theory.

Purpose of the Study:

• To investigate alpha-diversity patterns in rocky intertidal ecosystems across a wide latitudinal range (155°).
• To determine whether local or global-scale processes structure intertidal biodiversity.
• To examine changes in functional group composition with latitude.

Main Methods:

• Literature synthesis of data from 433 intertidal sites globally.
• Analysis of alpha-diversity patterns and functional group composition across latitudes.
• Comparison of the influence of local-scale versus global-scale drivers.

Main Results:

• Alpha-diversity showed hemispheric differences with a mid-northern peak, but no consistent tropical-to-polar decrease.
• Local-scale drivers significantly impacted alpha-diversity, outweighing global-scale effects.
• Species richness of predators, grazers, and suspension feeders declined with latitude, inversely related to algae.

Conclusions:

• Latitudinal diversity gradients are not a universal pattern in rocky intertidal zones.
• Local ecological processes are the primary determinants of intertidal biodiversity.
• Further sampling in polar and tropical regions is needed to enhance understanding of marine biodiversity.