The relative contribution of non-selection and selection processes in marine benthic assemblages

Area of Science:

• Marine Ecology
• Community Ecology
• Biodiversity Research

Background:

• Marine meiofaunal nematodes are ubiquitous with passive dispersal, suggesting less environmental limitation.
• Marine macrofauna have smaller populations and track environmental conditions, leading to more restricted distributions.

Purpose of the Study:

• To test the hypothesis that nematode assemblages are less environmentally limited than macrofauna.
• To compare the distribution drivers of meiofauna and macrofauna species.

Main Methods:

• Compared empirical species distributions of nematodes and macrofauna.
• Simulated communities under selection (environmental filtering) and non-selection (dispersal limitation) processes.

Main Results:

• Selection processes were the primary driver for both meiofauna and macrofauna assemblages.
• Rare species significantly contributed to the selection component.
• Non-selection processes explained 27% more species in nematodes compared to macrofauna.

Conclusions:

• A species-level approach is crucial for understanding selection and non-selection assembly processes.
• Dispersal and stochastic processes play a significant, yet often overlooked, role in marine species dynamics.