Hierarchical drivers of reef-fish metacommunity structure

Area of Science:

• Marine Ecology
• Biodiversity Science
• Spatial Ecology

Background:

• Coral reefs exhibit high biodiversity driven by complex interactions across spatial and temporal scales.
• Most coral reef studies analyze data at a single spatial scale, neglecting the hierarchical nature of these ecosystems.
• Quantifying the relative importance of processes across multiple scales remains a challenge in coral reef science.

Purpose of the Study:

• To quantify how alpha, beta, and gamma diversity vary with spatial scale in reef fish metacommunity.
• To evaluate the relative importance of site-, reef-, and atoll-level processes influencing fish metacommunity structure.
• To demonstrate the utility of hierarchical, information-theoretic approaches for analyzing multi-scale ecological data.

Main Methods:

• Utilized a hierarchical, information-theoretic approach to analyze fish metacommunity structure across 10 atolls in French Polynesia.
• Developed and compared 12 process-based hierarchical linear models representing hypotheses on reef fish community drivers.
• Assessed variation in fish abundance, biomass, and species richness at transect, reef, and atoll spatial scales.

Main Results:

• Fish biomass, species richness, and most functional groups were primarily linked to transect-level habitat diversity and atoll-lagoon size.
• Detritivore and grazer abundances correlated with potential larval dispersal covariates.
• Within-transect and among-atoll factors were the main drivers of alpha-gamma diversity relationships.

Conclusions:

• Habitat is the primary correlate of reef fish metacommunity structure across multiple spatial scales.
• Inter-atoll connectedness showed a weak correlation with nonrandom species clustering.
• Modeling hierarchical data and processes is crucial for understanding reef fish metacommunity dynamics.