Trait sensitivities to seagrass fragmentation across spatial scales shape benthic community structure

Area of Science:

• Ecology
• Marine Biology
• Conservation Biology

Background:

• Local ecological communities are shaped by hierarchical filters (abiotic and biotic) influencing species traits.
• Habitat fragmentation, a human impact, alters environmental conditions across scales and affects trait-environment interactions.

Purpose of the Study:

• To examine how environmental variation from habitat fragmentation influences benthic fauna community structure.
• To assess the role of species traits in predicting responses to fragmentation across microhabitat, patch, and landscape scales.

Main Methods:

• Quantified species abundance and biomass of seagrass epifauna and infauna across 86 sites in Back Sound, North Carolina.
• Related faunal community structure to environmental variables at microhabitat, patch, and landscape scales.
• Utilized fourth-corner analysis to link species traits to environmental variation and fragmentation effects.

Main Results:

• Overall community structure was predicted by environmental variation at microhabitat, patch (size), and landscape (number of patches, area) scales.
• Species traits explained as much variation in organismal densities as species identity.
• Planktonic-dispersing and deposit-feeding species thrived in contiguous landscapes, while suspension feeders preferred fragmented ones.

Conclusions:

• Hierarchical models of community assembly are supported, with trait-environment interactions across scales driving local composition.
• Fragmentation alters community assembly by affecting traits related to dispersal, mobility, and trophic mode.
• Climate change may further shift community dynamics by favoring species with planktonic larvae, potentially weakening environmental control.