Species identity drives ecosystem function in a subsidy-dependent coastal ecosystem

Area of Science:

• Marine ecology
• Ecosystem functioning
• Biodiversity research

Background:

• Declining species diversity profoundly impacts ecosystem functioning.
• Subsidized ecosystems, like sandy beaches, offer insights into biodiversity-ecosystem relationships.
• Sandy beaches rely on detritus from marine ecosystems for their food webs.

Purpose of the Study:

• To investigate how consumer species diversity and identity affect kelp wrack consumption on sandy beaches.
• To understand the role of species richness versus species traits in ecosystem functions.
• To assess the impact of biodiversity loss on coastal ecosystem services.

Main Methods:

• Experimental manipulation of invertebrate detritivore richness in laboratory mesocosms.
• Field assays to measure kelp consumption rates on beaches.
• Analysis of species identity, body size, and their influence on consumption rates.

Main Results:

• Consumer species richness had no significant effect on kelp consumption in field studies.
• Species richness showed a slight negative effect on kelp consumption in laboratory experiments.
• Species identity and body size of detritivores were the primary drivers of kelp consumption rates.

Conclusions:

• Species traits, particularly body size and identity, are more critical than species richness for ecosystem function in detrital food webs.
• Functional redundancy across species is high in these systems.
• Loss of large-bodied consumer species on sandy beaches could disproportionately impair ecosystem functions, threatening coastal biodiversity.