Abstract: Biodiversity-ecosystem function (BEF) research stems back decades and has seen a recent exponential growth of the field. Many questions remain about the importance of functional diversity (complementarity) versus redundancy, differential species effects, and the effects of abundance versus different diversity components. We examined the BEF relationship in deep-sea xylophagous bivalve communities using 63 experimental wood falls deployed ~2000m deep in the Gulf of Mexico. We quantified the relationships between spatial and trophic partitioning, species dominance, individual species effects, and community level properties on total wood consumption, our metric for ecosystem function. A total of 26,324 individuals from 12 xylophagous bivalve species were identified. Individual species inhabited complementary spatial and trophic niches, but species effects on total wood consumption greatly varied. The amount of wood consumed increased significantly with total abundance and species richness, although richness effects reflected increases in abundance. Ecosystem function among wood fall appears to be predominately a feature of highly abundant core species with greater functional diversity.