TY - JOUR

T1 - Species interactions and environmental context affect intraspecific behavioural trait variation and ecosystem function

AU - Cassidy, Camilla

AU - Grange, Laura

AU - Garcia, Clement

AU - Bolam, Stefan

AU - Godbold, Jasmin

PY - 2020/1/29

Y1 - 2020/1/29

N2 - Functional trait-based approaches are increasingly adopted to understand and project ecological responses to environmental change; however, most assume trait expression is constant between conspecifics irrespective of context. Using two species of benthic invertebrate (brittlestars Amphiura filiformis and Amphiura chiajei), we demonstrate that trait expression at individual and community levels differs with biotic and abiotic context. We use PERMANOVA to test the effect of species identity, density and local environmental history on individual (righting and burrowing) and community (particle reworking and burrow ventilation) trait expression, as well as associated effects on ecosystem functioning (sediment nutrient release). Trait expression differs with context, with repercussions for the faunal mediation of ecosystem processes; we find increased rates of righting and burial behaviour and greater particle reworking with increasing density that are reflected in nutrient generation. However, the magnitude of effects differed within and between species, arising from site-specific environmental and morphological differences. Our results indicate that traits and processes influencing change in ecosystem functioning are products of both prevailing and historic conditions that cannot be constrained within typologies. Trait-based study must incorporate context-dependent variation, including intraspecific differences from individual to ecosystem scales, to avoid jeopardizing projections of ecosystem functioning and service delivery.

AB - Functional trait-based approaches are increasingly adopted to understand and project ecological responses to environmental change; however, most assume trait expression is constant between conspecifics irrespective of context. Using two species of benthic invertebrate (brittlestars Amphiura filiformis and Amphiura chiajei), we demonstrate that trait expression at individual and community levels differs with biotic and abiotic context. We use PERMANOVA to test the effect of species identity, density and local environmental history on individual (righting and burrowing) and community (particle reworking and burrow ventilation) trait expression, as well as associated effects on ecosystem functioning (sediment nutrient release). Trait expression differs with context, with repercussions for the faunal mediation of ecosystem processes; we find increased rates of righting and burial behaviour and greater particle reworking with increasing density that are reflected in nutrient generation. However, the magnitude of effects differed within and between species, arising from site-specific environmental and morphological differences. Our results indicate that traits and processes influencing change in ecosystem functioning are products of both prevailing and historic conditions that cannot be constrained within typologies. Trait-based study must incorporate context-dependent variation, including intraspecific differences from individual to ecosystem scales, to avoid jeopardizing projections of ecosystem functioning and service delivery.

KW - bioturbation

KW - functional traits

KW - functional diversity

KW - community composition

KW - intraspecific variation

KW - trait expression

U2 - 10.1098/rspb.2019.2143

DO - 10.1098/rspb.2019.2143

M3 - Article

VL - 287

JO - Proceedings of the Royal Society B: Biological Sciences

JF - Proceedings of the Royal Society B: Biological Sciences

SN - 0962-8452

IS - 1919

M1 - 20192143

ER -