Behavioural interactions between ecosystem engineers control community species richness
Gribben, PE and Byers, JE and Clements, M and McKenzie, LA and Steinberg, PD and Wright, JT, Behavioural interactions between ecosystem engineers control community species richness, Ecology Letters, 12, (11) pp. 1127-1136. ISSN 1461-023X (2009) [Refereed Article]
Behavioural interactions between ecosystem engineers may strongly influence community
structure. We tested whether an invasive ecosystem engineer, the alga Caulerpa
taxifolia, indirectly facilitated community diversity by modifying the behaviour of a native
ecosystem engineer, the clam Anadara trapezia, in southeastern Australia. In this study,
clams in Caulerpa-invaded sediments partially unburied themselves, extending >30% of
their shell surface above the sediment, providing rare, hard substrata for colonization.
Consequently, clams in Caulerpa had significantly higher diversity and abundance of
epibiota compared with clams in unvegetated sediments. To isolate the role of clam
burial depth from direct habitat influences or differential predation by habitat, we
manipulated clam burial depth, predator exposure and habitat (Caulerpa or unvegetated)
in an orthogonal experiment. Burial depth overwhelmingly influenced epibiont species
richness and abundance, resulting in a behaviourally mediated facilitation cascade. That
Caulerpa controls epibiont communities by altering Anadara burial depths illustrates that
even subtle behavioural responses of one ecosystem engineer to another can drive
extensive community-wide facilitation.
Behaviour, bivalves, ecosystem engineer, epibiota, facilitation cascades, habitat-forming
species, invasive species, recruitment, trait-mediated indirect effects.