title: Relative Importance of Biotic and Abiotic Forces on the Composition and Dynamics of a Soft-Sediment Intertidal Community.
abstract: Top-down, bottom-up, middle-out and abiotic factors are usually viewed as main forces structuring biological communities, although assessment of their relative importance, in a single study, is rarely done. We quantified, using multivariate methods, associations between abiotic and biotic (top-down, bottom-up and middle-out) variables and infaunal population/community variation on intertidal mudflats in the Bay of Fundy, Canada, over two years. Our analysis indicated that spatial structural factors like site and plot accounted for most of the community and population variation. Although we observed a significant relationship between the community/populations and the biotic and abiotic variables, most were of minor importance relative to the structural factors. We suggest that community and population structure were relatively uncoupled from the structuring influences of biotic and abiotic factors in this system because of high concentrations of resources that sustain high densities of infauna and limit exploitative competition. Furthermore, we hypothesize that the infaunal community primarily reflects stochastic spatial events, namely a "first come, first served" process.
authors.affiliation: Department of Biology, University of New Brunswick, Fredericton, New Brunswick, E3B 5A3, Canada.
authors.forename: Travis G
authors.initials: TG
authors.lastname: Gerwing
authors.affiliation: Department of Biology, Mount Allison University, Sackville, New Brunswick, E4L 1G7, Canada.
authors.forename: David
authors.initials: D
authors.lastname: Drolet
authors.affiliation: Department of Biology, Mount Allison University, Sackville, New Brunswick, E4L 1G7, Canada.
authors.forename: Diana J
authors.initials: DJ
authors.lastname: Hamilton
authors.affiliation: Department of Biology, University of New Brunswick, Fredericton, New Brunswick, E3B 5A3, Canada.
authors.forename: Myriam A
authors.initials: MA
authors.lastname: Barbeau
mesh_terms: D000818:Animals; D001419:Bacteria / Q000145:classification*; D033364:Decapoda; D017753:Ecosystem; D004777:Environment; D011157:Population Dynamics; D012111:Residence Characteristics; D012988:Soil Microbiology