title: Uniform functional structure across spatial scales in an intertidal benthic assemblage.
abstract: To investigate the causes of the remarkable similarity of emergent assemblage properties that has been demonstrated across disparate intertidal seagrass sites and assemblages, this study examined whether their emergent functional-group metrics are scale related by testing the null hypothesis that functional diversity and the suite of dominant functional groups in seagrass-associated macrofauna are robust structural features of such assemblages and do not vary spatially across nested scales within a 0.4 ha area. This was carried out via a lattice of 64 spatially referenced stations. Although densities of individual components were patchily dispersed across the locality, rank orders of importance of the 14 functional groups present, their overall functional diversity and evenness, and the proportions of the total individuals contained within each showed, in contrast, statistically significant spatial uniformity, even at areal scales <2 m(2). Analysis of the proportional importance of the functional groups in their geospatial context also revealed weaker than expected levels of spatial autocorrelation, and then only at the smaller scales and amongst the most dominant groups, and only a small number of negative correlations occurred between the proportional importances of the individual groups. In effect, such patterning was a surface veneer overlying remarkable stability of assemblage functional composition across all spatial scales. Although assemblage species composition is known to be homogeneous in some soft-sediment marine systems over equivalent scales, this combination of patchy individual components yet basically constant functional-group structure seems as yet unreported.
authors: School of Biological Sciences and Centre for Marine Science, University of Queensland, Brisbane 4072, Queensland, Australia; Biodiversity Program, Queensland Museum, Brisbane 4101, Queensland, Australia. Electronic address: r.barnes3@uq.edu.au.
authors: R S K
authors: RS
authors: Barnes
authors: School of Earth & Environmental Sciences, University of Wollongong, Wollongong 2522, New South Wales, Australia.
authors: Sarah
authors: S
authors: Hamylton
mesh_terms: D000818:Animals; D044822:Biodiversity; D007448:Invertebrates / Q000502:physiology*; D009792:Oceans and Seas; D010944:Plants; D011156:Population Density; D011793:Queensland
keywords: Autocorrelation; Functional analysis; Sea grass; Spatial dispersion; Spatial variation; Zoobenthos