MEPS 239:115-128 (2002)  -  doi:10.3354/meps239115

Integrating heterogeneity across spatial scales: interactions between Atrina zelandica and benthic macrofauna

J. E. Hewitt1,*, S. F. Thrush1, P. Legendre2, V. J. Cummings1, A. Norkko1

1National Institute of Water and Atmospheric Research, PO Box 11-115, Hamilton, New Zealand
2Département de sciences biologiques, Université de Montréal, C.P. 6128, succ. Centre-ville, Montréal, Québec H3C 3J7, Canada

ABSTRACT: Techniques are needed to extend the generality of detailed experimental field studies. Multi-resolution sampling designs nest fine-scale sampling within information about broad-scale processes that may affect finer-scale data. These designs are very appropriate for studies seeking to detect the effects of processes operating over a variety of scales. We tested the utility of a novel, low-intensity/cost, multi-resolution sampling design in an investigation of the relationship between the suspension-feeding pinnid bivalve Atrina zelandica and surrounding benthic macrofauna. Interactions were modelled at different spatial scales, and a variety of covariates were included in the search for the best statistical and most sensible ecological model. We chose our sampling sites to encompass broad-scale gradients in A. zelandica density and size, depth, sediment characteristics and hydrodynamics. We found these gradients helped explain the relationship between A. zelandica and associated benthic macrofauna. Our results suggest that the strength of effects of A. zelandica on benthic macrofauna was dependent on 2 aspects of spatial scale: grain (the area over which A. zelandica measurements were made) and lag (the distance between where the A. zelandica and the macrofauna were sampled). By nesting fine-scale measures of benthic macrofaunal community composition within different spatial arrangements of individual A. zelandica, we were able to determine that the maximum distance between individual A. zelandica, rather than density estimates, better explained effects of A. zelandica on benthic macrofauna. This suggests the value of integrating broad-scale surveys with localised experiments so that organism interactions can be more generally interpreted on the basis of dynamics within landscapes rather than as density-to-density comparisons.

KEY WORDS: Multi-resolution sampling designs · Nested sampling · Physical gradients · Spatial scale · Interspecific interactions · Suspension feeders · Benthic macrofauna · Landscape phenomena · Surveys · Atrina zelandica

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