SPATIAL VARIATION IN SOFT-SEDIMENT BENTHOS

Variation (patchiness) in the distribution of organisms and other environmental variables exists at different spatial scales. This patchiness has important implications for comparative and descriptive studies of distribution and abundance because it complicates comparisons of abundance at the largest spatial scales. Although the existence of patchiness has been recognised for a long time, it has not been adequately addressed in most studies of marine soft sediments, which are often confounded (or 'pseudoreplicated') because of a lack of appropriate spatial replication. Spatial variation in the distribution of soft-sediment macrofauna in Botany Bay, Australia, is described using a nested, hierarchical sampling design. Significant variation was detected at spatial scales from 10 m to 3.5 km. Implications of patchiness for environmental sampling and monitoring, and the means ot overcoming associated problems, are discussed. The present study concerns the abundance of macrofauna, but the conclusions are general and are relevant to studies of other variables, such as pollutants.