Spatial and temporal variation in the structure of estuarine macroinvertebrate assemblages: implications for assessing the health of estuaries

摘要: As human impacts in estuaries are often pervasive (estuary-wide) and/or pre-existing, the identification of suitable reference points, from which to assess extent of impacts, is problematic. One solution compare potentially degraded with deemed be largely unmodified by activities. However, there a perception that individual too spatially and temporally dynamic allow valid comparisons made using such an approach. We tested this idea for commonly used indicator, benthic macroinvertebrates, factorial design incorporating both temporal spatial scales between within three adjacent meso-tidal river northern Tasmania. Variation macroinvertebrate assemblage structure was analysed permutational multivariate analysis of variance. Most variance occurred (68–82% variance) relative differences estuaries (24–14%) corresponding strong upstream estuarine gradient small-scale patchiness. Seasonal variation accounted 9–4% total indicating that were relatively insignificant when contrasted against variability estuaries. suggest sufficient replication at within estuary-scale, entire may act as whole systems, allowing studies examine potential within estuaries diffuse, pre-existing impacts.