Increased variability as a symptom of stress in marine communities
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An increase in variability between samples collected from impacted vs. control areas is described for four different types of marine communities: meiobcnthos subjected to organic enrichment, macrobenthos in the vicinity of the Ekofisk oil-field, reef-corals following the 1982-3 El Niño and fish on coral reefs which are subjected to mining. In each case there is a clear log-log relationship between the variance and the mean abundance for all species in a particular treatment group. The standard deviation for a given mean increases with increased perturbation in all cases, but is most marked for the meiobenthos and macrobenthos examples. Variability in species diversity (H') tends to increase with increasing levels of perturbation, but this increase is only significant for the macrobenthos. In all cases a pronounced increase in variability among replicate samples from perturbed treatments was revealed by multivariate analysis (non-metric Multi-Dimensional Scaling ordination). A comparative Index of Multivariate Dispersion (IMD) is suggested as a measure of this increased variability.
|Publication Type:||Journal Article|
|Copyright:||© 1993 Published by Elsevier B.V.|
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