MULTIVARIATE ANALYSIS OF COMMUNITY STRUCTURE OVERTEN YEARS FOLLOWING THE EXXON VALDEZ OIL SPILL

摘要

A 1990/1991 shoreline ecology program to assessthe fate and effects of the Exxon Valdez oil spill in PrinceWilliam Sound was updated in 1998 and 1999. This updateincluded a sediment sampling program for organisms at "worstcase" sites and at randomly chosen reference sites.Correspondence analysis (CA), a statistical method thatexamines animal communities in terms of their similarity, wasused to define community structure Statistical analysis of thedegree of similarity between communities was used to assesseffects of site-specific variables (sediment grain size, totalorganic carbon (TOC) and wave energy), interannual variation,and degree of oiling. Interannual variability had a significanteffect on community structure, whereas site specific variablesand degree of oiling did not. Differences in communities between1998 and other years were particularly dramatic. Theimportance of interannual change demonstrates the importanceof multi-year sampling and of appropriate study designs forseparating impact effects from the natural occurringenvironmental factors which affect biological communities.