

@mastersthesis {7088,
	title = {Fish and benthic invertebrate communities: {Analytical} approaches and community-environment relationships},
	year = {1992},
	note = {NN78757},
	school = {University of Toronto (Canada)},
	type = {phdPh.{D}.},
	address = {Ann Arbor},
	abstract = {I studied the variation in the interpretation of ecological communities due to changes in the type of statistical analysis employed. Using information gained from these studies, I examined the questions of whether fish and benthic invertebrates in 40 lakes from central Ontario exhibited concordant patterns in among-lake associations, and whether similar relationships existed between these communities and the lake physical and chemical environments. Choices in data standardization, such as ratio variables, were found to alter inter-variable covariation, often inducing {\textquoteright}spurious{\textquoteright} correlations. A comparison of various data standardizations, distance measures, and ordination techniques showed correspondence analysis provided the most consistent ordination regardless of data standardization. The related method of detrended correspondence analysis produced unstable results when different degrees of axis segmentation were used in the detrending procedure. Data standardization and distance measures had a greater influence in ordinations from principal components, principal coordinates analysis, and non-metric multidimesional scaling. A comparison of methods for assessing the number of non-trivial eigenvalues from principal components analysis found the traditional Kaiser-Guttman approach (i.e., eigenvalue \${\textgreater}\$1.0) and various additional methods greatly over-estimate the dimensionality of simulated data. A method incorporating bootstrapped eigenvalues and eigenvector coefficients or a method based on a broken-stick distribution proved most reliable. The fish and invertebrate communities showed similar patterns of inter-lake association. This concordance was tested using a new statistical procedure based on a randomized Procrustes analysis. Fish communities were associated significantly with lake morphology, but not water chemistry. Invertebrate communities lacked association with lake morphology, but a significant relationship with water chemistry was found. Differences in relationships between each community and the physical and chemical environment were attributed to specific ecological characteristics of the taxa and the biotic interactions between the communities.},
	keywords = {0329:Ecology, 0792:Aquaculture, 0792:Fish production, 0793:Freshwater ecology, Aquaculture, Biological sciences, Ecology, Fish production, Freshwater ecology},
	url = {http://search.proquest.com/docview/304024776?accountid=14270},
	author = {Jackson, Donald Andrew}
}
