Balancing Loss of Information and Gains in Efficiency in Characterizing Stream Sediment Samples

Abstract

Sediment description is becoming an essential consideration in many types of lotic research. This paper examines the necessity for detailed organic loss-on-ignition measures and inorganic particle-size-analysis in describing streambed sediment samples. Sediment samples (n = 94) were obtained from a 150-m stretch of the Madawaska River in central Ontario, and a full analysis (organic content and inorganic particle-size-analysis) of each sediment sample was carried out. The difference between every pair of sample points in the composition of sediment was summarized in a distance matrix of average taxonomic distances. We quantified the loss of information about variation in benthic sediment habitat when (i) organic content of the sediment was ignored, (ii) size fractions of sediment were pooled prior to analysis, and (iii) the presence or absence of size categories, rather than actual mass determinations, were used to describe sediment samples. Distance matrices were re-calculated with these cruder sediment ...