Date of Award
Program or Major
Master of Science
James F Haney
In 2007 the United States Environmental Protect Agency sampled 1157 lakes to determine the state of the nation’s lakes. The data they collected provided a unique opportunity to study the effects of eutrophication on zooplankton community structure across a range of lakes from a large geographical area. Using this data set two main questions were assessed: 1) what level of taxonomic identification is necessary to detect differences in zooplankton community composition as it relates to patterns in water quality and 2) in a dataset that has extensive spatial and temporal variability, how does one account for regional differences in zooplankton seasonal succession?
Thirty lakes in the northeast United States were analyzed using non-metric multidimensional scaling (NMDS), multi-response permutation procedures (MRPP) and indicator species analysis (ISA) to assess zooplankton community composition with taxonomic resolution evaluated to species, genus and family. Detectable patterns were observed across all levels of taxonomic resolution with the NMDS and MRPP. Using ISA, the highest level of taxonomic resolution (species) resulted in the most consistent indicators of lake trophic status. Identifications to genus gave comparable results for small cladocerans but not for copepods.
To assess whether zooplankton seasonal succession has to be taken into account when relating zooplankton communities to water quality, three groups of 48 lakes were selected from across the country. Two groups of lakes were selected at random and the third group was selected using a model that predicted the date of Daphnia maximum abundance based on latitude. The NMDS using the model resulted in the best ordination with an R2 of 0.94 and stress value of 10.49. Though these lakes had a detectable pattern in the zooplankton community, explaining the pattern based solely on lake trophic status may have been obscured by the state of seasonal succession indicating strong pressure by fish predation and or food limitation.
Dufresne, Jonathan, "DISCERNING DIFFERENCES BETWEEN ZOOPLANKTON COMMUNITIES BASED ON LAKE TROPHIC STATUS" (2017). Master's Theses and Capstones. 1137.