Diversity of the parasite assemblage of Fundulus zebrinus in the Platte River of Nebraska.

Changes in the values of the Shannon H' diversity index as determined for individual hosts (infraassemblage diversity), host samples (sample assemblage diversity), and for species density are reported for an assemblage of 7 parasites in Fundulus zebrinus in the Platte River in Nebraska for a 5-yr period. The parasites were: Myxosoma funduli (gill), Trichodina sp. (gill), Gyrodactylus bulbacanthus (gill), Salsuginus sp. (gill), Gyrodactylus stableri (body surface), and Neascus sp. (= Posthodiplostomum; eyes and body cavity). In addition, relative abundance and equitability are given for each of the study years. Mean infraassemblage diversity, sample assemblage diversity, species density, and equitability were all significantly negatively correlated with river streamflow (measured in cubic feet per second) of the year prior to the sample, but were independent of the concurrent year's streamflow. Over the long term, M. funduli and Trichodina sp. were the most, and G. bulbacanthus was the least, abundant. Species pair prevalence and relative density correlations showed few long-term patterns of co-occurrence or microallopatry. The strongest association was between M. funduli and the Neascus sp. and was attributed to similarities in ecological requirements of intermediate hosts.