Factors affecting the component community structure of haemoparasites in bank voles (Clethrionomys glareolus) from the Mazury Lake District region ofPoland

The prevalence and abundance of infections with haemoparasites were studied over a 3 year period in Clethrionomys glareolus (bank vole, n = 420) sampl ed from forests in the NE of Poland. Total species richness was 5 (Prevalen ce = Haemobartonella sp. 63.1 %, Bartonella grahamii 27.4 %, Hepatozoon erh ardovae 31.4 %, Trypanosoma evotomys 15 degrees, and Babesia microti 1.0 % ) with 81.9 %, of the voles carrying at least 1 species and a mean infracom munity; species richness of 1 1. Variation in species richness was determin ed primarily by season and year, and the interaction of these factors. The observed frequency distribution of intracommunity species richness did nor differ from that predicted by a null model, suggesting that there were no m arked associations between the species. Analyses of prevalence and abundanc e of infection with each species in turn, revealed that overall the princip al causes of variation were temporal and seasonal and their interaction, in trinsic factors such as age and sex playing only a miller role. However,. t he relative importance of specific extrinsic, and rarely intrinsic, factors varied and was distinct for each of the species in the study. Prevalence d ata revealed 1 sets of 2-way associations between en species, most varyingl y dependent on combinations of intrinsic and extrinsic factors. Analysis of quantitative associations suggested 4 sets of positive 2-way interactions, 3 of which remained after controlling for the effect of extrinsic and intr insic factors on the abundance of each species, but only one could be unequ ivocally accepted (Haemobartonella sp. + B. grahamii) after correction for multiple comparisons. These data are discussed in the context of the changi ng ecological profiles in this region of Eastern Europe and, in a wider con text, in relation to current understanding of the factors which shape compo nent community structures of haemoparasites in wild rodents.