Ecological Analyses of Helminth Populations in the Black Bear, Ursus americanus, from North America

Abstract

Faunal similarity was examined using a data base of 23 helminth species from 104 black bears collected in the southeastern United States. With the eight common helminth species, analysis of faunal similarity indicated relative consistency across nested habitat variables of host age and sex, and some degree of maturity of interrelationships between species within this helminth fauna. A basic dissimilarity in the helminth faunas of black bears across 11 geographic regions in North America resulted from (1) a distinct helminth fauna in the southeastern United States, but with considerable variation across four subregions, (2) a disparity of helminth species in the primary community represented by Dirofilaria ursi and Baylisascaris transfuga, which were the only host-specific species approaching ubiquitous distribution across all regions in North America, and (3) considerable diversity resulting from numerous shared species of raccoon and canid origin comprising a large secondary community of rare to common helminth species across the respective regions. Studies such as this one may lead to a more decisive means of delineating predictive models for the parasite species involved in epidemics. Previous studies on the helminth communities of several species of wild Carnivora in North