Higher parasite burdens are associated with lower body condition in a Norwegian moose population

Abstract

Parasites are ubiquitous in wildlife and can influence health and fitness. Thus, the inclusion of parasites in wildlife monitoring programs could provide important information for understanding declines in population body condition or recruitment rates. However, parasites are often neglected as a factor in wildlife management. We characterised the gastrointestinal parasite community of moose ( Alces alces ) in central Norway over an autumn hunting season and the following winter, using parasitological examination of faecal samples. We identified an age-related effect on parasite communities, including increased prevalence and abundance of Protostrongylidae species and increased community richness in yearlings compared to older moose. We also found that individuals with a lower body mass had higher burdens of Trichostrongylidae and Protostrongylidae species in autumn. There was some evidence for increased parasite burdens in males compared to females, while there was less evidence for seasonal differences between autumn and winter in a subsample of adult females. We found no strong associations between parasite burdens and moose population density. Our results add to the growing body of literature supporting the use of parasite burdens as proxies for an individual’s health status and potentially as predictors for fitness effects. In many Fennoscandian moose populations, the body condition and recruitment rates of individuals are declining, thus further monitoring of parasites may be needed to better understand the mechanisms behind these declines, including the potential role of parasites.

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