Helminth community structure in two species of arctic-breeding waterfowl

Abstract

Climate change is occurring rapidly at high latitudes, and subsequent changes in parasite communities may have implications for hosts including wildlife and humans. Waterfowl, in particular, harbor numerous parasites and may facilitate parasite movement across broad geographic areas due to migratory movements. However, little is known about helminth community structure of waterfowl at northern latitudes. We investigated the helminth communities of two avian herbivores that breed at high latitudes, Pacific black brant (Branta bernicla nigricans), and greater white-fronted geese (Anser albifrons), to examine effects of species, geographic area, age, and sex on helminth species richness, aggregation, prevalence, and intensity. We collected 83 and 58 black brant and white-fronted geese, respectively, from Arctic and Subarctic Alaska July-August 2014. We identified 10 known helminth species (Amidostomum anseris, Amidostomum spatulatum, Drepanidotaenia lanceolata, Epomidiostomum crami, Heterakis dispar, Notocotylus attenuatus, Tetrameres striata, Trichostrongylus tenuis, Tschertkovilepis setigera, and Wardoides nyrocae) and 1 previously undescribed trematode. All geese sampled were infected with at least one helminth species. All helminth species identified were present in both age classes and species, providing evidence of transmission at high latitudes and suggesting broad host susceptibility. Also, all but one helminth species were present at both sites, suggesting conditions are suitable for transmission across a large latitudinal/environmental gradient. Our study provides important baseline information on avian parasites that can be used to evaluate the effects of a changing climate on host-parasite distributions.

Keywords: Anser albifrons; Arctic; Branta bernicla nigricans; Climate change; Greater white-fronted goose; Helminth; Pacific black brant; Parasite community.

Graphical abstract

Fig. 1

Study sites in Alaska where Pacific black brant and greater white-fronted geese were collected for helminth examination in 2014; A) Yukon-Kuskokwim Delta (61° N 164° W) in Subarctic western Alaska and B) the Arctic Coastal Plain (70° N 154°) in Arctic Alaska.

Fig. 2

Predicted helminth species richness (SR) for Pacific black brant (BLBR) and greater white-fronted geese (GWFG) collected from Subarctic and Arctic Alaska (2014). Circles represent predicted means and error bars denote 85% confidence intervals. Predictions are based on the most supported model from AIC_c selection and all interactions include lower-order effects (see title).

Fig. 3

Predicted prevalence (top) and helminth infection intensity (bottom) for the nematode Trichostrongylus tenuis enumerated in Pacific black brant (BLBR) and greater white-fronted geese (GWFG) collected in Arctic and Subarctic Alaska (2014). Circles represent predicted means and error bars denote 85% confidence intervals. Predictions are based off the most supported model from AIC_c selection and all interactions include lower-order effects (see titles).

Fig. 4

Predicted prevalence (top) and helminth infection intensity (bottom) for the cestode Drepanidotaenia lanceolata enumerated in Pacific black brant (BLBR) and greater white-fronted geese (GWFG) collected in Arctic and Subarctic Alaska (2014). Circles represent predicted means and error bars denote 85% confidence intervals. Predictions are based off the most supported model from AIC_c selection and all interactions include lower-order effects (see titles).

Fig. 5

Predicted helminth infection intensity for combined cestodes identified in Pacific black brant (BLBR) and greater white-fronted geese (GWFG) collected in two locations (i.e., Arctic and Subarctic) in Alaska (2014). Circles represent predicted means and error bars denote 85% confidence intervals. Predictions are based off the most supported model from AIC_c selection and all interactions include lower-order effects (see title).

Fig. 6

Predicted prevalence (top) and helminth infection intensity (bottom) for the cestode Tschertkovilepis setigera enumerated in Pacific black brant (BLBR) and greater white-fronted geese (GWFG) collected in Arctic and Subarctic Alaska (2014). Circles represent predicted means and error bars denote 85% confidence intervals. Predictions are based off the most supported model from AIC_c selection and all interactions include lower-order effects (see titles).