The helminth community structure as an indicator of habitat use: the case of the Baird’s Sandpiper (Calidris bairdii) and the White-Rumped Sandpiper (Calidris fuscicollis) on their non-breeding grounds in Patagonia

Abstract

During migrations, birds are exposed to a wide variety of parasites. It has been suggested that shorebird migration and other movements play a critical role in structuring their parasite communities. The objective of this study was to characterize the helminth communities of two sympatric Nearctic migratory shorebird species in their non-breeding grounds in Argentine Patagonia and to assess what factors influence their structuring. The migration of these two bird species span from pole to pole as they breed in the Canadian Arctic and winter at southernmost South America. In contrast to the Arctic, the helminth communities of these birds have never been studied at their austral non-breeding sites. A total of 44 Calidris bairdii and 50 Calidris fuscicollis collected at various coastal marine and inland sites were analyzed for helminths. Ecological parameters were calculated at component community (host population) and infracommunity (single individual hosts) levels. A total of 26 helminth taxa were found, included in 14 families and 20 genera. Results showed that parasite richness and total prevalence were higher in C. bairdii than in C. fuscicollis. Richness, diversity, dominance and abundance values in the infracommunities were generally low, being lower in C. fuscicollis. The infracommunities were characterized by being heterogeneous, unstructured and unpredictable. Possible causes of this pattern are discussed. It is clear that multiple factors influence parasitic diversity; however, considering our observations, we think that habitat use is possibly the main structuring factor of the helminth communities of these two shorebird species.