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Title: PROTOSTRONGYLUS STILESI (PROTOSTRONGYLIDAE), ECOLOGICAL ISOLATION AND PUTATIVE HOST-SWITCHING BETWEEN DALL'S SHEEP AND MUSKOXEN IN A CONTACT ZONE

Author
item Hoberg, Eric
item KUTZ, SUSAN - UNIV SASKATCHEWAN, CANADA
item NAGY, JOHN - GOVT NWT, CANADA
item JENKINS, EMILY - UNIV SASKATCHEWAN, CANADA
item ELKIN, BRETT - GOVT NWT, CANADA
item BRANIGAN, MARSHA - GOVT NWT, CANADA
item COOLEY, DOROTHY - YUKON TERRITORY, CANADA

Submitted to: Comparative Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/23/2001
Publication Date: 1/20/2002
Citation: HOBERG, E.P., KUTZ, S.J., NAGY, J., JENKINS, E., ELKIN, B., BRANIGAN, M., COOLEY, D. PROTOSTRONGYLUS STILESI (PROTOSTRONGYLIDAE), ECOLOGICAL ISOLATION AND PUTATIVE HOST-SWITCHING BETWEEN DALL'S SHEEP AND MUSKOXEN IN A CONTACT ZONE. COMPARATIVE PARASITOLOGY. 2002.

Interpretive Summary: Disruption of contemporary ecological isolating barriers for parasites and pathogens can result from habitat perturbation, anthropogenically or climatologically driven, and from management practices that influence the distribution of ungulate hosts. Although we recognize these factors, few field studies have documented the interplay and influence of these mechanisms on the distribution of pathogenic parasites. Lungworms, Protostrongylus stilesi, were found for the first time in introduced muskoxen Ovibos moschatus wardi from the Arctic Coastal Plain, Yukon (YT) and Northwest Territories (NT), Canada and Ovis dalli dalli from the northern Richardson Mountains, NT. Occurrence of P. stilesi in a population of introduced muskoxen is indicative of a contemporary host-switch from Dall's sheep. Parasite specificity is ecologically based and contextual, and as zones of contact become more extensive or the temporal limits on ecological segregation of hosts are relaxed, we may observe increasing instances of host-switching by parasites or pathogens. Biotic impacts to northern systems linked to climatologically and anthropogenically driven global change and the effects of management must be tracked within the context of biodiversity survey and inventory for monitoring ecosystem-level perturbations. A developing interface for muskoxen, wild sheep, and parasites along the Mackenzie River ecotone represents a natural model or field laboratory to examine these processes.

Technical Abstract: Lungworms, Protostrongylus stilesi, were found for the first time in Ovibos moschatus wardi from the Arctic Coastal Plain, Yukon (YT) and Northwest Territories (NT), Canada and Ovis dalli dalli from the northern Richardson Mountains, NT. Occurrence of P. stilesi in a population of introduced muskoxen is indicative of a contemporary colonization event from Dall's sheep; specificity may be ecologically based and contextual. Colonization of muskoxen by P. stilesi may be a predictable event in zones of sympatry with Dall's sheep; exposure to infection may coincide with occupation of winter ranges of Dall's sheep by muskoxen during the summer season. Disruption of contemporary ecological isolating barriers can result from habitat perturbation, anthropogenically or climatologically driven, and from management practices that influence the distribution of ungulate hosts. Thus, if zones of contact become more extensive or the temporal limits on allopatry are relaxed, we may observe increasing instances of host-switching by parasites or pathogens. Recent expansion of muskoxen populations on the mainland resulting in range overlap with Dall's sheep is also expected to lead to new contact zones for endemic O. moschatus moschatus and introduced O. moschatus wardi that could further influence parasite distribution. Biotic impacts to northern systems linked to climatologically and anthropogenically driven global change must be tracked within the context of biodiversity survey and inventory and archival collections.