Linking partial migration to endo- and ectoparasite infection of collared and uncollared elk (Cervus canadensis)

• Author / Creator

  Normandeau, Jacalyn

• Ungulate ecology studies can focus on forage-predation interactions, but parasites also can have significant impacts on body condition, fecundity, and survival in ungulates. The effects of migration on parasite exposure are not well understood, but exposure may differ on allopatric summer ranges. I studied parasites in a partially migratory elk (Cervus canadensis) population that winters at the Ya Ha Tinda bordering Banff National Park in Alberta. Close to 50% of the elk remain on the Ya Ha Tinda year-round with equal numbers of elk migrating westward into the high elevations of Banff National Park and eastward to low-elevation industrial forests. I sampled fecal pellets of unmarked elk from May to August 2017 and 2018 to compare diversity and abundance of parasite groups in elk following each of the three migratory tactics. I also sampled pellets of radiocollared elk from March to April 2018 and 2019 to relate prevalence and intensity of liver flukes (Fascioloides magna) to previous summer’s use of wetlands, elevation, forage biomass, and areas of elk concentration. Parasite eggs were isolated from pellets and identified via morphology microscopically. In winter, I compared hair loss due to grooming for winter tick (Dermacentor albipictus) and grooming behaviours among the migratory tactics. I assessed behaviours of 66 focal individuals on the winter range in 2019 and used close-up images taken from horseback to quantify hair loss. I focused on liver flukes because they are capable of causing mortality in elk at high intensity of infection and on winter ticks because they can promote weight loss and mortality. For endoparasites, I assessed predictions contrasting parasite levels among migratory tactics with hypotheses indicating that migration (1) allowed elk to escape parasite exposure, (2) exposed migrants to novel parasites or habitats of secondary hosts on allopatric ranges, and (3) potentially facilitated recovery on the allopatric range. For ticks, I assessed whether hair loss was related to grooming and whether grooming for ticks was costly by reducing foraging, rumination, and vigilance. I also assessed whether radiocollars alleviated tick irritation and therefore reduced grooming or whether they promoted hair loss. I found migrant elk had more diverse and higher parasite abundance than resident elk. Prevalence and intensity of liver flukes were highest in eastern migrants, which was consistent with earlier migration to a warmer, low-elevation summer range with a greater extent of secondary host habitat (i.e., the wetland). An increase in grooming in winter was associated with a decrease in foraging time and an increase in time spent resting, but grooming comprised only 1.1% (~ 2 minutes during a 12hr period) of the elk activity budget during the daylight hours. Radio-collars had an additive effect on neck hair loss and I found no evidence of collars reducing tick infestation. Higher infections of internal parasites in eastern migrants of the Ya Ha Tinda elk population could reduce the relative fitness benefits that have promoted the emergence of this migratory tactic. My study is among the first to assess fine-scale habitat use of individual elk relating to liver fluke infection and to quantify grooming for ticks in elk across all activities, adding to our understanding of how parasites may directly and indirectly contribute to a shifting pattern in migration.

• Subjects / Keywords

  • liver fluke
  • migration
  • winter tick
  • elk
  • hair loss
  • collar
  • parasite

• Graduation date

  Fall 2019

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-wnd5-rg47

• License

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