A feasibility assessment of wolf reintroduction to the Cape Breton Highlands
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Date
2018
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University of New Brunswick
Abstract
This thesis reports an assessment of the feasibility of establishing a viable population of Wolves (Canis sp.) on Cape Breton Island, Nova Scotia as a means of determining if Wolves can limit Moose (Alces alces) abundance in Cape Breton Highlands National Park (CBHNP) to densities desired by Parks Canada ecologists (e.g., 0.5 Moose/kmĀ²). As apex carnivores, Wolves are effective in preventing ungulate populations from reaching hyperabundant levels. It is uncertain which Canis species was present in the region prior to pre-European settlement and therefore, I used ArcGIS and Marxan to estimate the amount of available habitat for both Gray (Canis lupus) and Eastern Wolf (C. lycaon) to form territorial packs on Cape Breton Island. The population viability analysis programme VORTEX was used to predict the population size of a viable population, as well as the size needed to limit Moose (A. a. andersoni) abundance to levels less likely to impact vegetation. VORTEX simulated the population by evaluating the annual life cycle and tracking mate selection, reproduction, mortality, increment of age by one year of individuals, as well as migration among populations, removals, and supplementation. Based on the VORTEX model simulations of the long-term viability of both Wolf species, the optimal and suboptimal habitat within the National Park and adjacent highland areas could support 30 C. lupus (16 inside the Park and 14 outside of the Park), or 33 (17 inside the Park, and 16 outside of the Park) C. lycaon, respectfully. Results identified several factors important to the long-term viability of Wolf populations: 1) the percentage of adult females breeding; 2) carrying capacity; and: 3) mortality rates. If the percentage of female breeders (C. lupus) remains 55% or higher, and Wolves are not subject to immediate and long-term anthropogenic mortality risk (modelled as 30% inn mortality pups, 10% in adults), the population maintains a carrying capacity of n = 36 with a low probability of extinction (<0.25). However, based on mainly negative public attitudes to Eastern Coyote in the region, it is presumed that mortality rates will be high outside of the National Park; a Park-only population size of 16 Gray Wolves would not be viable, nor reduce Moose density to desired levels. Even if mortality rates outside the Park were low, population models suggested Wolves may not reduce Moose to desired levels. A static functional response model of Gray Wolves to changing Moose density suggested that a larger Wolf population than theoretically modelled would be required to reduce the local Moose population to desired densities. A preliminary deterministic modelling approach indicated that 30 Wolves might reduce the Moose population to desired densities when the Moose population has a growth rate of 0.1. In conclusion, the likelihood of reintroduced Wolves reducing Moose in CBHNP to desired levels depends on mortality rates outside of the Park is low because the Park itself is too small to contain a viable population of Wolves. Further work on societal attitudes to Wolves would be vital before any Wolf reintroduction program is considered.