Introduction and Background
Mountain Goat population in British Columbia’s Rocky Mountains and Columbia Mountains have severely decreased, in some areas even below critical population size of 50 individuals. Knowledge about the causes of these declines is required in order to implement efficient population restoration and sustainable management strategies. One probable threat to Mountain Goat is repeated disturbance, especially increasing helicopter recreational activities that could be responsible for population movements and habitat use changes. Heliskiing is an expanding business and as such its impacts on Mountain Goat populations keeps growing. Contradictory information suggests that Mountain Goats adapt to helicopter presence. To address this issue, an accurate study of the effects of heliskiing on the movement and habitat use of Mountain Goats is needed and is lacking up to date. The Wildlife Guidelines for Backcountry Tourism/Commercial Recreation of the government of British Columbia highlights this lack of knowledge especially about long-term consequences and proposes measures to address wildlife concerns including those concerning Mountain Goat.
The goal of this thesis was to assess the impacts of a gradient of heliskiing activities on movements and habitat selection of female Mountain Goats at a daily to seasonal scale. Those data will serve as a basis for long-term studies and provide suggestions to improve preservation management strategies related to heliskiing activities relative to the Wildlife Guidelines of the provincial government.
Methods, Material and Studied Area
During three years, from 2007 to 2010, data about habitat selection and movements of 11 female Mountain Goats correlated to their reaction to a spatial and temporal gradient of helicopter activity were collected in the North of British Columbia thanks to GPS-collars placed previously during capture of the individuals.
This thesis consists of two sections.
The first one focuses on abnormal movement changes in reaction to a gradient of helicopter activities at a daily and seasonal scale and aims to identify the implicated factors. The strategy used for this section is described in more details in the thesis and includes several steps : location and capture of Mountain Goats, location of heliskiing activity, comparison and identification of interaction areas corresponding to overlapping locations and timing, identification of seasonal habitat, quantification of movement changes related to heliskiing activity at a medium time scale and identification of the factors affecting this movement reaction.
The second section focuses on establishing if female Mountain Goat adapt their habitat selection patterns in reaction to a gradient of heliskiing activities at a seasonal scale. The method used for this section includes location of Mountain Goats, collection of data by helicopter equipped with on-board GPS, quantification of heliskiing activity exposure at a seasonal scale and identification of the habitat selection patterns.
The studied area is situated in the Northern Skeena Mountains that is encompassed in the Last Frontier Heliskiing tenure area in the North of British Columbia.
Results and discussion
The analysis realized for the first section show that abnormal movement is correlated to the proximity of helicopter activity and to the distance to escape area. At a daily level, data indicate that habitat range was larger after helicopter exposure for 3 Mountain Goat of 11 but without global displacement of the habitat range. At a seasonal level, data indicate that seasonal habitat size and seasonal movements were not impacted by intensified helicopter exposure.
The analysis realized for the second section did not indicate avoidance of helicopter exposure areas in their habitat range. However there were some indication of preference for security terrain when helicopter exposure grew.
The results of the first section suggest that female Mountain Goat movement and habitat ranges are intensified and enlarged at a daily scale in reaction to helicopter activity occurring in a 2km range but impacts can be avoided at a seasonal scale if pre-measures are taken such as 1,500m prohibited areas corresponding to winter habitats and limited exposure frequency.
As the general frequency of helicopter exposure used for the second part of the thesis was low, the information collected can not be extended to areas with higher rate of helicopter exposure. Indeed, the impacts on habitat selection in such areas could deviate from those obtained here.
One of the Mountain Goat management goals is to temper population threat. This thesis evaluates the threat related to disturbance from heliskiing exposure to improve understanding of the management strategies needed.
Different management recommendations have been detailed in the thesis. First, it is highly suggested to not base management decisions implicating long-term population movement or habitat selection on short-term studies results as the correlation between short-term and long-term effects are extremely uncertain. Second, according to the results of the thesis, application of the prescribed separation distance of 1,500 m between helicopter activity and Mountain Goat population or habitat in combination with other preventative measures is expected to allow avoidance of major Mountain Goat movements and habitat selection perturbation. Third, following a study that identified the areas of the Last Frontier Heliskiing (LFH) tenure that contains Mountain Goat winter habitats, LFH adapted their activity sector in 2007 to limit helicopter exposure in a 1,500m area around those winter habitats. The results of the thesis provide data to assess the efficiency of those measures. Further recommendations to improve management guidelines of heliskiing activity are expressed.
The controversy concerning the fact that the governmental guidelines need to be enforced or on the contrary need to be less restrictive has been debated in the thesis.
This three years thesis provides information that indicate that heliskiing activity negatively impact Mountain Goat movement, range size and sometimes habitat selection at a daily scale. Those results reveal that attempts to implement the government guidelines were not sufficient enough to avoid complete perturbation of Mountain Goat population. However at a seasonal scale there was no strong proof of disturbance from heliskiing exposure.
If the goal is to avoid any impacts on the Mountain Goat population, further recommendations should be integrated to the guidelines. Otherwise, if low perturbation is accepted as it does not affect population at a seasonal scale, the guidelines applied are sufficient and should be implement for all helicopter activities and not only for heliskiing activity.
Further research is recommended in the thesis to improve knowledge and understanding of impacts of helicopter activity on Mountain Goat population.
- Source Becky A. Cadsand. September 2012. Responses of Mountain Goats to Heliskiing Activity: Movements and Resource Selection. 140 p.