Ecological limits to human disturbances – A case study involving trails

Human Activity Differentially Redistributes Large Mammals in the Canadian Rockies National Parks 

James Kimo Rogala, Mark Hebblewhite,Jesse Whittington,Cliff A. White,Jenny Coleshill and Marco Musian 
Ecology and Society 16(3): 16.

Burgeoning population is causing irrevocable havoc in many wilderness areas. Parks are susceptible to habitat degradation. Indirect habitat loss is also possible as a result from both natural and anthropogenic disturbances. This new study on the human impact on wildlife in some of Canada’s most popular national parks has identified limits at which trails can be used before ecological disturbance sets in. Even though the thrust is on Canadian Parks the results arrived at has implications for mangers worldwide.

The researchers say human activity on trails and roads may lead to indirect habitat loss, further limiting available habitat. Predators and prey may respond differentially to human activity, which in turn has the potential for disrupting ecological processes

The researchers investigated the relationship between wolf and elk distribution and human activity using fine-scale Global Positioning System (GPS) wildlife telemetry locations and hourly human activity measures on trails and roads in Banff, Kootenay, and Yoho National Parks, Canada. They observed a complex interaction between the distance animals were located from trails and human activity level resulting in species adopting both mutual avoidance and differential response behaviors. In areas < 50 m from trails human activity led to a mutual avoidance response by both wolves and elk. In areas 50 - 400 m from trails low levels of human activity led to differential responses; wolves avoided these areas, whereas elk appeared to use these areas predation refugia. These differential impacts on elk and wolves may have important implications for trophic dynamics.

As human activity increased above two people/hour, areas 50 - 400 m from trails were mutually avoided by both species, resulting in the indirect loss of important montane habitat.

The researchers contend that if park managers are concerned with human impacts on wolves and elk, or on these species’ trophic interactions with other species, they can monitor locations near trails and roads and consider hourly changes of human activity levels in areas important to wildlife.

The researchers sign off with the following words “The circadian cycle has been the finest temporal scale used by previous studies that associate wildlife distribution to human activity. Our research documented that wildlife avoidance occurs at finer spatio-temporal scales than previously studied. We found that wolf and elk selection of locations near trails and roads was dependent on hourly human activity levels and the distance to the human linear feature. A failure to properly address the scale at which wildlife respond to human activity could lead to mistaken conclusions about habitat selection. Proper assessment of the relationship between fine-scale human activity and wildlife distribution may have important implications for animal energy budgets, human-wildlife and predator-prey interactions, ecological trophic cascades, and wildlife viability.”