Elk Harvests and Herd Reconstruction in Alberta for Adaptive Management

• Author / Creator

  Trump, Tyler

• In wildlife conservation, long-term monitoring is often justified by wildlife agencies as they allow managers to inform stakeholders, avoid conflicts, and to evaluate the results of management interventions. However, many wildlife agencies insufficiently or inadequately use these data in their management decisions. Two of the most common causes of inefficient monitoring are surveillance monitoring (monitor for monitoring sake, without evaluation) or not having the budget to properly monitor management interventions. For example, like most wildlife agencies in North America, Alberta, Canada, has been collecting data on the harvest of its hunted populations, including elk (Cervus elaphus), but has not evaluated the regulatory results and trends alongside relevant data such as predator populations abundance. Large predator populations are often believed to cause a decrease in hunter harvest because of direct competition for prey species with the hunter. In Alberta, grizzly bear (Ursus arctos), cougar (Puma concolor), and wolf (Canis lupus) populations have been increasing in recent years. To examine trends in the elk harvest results collected by the Alberta Environment and Parks from 1995 to 2016, we first digitized and attached the annual regulatory history, elk harvest, and hunter success results to each Wildlife Management Unit (WMU) across Alberta and then used linear regression to estimate trend. Over the 22-year period, the average annual harvest increased for both General (3.62%) and Special (9.74%) seasons. Average annual hunter success also increased for both General (0.3%) and Special (0.4%) seasons. Hunter effort showed no significant change (p > 0.05). Our results suggest that the increasing large predator populations are not having an impact on the hunter harvest of elk. Furthermore, the data suggests that Alberta’s elk populations may even be increasing with Alberta’s management interventions.Alberta has also collected aerial survey data for its elk populations for many years but has done so sparingly due to budget constraints. Although aerial surveys are the most common method of monitoring ungulate populations because of their ability to cover large areas in a short amount of time, they are severely limited by the monetary cost to perform them, forcing places like Alberta to use them infrequently. For example, aerial surveys with moose (Alces alces) and elk occur as rarely as once every 10 years per WMU, hindering a wildlife managers ability to detect trends with the data. We demonstrated a method of population estimation using a population reconstruction model as an alternative to aerial surveys to estimate elk population size at a more cost effective and annual basis. To fill the parameters of the model, we conducted postseason (post-harvest) ground classification surveys 2 days per week from 3 February 2018 to 16 March 2018 to find herd composition data on bulls, cows, and juveniles in WMU 302 in southwestern Alberta. Because the reconstruction model requires preseason herd ratios, we then developed a model to convert postseason ratios to preseason ratios using hunter harvest from Alberta’s harvest surveys. By updating the reconstruction model with the hunter harvest, our annual elk population estimates were comparable to the most recent aerial survey (a minimum population estimate in the 2015). We believe our method will benefit wildlife managers by giving them the ability to collect population data on an annualized basis, further allowing them to assess population trends and to evaluate the efficacy of their harvest management interventions.

• Subjects / Keywords

  • elk
  • harvest
  • adaptive management
  • Alberta
  • reconstruction

• Graduation date

  Spring 2019

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-2pdv-jw50

• License

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