Habitat Quality and Conservation for Ferruginous Hawks Using a Cumulative Effects Approach

  • Author / Creator
    Ng, Janet W.
  • Human land use and climate change can contribute to cumulative effects, which are the collective impacts from environmental and anthropogenic processes over space and time. Exploring the cumulative effects of landscape and climate change together is important for identifying potential interactions, assessing their relative influence, determining the spatial extents of their influence, and understanding their potential impact on populations. Landscape alterations from human land use can improve, degrade, or leave unaffected habitat quality for species populations. Modern landscapes often have multiple land uses, creating the potential for cumulative effects, particularly for wide-ranging animals that are likely to encounter multiple land use and human infrastructure. In the Canadian prairies, grassland loss and degradation, primarily from agriculture, are thought to be responsible for the decline of many species, including grassland birds. Energy development infrastructure and sensory disturbance can further degrade habitat and negatively affect certain wildlife populations. Climate change in this region is expected to increase seasonal temperatures, decrease precipitation during the summer, and increase the frequency and severity of storms. Changing climate is also a dominant driver of populations, sometimes more so than habitat loss. My overall objective is to evaluate how the cumulative effects of landscape, seasonal weather, and climate change influence Ferruginous Hawk (Buteo regalis) habitat use, reproduction, and simulations of overall population demography. My study was conducted in the grassland biome located in southern Alberta and Saskatchewan where the human footprint from multiple land uses is extensive and where climate change is altering weather patterns. I found that heterogeneous landscapes with moderate amounts of cropland and grassland, and moderate edge density were predictors of higher home range habitat selection, relative nest abundance, and nest survival. Climate and seasonal weather were also predictors of home range habitat selection and reproductive performance. High densities of active oil wells were negatively associated with nest survival, while density of active gas wells was positively associated. Seasonal weather was also a strong predictor of nest survival and brood provisioning. Seasonal weather influenced prey diversity, and hawks that delivered more diverse prey were more likely to return more biomass compared to hawks that deliver only Richardson’s Ground Squirrels (Urocitellus richardsonii). We used our habitat and reproduction models to develop predictive maps that could be used for prioritizing conservation and identifying avoidance zones for development to reduce risk to Ferruginous Hawk. Our spatially-explicit population model demonstrated that land cover change has a greater relative influence on the Ferruginous Hawk population in Canada compared to climate change, given the scenarios we simulated. Ferruginous Hawks are a species at risk and face multiple threats. Understanding the influence of each threat, their cumulative risk, and their relative influence on the species, over space and time, is critical for developing conservation and recovery plans. My thesis contributes to the research of cumulative effects of landscape and climate change on breeding Ferruginous Hawks and demonstrates the utility of a cumulative effects approach for population conservation and recovery.

  • Subjects / Keywords
  • Graduation date
    Spring 2019
  • Type of Item
  • Degree
    Doctor of Philosophy
  • DOI
  • License
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