Landscape- and Micro-scale Habitat Selection by Greater Short-horned Lizards

• Author / Creator

  Fink, Krista A

• Identification of critical habitat for species at risk is an essential component of the protection of rare species under Canada’s Species at Risk Act. In this study, I identified important microsite and landscape-level habitat characteristics for endangered greater short-horned lizards (Phrynosoma hernandesi) at their northern range limit in Grasslands National Park, Saskatchewan, Canada. A total of 650 km of transect surveys were used to analyze habitat selection based on locations where lizards were detected relative to available random locations. At the microsite level, I compared occupied locations (n = 118) to random landscape (n = 234) and random home range locations (n = 117) in 0.3 m2 ground cover plots and 0.12 m2 thermal plots using a classification and regression tree. Comparisons of occupied and random landscape microsites suggested that lizards selected microsites with higher diversity of ground cover types, especially in areas with high cover of exposed soil. At the home-range scale, lizards selected habitats with complex combinations of ground cover types and thermal characteristics. Selection was greatest for microsites with low vegetation height, low cover of lichens and mosses, and minimum temperatures that were >26.2°C, although other combinations of microsite characteristics were also supported at the home-range scale. A model of landscape-scale habitat selection (resource selection function) was also estimated for the Park using 101 lizard locations and 5000 random available locations sampled along 650 km of meander transects. Habitat selection in summer was predicted best by juniper-dune vegetation community,
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  vegetation patchiness, and perhaps paradoxically areas of lower solar radiation. This model was used to define critical habitat for conservation management and to estimate an index of population size for the Park using the number of lizards detected, strip width of transects and classified habitat resulting in ~13,000 adult lizards. This population index provides a baseline for monitoring the success of conservation actions. As new information becomes available for this under-studied species, improvements in the definition of critical habitat should be considered.

• Subjects / Keywords

  • CART
  • Thermal habitat
  • Phrynosoma
  • RSF
  • Phrynosoma hernandesi
  • Grasslands National Park
  • Critical habitat

• Graduation date

  Fall 2014

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3VM2K

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.