Biology and control of Russian thistle (Salsola tragus L.) in bighorn sheep (Ovis canadensis Shaw) winter ranges in montane grasslands of Jasper National Park, Alberta, Canada

• Author / Creator

  Antill, Timothy

• Russian thistle (Salsola tragus L.) invaded areas of native montane grassland important to winter survival of bighorn sheep (Ovis canadensis Shaw) were studied in Jasper National Park, Alberta, Canada. The biology of Russian thistle and its control in the Park were studied in the field and greenhouse. Russian thistle in grasslands were 9.1 cm tall with 37.5 seeds per plant, whereas larger plants in naturally disturbed habitats were 29.8 cm tall with 1562.4 seeds per plant. Plants travelled up to 4,180 m during dispersal. With soil seed contact, litter depth did not inhibit performance or survivability; without soil contact, thick litter reduced germination and plant performance. Russian thistle responded positively to increased greenhouse temperature and drier conditions. Seven control treatments involving herbicide, seeding mixes, hand pulling, and grazing exclusion were assessed. Grazing exclusion was the best field management option, increasing litter and biomass, while reducing Russian thistle density and biomass.

• Subjects / Keywords

  • Bighorn sheep
  • Jasper National Park
  • Winter range
  • Salsola tragus
  • Invasive species
  • Russian thistle

• Graduation date

  Spring 2010

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3JS7D

• 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.