Indicators of native bee communities in Alberta’s agricultural zone

• Author / Creator

  Sturm, Ashton B

• Bees are a key component of terrestrial ecosystems and provide valuable ecosystem services to both natural and agricultural landscapes. It estimated that 87.5% of native plants benefit from pollination, including 1/3 of global food crops. Additionally, pollination by bees provides maximized yields for commercial pulse crops, which has significant economic benefits. Unfortunately, bees are in decline. With an increasing demand for higher crop production to support the growing human population, the need for conservation efforts to maintain native bee populations is becoming increasingly important. In this study, I investigated how two major agricultural practices (grazing by livestock and production of canola, Brassica napus) in Alberta affected native bee pollinators and assessed whether an apex group of the bee community (cleptoparasites) could be used as an indicator taxa to predict the size and species richness of the non-parasitic bee community. I evaluated bee responses to changes in the flowering plant community and land use type, across a large environmental gradient over a two-year study period. I used rangeland health assessments to determine the condition of grasslands from grazing, and compared bee community abundance, richness, diversity and evenness to varying degrees of rangeland health across four study regions. Grazed sites that were considered healthy had higher bee abundance, richness and diversity than grazed sites that were unhealthy, suggesting that grazing can be beneficial to the bee community when managed appropriately. Cleptoparasites were useful for predicting overall bee community abundance in both grasslands and canola fields when environmental conditions were unfavorable, however when floral resources were abundant this relationship was lost. In addition, cleptoparasite richness did not predict bee community richness. Overall, the cleptoparasite guild was not an effective indicator taxa for the larger bee community in this study system. Results from this work suggests that assessing bee communities for conservation, and implementing effective monitoring schemes is a complex task. Finding alternative strategies, including the investigation of prospective indicator taxa is important, but managing for biodiversity through responsible land use is essential. This study demonstrates that cattle producers can aid in conservation efforts for native bee communities through responsible range management.

• Subjects / Keywords

  • Rangeland
  • Alberta
  • Cleptoparasite
  • Biodiversity
  • Rangeland health
  • Bees
  • Grasslands

• Graduation date

  Fall 2017

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3X63BK3N

• 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.