Fire history, landscape biodiversity and indicators for sustainable management of the boreal mixedwood forest

• Author / Creator

  Bergeron, Colin

• I examined the response of invertebrate assemblages to the forest mosaic established by past fire events, and tested the performance of trees as biodiversity surrogates in accurately reflecting relationships between fire history and invertebrate assemblages. Over 80 % of the studied landscape originated from three fire events; 35 % from 1895 (107 years before sampling), 20% from 1877 (125 years before sampling), and 30% from 1837 (165 years before sampling). Less than 8% of the forest originated before the earliest fire detected in 1837. Even in the absence of fire for over a hundred years, sites with different fire history exhibited major differences in beetle composition and diversity. Oldest sites supported the highest richness followed by sites originating from the most recent fire event. Sites originating from the intermediate fire events had the lowest species richness. Furthermore, the relationship between ground beetle assemblages and fire history corresponded to the directional succession shift from hardwoods to conifers described for the mixedwood boreal forest. I found that canopy tree composition was a good indicator of the relationship between fire history and carabid assemblage. However, comparison of biodiversity surrogacy models built from either ground survey of trees or data derived from aerial photography reveals that both confusion among tree species and inaccurate detection and estimation of less common trees species reduced the effectiveness of forest inventories as biodiversity surrogates. Ecosystem classification maps generated from multiple geo-referenced forest attributes performed better as biodiversity surrogates, especially in the detection of crucial old growth habitat. Composition and diversity of three invertebrate taxa (ground beetles, rove beetles, and spiders) were closely correlated to the ecosystem classification map. The use of many taxa improved the sensitivity of the biodiversity indicator to habitat parameters. Pitfall trapping biases were constant among forest types enabling a proper comparison of ground-dwelling invertebrate assemblages between different forests. However, consistent and proper installation of traps is required because catches of some taxa were drastically influenced by placement of the pitfall trap. Considering landscape history in the elaboration of conservation strategies for the extensively managed portion of the boreal forest will foster preservation of biodiversity.

• Subjects / Keywords

  • Boreal mixed-wood forest
  • Fire history
  • Sustainable forest management
  • Biodiversity

• Graduation date

  Spring 2012

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3KT25

• 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.