Soil Mesostigmata (Arachnida: Parasitiformes) in boreal forests of Alberta: diversity and utility as indicators of disturbance

• Author / Creator

  Meehan, Matthew Lawrence

• Soils provide numerous ecosystem services, including provision of nutrients for plants, sequestration of greenhouse gases, and serving as habitat for soil animals. Soil animal diversity is immense, and many undescribed taxa still remain. One prominent group that inhabits soils is mites (Arachnida: Acariformes, Parasitiformes). Globally, there are 55,000 species of mites described, but true species richness is believed to be ~1,000,000. Soil mites can be split into two superorders, Acariformes and Parasitiformes. Within Parasitiformes, Mesostigmata is the most species-rich order with 11,000 described species. In soils, mesostigmatid mites mainly prey on nematodes and collembolans. Mesostigmatid mites are important for ecosystem function as they are connected to the three main energy flows in soil: primary production from plants, and fungal and bacterial energy channels. Although Mesostigmata are commonly found in soils, in North America little is known about their diversity or the environmental and spatial factors that influence their assemblages. In Chapter 2, I identified mesostigmatid mites from the boreal forest in northern Alberta to catalogue their diversity. Soil samples were collected by the Alberta Biodiversity Monitoring Institute (ABMI) and provided by the Royal Alberta Museum. In total I identified 109 species/morphospecies of Mesostigmata from 46 genera and 21 families. Once identified, I made a public pictorial database illustrating all the species/morphospecies found in my thesis. This database will hopefully aid other researchers in their identifications of mesostigmatid mites. In Chapter 3, I analyzed environmental and spatial features to assess their influence on Mesostigmata assemblages. I found that moss cover, precipitation and disturbance intensity were the variables most strongly correlated with assemblage structure. In addition, I found that distance between sampling points explained as much as environmental variables, and that Mesostigmata assemblages become more dissimilar from each other with increasing distance. In contrast to mesostigmatid mites, oribatid mites (Acariformes: Oribatida) are mainly detritivores and fungivores. They are the most diverse mite group found in soils, as well as the most abundant. Current protocols employed by the ABMI require identification of oribatid mites to species, but there has been no assessment by ABMI as to whether they are useful indicators of disturbance. In Chapter 4, I tested whether mesostigmatid and oribatid mites can act as bioindicators for three disturbance types that commonly affect boreal forests in Alberta (fire, harvest and linear features) at three taxonomic levels (species, genus and family). I found that mesostigmatid mites were bioindicators for all three-disturbance types, while assemblages of oribatid mites indicated only fire and linear disturbance. In addition, I found that genus- and family-level identifications could be used instead of species-level identifications, as they both can adequately indicate disturbance. This suggests that coarse taxonomy can be used instead of species-level identifications, which may ease the identification process for researchers.

• Subjects / Keywords

  • Taxonomy
  • Mesostigmata
  • Boreal
  • Soil
  • Disturbance
  • Forests

• Graduation date

  Spring 2018

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3QR4P58V

• 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.