Influence of stand composition on predatory mite (Mesostigmata) assemblages from the forest floor in western Canadian boreal mixedwood forests

• We studied mesostigmatan mites in boreal forest floors.
• Species richness, dominance and community composition differed by stand type.
• Forest floor thickness and pH influenced community composition.
• Coniferous trees were important in structuring mesostigmatan assemblages.

Mesostigmatan mites dwelling in forest floors are the least abundant of soil mesofauna, however, they play an important role by regulating population sizes of other microarthropods. In this study, we evaluate the impact of stand type on the structure and community composition of predator mites from the Mesostigmata order in forest floors from undisturbed deciduous stands dominated by Populus tremuloides, coniferous stands dominated by Picea glauca, and mixed stands in the western Canadian boreal forest. We observed differences in species richness, dominance and community composition among the stand types. Coniferous and mixed stands had higher mesostigmatan species richness than deciduous stands. Coniferous stands had a different community composition than deciduous and mixed stands, indicating the importance of coniferous trees in structuring mesostigmatan assemblages. Although forest floor pH varied within a narrow range, it was important in explaining variations in mesostigmatid community composition. Mesostigmatan assemblages were also distinguished according to forest floor thickness, probably reflecting species-specific habitat preferences within accumulated litter. Maintaining coniferous trees will be necessary for conserving the natural patterns of mesostigmatan mites in western Canadian boreal mixedwood forests.