Twenty-nine species of vascular plants commonly occurring in the Boreal Forest Region of northeastern Ontario were examined for the presence of mycorrhizae. Four species were ectomycontiizal, 4 both endo- and ecto-mycorrhizal, and 15 endomycorrhizal. Among the Ericaceae, one had arbutoid mycorrhizae and five ericoid mycorrhizae. The distribution of Cenococcum geophilum among the ectomycorrhizal and arbutoid plants is compared. Selected findings are discussed in relation to reports in the literature.

Thirty-one species of vascular plants commonly occurring in the Boreal Forest Region of northeastern Ontario were examined for the presence of mycorrhizae. Two species were ectomycorrhizal, 3 both ecto- and endo-mycorrhizal, and 15 endomycorrhizal. Two species of Ericaceae had ericoid mycorrhizae and one had both ericoid and arbutoid mycorrhizae. Eight species, unexpectedly including three species of Rosaceae and two of Saxifragaceae, completely lacked mycorrhizae. The significance of the findings concerning the Betulaceae, Fraxinus, the Ericaceae, Rosaceae, and Saxifragaceae are discussed, as is occurrence of Cenococcum-type infections among the species.

1. Anthropogenic activity underpins the creation of urban ecosystems, often with introduced or invasive species playing a large role in structuring ecological communities. While the effects of urbanization on charismatic taxa such as birds, bees or butterflies have received much attention, the impacts on small and inconspicuous organisms remain poorly understood. 2. Here, we assess how the community structure of leaf litter-inhabiting microarthropods in city parks varies along an urbanization gradient in Toronto, Canada. At each park, we established paired forest understorey plots which were either dominated by native vegetation or dog-strangling vine Vincetoxicum rossicum, an invasive species that is spreading throughout northeastern North America and abundant in urban areas. We compared microarthropod richness, abundance and diversity in ecological traits between invaded and non-invaded plots as well as compositional dissimilarities among plots across the urbanization gradient. 3. We recorded 123 genera and found (a) there was a negative effect of urbanization on microarthropod richness and abundance but only in invaded plots; (b) richness and abundance increased continuously with urbanization in non-invaded plots, but peaked at intermediate urbanization levels in invaded plots and (c) there was significant turnover with increasing urbanization, with distinct communities represented in highly urbanized areas compared to less urbanized areas, regardless of whether invaded. We also found litter microarthropod richness and abundance increased with soil ammonium and decreased with nitrate. These trends were especially strong for fungivorous microarthropods; however, there was no relationship between soil nutrients and urbanization or invasion. 4. Urbanization and biological invasion drive biodiversity change, and there is a need to disentangle these effects on ecological communities and related ecosystem processes. We show microarthropod communities change with urbanization, with the effects of invasion most prominent in non-urban areas. Here, there is high richness and abundance but low ecological trait diversity, possibly because certain feeding traits are excluded and others overrepresented.