(e.g. depth, thermal and oxygen
conditions), secondarily by water chemistry (e.g. acidification) and
biotic interactions (e.g. predation). Species within these lakes
experience period extinctions due to environmental conditions. We are
studying the colonization and extinction of fish species within lakes
and their connecting waterways and stream systems to quantify the role
of these factors in determining fish community structure, the
metapopulation aspects of the fish communities, and the potential for
species invasions.
The introduction or colonization of non-native or exotic species has
a major impact on these fish communities. With the introduction
of non-native predatory fishes, there is a major reduction in the
biodiversity of the fish community, principally the smaller species of
fish. There is a strong interaction between these predatory
species and the habitat complexity in aquatic systems. We have
been developing and comparing new approaches to quantify aquatic
habitats to better understand these linkages. This
understanding also aids us in studies related to ecological
restoration. Understanding factors contributing to the
establishment of exotic species is also a key research area and we are
using an exotic zooplankton species, Bythotrephes
longimanus, to determine determine lake characteristics
favouring its establishment and general approaches to predicting where
it, or other species, may establish.
We study various aspects related to biodiversity and conservation
biology. Work on redside dace (listed as Endangered under
COSEWIC) is determining the role that various landscape features have
on the distribution and survival of this species. More detailed
field studies are examining the spatial stucture of populations and how
they use complexes of pools to survive under increasingly urbanized
environments around Toronto. Crayfish communities are showing
widespread declines in their abundance and species richness across
large areas of Ontario. Factors contributing to these large-scale
declines are being studied through field and lab research projects.
Given the large number of species found in communities and the
diverse environmental variables associated with them, we work with
aspects of statistical ecology. In particular much of this is directed
at assessing and developing methods of multivariate statistical
analysis. Such analyses permit the summary of community patterns and
their relationship with the physical and chemical environment.
We have been developing models and approaches to predict the spatial
distribution of species, their association to habitat conditions, and
the resulting communities.
Lab Personnel
Selected Publications and Things in the Works
Procrustes Analysis and PROTEST
