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Assessing and modelling cumulative effects on biological communities 

John Gunn and John Bailey (co-PIs/Laurentian University)
Chris Jones (PhD candidate/Laurentian University)


As specified in the approved CWN proposal, our project will do the following things:

  1. Describe normal ranges of biological condition for Muskoka lakes and rivers (benthic invertebrates)
  2. Describe biological baselines for lakes and rivers
  3. Evaluate bioassessment indicators, and derive biocriteria (numerical pass-fail thresholds for judging ecological condition) for promising ones
  4. Model expected biological condition under alternate climate and development futures (assuming we can reasonably model biological responses to physiographic variation and stressor exposure)
  5. Make recommendations regarding design of a cumulative-effects monitoring program for the District of Muskoka


Physiography influences a lake’s or river’s potential to support living communities, and influences how responsive that waterbody’s communities will be to human activities. Mapping and geospatial analyses have been underway for months to delineate stream and lake catchments and characterize their physiographic qualities and stressor exposures. In past weeks, we have grouped lakes and streams using a variety methods (see Figure 1 for an example), and the resulting physiographic/sensitivity classification schemes are now being evaluated. Reference and impacted lakes and streams are also being identified.


Update - November 2013

A variety of maps were consulted to identify minimally impacted reference lakes and streams, and to identify lakes and streams impacted by human activities. These maps provided us an understanding of the range in natural habitats and human-related ecological stressors present in Muskoka's watersheds. We planned a lake and stream survey with the intent of characterizing water chemistry and biological community structure across the range of lake and stream types in Muskoka.

During the summers of 2012 and 2013, water and benthic invertebrates from more than 100 lakes and 100 streams were collected. These samples will be processed over the coming winter. The resulting data will be analyzed to create the 5 categories of new knowledge listed above. Reports, to be written in fall 2014 or winter 2015, will describe our methods and results, and will discuss the societal relevance and water-management implications of the study.

Collecting benthic invertebrates and characterizing habitat at a location in Lake Joseph, 2012 Collecting a water sample from a small stream, just inland from Georgian Bay