FINAL REPORT - International Joint Commission

ANNEX 2
A. Environmental Technical Work Group Summary
Objectives
The Environmental Technical Work Group (ETWG) was tasked with defining the ecological response of the
Lake Ontario–St. Lawrence River (LOSL) system to different water level and flow conditions and finding
criteria to guide development of a regulation plan that could benefit the environment. Like the other
technical work groups, the Environmental Group used performance indicators (PIs), or more specifically,
metrics of performance indicators to define the environmental response to a particular regulation plan.
The indicators were designed to provide quantitative information on the behavior of various aspects of the
ecosystem (e.g., wetlands, suitable habitat), including population measures for a number of faunal species,
among them species at risk.
Data Collection and Evaluation Methodology
Members of the Environmental Technical Work Group developed and undertook field research programs
that would permit the development of predictive relationships for how those species or guilds of species
would respond to patterns of water levels and flows in the Lake Ontario–St. Lawrence River system. The
Work Group conducted more than 20 research studies for the purpose of quantifying the linkage between
various ecosystem components and water levels/flows in the Lake Ontario–St. Lawrence River system.
Through its work, a complete set of over 400 ecological performance indicators was developed by the
Environmental Technical Work Group to represent habitat supply and/or population response in each of
three regions (Lake Ontario, the upper St. Lawrence River and the lower St. Lawrence River) for six
indicator groups: wetland vegetation, fish species/guilds, wetland birds, herptiles (amphibians and
reptiles), mammals, and species-at-risk. A specific metric (and associated units) was identified for each
performance indicator. The performance indicator metric provides a means for measuring and computing
the response of that particular indicator. For example, fish habitat supply indicators were calculated as
weighted suitable habitat area in hectares.
In the development of a conceptual model of the linkages between the environment and water levels and
flows, wetlands were identified as a fundamental component of the process. Wetlands respond to the
frequency of high and low water levels through the coverage and diversity of plant species. Changes in
wetlands result in associated changes in suitable habitat for species, and, in many cases, the response of a
particular species is directly tied to the response of the wetlands. However, water levels and flows can also
affect faunal species directly. The species-at-risk group includes members of the other faunal groups,
which are considered separately because of their special interest status (including, in most cases,
protection by law). A flow chart illustrating the generalized linkages between faunal responses, wetland
habitat, and water levels and flows is provided in Figure A-1.
18 Options for Managing Lake Ontario and St. Lawrence River Water Levels and Flows