I invite you to envision a woven tapestry waving in the wind. Each thread contributes a small piece to the myriad of unique patterns coming together to form a much larger work of art. Intact, the tapestry can bend and move with the ever-changing breeze due to the strength of each thread coming together with the others. If some of those threads are pulled out, moved around, or weakened, however, the tapestry risks being torn or unravelled by even the smallest gust.
As development pressures, climate change, and other threats drive the loss of wetlands in Ontario and across the globe, we risk losing critical threads in the complex tapestry that creates and maintains the natural world.
While many people are fighting to protect Ontario’s remaining natural wetlands, expanding urban and industrial developments continue “pulling threads” from those lacking legal protections. In response, various levels of government have pursued a strategy called “wetland offsetting,” which aims to compensate for the damage done.
What is Wetland Offsetting?
Wetland offsetting involves a trade-off. Theoretically, it should create, restore, and/or enhance wetland ecosystems near where development has negatively impacted an existing wetland. It should be done such such that there is no net loss – ideally net gain – of wetland area and values (including biodiversity, ecosystem function, and/or social and cultural values). It should only be pursued as a final step in the “mitigation sequence” which describes a series of planning stages to avoid, minimize, and mitigate impacts from development before designing offsets for the residual damage.
“measurable conservation outcomes of actions designed to compensate for significant residual adverse biodiversity impacts arising from project development after appropriate prevention and mitigation measures have been taken.”
Ancaster residents are fighting to protect the Garner Marsh which is targeted for development on the basis that an open water feature will be constructed nearby.
Many Kingston residents are opposing a development proposal that would adversely impact a Provincially Significant Wetland on the basis that the damage can be offset through remediation and restoration.
Risks and Uncertainty in Wetland Offsetting
Much of the concern about wetland offsetting stems from the fact that the loss of wetland ecosystems is guaranteed, while timely compensation for those losses is extremely uncertain. Recent research has revealed that even the most rigorous and well-established wetland offsetting programs (i.e., the United States’ wetland offsetting under the Clean Water Act) have been unsuccessful in achieving no net loss.
Furthermore, a study by Pezzati et al. (2018) estimated that wetland biodiversity often requires 10-1,000 years to recover after disturbance, even when supported by active restoration. This highlights the risk of incurring extended “temporary” losses when wetlands are removed for development under the questionable assumption that restoring another site will promptly provide adequate compensation for the lost ecosystem functions and biodiversity.
Moving Forward with Caution
Despite the risks associated with wetland offsetting, urban and industrial expansion will not stop completely. Therefore, meticulous implementation of strict offsetting protocols represents an opportunity to compensate for at least some of the resulting damage to natural wetlands.
Sarah Hasenack (she/her) joined Ontario Nature as a Wetland Conservation Intern in Spring 2022. She has a passion for the protection and appreciation of nature fostered through years of family camping and hiking trips, which is now backed up by a Bachelor and a Master of Science in Environmental Sciences completed at the University of Guelph.