I want to first thank the committee for inviting me to come and share my concerns about environmental threats to the integrity of the Great Lakes. I am a professor of biology at McMaster University and I also serve as the director of the life sciences program.
It just occurred to me that we're going down in age here. Everybody knows Jeff is the youngest. I'm not yet emeritus.
Since starting at McMaster University in 1991, I have established the research program on the ecology, conservation, and restoration of Great Lakes coastal wetlands. I have trained 37 graduate students and 100 undergrads to date.
My students and I use a landscape approach—this is more a holistic approach, rather than reductionist—to understand how human activities affect the health of coastal wetlands, and have developed ecological indicators to assess the negative effects of agriculture, recreation, and urbanization. We also study the impact of invasive species and water level fluctuations on wetland health.
Over the past 20 years, we've sampled approximately 300 coastal wetlands throughout the five Great Lakes. Since 2003, however, our lab has focused almost exclusively on the many coastal wetlands of eastern and northern Georgian Bay, wetlands that had not been sampled or assessed before we started there 10 years ago.
It's important that you understand what I mean by a coastal wetland. These are wetlands that occur within two kilometres of the shoreline and are connected to the Great Lakes or a connecting channel by surface water at the 100-year high water mark. They are some of the most productive freshwater ecosystems, supporting extremely high biodiversity, and they include more than 80 species of Great Lakes fishes that spend at least part of their life cycle in them.
There are many free ecosystem services provided by these coastal wetlands. They include filtering water for domestic use, preventing floods, and recharging groundwater. Unfortunately, 75% to 90% of the wetlands that were here 250 years ago have already been lost. They've been infilled or dredged for farmland and for building cities. Many of the remaining wetlands are suffering from increased nutrient and sediment load and are being degraded by the presence of invasive species, such as the common carp, Eurasian milfoil, and the common reed. By regulating water levels of the Great Lakes, we've also interfered with the natural fluctuations that coastal wetlands need to keep themselves healthy.
The first 10 years of my career at McMaster were spent on the restoration of Cootes Paradise marsh. This is in Hamilton; it's part of the Hamilton harbour area of concern. Like other AOCs, Cootes Paradise marsh became degraded over a very long period from decades of untreated sewage being discharged into it. It finally succumbed to the ravages of regulated high water levels and unchecked growth of common carp in the 1970s.
In the 1980s and 1990s, millions were spent in restoration to exclude carp from the marsh and to educate the public about the importance of watershed stewardship, but these efforts have returned only a very small portion of the ecosystem functions. The marsh is still in a degraded state after 20 years of study and management, and sadly, it will continue to require human intervention for the foreseeable future.
What I learned from this experience is that it's far easier and less expensive to spend money up front protecting these coastal wetlands from damage than it is to neglect them and then try to restore only a fraction of their original functions.
Of the 17,000 kilometres of shoreline around the five Laurentian Great Lakes, Lake Huron accounts for 36%. Much of the coastline of Georgian Bay is dotted with islands. In fact, there's an estimate of 30,000 islands. I have never counted them. They are called the Georgian Bay archipelago, which is the largest freshwater archipelago in the world.
With such a long coastline, it's not surprising that Georgian Bay also contains disproportionately large amounts of coastal wetlands. Our research documented that cumulatively, Georgian Bay has more coastal wetland area than any other Great Lake, more than 17,000 hectares, compared with only 12,000 hectares in each of Lake Erie or Lake Ontario.
What is even more unique in the context of the Great Lakes is that most of these coastal marshes, the portion of the wetland that occurs below the shoreline, is still in excellent condition. Using a suite of ecosystem indicators that we have developed, we have found that more than 50% of the marshes in lakes Michigan, Erie, and Ontario are currently designated as degraded, while more than 70% of the marshes in Georgian Bay and Lake Superior are designated excellent and unimpacted. The highest proportion of very good and excellent quality wetlands and the least number of degraded wetlands exist in Georgian Bay.
Our work in Georgian Bay has shown that these marshes provide very high-quality reproductive and foraging habitat for fish and wildlife, including species at risk, such as the Blanding's turtle. These coastal wetlands are typically low nutrient, because the catchments are on the Precambrian Shield and they have minimal human disturbance. Their hydrology and the water chemistry are also heavily influenced by their connection to Georgian Bay through the surface water. All of the wetlands that are hydrologically connected with Georgian Bay exhibit fluctuations in water levels, seiches, that vary by 50 centimetres over a day, or by more than a metre between years.
These hydrologic connections play a critical role in maintaining aquatic biodiversity. They prevent monocultures of emergent and floating vegetation from forming. They facilitate frequent exchange of chemical constituents between wetlands and Georgian Bay and allow daily and seasonal migration of fish, such as northern pike and muskellunge, in and out of wetlands.
Although the coastal wetlands of Georgian Bay are still among the least human disturbed, the sustained drop in water level of close to a metre over the last 15 years, the expansion of road networks and increases in cottage and residential development, and the invasion by non-native species such as the zebra and quagga mussels, the round goby, and the common reed are threatening the integrity of these sensitive ecosystems.
I would like to spend a little time now to describe each of these threats.