In the last eight years, conservation agencies and organizations completed multiple wetland restoration projects in Lake Ontario coastal wetlands. Many of these aimed to restore habitat for waterfowl and state endangered birds, such as Black Tern (Chlidonias niger), as well as other wildlife, including muskrats (Ondatra zibethicus) and northern pike (Esox lucius). Great Lakes coastal wetland habitats in New York were considerably degraded over the last 60 years, but how and why they were degraded is a complicated situation.

Great Lakes Coastal Wetlands: The Problems

New York State includes shoreline on two of the five Great Lakes: Erie and Ontario. Lake Ontario is unique in that it is located farther downstream, farther north, and is much deeper than Lake Erie, but most of all because its water level is regulated. In 1958, the Moses-Saunders Power Dam was completed on the St. Lawrence River, marking the beginning of lake-level regulation on Lake Ontario. As seen in a few of the other Great Lakes, lake levels naturally fluctuated seasonally and also year-to-year, but also fluctuated between multi-year periods of highs and lows (Figure 1). Lake-level regulation reduces the range of lake levels, essentially eliminating extremes, and eliminating the multi-year periods of low lake levels (Figure 1). Without significant lake-level fluctuations, vegetation in Lake Ontario coastal wetlands dramatically changed. As shown in Wilcox et al. (2008), extended periods of high lake levels without any periods of lower lake levels allowed invasive narrow-leaved (Typha angustifolia) and hybrid cattail (Typha x glauca) to overtake areas of the wetlands typically dominated by sedge-grass meadow species. Cattail thrives during persistent inundation during higher lake levels and outcompetes native sedge-grass meadow species, which can withstand periods of drier soil conditions (Wilcox et al. 2008). Sedge-grass meadow habitat adds diversity to wetland habitat and is often used by spawning northern pike, and preferred by marsh birds such as Sora (Porzana carolina) and American Bittern (Botaurus lentiginosus). For example, cattail cover at Lakeview Pond, on the eastern shore of Lake Ontario, increased from 31.8% in 1959 to 45.1% in 2001, while meadow marsh cover at the site

decreased from 22.1% in 1959 to 4.6% in 2001 (Wilcox et al. 2008). Cattail cover on Goose Bay, near the source of the St. Lawrence River, increased from 11.4% in 1959 to 47.1% in 2008, while meadow marsh cover decreased from 41.6% in 1959 to 3.1% in 2001 (Wilcox et al. 2008). Lake-level regulation essentially New York Birders 5 April 2019 turned these Lake Ontario coastal wetlands into cattail monocultures.

Further, a horde of invasive species expanded into the Great Lakes over the last 60 years, including the well-publicized zebra (Dreissena polymorpha) and quagga mussels (Dreissena bugensis), and round goby (Neogobius melanostomus) amongst many others. Aside from invasive cattails, Phragmites australis, frogbit (Hydrocharis morsus-ranae), purple loosestrife (Lythrum salicaria), water chestnut (Trapa natans), and other invasive plants continued to expand in Lake Ontario wetlands. If invasive species and water-level regulation aren’t enough, coastal wetlands also suffered from point-source and non-point source pollution, as well as increased development on adjacent land.

Great Lakes Coastal Wetlands: The Restoration

While the plethora of problems facing coastal wetlands on Lake Ontario makes restoration complicated, there were a number of successful projects completed. Most of these involved digging channels and potholes throughout the existing cattail dominated wetland. Due to cattail invasion and the lack of muskrats (low lake levels in the winter freeze them in their huts) and to lake-level regulation, many natural potholes and channels in the wetlands were closed in. Channels and potholes will help open the wetlands up and create protected places with varied vegetation, ideal for waterfowl and nesting Black Terns. Floodwood Marsh in the Lakeview Wildlife Management Area (WMA) on the eastern shore of Lake Ontario was restored using the channeling and potholing techniques in 2011. A few years later, Ducks Unlimited used similar techniques to restore Buck Pond and Buttonwood Creek in Braddock Bay WMA on the south shore of Lake Ontario. However, they used the spoils from digging the channels and potholes to create adjacent habitat mounds set at elevations ideal for sedge-grass meadow species to grow in the context of the new lake-level regulation plan. This, coupled with cattail treatment and removal, allowed native sedge-grass meadow species to grow and create diverse wetland habitat for birds, such as American Bittern, Least Bittern (Ixobrychus exilis), and Sora, which utilized these areas immediately after restoration work finished.

Since those first projects, four more wetlands were restored by U.S. Fish & Wildlife Service, Ducks Unlimited, and Army Corps of Engineers crews in Braddock Bay WMA. The Braddock Bay restoration included reconstruction of the barrier beach, which eroded after lake-level regulation began. This could potentially provide habitat for federally endangered Piping Plovers (Charadius melodius), which have slowly increased in the Great Lakes due to extensive conservation work in recent years. Construction for two more projects is scheduled to be completed this winter; channeling and potholing at Cranberry Pond in Braddock Bay WMA, and Buckhorn Island State Park on Grand Island in the Niagara River. Continued restoration work in Lake Ontario wetlands is crucial to improving these habitats for wetland birds. Rails and bitterns, along with nesting waterfowl, need healthy coastal wetlands to thrive. Further, restoration work should continue to improve habitat for Black Terns, despite the fact that the species has been extirpated from the south shore of Lake Ontario for many years. However, restoration work on the eastern shore of Lake Ontario will improve their habitat there and hopefully keep them in that area for many years to come. The key to all of this is monitoring the bird populations. While the restoration projects include some funds for monitoring, short-term monitoring is not enough. As the weather gets warmer, head out to some of these coastal wetlands and go birding, and try and find some marsh birds while you’re there. Further, the upcoming Breeding Bird Atlas will be a great excuse to go birding in these areas and figure out what marsh birds are breeding in these many coastal wetlands. Atlasing will help identify which wetlands may need to be restored or identify which restoration projects were successful. Either way, go out into the field and find some secretive marsh birds this summer!

References:
Wilcox, D. A., K. P. Kowalski, H. L. Hoare, M. L. Carlson, and H. N. Morgan. 2008. Cattail invasion of sedge/grass meadows in Lake Ontario: photointerpretation analysis of sixteen wetlands over five decades. Journal of Great Lakes Research 34: 301-323.