Cootes Paradise and other marshes benefit from Great Lakes low water levels

Low water levels could lead to a massive regeneration that Cootes Paradise needs, says RBG.
Cootes Paradise hasn't had a massive regeneration since the '50s, the RBG's Tys Thysmeyer said. (Terry Asma/CBC)

Low water levels in the Great Lakes are good news for marsh and wetlands like Hamilton's Cootes Paradise.

"It's a very good thing," said Tys Thysmeyer, head of conservation at the Royal Botanical Gardens. "The wetlands around the shores do major regeneration of their reeds, things like cattails, when the water is low so they can generate from seed."

When water levels are low, the marshland is exposed and seedlings have the opportunity to grow. In Cootes Paradise, fish and other wildlife chew on or make nests from theses reeds and they get used up over time.  Lake levels have been controlled since the1950s, and right now, the marsh is enjoying a low water cyce that hasn't happened in more than 50 years

"It's a regenerative cycle," Thysmeyer said. "You got to have the reeds to support the fish and wildlife. And the fish and wildlife actually take out the reeds over time so you need a low water period to do a huge regeneration of these things."

Steep drops in water levels are a result of a lack of precipitation and warm weather, John Nevin of the International Joint Commission, an organization tasked to assist Canadian and U.S. governments with problems in the Great Lakes, told CBC News.

"Evaporation is actually the number one cause of water loss in the Great Lakes," he said.

Right now, the water level in Cootes' 320-hectare marshland is only about six inches lower than average, but a decrease could keep up if we have a warm summer and water evaporates. Thysmeyer said last year, levels in Cootes were also low.

It's been a while since the marshland has seen an intensive regeneration that is needed.

Cootes Paradise had a "dry" period in 1934 and 1935, when levels were about two feet lower than they are today, Thysmeyer said. In 1957, the International Joint Commission instituted Great Lake water level regulations that eliminated the very low and very high levels, Thysmeyer said.

"Massive period of regeneration hasn't happened since the '50s really," he added.

Low water levels also help keep invasive species like carp, a species that flourishes in flooded plains, away for marshlands like Cootes.

There were once 100,000 carp in Cootes Paradise, Thysmeyer said. Now, the RBG try to keep Cootes 99 per cent carp free. He estimates there are about 200 carp swimming the marsh this season - that number is certainly within their goal, he said..

Thysmeyer isn't convinced serious regeneration will happen this season. There was enough rain in April that the seedlings that could grow are underwater, he said.

"[Cootes] could use double what it had [in acres]," he said. "It's picked up 65 hectares. It needs about needs another 30 or 40."