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Nature Link

With Blake Mann

Effects of low water levels

Tuesday, February 25, 2003

Recently, we have seen the lakes and rivers at an almost all-time low water level. Natural things go in cycles, and the downward trend in water levels is no exception. Only a few years ago, we were complaining about water levels being very high, but recent levels can be attributed to lack of precipitation. The last few winters have seen little snow, and the rest of the year has seen little rain. The hot sunny days of the last two summers also contributed, as there was tremendous evaporation of surface water under these conditions.
Current changes in the physical appearance of the landscape are a direct result of the low water and lack of precipitation. Vegetation has taken over former wet areas and stands of open water. Both native and exotic species of plants can be seen. One of the most prolific and most obvious plants one can see these days is Phragmites, Phragmites australis. It is sometimes called "elephant grass" due to size and height (up to 15 feet).
Although phragmites is a native plant seen on all continents, it is unsure why the plant we see nowadays is so large, aggressive, and widespread. In recent years, it has appeared everywhere in former wetlands, riverbanks, etc. It is very aggressive and takes over more desirable species. It is extremely difficult to control or eliminate, and attempts to do so may make the situation worse. Phragmites cannot be effectively controlled by burning, and cutting has limited results. Cutting must be done at a very specific time to do any good. Some herbicides sprayed at the right time can be effective. "Rodeo" can be used effectively, although it is apparently not legal in Canada.
My personal observations have noted that phragmites is everywhere and causes problems. Former wet areas, marshes and sloughs have been overtaken by this "weed". It creates a "barrier" in which you cannot even walk or see through. For example, many of the sloughs and marsh areas in Rondeau Provincial Park have been over-run by this plant. There used to be open areas of water there, but as a result of the low water cycle, phragmites and other plants have "dried" up the sloughs. This can create serious problems for endangered species like the Prothonotary Warbler. Their prime habitat has been greatly reduced by this and other factors. Even travelling along river courses like the Snye, the banks are almost completely lined by a thick wall of phragmites. Visibility is curtailed.
The accompanying photo is one I took a few years ago of the "Chicken Island" wetland just north of the intersection of highway 78 and the Kimball Sideroad near Wallaceburg. It was always a popular hiking destination for kids in the summer. I remember doing it myself, as it was the "in-thing" to do when you were a kid. There always used to be open water there, and it was a great place to view waterfowl and shorebirds in both migration and nesting seasons. About three years ago, when the water level dropped, this area dried up.
This is a good example how low water levels can change a natural area. Soon after, the weeds and plants like Smartweed and a bit of Phragmites took over completely. Last year, the dyke was modified, and water was pumped in. Ducks Unlimited has an agreement here to control the water level and maintain it as a wetland. This will enhance the wildlife habitat, and hopefully preserve it for future generations.