Saturday, May 9, 2009

Wisconsin lakes face growing threats

A looong article in the Rhinelander Daily News (Wisconsin): Having experienced a protracted period of summer drought, the water table in the Northern Highlands region is low, and as a result, so are many lakes and reservoirs. As scientists debate whether the drought is a cyclical event or evidence of a micro-climate shift, Northwoods residents are increasingly wondering whether low lake levels are threatening the health of the region’s most valuable natural resource.

Anticipating those concerns, Sandy Gillum, a retired ecologist who has worked extensively with the Wisconsin Department of Natural Resources and vice president of the Wisconsin Association of Lakes, organized a seminar at Northland Pines High School last Saturday with the intention of answering questions about the effects of low lake levels on lake ecosystems.

... Gillum fundamentally believes that the exposed lake beds and deeper light penetration caused by low lake levels can create new ecological zones in the lake’s ecosystem that can prove fertile ground for invasive species. “Invasive species are opportunists. Plow up a field and what grows first? Dandelions,” she said. The message Gillum took from her own seminar was that the current conditions call for greater vigilance where aquatic invasive species are concerned.

…Jim Asplund, the DNR’s lakes and wetlands statewide limnologist, has been tracking northern Wisconsin’s low lake levels. Asplund attended the seminar at Northland Pines at Gillum’s invitation to share his thoughts on low lake levels. Asplund said lake levels in this part of the state have fluctuated roughly on a 30-year drought cycle, but recent studies of lake levels and groundwater well levels have begun to point to more serious possibilities. “Some lakes are at historical low levels and that might be more indicative of climate change,” Asplund said….

Sunset on Balsam Lake, Wisconsin, shot by peterrieke, Wikimedia Commons via Flickr, under Creative Commons Attribution 2.0 License 

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