2.3.2 Biologic Integrity
The Gleason Lake Creek subwatershed is mostly developed, with few intact areas of minimal disturbance. The Minnesota County Biological Survey did not identify any landscape areas of biological significance in this subwatershed, although just outside of this subwatershed is the Wood-Rill Scientific and Natural Area in Orono. Some wooded and wetland areas around Hadley Lake and a few pocket wetlands and wooded areas elsewhere in the subwatershed provide the most significant areas of habitat and biological integrity.
The most recent DNR fish survey for Gleason Lake was conducted in 1996. It identified a fishery dominated by bluegills and black crappies. Pumpkinseed sunfish were also found in above-average numbers. Northern pike were abundant. Eurasian water milfoil has been confirmed in Gleason Lake since 1998. An aquatic vegetation survey was completed in 2002 for the Gleason Lake Management Plan. Gleason Lake is almost entirely littoral (less than about 15 feet deep), with extensive aquatic vegetation dominated by coontail. Curly leaf pondweed was detected at one-third of the stations sampled in the lake. The Plan speculated that the dense coontail growth was the likely cause of better-than-expected water clarity because it shades the sediments and prevents photo release of phosphorus. Milfoil was not found to be a concern.
Biological sampling on Gleason Creek was conducted as a part of the Upper Watershed Stream Assessment. Two sites were sampled; only one yielded more than the 100 organisms typically needed to assure sample reliability. The F-IBI – an Index of Biotic Integrity identified to the organism’s family level – fell into the Poor category. Seven taxa of organisms were found, dominated by pollution-tolerant species. Water quality, lack of habitat, and hydrology limit macroinvertebrates in Gleason Creek.
Some scattered wetlands were identified in the 2003 MCWD Functional Assessment of Wetlands (FAW) as having high vegetative diversity and wildlife habitat potential as well as having high aesthetic values (see Figure 13). Wetlands riparian to Gleason Lake were noted as important fish habitat.