2.3.2 Biologic Integrity

Landscape

Large areas of undisturbed or minimally disturbed forest and wetland in the subwatershed, including the headwaters areas surrounding School Lake and Holy Name Lake and wetlands along Long Lake Creek, have been designated Regionally Significant Ecological Areas by the DNR (see Figure 6).  The Minnesota County Biological Survey (MCBS) determined that several areas in the subwatershed were of high biodiversity significance, with high-quality native plant communities.  The largest of these areas are within the two Scientific and Natural Areas in the subwatershed – Wolsfeld Woods and Wood-Rill.  The Minnesota Natural Heritage Information System lists two species of state special concern in the subwatershed: red-shouldered hawk and cerulean warbler.

Lakes

Table 1 below details fish survey data available within the subwatershed.  Holy Name Lake has in the past been stocked with walleye, bluegills, and largemouth bass, but due to its shallowness the lake is subject to winterkill and the DNR no longer stocks this lake.  No aquatic vegetation data is available for the lakes in the subwatershed.  Eurasian watermilfoil has been confirmed in Long Lake since 1992. 

Table 1.  DNR fish survey data.

Lake 

Survey Year

Fishery

Dominant Fish

Long

2001

Sport

Northern pike, bluegill, black bullhead, yellow bullhead

Mooney

1992

Pan

Black bullhead, black crappie, northern pike

Holy Name

1994

 

Black bullhead only

Wolsfeld

1993

Pan

Black bullhead, black crappie, bluegill, northern pike

School

1979

 

Black bullhead only

Tanager

1992

Sport

Northern pike, walleye, bluegill, black bullhead, yellow bullhead

Source: Minnesota DNR.

Long Lake is under a Fish Consumption Advisory for mercury, and was added to the state’s list of Impaired Waters in 1998 for that reason.  The Minnesota Department of Health, Minnesota Pollution Control Agency (MPCA), and the DNR have collaborated to monitor fish for contaminants at over 1,000 sites in Minnesota.  Fish from popular lakes and streams and those from known or suspected polluted sites are routinely collected and tested for mercury, which is found in most fish tested in Minnesota lakes, and PCB contamination.  These test results are used to monitor pollution and to provide more specific fish consumption advisories beyond the general advisories for Minnesota.  More detailed fish consumption advice that is similar to or slightly more restrictive than the general advice has been prepared for Long Lake.  Mercury contamination is being addressed by a region-wide TMDL process by the MPCA.

Streams

Biological sampling on Long Lake Creek was conducted as a part of the Upper Watershed Stream Assessment.  Four sites were sampled for macroinvertebrates; only two yielded more than the 100 organisms typically needed to assure a statistically valid score.  The F‑IBI – an Index of Biotic Integrity identified to the organism’s family level – fell into the “Fairly Poor” category.  Diversity was very low, even at sample sites with apparently adequate habitat and hydrology.   Water quality likely limits biological integrity in Long Lake Creek.  Field staff noted the presence of fish in the creek, including a 12 inch large mouth bass.

Wetlands

A high density of wetlands are present in the subwatershed. In the 2003 MCWD Functional Assessment of Wetlands (FAW), many were identified as having exceptional to high vegetative diversity and wildlife habitat potential as well as high aesthetic values (see Figure 13).  Wetlands riparian to the lakes as well as in-line wetlands on Long Lake Creek and the upper tributaries were noted as having high fish habitat potential.