Lake Study - Preliminary Results


Morton Lake - Point Intercept Aquatic Plant Survey Map used summer 2018

In 2017, Natural Lakes (NL) partnered with the Presque Isle Town Lake Committee (PITLC) to secure a $56,000 DNR grant to survey our four lakes. The primary goal of the survey was to check for aquatic invasive species, but the survey also checked plant diversity, water quality, and shoreline health. All of these elements are critically important for healthy water and a healthy fish population.


For many years, PITLC has taken the lead on securing lake study grants for Presque Isle waterways. The grant survey work is done by biologists from White Water Associates located in Amasa, MI. The Natural Lakes grant was secured in 2017, and the survey work was done in 2018. During 2019, White Water will confirm results and will draft preliminary reports. Final reports will be submitted to the DNR in June, 2020.


White Water provided us a preliminary report for Natural Lakes. The following table summarizes the survey activities and the AIS findings:



The following is a description of the four surveys:

Point-Intercept Aquatic Plant Survey: White Water field staff used the WDNR’s point intercept (PI) aquatic plant survey protocol for conducting the aquatic plant surveys at Natural Lakes. At the core of the PI survey is a grid of sampling points provided by the WDNR using an algorithm based on lake size and shape (see example maps below for Natural Lakes). Latitude and longitude coordinates allow navigation to each sample point. The spatially explicit plant, depth, and substrate information collected at each point can be used to create a variety of ecologically-based maps and calculate metrics such as number of sites where a plant species is found and relative percent frequency of species occurrence. The data will also allow calculation of metrics such as species richness, Simpson Diversity Index, and floristic quality index. The PI protocol establishes a repeatable survey so that plant communities can be directly compared over time. Previous PI surveys on the subject lakes (last done in 2009 - read 2009 reports here) will allow direct comparison of many metrics and an assessment of changes in the plant community condition over time.


There were 418 locations sampled in Morton, 511 locations in McCullough, 185 locations in Beaver, and 214 on Dunn. Click on the links below for the map for each lake.


McCullough Lake Point Intercept Map

Morton Lake Point Intercept Map

Beaver Lake Point Intercept Map

Dunn Lake Point Intercept Map

Aquatic Invasive Species (AIS) Survey: White Water biologists used the WDNR Aquatic Invasive Species Early Detection Monitoring standard operating procedures to specifically look for non-native invasive plants and animals in the lake. The technique involved observations made while boating, wading, and walking the shoreline. A zooplankton tow net was also used to look for spiny water fleas.


No AIS were found on McCullough or Dunn. Chinese Mystery Snail was found in Morton, Reed Canary Grass was found along the shores of Morton and Beaver, and Narrow-leaved Cattail was found along the shore of Beaver. While it is preferred to have no AIS in our waters, Chinese Mystery Snail, Reed Canary Grass, and Narrow-leaved Cattail are not high priority invasives and were not found in large numbers.


Chinese Mystery Snails are found in close to 100 lakes in Vilas county. During the survey, Whitewater biologists found just two snails, so we do not have a large infestation. There is not a lot we can do about the snails. If you find one, seal it in a bag and dispose of it in the garbage. Do not toss onto the shore, as the snail can survive up to two weeks out of water or an animal may transport it. If you find a larger cluster of snails, please contact the invasives species committee so we can clean the cluster and check the surrounding area. Click on the following link from the Discovery Center for more information on the snails:


Mystery Snails - North Lakeland Discovery Center


Reed Canary Grass and Narrow-leaved Cattail are not high priority invasives. Reed Canary Grass is present in every county in Wisconsin. It is so common there is really nothing we can do about it. We will try to remove the Narrow-leaved cattail. We are working with Whitewater to identify the location and get rid of the plants.

Shore Land and Shallow Water Habitat: White Water biologists conducted a shore land and shallow water habitat assessment on Natural Lakes following a rigorous protocol established by the WDNR. This survey was employed to better understand the character and quality of the critical near-shore habitats. A parcel by parcel evaluation of the riparian area (the land near the lake) and the littoral zone (shallow water habitat) will be used as baseline data for the lakes and to inform any needed shore land protection and/or restoration. The littoral zone quality was evaluated based on human structures, aquatic plants, and other habitat features. Part of that investigation was to locate and enumerate all large woody habitat. The riparian zone was evaluated based on criteria such as plant cover type, human structures, water runoff, and erosion.

Water Quality Survey: White Water biologists collected water samples from Natural Lakes (McCullough, Morton, Beaver, and Dunn) for analysis at the Wisconsin State Laboratory of Hygiene. Results from these analyses will give information about the trophic status of the lakes and indicate how productive it is of organisms such as algae, plants, and fish. The data also serve as indicators of unexpected changes in the lake environment.

Floating Workshops: Education of lake stewards is an important part of the project. In summer of 2019, White Water Associates will present a floating workshop on Natural Lakes for those interested in learning about the health and biology of the lakes. These interactive sessions involve cover many topics of lake ecology using specific examples from Natural Lakes studies. Questions and other contributions from participants are welcomed.

If you are interested in the lake survey process and want to ask your own questions about our lakes, please join us for our floating workshops. Dean Premo, President of White Water, will lead an on-water discussion discussing the different surveys done on the lakes. The two workshops will be:

  • Friday June 28th 9-11:30am - Morton Lake

  • Monday July 15th 9- 11:30am - McCullough

We need an RSVP for these workshops. Please send an email to invasives@naturallakes.net so we can plan the number of pontoons we will need for the workshop.


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