The Lake Puckaway Comprehensive Management Plan published in 2017 asserts the following three goals:
1. Collect current and historical data
2. Raise overall understanding of the lake
3. Develop a management plan to increase the overall health of the lake
The plan is built on data collected from 2016 and earlier to describe the condition of the lake from that time and before.
The lake is described in the following terms:
1. “hypereutrophic system with high nutrient and algal levels and low water clarity”
2. “Aquatic plant studies conducted in 2015 indicate that the lake is sparsely vegetated…leaving over 80% fo this shallow lake without aquatic plants”
3. “While invasives, curly-leaf pondweed, brittle naiad, and Eurasian water milfoil were located, neither seems to be in overabundance”
Compelling data was collected and presented primarily in bar graph format with the years spanning the x-axis to illustrate changes over time. As an example, data in bar graphs seem to show that in the 2010’s phosphorus levels trend more toward fair rather than poor level of the earlier 2000’s. The data also described a decrease in lake vegetation over a similar time period, a reduction in vegetation from 2005 - 32% to 19% in 2015. it also notes no statistical difference in occurrence of coontail and milfoil between 2005 and 2015.
The comprehensive plan claims correctly that a diversity of native plants both aquatic and terrestrial would provide various benefits to lake health, such as:
1. “Vegetated shorelands prevent polluted run off from entering lakes by filtering this water or allowing it to slow to the point where particulates settle”
2. “Roots of shoreland plants stabilize the soil thereby preventing shoreland erosion”
3. “Diverse aquatic vegetation provides habitat and food for many kind of aquatic life including fish, insects, amphibians, waterfowl, and even terrestrial life.”
4. “Lakes with diverse aquatic plant communities have higher resilience to environment disturbances and greater resistance to invasion by non native plants….because Lake Puckaway contains a relatively high number of native aquatic plant species, one may assume that the aquatic plant community has species diversity.”
These action items are noted in the plan in order to boost native plant populations, increase water clarity and reduce phosphorus levels:
1. Reconstruction of part of the dredge bank
2. Reconstruction and stabilization of pancake island
3. Construction of new island habitat to be considered
4. “Periodic reductions in the water levels during the growing season”
5. “The management goals should always include the control of invasive species and restoration of native communities through environmentally sensitive and economically feasible methods.”
The expected outcomes include:
1. Increase in native plants, anticipating “the large lotus communities in Lake Puckaway provide a valuable wildlife habitat, stabilize bottom sediments, and reduce non-native plant colonization” and also the establishment of: common arrowhead, common bur-reed, water stargrass, soft stem bulrush.
2. “It is expected that the majority of additional growth would occur in the lake’s eastern basin, leaving much of deeper western basin in an open-water state as it is now”
In doing some digging, I was unable to find the data for phosphorus, chlorophyll-a, and water clarity for years 2017 and later.
Based on the spread of milfoil from Haystack Point out towards the area south of the Log Cabin, the general description of lake presented in the comprehensive plan is no longer accurate. Anecdotally, in monitoring our own shoreline, terrestrial plants near the water are dominated by invasive plants like mullein, common reed, purple loosestrife and reed canary grass, as well as plants that deer won’t eat like stinging nettle.
It is worth noting that one practice described in the plan to control invasive plants is drawdown. It is described as common in temperate places and likely occur in the winter.The plan notes that “this technique to control aquatic plants, should not be confused with water level management to enhance the aquaitc plant community of a lake as they are two different actions and have substantially different requirements for success.” And notes some significant disadvantages: “potential to upset the lake ecosystem and have significant impacts on fish and other wildlife, adjacent wetlands may be altered due to lower water levels, may enhance the spread of certain undesirable species like common reed and reed canary grass.”
Here are my open questions to consider in regards to how the state of the lake may have changed since 2016:
1. Is a lack of aquatic vegetation in the lake still a primary concern?
2. How have the numbers for phosphorus, chlorophyll-a, and water clarity changed since 2016?
3. As it no long appears accurate to state that there is not an abundance of hybrid milfoil, do we need vegetation survey data to understand the lake’s present state?
4. What exactly is the difference between a drawdown intended to reduce invasive plants vs a drawdown to enhance the plant community? (In other words will a growing season drawdown increase the abundance hybrid milfoil?)
5. If the previous objectives have been met (ie lowering phosphous levels and improving water clarity), what new objectives and plans do we make in order to acheive them?
As a native plant gardener, I concur with the plan’;s assessment that a diversity of native plants bring significant benefits, having tracked increased bird and pollinator diversity in my yard over a 10 year period as I increased the plant diversity.
However, it’s also worth noting that when it comes to aquatic vegetation, aquatic native plants are less accessible than terrestrial native plans and needing DNR approval is also a hurdle preventing interested parties from participating.
In my yard if I had simply left bare earth, it would have been consumed by Ground Ivy, Dandelion, Chicory, and Burdock. The process of actively planting native plants while weeding out the invasive is of great importance and builds resilience as the planted natives are able to seed themselves. My assumption is that many of the lake stakeholders (hunters, fishermen, birders, property owners) care about the health of the lake and want to see strong and stable fish and bird populations. I also suspect that many can appreciate the aesthetics of lotus, water lily, broadleaf cattail, swamp milkweed, and blue flag iris. However it is unclear how we go from today’s state which appears to be a shallow lake with clear water, heavily vegetated with milfoil to a clear, shallow lake supporting a diversity of native plant and animal species.
No comments:
Post a Comment