Where water meets the land: the relationship between healthy shorelands and healthy lakes

Shorelands may look peaceful, but they are actually the hotbed of activity on a lake. 90% of all living things found in our lakes—from fish, to frogs, turtles, insects, birds, and other wildlife—are found along the shallow margins and shores. Many species rely on shorelands for all or part of their life cycles as a source for food, a place to sleep, cover from predators, and to raise their young. Shorelands and shallows are the spawning grounds for fish, nesting sites for birds, and where turtles lay their eggs. There can be as much as 500% more species diversity at the water's edge compared to adjoining uplands.

Shoreland plants provide food and cover for the lake's creatures. They also prevent shoreline erosion by buffering lake waves and slowing down runoff washing into the lake from the watershed. Plants help filter pollutants entering the lake, use nutrients that might otherwise be consumed by algae, and aquatic plants release oxygen into the water which helps support lake fish. In addition, natural shorelines can also help control flooding, make it harder for aquatic invasive species to establish themselves in a lake, muffle noise from watercraft, and preserve privacy and natural scenic beauty.

Lakes are buffered by shorelands that extend into and away from the lake. These shoreland buffers include shallow waters with submerged plants (like coontail and pondweeds), the water's edge where fallen trees and emergent plants like rushes might be found, and upward onto the land where different layers of plants (low ground cover, shrubs, trees) may lead to the lake. A lake's littoral zone (see graphic below) is a term used to describe the shallow water area where aquatic plants can grow because sunlight can penetrate to the lake bottom. Shallow lakes might be composed entirely of a littoral zone. In deeper lakes, plants are limited where they can grow by how deeply light can penetrate the water.

Shorelands are critical to our lake’s health, and they are sensitive areas. Activities such replacing natural vegetation with lawns, clearing brush and trees, importing sand to make artificial beaches, and installing structures such as piers, can cause water quality decline and change what species can survive in the lake.

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Role of natural shorelands in protecting water quality

Shoreland buffers slow down rain and snow melt (runoff). Runoff can add nutrients, sediments, and other pollutants into our lakes, causing water quality declines. Slowing down runoff helps that water soak (infiltrate) into the ground. Water that soaks into the ground is less likely to damage lake quality and recharges groundwater that supplies water to many of Wisconsin's lakes. Slowing down runoff water also reduces flooding, and stabilizes stream flows and lake levels.

Shoreland buffers also help keep lakes cleaner by filtering excess sediments and nutrients from runoff water. Shoreland wetlands act like natural sponges trapping nutrients where nutrient-rich wetland sediments and soils support insects, frogs, and other small animals eaten by fish and wildlife.

Shoreland forests act as filters, retainers, and suppliers of nutrients and organic material to lakes. The tree canopy, young trees, shrubs, and forest understory all intercept precipitation, slowing runoff, and contributing to water infiltration by keeping the soil's organic surface layer well-aerated and moist. Forests also slow down water flowing overland, often capturing its sediment load before it can enter a lake or stream. In watersheds with a significant proportion of forest cover, the erosive force of spring snow melts is reduced as snow in forests melts later than snow on open land, and melt water flowing into streams is more evenly distributed. Shoreland trees grow, mature, and eventually fall into lakes where they protect shorelines from erosion, and are an important source of nutrients, minerals and wildlife habitat.

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Natural shorelands role in preventing aquatic invasive species

In addition to removing essential habitat for fish and wildlife, clearing native plants from shorelines and shallow waters can open up opportunities for invasive species to take over. Like tilling a home garden to prepare it for seeding, clearing shoreland plants exposes bare earth and removes the existing competition (the cleared shoreland plants) from the area. Nature fills a vacuum. While the same native shoreland plants may recover and reclaim their old space, many invasive species possess "weedy" traits that enable them to quickly take advantage of new territory and out-compete natives.

Just like a home garden, weeds often pop up more quickly and often than desired plants, and a gardener must continue to pull them out before they take over the available space. The act of weeding creates continual disturbance, which in turn benefits plants that behave like weeds. Weeds find it difficult to elbow into undisturbed environments, and they will usually die out if disturbance ceases. Our modern day practice of mowing our lawns is a example of keeping an ecosystem in a constant state of disturbance—to the benefit of invasive species no less (grass, dandelions, and clover are all native to Europe)! Keeping your shoreline intact is a good way to minimize disturbance and minimize opportunities for invasive species to gain a foothold.

Disturbance and Invasions (PDF 715 KB)

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In his own words: the value of natural shorelands to a lakefront property owner

Remember paddling down a tranquil stream? Fishing with grandpa? Watching a sunset with someone you love from the end of a dock? Many of our most treasured waterfront memories happened either on the shore or within view of one. The following observations on shorelines are from Sam Lewis, waterfront property owner for more than sixty years on Lake Nancy, Washburn County (originally published in the fall 2006 edition of The Lake Connection).

To me a shoreline is much more than a meeting place of land and water. There is a magical allure to a shoreline. Shores are dynamic flowing ecosystems. When I look at a shoreline I try to appreciate some of the things that are happening there. Along our shore we might run across a baby snapping turtle hiding under some leaves. We could encounter some frogs or tadpoles sunning themselves in the shallow water. We might see insects in the process of hatching or minnows scurrying along among the reeds. There is a chance you could see a bass protecting its nest or a crayfish scuttling along.

While walking up and down our shoreline on Lake Nancy, most of which we have kept as wild as possible, I have seen a kingfisher sitting on a dead limb of a birch tree keeping a close eye out for minnows to snatch. There have been eagles landing to pick up dead fish for their dinners. I have seen merlins—very fast small falcons—swoop to try to catch songbirds on the wing. It is fun to watch the spotted sandpiper run up and down the shore bobbing to grab insects. Every summer morning at 4 or 5 a pair of song sparrows starts singing from their bush on the shore. Generations of song sparrows have nested in the same bush.

As far as vegetation is concerned, a natural shoreline in our area could contain hundreds of different kinds of plants, both on land and in the water. We may have 15 or 20 kinds of lake weeds along our shore including reeds and pickerel weed—which produces a tall spike of blue flowers later in the summer. During the course of spring, summer and fall there are more than 100 kinds of wildflowers which bloom along the shore. Some of them manage to live in the dry sandy bank while others live in the sand close enough to the water that their roots grow right down into the water table. I have counted as many as 20 species of wildflowers in 10 feet of shoreline.

In addition to these plants, there are numerous other species such as shrubs, trees of many kinds, mosses, lichens and grasses that can be counted. All of these creatures and plants benefit from the intersection of the soil, water and sun.

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Threats to shorelands

When a landowner develops a waterfront lot, many changes may take place including the addition of driveways, houses, decks, garages, sheds, piers, rafts and other structures, wells, septic systems, lawns, sandy beaches and more. Many of these changes result in the compaction of soil and the removal of trees and native plants, as well as the addition of impervious (hard) surfaces, all of which alter the path that precipitation takes to the water.

Building too close to the water, removing shoreland plants, and covering too much of a lake shore lot with hard surfaces (such as roofs and driveways) can harm important habitat for fish and wildlife, send more nutrient and sediment runoff into the lake, and cause water quality decline.

Changing one waterfront lot in this fashion may not result in a measurable change in the quality of the lake or stream. But cumulative effects when several or many lots are developed in a similar way can be enormous. A lake’s response to stress depends on what condition the system is in to begin with, but bit by bit, the cumulative effects of tens of thousands of waterfront property owners "cleaning up" their shorelines, are destroying the shorelands that protect their lakes. Increasing shoreline development and development throughout the lake's watershed can have undesired cumulative effects.

Shoreland development density & impervious surfaces: how much is too much for our lakes and streams? (PDF 863 KB)

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Things you can do to preserve shorelines

 

Shoreland preservation and restoration

If a native buffer of shoreland plants exists on your property, that's great! You can preserve what you have, and take care to minimize impacts on your impressive natural shoreline when contemplating lake property projects.

If your shoreline has been altered, the good news is that it can be restored. Shoreline restoration involves recreating buffer zones of natural plants and trees. Not only do quality wild shorelines create higher property values, but they bring many other values too. Some of these are aesthetic in nature, while others are essential to a healthy ecosystem. Healthy shorelines mean healthy fish populations, varied plant life, and the existence of the insects, invertebrates and amphibians which feed our fish, birds and other creatures.

See the lake stewardship activities page for shoreland restoration resources.

Leave fallen tress in the water

Leave fallen trees in the water to provide habitat for fish and wildlife. Trees that have fallen into the lake are an important source of nutrients and minerals for our lakes, and help protect shorelines from erosion. Fallen wood forms critical habitat for tiny aquatic organisms that feed bluegills, turtles, crayfish and other critters. Many species—such as turtles, frogs, dragonflies, songbirds, and otters—use downed trees as both a feeding area and hiding place. Fallen trees are also an important source of nutrients and minerals for our lakes, and they help protect shorelines from erosion.

Install a reasonably sized pier

Installing one reasonably sized pier will not significantly affect the health of the lake, however the cumulative effect of installing many piers may impact shoreland habitat and overall lake quality. The larger the pier the more shoreland area it can potentially disturb and shade.

The assertion that piers make good fish habitat is commonly repeated, but recent studies are showing that the opposite is true. Piers can shade out plants, which are important habitat for fish, and can "break" contiguous shoreland habitat. In addition to shading plants underneath the pier, property owners often must clear additional plants away from their pier in order to launch boats.

See Department of Natural Resources piers page (exits site) for Wisconsin's pier rules

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