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The Shore Primer

How To Preserve Your Shore's True Nature

First, prepare for a waterfront expedition (sunglasses, big hat, sunscreen, binoculars to see what the neighbours are doing) and take along a supply of refreshments - this kind of in-depth field study can be demanding. Next, park yourself in a deck chair with a waterfront view (the dock makes a good spot) and take a good look around. The natural shore has four components, beginning underwater and extending upland (farther than you'd think). Shore experts call these components the littoral zone, the shoreline, the riparian zone , and the upland zone, and each plays a critical role in keeping your lake healthy. As important as these separate roles are, however, it's vital to remember that the shore is a natural progression - each area shades into the next in a gradual, almost seamless transition. Altering any portion of this region affects the whole, diminishing its ability to support life on the lake.

The Littoral Zone: A Lakeside Daycare

Sitting on your dock, you're perched in the littoral zone, the area from the water's edge to roughly where sunlight no longer penetrates to the lake bottom. As much as 90 per cent of the species in the lake either passes through or lives in this zone. Algae float freely in the water or attach themselves to twigs, stones, and plants. Microscopic water bears (freshwater invertebrates that look like tiny lumbering bears - if you ignore the two extra legs) graze on aquatic plants. Yellow perch spawn in the shallows, while northern pike lurk among the sedges. Black ducks forage in the pond weeds, and turtles loaf on the trunks of fallen trees.

The water in front of the shore acts as the nursery, daycare, and cafeteria for a range of species, offering foraging areas and hiding spots and a shallow, relatively protected area for young fish and amphibians to grow. Aquatic plants and downed trees are a crucial part of the system, with the plants acting as the lungs of the lake, converting sunlight into food and releasing oxygen in the process, and providing food and shelter for other creatures. Once submerged, wood becomes a 24-hour diner for turtles, crayfish, and small fish, its surface covered by a smorgasbord of tiny plants and invertebrates. Downed trees also act as hiding spots for small fish, nesting areas for bass, and good spawning zones for yellow perch.

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How we can help the littoral zone stay healthy:

The water's edge is also a focal point for human activity. Perhaps even now you can see the kids leaping from the swimming raft and hear Grampa muttering curses as he fiddles with the outboard. While we don't intend to, it's easy for humans to interfere with the delicate operations of the littoral zone. If Grampa accidentally spills two-stroke fuel, for example, the juvenile perch will be looking for a new daycare. The simplest way to keep the littoral zone vibrant and healthy is to tinker with it as little as possible:

• Use your dock as a bridge over the weedier shallows, and moor a swimming raft out in deeper water, rather than frightening away fish and birds by ripping out aquatic plants to make a swimming area.
• Leave trees where they fall, unless they're a hazard to boats or swimmers. Typically, only a few trees along a kilometre of waterfront will tumble into the water during a year. When a cottager yanks out all the trees lining the waterfront, habitat formed by fallen trunks and branches that took decades to accumulate is destroyed in a single summer.
• Don't even think about building a beach. Until shoreline regulations were imposed to discourage the practice, many folks liked to "improve" their swimming areas by bringing in a few truckloads of sand and dumping them on the shore. So what's the harm in that? When the sand erodes, as it almost certainly will, it smothers spawning areas for smallmouth bass, buries mayflies in their burrows, and covers the vegetation where frogs and toads lay their eggs. The impact ripples through the food chain: Without frogs and tadpoles to eat decaying aquatic plants and insects, more oxygen-depleting algae fills the lake and more bugs swarm the shore; The blue heron moves on when its amphibian quarry grows scarce. While a beach may be fun for sunbathers, it is no picnic for littoral residents.

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The Shoreline: Glue for the Waterfront

Thanks to thousands of years of practice, natural shores are among the world's most effective, least expensive erosion controls. The mix of plants, shrubs, and trees forms a complex web of roots and foliage that knits the waterfront together, holding the bank in place and fending off the impacts of wind, rain, waves, and boat wake.

The bulwark against erosion is the shoreline, the place where land and water meet. In its natural state, the shoreline is a profusion of stones, plants, shrubs, fallen limbs, and tree trunks. But it's also a busy intersection, with animals, insects, and birds travelling back and forth. Moose and deer pick their way down to the water to forage or drink. Mink skulk about on hunting trips. Water birds waddle from their nests to the water. Overhanging vegetation shades and cools the water, and acts as a fast-food outlet for fish by producing a rain of aphids, ants, and other insects that slip from their perches above.

How we can help keep the shoreline together:

Things start to come apart when people remove the vegetation whose roots act as the glue that holds the shoreline together. The resulting erosion sends a stream of silt coursing into the water where it damages spawning areas. Lake trout, for example, lay their eggs on a clean, rocky shoal. Water circulating around the eggs carries oxygen to the nascent trout, but when silt covers the eggs, the unhatched fish are suffocated.

The usual solution is to replace the natural shoreline with a breakwall made of concrete or steel. In environmental terms, this converts a lively waterfront into a sterile environment. By imposing a sharp vertical drop-off on the shore, a breakwall limits the ability of plants to re-root up or down the bank as water levels rise and fall, typically reducing waterfront vegetation by one-half to three-quarters. The decline in the number and diversity of aquatic plants has a ripple effect, reducing habitat for fish, birds, and amphibians. (In financial terms, a breakwall is almost always an expensive temporary fix. Because artificial materials lack the resilience of the natural shore, a homemade vertical shorewall often lasts only a decade or so before cracking and falling apart.) To maintain a healthy shore:

• Leave the natural vegetation on the land and in the water.
• Don't replace the shoreline with a concrete walkway or breakwall.
• Don't infill the shore, or build groynes - stone fingers stretching into the water that are designed to control erosion. Not only does this destroy parts of the littoral zone, but it may alter water currents and increase erosion on adjacent properties, irking human and non-human shoreline residents alike.

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The Riparian and Upland Zones: The Lake's Doormat

Most parents install a mat at the cottage door so little shore rats can wipe their bare feet or remove their shoes. Lakes have a similar "contaminant" barrier: the riparian and upland zones.

There are a lot of nasty things waiting to catch a lift down to the lake when a heavy rain courses down the slope, including seepage from septic tanks, fertilizers and pesticides, deposits from family pets, and oil or gas spilled on the driveway. One of the main contaminants from cottage runoff is phosphorus, a "nutrient" that occurs in nature, as well as human-made products, such as fertilizer and detergent. On its own, it helps nourish life in the lake, but when we add to that natural load, phosphorus leads to poorer water quality, algal blooms, and less oxygenated habitat for cold-water fish.

Fortunately, the jumble of trees, shrubs, and grasses along a natural shore forms a "buffer" that helps filter out these undesirables: In the riparian zone - the section of land closest to the shore - the thick layer of low foliage controls erosion and sifts impurities out of surface runoff. Leaves and branches break the force of falling rain, which is further slowed by the rough surface of leaf litter, pine needles, and broken twigs; the water is then absorbed by plant roots or the soil. But as well as being a filter for the lake, the riparian zone is also a refuge for wildlife: Water birds nest in the tall grasses near the water; warblers flit among the jewelweed; and when the area is flooded during the high-water period - even if there is only 18 cm of water - pike will thrash their way over the spring-flooded banks, scattering their roe in the lake-edge nursery.

The higher, drier ground called the upland zone is typically forested with the kinds of trees that take advantage of better drainage, including sugar maples, white and red pines, red oaks, ash, hemlock, balsam, and birches. The deep roots of the trees stabilize the slopes, while their foliage buffers the shore from winds. The forest canopy also cools the area by maintaining shade and boosting humidity in the summer. In winter, it shelters deer, chickadees, porcupines, grouse, and snowshoe hare.

Together, these two zones form a doormat so effective that one shoreline expert estimates only 10 per cent of the runoff actually makes it into the lake, and much of the sediment and other pollutants is filtered out before reaching the water. If the lake bottom doesn't drop off too quickly, then the remaining guck will tangle with another barrier of aquatic plants in the littoral zone, where the jumble of bulrushes, arrowhead, cattails, and pickerel weed slows the influx of runoff and consumes many of its nutrients.

How we can keep the riparian and upland zones in place:

Almost any kind of development can fray the lake's doormat, and some projects can toss it out altogether. Even in the upland zone, the hard surfaces of paved driveways, shingled roofs, and patios shed water, increasing runoff and heightening the danger of erosion. Sediment carried into the water is a greater concern during construction, when land is being cleared for a cottage, garage, or even just a lawn. Here are a few ways you can assist the lake's natural filtering system:

• Eliminate potential pollutants by being careful with gas and oil around the cottage, avoiding the use of fertilizers and pesticides, and maintaining your septic system with regular pump-outs. Be careful not to overload the septic system with too much water, especially if you have a dishwasher or hot tub that drains into it, or a big crowd for a weekend. Working the system too hard shortens its life, and can send some unpleasant things seeping toward the lake.
• Maintain as much riparian and upland vegetation as possible.
• Opt for softer surfaces (pea gravel, wood chips, interlocking brick) rather than concrete and asphalt.
• When building on your property, replant disturbed areas as quickly as possible, and landscape grassed swales around the cottage to catch and encourage infiltration of rainwater flowing off the roof. Be especially careful in the riparian zone, where any soil dug up is apt to be washed straight into the lake during the next rainfall. Leave the riparian plants, shrubs, and trees in place.
• Keep flower and vegetable gardens well away from the lake.

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You Can Save Your Lake from Premature Aging

Depending how you and your waterfront neighbours choose to treat the natural shore, you can dramatically alter your lake's lifespan - for better or for worse.

Like any cottager, a lake ages, in a natural process called eutrophication. Over thousands of years, it develops the aquatic version of midriff bulge as sediment, erosion, and the growth and decomposition of plants eventually fill in the bottom, converting it to a bog and, finally, more or less dry land.

On the geologic time scale, this is a good and normal thing - a healthy eutrophic lake supports all sorts of warm-water fish, such as largemouth bass and pike. But when humans fast-forward the process by tearing out the shoreline buffer zone and dumping too many nutrients such as phosphorus into the lake, the water begins to change too rapidly for the life that depends upon it. It becomes murkier as plant and algae growth explodes, the added vegetation consuming the oxygen normally shared with other aquatic creatures. Trout suffocate in the new environment, while carp flourish. The lake ages before its time.

Because eutrophication is often the result of a lot of small actions - poor septic systems, using high-phosphate soaps, removing shoreline plants - it can also be arrested by the efforts of landowners. By understanding how a natural shore functions, and then acting collectively to preserve, not destroy, that critical balance, individuals can make a difference.

1. When vegetation at the water's edge is cut down, wildlife habitat is lost and more polluting runoff reaches the lake.
2. Clearing woody debris and aquatic plants from the shallows means fish no longer come to spawn nor herons to feed.
3. A concrete breakwall is a sterile barrier, extinguishing shoreline vitality.

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