When it comes to clean water and wildlife habitat, the importance of riparian buffers – the strip of land next to a waterway – cannot be overstated.
The need to conserve these areas has become critically important owing to their ability to filter out excess nutrients, particularly nitrogen, animal waste and pesticides, which help to keep these and other pollutants out of our lakes and rivers.
“Buffer is an important word,” says Teddi Stark, Watershed Forestry Program Manager for the Pennsylvania Department of Conservation and Natural Resources.
“It really is just that, a buffer against nutrient pollution from agricultural operations, lawns and other human activity from washing into the water. Stormwater carries pollutants downhill to water— but a riparian buffer stops it.”
Riparian buffers can remove anywhere from 12 percent to 100 percent of excess nitrogen in surface water.
According to Stark, this protective interface should be at least 50 feet wide, though 35 feet can provide adequate benefits. A riparian buffer might need to be much wider depending on how steep the slope is, the makeup of the soil, flood patterns, how
the nearby land is being used and what the buffer is filtering.
Take nitrogen, which washes into our waterways, spurs harmful algal blooms and produces dangerous nitrate in drinking water. According to the Environmental Protection Agency (EPA), riparian buffers can remove anywhere
from 12 percent to 100 percent of excess nitrogen in surface water, depending on the width and vegetative cover of the buffer.
While a wider buffer offers more protection for a waterway, it’s not an exact correlation. A sparsely vegetated, poorly drained or gravelly riparian buffer that is three times wider than a buffer with large amounts of organic matter might only be
a third as effective at filtering out excess nitrogen.Encouraging regrowth in popular places like the Potomac River sometimes requires discouraging foot traffic.
A travel zone and nursery for wildlife
Another consideration is wildlife. A riparian area used as a wildlife corridor also needs to be broad, the wider the better. The Indiana Division of Fish and Wildlife recommends riparian areas on either side of a river or stream to be at least 50 to 100
feet across in order to provide food, nesting opportunities, protective cover and migratory lanes. Whether used by large animals like deer or smaller animals like squirrels, reptiles or birds, a healthy and wide riparian zone allows their young to
mature and disperse safely to new territories.
Conserving existing riparian buffers and restoring others, we protect our waterways, which will save time and money and avoid potential hardship in the future.
Bird species that depend on waterside habitat to nest, feed and raise their young – such as bald eagles, osprey, herons, wood ducks and mergansers – take advantage of riparian zones. These land-water interfaces are also vital for migrating
songbirds, providing places to rest, eat and rehydrate on their seasonal journeys north and south.
Fish as well as terrestrial wildlife also need shade, which is often found only in riparian areas, particularly in regions of the country that are primarily prairie or farmlands.
Shade can improve water quality too. “Algal blooms can indicate a riparian buffer might not be healthy… because there’s too much light or it’s too hot, so the ecosystem is not processing properly,” says Stark.
How to Repair a Riparian Area
- Choose a location. If you don’t own property along a waterway, volunteer to work on riparian areas that are on public land, such as parks or beside a boat launch.
- Go wild. As a culture, we like clean landscapes, that is, mowed to the water’s edge. But healthy streams have wild edges. While small swaths of a riverbank can be mowed around a bench or a boat ramp without a detrimental
effect, allow the rest of the riparian area to return to its native, wild state.
- Consider how water flows. When planning how to restore a riparian area, consider how water flows into that waterbody. Plan to reforest along the routes that water travels, while leaving other areas open.
- Get funding. Many states, counties and conservation districts provide expert assistance and grant programs for riparian restoration.
- Grow native plants. Your state’s department of natural resources or native plant society can provide a list of plants and other expertise. Generally, trees should be planted 15 to 20 feet apart, and shrubs should be about
six feet apart.
- Maintain what you plant. The first five years are critical, especially if there are a lot of deer or voles that will eat young plants or invasive plants that often crowd out the natives. After that, the area will likely be self-sustaining
with much less need for human care.
- Plant as wide a swath as you can. The wider the restoration area, the more effective it will be at filtering pollutants, controlling sediment in runoff and erosion, and supporting wildlife. It’s okay to start narrow if that’s
what your manpower and resources allow. Then as the land becomes available, widen the zone over time.
Buffers need native plants
Riparian buffers consist of vegetation that requires wet soil and ideally a combination of native trees, shrubs and other plants. Stark emphasizes that everything growing in the buffer should be native to the area because the root systems of those
plants have evolved to be dense enough to prevent erosion, to truly slow down and absorb pollutants and to capture excess sediment and other matter that can muck up a stream. Plus, they provide needed leaf litter in appropriate amounts.
By letting manicured riverbanks become wild again, the water below them is soon cleaner, and wildlife returns, often within a couple of years.
“Native plants are the basis of the food web and a healthy ecosystem,” says Stark. “They naturally exist there and have root systems that filter and stabilize banks and shorelines. When native leaves fall into a stream, they
become a food source for insects at the bottom of the food web.”
“We’ve learned that insects don’t eat nonnative leaves or other nonnative plant tissues. A healthy insect population is a critical component of sustaining all wildlife and plant life, both on land and in the water.” Nearly
all terrestrial birds, for example, depend on insects to feed their young.
Bugs need the buffers too
Insects use riparian buffers like other types of wildlife – for nesting, foraging for food and shelter. What’s more, some insect species, such as dragonflies, stoneflies and mayflies, begin life in the water then depend on the riparian
zone to complete their lifecycle. The leaf litter from the riparian zone that falls into the water supplies nutrients for algae (the good kind), which these bugs eat. Then, fish eat the bugs. In other words, the riparian zone, though not underwater,
supports the aquatic food web.
Lately, pollinators, particularly bees, have spotlighted the need to repair riparian zones. According to EPA, one in every four bites of food we eat depends on bees for pollination.
While other pollinators, including butterflies, moths, bats and birds also sustain most plant ecosystems on our planet, U.S. farmers depend on bees for over $15 billion in crops each year. Yet over the past three decades, the number of bees (and
other pollinators) has declined by staggering amounts due to viruses, fungal infections, exposure to pesticides and other chemicals, climate change, and loss of habitat. According to a study by the University of Maryland, in 2016 alone, beekeepers
lost 44 percent of their colonies – a crisis, indeed, but riparian areas have emerged as part of the solution.
The well-known European honeybee, maintained in hives by beekeepers, gets most of the attention and credit for pollination. But there are about 4,000 bee species native to North America, and many of them are extremely effective pollinators. They
too depend on appropriate habitat and native plants, and they deserve the same protections that honeybees need.
In 2021, a study published in Restoration Ecology pointed to the potential of riparian zones in successfully sustaining bee populations if the right mix of shrubs and flowering forbs is available. Often the woody plants required by pollinators
for food and shade are only found in these vital riparian zones. Our ecosystems need all types of native pollinators to remain vibrant, and riparian buffers serve a key role in sustaining those populations.Native plants and trees along streambanks also help to prevent or reduce runoff from agricultural lands.
Bringing back buffers
On the bright side, we can help restore riparian buffers. By planting native trees and shrubs and allowing native ground covers to return to the side of a lake or stream, we can bring back healthy riparian areas.
Though it takes a couple of decades for trees to grow big enough to produce an effective canopy shade and mast (food for wildlife), their root systems quickly develop and have a positive impact almost immediately, catching excess nitrogen and
By letting manicured riverbanks become wild again, the water below them is soon cleaner, and wildlife returns, often within a couple of years. People are happier, too, with cleaner water to drink, more fish to catch and more wildlife numbers and
diversity to enjoy.
“It’s much easier to keep clean water clean than to treat polluted water,” Stark reminds us. “Healthy riparian areas are a natural way to have clean water.”
By conserving existing riparian buffers and restoring others, we protect our waterways, which will save time and money, and avoid potential hardship in the future. So, let’s start planting!
Reaping the Benefits of a Riparian Buffer
From a conservation point of view, riparian buffers offer these important benefits:
- Filtering excess nutrients, pesticides and animal waste, and thus preventing these pollutants from entering waterways and our drinking water.
- Stabilizing banks and shorelines, reducing erosion and undercutting of riverbanks.
- Capturing sediments and pollutants from runoff.
- Providing critical shade, shelter and food for aquatic and terrestrial wildlife.
- Providing migration corridors for wildlife.
- Mitigating flood damage downstream by absorbing runoff.
- Improving recreational opportunities by keeping fish habitat healthier and by providing better wildlife watching.
- Diversifying income for landowners. By planting natives that produce fruit or nuts – like pawpaw, persimmon, elderberry or hazelnut – growers can offer a hard-to-find, local produce.
Ikes Make it Happen
In 2013, the League’s Franklin County Chapter in Pennsylvania decided to return an immaculately mowed quarter-mile stretch of riverbank along Conococheague Creek to a riparian buffer.
The 25-acre property, owned by the League chapter, is open to the public, attracting anglers, birders and Scouts, who sometimes camp there. There’s also a playground. Part of the property is bounded by an old raceway parallel to the
stream, creating a 300-foot-wide, island-like tract. Their goal was to turn all of the land between the creek and the raceway, or about a third of the property, into a riparian buffer.
“We stopped mowing and started small,” recalls Mike Kusko, a chapter member and former forester at nearby Michaux State Forest. Kusko led the project and helped with much of the planting, which included American sycamore, swamp
white oak, spicebush, buttonbush and elderberries.
“The elderberries grew fast and now bear fruit. When the fruit is available, the songbirds really dive in,” says Kusko. “It’s going to take more time for acorns. Trees take longer to mature.”
The League chapter partnered with the Franklin County Conservation district, who helped them access an initial $4,000, from a grant that the Pennsylvania Department of Conservation and Natural Resources (PA DNR) had received from the National
Fish and Wildlife Foundation’s Chesapeake Bay Stewardship Program. The local Ikes used the money to purchase and plant the first tree and shrub seedlings, enough to cover one acre along the creek.
Subsequent grants from the PA DNR, totaling another $9,200, supported two more plantings over another 2.3 acres. The chapter also found other funding sources, including $10,000 from the Trees for Tracks program even though the property does
not abut a railroad right-of-way. Over the last decade, the chapter has planted about 600 trees and shrubs, a little each year that have added up to a huge change for the good.
“The ducks are back,” recalls Tom Cutchall, chapter president. “There are more of them now. Songbirds, too.”
And the water quality is clearly better. “The creek is really holding fish. There’s been an obvious decrease in runoff. It’s definitely made a difference.”
In a similar effort, the Charles E. Piersall Chapter in Casper, Wyoming, has been engaged in a large-scale effort to restore the riparian buffer of the North Platte River, which is an important trout fishery.
That ambitious effort has involved removing invasive Russian olive trees, replacing them with willows, cottonwoods and chokecherries, and restoring more than three acres of wetlands along the river.
Top photo: Wood ducks and other waterfowl and wildlife need healthy shorelines like this one near Roberts, Montana. Credit: Lisa Ballard.