Streams are an important part of fish and wildlife
habitat, and more so than simply as a source of water. The vegetation associated
with streams is equally important because it determines how beneficial the
stream actually is for many animals. Strips of trees, shrubs, and other plant
life along streams that are retained for environmental benefits are known as
streamside management zones. These zones are vital because their fertile soils
produce rich plant and animal life. For example, wood ducks and waterthrushes
rely on insects and plants found primarily around streams and other wet areas.
The number of wildlife species like these, and how much they use an area,
directly depends on the food and cover the plants offer. Streamside vegetation
also casts shade so that temperature and oxygen levels are properly maintained
for fish and other aquatic life. Another reason streamside management zones are
important is that they directly impact water quality by filtering out soil
runoff, pesticides and fertilizer. In many situations, protection of streamside
areas can even help landowners retain more of their bottomland property; some
farmers see their bottomlands continually slumping into rivers or streambeds
because of the lack of soil-stabilizing vegetation.
There are many options in streamside management. However,
all of them include the maintenance or creation of adequate vegetation. Although
any width of woody or grassy vegetation is better than none at all, providing at
least 15 feet of permanent vegetation on a streamís sides should be a minimum
goal for even the smallest streams (see Table 1). Ideally, streamside management
zones of at least 150 feet on each side of a stream or river should be
maintained. Where adequate tree or shrub cover is already present along a
stream, it can simply be preserved or perhaps enhanced. For help with streams
that have severe erosion problems you should consult your county Natural
Resources Conservation Service office, the Kentucky Division of Water, or your
regional Kentucky Department of Fish and Wildlife Resources Wildlife Division
Trees are the best type of vegetation to establish and/or
maintain on the 15-100 feet of ground directly adjacent to each side of streams.
If you are planting trees, use species that are suited to the soil type and
water conditions present. Planted tree seedlings should be spaced 10-12 feet
apart (or about 500 trees per acre). In flood-prone bottomland areas, use tree
species such as swamp white oak, swamp chestnut oak, pin oak, Shumard oak, bald
cypress, pecan, shellbark hickory, and green ash. For streamsides that are not
normally flooded, select from species such as white ash, white oak, northern red
oak, cherrybark oak, shagbark hickory, tulip poplar, persimmon, American
sycamore, and American beech. Shrubs such as elderberry, viburnum, and dogwoods
can be planted also, but they usually volunteer anyway.
Natural revegetation, or simply allowing a streamside to
grow up in volunteer trees, is a viable option in many situations. However, you
have less control over the species of trees that will grow up in the streamside
management zone and it may take longer to get the desired results. Typically,
light-seeded tree and shrub species such as elms, maples, sycamore and ash grow
up in a naturally revegetated area during the first several years.
Establishing of a zone of grasses and forbs (desirable
broadleaf plants) between the zone of woody vegetation and crop, hay, or pasture
fields is highly beneficial. A field border of native warm-season grasses or
beneficial cool-season grasses (see figure 1) would increase the nutrient and
sediment filtration effectiveness of the zone, while also providing grassland
cover to wildlife in the area. When planting grasses, do not use tall fescue.
Fescue is poor wildlife cover, plus its invasiveness limits other plants that
are more beneficial to wildlife.
The most important thing a landowner can do for a
streamside area is to protect it. Protecting stable streamside zones are much
less expensive than correcting severe erosion problems and restoring degraded
streams. Where a pasture field borders a streamside protection zone, cattle
should be excluded from the streamside zone by fencing. Developing upland water
sources such as ponds and stock tanks for cattle is recommended. When cattle
have unrestricted access to streams they destroy beneficial streamside
vegetation, causing banks to become unstable and erode. Livestock manure also
reduces water quality (for example, high E. coli bacteria levels in the
water supply) if access to streams is not limited. Unfortunately, on many farms
streams are the only water sources for cattle. In those cases fencing can be
used to provide limited access points to stream water supplies.
Some landowners may wish to remove a few trees, or perform
"timber stand improvement," on the wooded portion of their streamside
protection zones. This may be beneficial in some situations, provided that a
sufficient number of favored trees are left. Consult with a wildlife biologist
or forester before thinning along a streamside.
Placement of nesting boxes would be a welcome addition to
any streamside area with the right cover type. Some wildlife species that use
properly constructed nesting boxes in this setting include wood ducks,
prothonotary warblers, great-crested flycatchers, and eastern phoebes. Another
enhancement for streamside zones would be the addition of brush piles for cover.
Given the opportunity to thrive, the natural or planted permanent vegetation
along a streamside will provide numerous benefits to wildlife, fish, water, and
Table 1. Widths of streamside
management zones (SMZ) and associated benefits.