A habitat is a
place or environment where a distinctive plant or animal naturally or
normally lives and grows. Habitats are vast and can range from land to
sea, and microhabitats can exist inside of other habitats.
Wetlands
Lakes and Ponds
Riparian Forest
Buffers
Wetlands
A wetland is a
complex ecosystem that is very important to the environment. There are
several technical definitions of wetlands, but for our purposes we will
define it as the EPA states: “those areas that are inundated or
saturated by surface or ground water at a frequency and duration
sufficient to support, and that under normal circumstances do
support, a prevalence of vegetation typically adapted for life in
saturated soil conditions”. Some common names of wetlands are a swamp,
bog, marsh, fen, or a vernal pool. Wetlands were once deemed a nuisance.
Prior to the 1970’s the drainage and destruction of wetlands were
accepted practices in the United States and were even encouraged by
specific government policies. At the time of European settlement
in the early 1600’s, the area that was to become the coterminous United
States had approximately 221 million acres of wetlands. Only about
103 million acres remained as of the mid 1980’s.
An area is classified a
wetland based on three defining characteristics – hydrology,
soils, and vegetation. Just because you see water
doesn’t mean an area is a wetland, or vice versa; just
because there is no
obvious water doesn’t mean that an area is not a wetland.
Wetlands do not always occur at the assumed “bottom of a hill” where
water collects. You may come across a wetland at the top of a hill from
a perched water table.
The first component
of defining hydrology is difficult. It involves determining the water
flow of an area throughout the year, and the drilling of test wells.
Digging test pits or taking core samples, and then studying the
cross-section and the colors of the layers of soil determine the
presence of hydric soils. Munsell color charts are used to detect
gleyed soils. These are an indication of a wetland by their grayish
appearance resulting from lack of oxygen. The final and easiest
component (for some) of a wetland system is to identify the flora. The
presence of hydrophytes – water-loving vegetation, are a strong
indicator of a wetland. Wetland delineators look for plants that can
handle living in an oxygen-poor environment and still thrive.
Wetlands are home
to a variety of organisms and provide breeding grounds, nesting sites
and also the habitat requirements of many threatened and endangered
plants and animals. Over one-third of these threatened and endangered
species live only in wetlands, and one-half use wetlands and some
point in their existence. Some examples of organisms living in wetlands
are marine fish and shellfish, breeding birds, mammals, commercial and
game fish, migratory waterfowl, and macroinvertebrates.
Lakes and ponds are
defined as a basin or hole that collect and contain water. As
described by the PA Lake Management Society, a lake is five acres or
more in size and a pond is less than five acres. Lakes and ponds
are natural or man-made freshwater bodies of water that share similar
characteristics and species. They not only provide habitats, but also
recreational opportunities, drinking water to residents, flood
protection, irrigation, power generation, tourism, and as a place of
tranquility.
Lakes and ponds are
homes to species in all five kingdoms:
Kingdom name
Types of Organisms
Prokaryotes (no
distinct nuclei)
Monera: Aquatic
bacteria and blue-green algae
Eukaryotes
(slightly more structured than the Prokaryotes; have more
distinctive nuclei)
Protista:
algae, protozoa, slimemolds, water molds, white rusts and downy
mildew
Fungi
Decomposers
Plants
Contain
chloroplasts, a cuticle, vascular tissue, true seeds, and flowers
Animals
Vertebrates and
invertebrates, possess true tissues, organs, a mouth, and a
digestive cavity
There are four
easily distinguishable habitats in a lake or pond. They include the
surface film, open water, bottom, and the shore.
Organisms that live
on the surface film consist of free-floating, air-breathing, and ones
that have adapted features such as the ability to “walk on water”,
caused by the surface tension of the water. These include
water striders, duckweed, whirligig beetles, and some mosquito larvae.
These organisms feed on one another, floating materials, or dead
organisms that have died and float around in the water. The
open-water community is home to free-swimming animals such as fish and
microscopic plants and animals, called drifters, or plankton.
Lakes and ponds
are by no means stagnant; they are continuously going through processes
that change their characteristics. From night to day, significant
changes in dissolve oxygen concentrations occurs, as a result of both
plants and animals consuming oxygen during the night and plants
producing oxygen during the day. This is referred to as diel
variations in dissolved oxygen.
A more noticeable
variation in these water bodies are the seasonal variations in
temperature. The most obvious example of this is when the water
body freezes in the winter. Lakes become stratified in both winter
and in summer as more dense water makes its way to the bottom and less
dense water floats on top. The density of water is a direct
relationship with the water's temperature, with density increasing with
colder temperatures until it reaches 4oC, from which it
becomes less dense until it reaches 0oC. This is why
ice floats! In the summer, a temperature/density gradient also
occurs in water bodies that are deep enough to withstand heavy winds.
This density stratification prevents the water in the lake from mixing,
and often times becomes a limiting factor in where organisms can live.
As a result of this stratification, gas exchange throughout the water
column ceases, and if there is not enough dissolved oxygen in the bottom
waters, fish and other organisms can not live anywhere else but the
upper levels of the water body. This is what occurs as lakes
become older or polluted, when decomposing plant material consume the
oxygen in the bottom waters faster than it can be replenished.
This was a very
brief introduction to lakes and ponds. An excellent source of full
discussions about lake and pond chemical, physical, and biological
characteristics can be found on the
Water
on the Web located at this link. Please refer to this web site
for a more complete overview of the subject matter.
Riparian Forest Buffers
All waterways including streams, rivers, lakes, and
wetlands are surrounded by land. The waterway, along with the
adjacent land, is known as the riparian zone. A healthy riparian
zone provides benefits of high water quality for people and wildlife. A
riparian forest
buffer, the most beneficial buffer, is the vegetated land
between a stream and the adjacent non-forested land use. Buffers function in many
different ways. They protect water quality, improve habitats for
plants and animals, and also preserve the stream’s natural
characteristics.
Riparian forest
buffers consist of large trees, shrubs, and herbaceous vegetation that
formas layers from the ground tot eh treetops. These buffers serve
many different functions:
Traps and filters
sediments, nutrients, and chemicals from surface water runoff
Anchors and
protects stream banks with soil-holding roots
Healthy organic
forest soils support beneficial microbes that convert and hold nutrients
like nitrogen
Provides shade
that moderates water temperatures in nearby waters
Plant roots keep
the soil porous so water is absorbed, which can reduce flooding
potential
In-stream food web
and habitats are enhanced by adding twigs, leaves, fruit seeds, and
organic debris to be consumed by insects and bacteria
Birds, mammals,
and other animals find food, water, nesting sites, and corridors for
moving between areas.
A
riparian buffer is home to numerous habitats because it encompasses
trees, shrubs, grasses, and aquatic areas. The plants that live in a
buffer usually can handle water flow over and around them, have well
developed root systems, and can survive in wet areas. Some examples of
these plants include River Birch, Green Ash, Red Maple, Sycamore, Sweet
and Black Gum, Water and Pin Oak, Grey stem Dogwood, and many Willow
species.
A riparian forest
buffer provides habitat to many migratory songbirds, herons, wood ducks,
amphibians, turtles, foxes and eagles. Also providing
habitat are the streams that meander through a riparian buffer.
Migratory fish find it suitable to spawn here, along with shad, herring,
perch, and striped bass. Other aquatic organisms, as well as small fish
find habitat in trees and debris by the stream. When you think
about it, where are the best trout fishing holes? Underneath those
large willow trees whose roots create dense mats that jet out into the
water.
