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urinp pc*rio<Ijj of dro;i;,'h»., ii
<br />•n lik«* the- uplands, hui at a
<br />plant conditions, and thus
<br />inimi'ls or wildlife,
<br />mportant to a wetland's
<br />in« man with a natural
<br />le extremes of flooding and
<br />s and animals depend on
<br />for their existence. For
<br />stiimilate the growth of
<br />2 slightly above the water
<br />depend upon the gradual
<br />r.s. Likewise, the lowering
<br />ling places for ducks and
<br />innturul patterns of water
<br />damage those specie.^.
<br />-T hydrology generally
<br />This can Ire .seen in Figure
<br />pland runoff is slowed by
<br />his water into the g. ound
<br />Lering the marsh and also
<br />der agricultural or urban
<br />E!.s. Greater amounts of
<br />overland flow, covering
<br />' in the spring and in turn
<br />groundwater recharge in
<br />mmping groundwater for
<br />ion is more exaggerated
<br />to a greater degree,
<br />ibili/.e water supplies—to
<br />er areas of the watershed
<br />i;ht in the immediate area
<br />protect our wetlands,
<br />ds, the low prairies, the
<br />marshes that are wet only
<br />.‘d. 'I he.se areas are often
<br />t contributions to our
<br />•i • •:% ■ 0
<br />V . 1 .'r:;*
<br />fj>
<br />i!
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<br />»■
<br />j
<br />>1-
<br />i
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<br />1
<br />WcthiipiN. (Seiieriil Knvlri»nnicnt«l lleHlih, Diversity
<br />Wetl.iuils |iii>\i<le esseutini bret'ding, nesting, resting,
<br />*aiid l^•••^li^g gnuimls amt preilutor-csca|>e cover for many
<br />kinds of fish ami wildlife. Since the footl webs of land and
<br />«at«T are nmst intimately connected in wetlands, they are
<br />ihus iin|Nirtanl for supporting a wide variety of both land
<br />and water aiiiinuls. Likewise, wetlands provide habitats
<br />for a wide range of vegetative communities which could
<br />not exist without them. In these ways wetlands provide
<br />the lM?nefits of a healthy environment. They are sites for
<br />recreation, research, and education; they support wildlife
<br />and game for hunting, fishing, and trapping, and they add
<br />l»» the aesthetics of the community. Local government
<br />should be concerned about the.se benefits because they ore
<br />intricately connected with the desire to promote the most
<br />suitable use of land, to prevent nuisancedike uses of land
<br />which harm common resources, and to protect residential
<br />({uality and the economic base of the community.
<br />'lo a large extent, if marshes are performing their
<br />various water*rclatcd functions properly, species diversity
<br />and environmental health will follow as a matter of course.
<br />However, it is important to understand how species
<br />diversity works and why it is important. Present
<br />ecological theory urges that the more varied an
<br />environment is in terms of habitat, flora, and fauna, the
<br />more stable it is. Stability in an ecosystem means the lack
<br />of largo fluctuations due to inside or outside disturbances.
<br />Species diversity ensures that the more channels there are
<br />for diverting and dispersing the results of disturbance, the
<br />less likely it is that there will be abrupt population
<br />changes.
<br />'I'his process can be appreciated by looking at its
<br />opp()site, monoculture. The farmer replaces hundreds of
<br />plant species by one —soybeans, for example. The results
<br />are attacks by pests, outbreaks of weeds, and disease.
<br />Since the most important way in which the multitude of
<br />species in a natural community interact is through the
<br />food web, it is easy to see why there are pest outbreaks
<br />among the crops. With a large amount of one type of food
<br />available, the plant-eating pests, or herbivores, increase
<br />rapidly along with the increase of the food supply. 1 ’he
<br />former sprays pesticides on the pest population, but in the
<br />process kills or harms the birds and insects which feed on
<br />the pests, making the situation even more uncontrollable.
<br />It is reasonable to assume that the existence of alternate
<br />prey and predator animals will help stabilize populations.
<br />The racoon, for example, has the eggs of several different
<br />species of marsh birds to eat, as well as crayfish and
<br />numerous other foods. No single prey population will take
<br />the brunt of the raccoon ’s foraging. From the raccoon's
<br />point of view, if one prey population fluctuates, he can still
<br />survive. The presence of several different predator species
<br />will also be important in controlling populations. A frog,
<br />for example, can be eaten by a heron, a bittern, or an
<br />osprey, among others. If one predator population i.s low,
<br />the others will keep the frogs from becoming too
<br />abundant. The same kinds of relationships exist
<br />throughout the mat'sh ecosystem. The muskrat, as a
<br />herbivore, keeps the cattail population stable so that it
<br />will not choke the marsh.
<br />Within a healthy, diverse ecosystem, each plant or
<br />animal species will have its ow ’n functional pt^sition, or
<br />niche. A niche is the sum of the rc1:«iionships a species has
<br />with the rest of the system: what it eats, how, and when;
<br />what temperature it prefers; whether it is active by day or
<br />night; what plants it uses for cover and nesting; and so on.
<br />The theory of the niche assumes that species avoid dinct
<br />competition by not u.sing the same resources in the same
<br />way at the same place and time. Niches may overlap
<br />partly, but not completely. 'I’hus species comp!t?ment
<br />each other, rather than being in constant, direct
<br />competition.
<br />Wetland eco.systcms arc more complex in term*: of this
<br />species diversity than some other systems. One
<br />explanation i.s that they have a number of edges or
<br />boundarie.s between structurally different vegetation. At
<br />such edges the greatest diversity occurs. Along their
<br />immediate uplands wetlands may be surrounded by trees
<br />or shrubs; as the gradient declines there may be sedge
<br />meadows or shallow marshes; finally, there is a change to
<br />deep marshes and open wrater. Kach of tht;se areas
<br />provides niches for different plants and animals. Generally
<br />man simplifies these systems by creating conditions
<br />unfavorable to certain plants and animals. We can crowd a
<br />marsh so that predators such as minks and foxes do not
<br />have enough escape routes. Or excess nutrients and
<br />siltation can give advantage to one floral species over
<br />anotlicr, re.sulting in an itnbnlaiico.
<br />By umlerstanding the function of a marsh in providing
<br />species diversity through its niches and edges, it is
<br />IHissiblu to style a regulatory pr(»grum that will be
<br />compatible. When alterations ore necessary along the
<br />edges of the marsh, it is possible to maintain a gradient
<br />that will pre.serve the diversity. By thinking of wetland
<br />syst<!ins as a number of marshes connected by streams or
<br />other modes of linear movement, man will have his homes
<br />and the fo.xes will have their escape routes. By thinking in
<br />terms of the wetland’s function of diversity, it is possible
<br />to implement a public policy goal which says: We want to
<br />prot(?ct wetlands because they provide recreation,
<br />education, and general environmental health.*
<br />Coastal Wetlands
<br />Improving water quality, moderating floocis and
<br />stabilizing water supplies, and providing overall environ
<br />mental healtli and diversity are important functions of
<br />coastal wetlands, too. But because they are at the
<br />boundary of our hind and sea resources, coastal wetlands
<br />have several umbiue characteristics and ways in which
<br />they serve tin* public interest.
<br />A. Coastal wetlands provide varied habitats for
<br />wildlife. Coastal wetlands are those partially or completely
<br />submerged areas of vegetation which occur along the
<br />coastline, particularly along the wide continental shelf of
<br />the Atlantic anti Gulf coasts. They may lie. along the
<br />margins of bays, estuaries, or lag'oons, those confined
<br />coastal water bodies with varying degri>es of connection to
<br />the sea. 'I’hey can be freshwater marshes along estuaries
<br />where river; mix with the sea, or they can be salt water
<br />marshtfs or tidal flats fed by incoming ocean tides. (See
<br />Table 2 for a listing of coastal wetland typn.s.) Like inhmd
<br />wetlands, these coastal wetlandts may be constantly
<br />submerged or mtiy be alternately dry or wet, depending o.n
<br />the seiisontil (low of rivers or the flurluations in iide:i.
<br />43
<br />I
<br />t-fr
<br />r
<br />Tln'se wet
<br />stni, they ni
<br />During spi i
<br />adjacent con
<br />in other set
<br />dominant IV •
<br />shellfish, as
<br />gradual, va
<br />estuaries, bt
<br />interference
<br />alter the nati
<br />The striped I
<br />marshes for
<br />areas for rea
<br />Cliannelizi
<br />groundwater
<br />and creeks ii
<br />decrease the
<br />or bay. Of ci
<br />after use by
<br />sea, the ava
<br />remains suf
<br />needed to su
<br />B. Coasta
<br />many varieti'
<br />and store the
<br />coastal wetia
<br />are 20 times
<br />times more
<br />Though coas
<br />of plants ant
<br />plants and s<
<br />more like a h
<br />In part bee
<br />as the varii
<br />coastal wetia
<br />and game fis
<br />Mexico for f
<br />Many water
<br />wetlands. Int
<br />decreasing it
<br />ability to tr;
<br />highly prod(
<br />example, the
<br />through the I
<br />be trapped ai
<br />water or ever
<br />coastal w'ctlm
<br />C. Coastal
<br />Like inland i
<br />retain signific
<br />can also absoi
<br />inland areas 1
<br />ran deprive a
<br />against hurrtc
<br />D. Because
<br />coastlines, co;
<br />disturbances,
<br />dredging and
<br />input, coastal
<br />increase or d<
<br />highly su.scepi
<br />44
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