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<br />89 <br /> <br />.,.:, <br /> <br />nation'. wetland. have been drained. Likewise, l~ttle information is <br />available on the more recent losses of wetlands, such a,; during the last 30 <br />years. Reports strongly suggest that drainage is takinig place very rapidly <br />and in spite of prote'Stive legislation. One estimate Pllts the yearly loss <br />of, wetlands at 1.2xl0 ha (300,OOQacres)" ' <br /> <br />One estimate reported that the state of Iowa once had 4.8xl05ha <br />(1,196.392 acres) of "swamplands" available for "reclam..tion" to <br />agricultural lands (Shaw and Fredine 1956). Since many of the wetlands of <br />the so-called corn belt were long ago drained and converted to cropland, <br />estimates are that almost 95 percent of Iowa's wetlands have been destroyed <br />(Bishop 1981) and that the remaining wetlandn are mostl~, in state o'omership. <br />Other surveys disclosed that the Rainwater Basin of south-central N,ebraska <br />had lost over 80 percent of its marshes by the 1960's. Great Lakes wetland s <br />have decreased by 71 percent (Jaworski and ~~phael 1979). Southeastern <br />Wisconsin had lost 61 percent of its wetlands by 1968. Michigan was losing <br />2632.5 ha (6,500 acres) per year in 1978 (Anc)n. 1978) iilIld a small segment <br />of North Dakota lost over 10 percent of its remaining W\!!tland from 1966 to <br />1980. Wetland drainage in the prairie pothole region of the United States <br />resulted in an estimated loss of 50 percent by 1950. MJlnn~sota, South <br />Dakota, and North Dakota combined lost an eSI:imated 5. Od 0 ha (125,000 <br />acres) of prairie pothole wetlands between 1964 and 1968. A survey <br />conducted by the Fish and Wildlife Service in 1964 and ,again in 1974 <br />revealed that over 40 percent of the potholes existing ;In 1964 in western <br />Hinnes~ta :;ad been destroyed in the subsequent 10 year period. In 1954 only <br />1. 8xl 0 ha (450,000) wetland acres remained of Cali fornb' s original <br />1.4xl06ha (3.5 million). Comparison of a 1914 and 1959 study indicated <br />that 45 percent of Connecticut's coastal marshes had been lost. At that <br />rate of destruction. it was predicted that only 14 perc..nt of the coastal <br />marshes would remain by the year 2000. <br /> <br />The national trend of converting "" tlands to agricultural and other <br />land use~ continues (Figure 1). It is predic;ted that the most extensive <br />conversions of wetlands are likely to occur in the, bottcmland hardwood <br />swamps and overflow wetlands of the South (NAS 1981). l'early 80 percent of <br />such areas have been lost in the lower Mississippi Vall..y (MacDonald et al. <br />1979), and as the South becomes more important in the production of <br />agricul tural commodi ties, 25 percent of the remaining area could be drained <br />by 1995 (NAS 1982). <br /> <br /> <br />." <br /> <br />......_ 'fl' <br />.o'_.u <br />'_010.101 <br />'1M ,_ '... _ .... IlIlO ,'.. <br />..~ <br /> <br />n;uu 1 alt t_ted ar.. of <br />r..dnlng ..Uandl in t.h. Onltad <br />IUt.. and 1111 t.M Pcaid, Potboll <br />.tat... l'50-1t77. KlU1CW:1 <br />Adapt" r~ Ah and J'r"lM lIsti <br />and ~ U.... <br />