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• Grassland/Savanna/Steppe • Cropland '1 00 istorically, grass­ lands occupied • Grassland/Savanna/Steppe 600 Happroximately • Cropland one billion acres in the 500 U.S. - about half the land on ~ mass of the 48 contiguous ...:;l 400 0 on states (Figure 1) . c Grass lands wes t of the Rocky Mountains .2 300 2 (approximately 332 million acres) were largely retai ned under federal manage­ 200 ment, while more than 90 percent of 100 those lands east of the Rockies (approxi­ mately 565 million acres) were placed under private ownership. o 1850 1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 Year Figure 2. Estimated land coverage by native Grassland/Savanna/Steppe versus Croplands in the U.S. west of Why Are Grasslands Important? th e Mississippi Rive r, 1850- 1990. Data Source: Raman kutty and Foley (1999). Grasslands provide both ecological and economic benefits. The importance of Grasslands support recreational based 1990, the loss of grasslands outpaced the grasslands lies not only in the immense activities such as hunting, fishing, and gains in cropland by over 1.5 to 1 - area they cover, but also in the diversity wildlife viewing. Accordi ng to the U.S. pointing to an increase in grassland con­ of benefits they produce. Fish and Wildlife Service, these activities version to uses other than cropland. Grass lands provide valuable ecological generated over $37 billion in 1996 fo r Between 1982 and 1997, National services such as nutrient cycling and stor­ the states wes t of the Mississippi . Resources Inve ntory data indicate that age of atmos pheric carbon. Foll owing cul­ Observers increas ingly note the benefits over 22 million acres of rangelands were tiva ti on, grassland soils are likely to lose of open space and scenic amenities of converted to other uses (Figure 3). Most up to 50 percent of their origin al carbon grasslands. For example, prices for land of th is loss was to cropland (abo ut seven within the fi rs t 40 to 50 years. bordering open space (includi ng grass­ million acres) and development (about Grasslands are key to an efficient hydro­ lands) , have been found to be 7 to 32 3.3 million acres). Almost three-quarters logic cycle. T he quality and quantity of percent higher than those not bordering of a million acres of rangeland were put water runoff and infiltration is dependent open space. into the Conservati on Reserve Program upon the quality of ground cover. The (CRP) in that time. biotic diversity of the grasslands has his­ Trends in Grasslands However, the actual loss in total range­ torically supported a diverse assemblage T he majority of grassland conversions land acreage since 1982 was about half of of species. have been to cropland, begi nning with that reported by the N RI due to the con­ Native grasslands and rangelands direct­ the tallgrass prairi es and savannas of the version of land from other uses back to ly support the livestock industry. mid-western states and continuing to the rangeland (Figure 4). While this reversal Grasslands comprise over 95 percent of Central Valley in California. From 1850 in land use softens the total loss in range­ the acreage it takes to maintain beef catrl e to 1990, grasslands wes t of the land, the ecological function of re-con­ in the Great Plains and Western U.S. Mississippi River declined by almost 290 verted rangeland is less effective than his "resrored" rangeland is also more likely ro be in smaller, disco ntinuous parcels, reducing its value as wildlife habi[at rela­ _ ITAl..l.GAAa~ tive ro native grasslands. _ '_'OMs.>.V _ _ lTAUGI'I4t_e _ ,CJ:IAS'! .... _II! .. 1l~1 ..._ ~ u~, __ _ ,,_...ocm __ _ • ~H-Wc.AAllS _ _ "~,,~ Factors Influencing Grassland D I~,t.,...1! _ ,,~~ _ 'OOIUJ_~ D 1f0U0ll_~ Disappearance Figure 1. Coverage of pre-settlement grasslands in the contiguous U.S.. by type. Adapted from Kuchler (1975). Hisrorically, the greatest threat ro grass­ land in the U.S. has been the plow. While What Can Be Done? the trend of converting grasslands ro crop­ Unless abated, these forces will concinue land is still important in some areas, dur­ Figure 3 Rangeland acres (1,0005) lost ro remove grasslands from their hisrorical ing the past several decades other trends to other land uses between 1982 and uses, and fragment the remaining areas so have emerged ro threaten the existence 1997 (22,120,000 total acres lost). that d1ey may not be of sufficient size to and health of grasslands. 729 support their natural biodiversity. Pressure from growth in human popula­ Poli cymakers can slow the pressure for tion and per capita income, and the fragmentation by developing government resulcing demand for property and servic­ programs that provide incentives ro private es, is an ever-increasing threat ro the tra­ grassland owners ro facili[ate grasslands ditional use of grasslands. Between 1990 retention and resroration. and 2000, the 22 states west of the Ensuring that government policies do Mississippi River gained more than 16.5 not provide incentives ro retain marginal million people - a 17.3 percent increase. cropland, or convert Many of the remaining grasslands are • Cropland grassland to cropland, • Pasture land located in areas with high natural ameni­ would enhance reten- • Forest Land ties. Low returns ro ranching industry tion and restoration of Other Ru ral Land and an aging population of grassland Rangeland acres (1,0005) grasslands under pri- Figure 4 Developed Land owners combined with the longest eco­ gained from other land uses between . vate ownership. • Water & Federal 1982 and 1997 (1l,360,000 total Expanding programs nomic boom in U.S. history, advances in .CRP acres gained), telecommunications, and other socio-eco­ d1at provide incentives nomic changes, contribute pressure to ro retain or resrore wildlife habitat and convert grasslands into large lot, rural res­ encourage wildlife-based land use enter­ idential developments. prises could also benefit grasslands resrora­ A common, unintended result of many tion (similar to USDXs Environmental agricultural support policies has been ro Quality Incentives Program, a progran1 provide incentives to convert grasslands ro that helps farmers defray the cost of imple­ crop production andlor ro thwart the re­ menting Best Management Practices that conversion of cropland back ro grass by preserve and enhance surface water and making land more profitable in cropland growldwater quality by reducing nutrient­ laden runoff and leaching). .
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