Endangered Species Handbook

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Grasslands, Shrublands, Deserts

Drylands of the World: NORTH AMERICA: Page 3

     Ecological studies of the remnants of tallgrass prairie reveal them to be extremely rich in plant diversity, with up to 500 different species (Madson 1993).  Of these, at least 150 species are grasses, with about 10 dominant kinds (Madson 1993).  In the eastern portions, savannah with islands of forest, or grassland surrounded by forest, dominated (Brown 1985).  Further west, isolated trees or groves, primarily oaks and hickories, replaced forest islands.
 
     In Illinois, at the eastern edge of the original tallgrass prairie, only seven hundredths of one percent remains (.07 percent); this pitiful remnant makes a mockery of the state's nickname, "The Prairie State" (Stevens 1995).  The original 21 million acres of Illinois tallgrass disappeared rapidly under the plow, leaving about 2,500 acres (Line 1997), of which only 11.2 acres of untouched prairie savannah exists (Stevens 1995).  Even these remnants are so fragmented and poor in species that scientists can only guess at the original components of this ecosystem.
 
     One of the rarest tallgrass birds is Henslow's Sparrow (Ammodramus henslowii), a small brown-and-black striped songbird, which breeds from the Northeast west to South Dakota and Kansas and south to North Carolina.  This bird prefers fairly tall native grass species with scattered shrubs and woody growth, and requires a range of at least 500 acres (Line 1997).  It was first listed on the National Audubon Society's annual Blue List of declining species in 1974, and by 1986, it was reported very rare or absent in many parts of the Northeast, Appalachia and the Great Lakes region (Ehrlich et al. 1992).   The disappearance of tallgrass prairie is directly responsible for the decline of this sparrow, and it cannot survive in the tiny fragments that persist.  Henslow's Sparrow may soon qualify for listing on the Endangered Species Act.  The Fish and Wildlife Service (FWS) appraised its rate of decline at 93 percent since 1966, one of the most drastic for any North American breeding bird (Line 1997).  FWS considers it a Migratory Nongame Bird of Management Concern; although a 1996 status survey found the species to be greatly reduced, the Service has not designated it an endangered species (Line 1997). 
 
     Historical records indicate that Henslow's Sparrows were abundant in the Midwest, from Wisconsin through Illinois, during the 19th century.  Today, these birds are so rare that birdwatchers travel for hundreds of miles to see one.  Their song is very unsparrow-like, a short staccato "se-LICK" which can be mistaken for an insect's call.  Only four areas in the country still contain colonies of Henslow's Sparrows with populations of 400 or more nesting pairs:  Missouri; The Nature Conservancy's Tallgrass Prairie Preserve in Oklahoma; Fort Riley, an army base in Kansas; and Jefferson Proving Ground in southern Indiana (Line 1997).  Fort Riley is home to other rare grassland birds such as the Grasshopper Sparrow (Ammodramus savannarum), which has declined 66 percent overall, and has suffered a 96 percent decline in New York State since 1966 (Line 1997).  Grasshopper Sparrows prefer shortgrass and open habitats devoid of brush and weeds and prosper when grasslands are mowed annually rather than burned, leaving seeds and insects (Swengel and Swengel 1997).  The Sedge Wren (Cistothorus platensis), a state-listed species also resides on Jefferson Proving Ground (Pruitt 1997).  Almost half the base, including all the grasslands, is off-limits to human access because of an estimated 1.5 million rounds of unexploded ordnance (Pruitt 1997), a fact which may work to the benefit of these rare species since large numbers of people can disturb these birds, causing them to desert ideal habitat.  The future of these birds depends on the success of various efforts to protect and restore tallgrass prairie east of the Mississippi River.
    
     The colorful Bobolink (Dolichonyx oryzivorus), a member of the blackbird family, Icteridae, nested in large numbers in overgrown fields and native grassfields until the last few decades.  These birds migrate in immense flocks, wintering in South America.  In recent years, however, they have become rare in many areas, as more and more hay fields are mowed during their nesting periods, or plowed for agriculture.  They have also lost wintering habitat to agriculture.  Bobolinks have incurred an average of 90 percent decline in the Midwest, according to results from bird censuses conducted in the early 1990s, as analyzed by the Biological Resource Division of the U.S. Geological Survey.  In one New York study, hay mowing caused the loss of 94 percent of Bobolink nests, while in undisturbed fields, 80 percent of the chicks survived (Line 1997).  Conservationists and ornithologists have launched education programs to convince farmers to delay mowing their fields until late summer when these birds have finished nesting.
 
     The largest remaining area of untilled tallgrass prairie, totaling about 60,000 acres, is found in the Flint Hills of Kansas and in the Osage Hills of Oklahoma; these grasslands were not plowed because both lie atop rugged limestone rock formations and have a comparatively thin topsoil.   A national tallgrass prairie park was first proposed decades ago.  Private owners of the land in the Flint Hills opposed federal legislation first introduced in 1962 to create such a park and, for more than 30 years, refused to sell or donate virgin prairie that stretches for about 100 miles (Madson 1993).   Finally in 1996, after decades of lobbying by conservationists, the United States Congress authorized a national tallgrass prairie park and President Bill Clinton signed the bill into law, the first federal protection for this extraordinary habitat.   The new Tallgrass Prairie National Preserve in the Flint Hills of east-central Kansas covers 10,894 acres.  Disputes continue with neighboring cattle ranchers opposing the preserve and recommending that the land continue as a cattle ranch, legally possible under the Preserve designation, a less stringent category than National Park.  Ecologists, however, have proposed restoring the original plant life, which has become less diverse after generations of cattle grazing.  The preservation of this land is a great victory for environmentalists who have long worked toward this goal.  Only with time will the enmities and differences be settled, hopefully on the side of the natural environment. 
 
     In Iowa and Minnesota, the Fish and Wildlife Service is planning to establish the Northern Tallgrass Prairie Habitat Preservation Area.  Through purchases of land and easements, the area will cover come 70,000 acres (Line 1997).  In Wisconsin, the International Crane Foundation has reestablished prairie on its land.  An innovative program in the state allows dairy farmers to set aside one third of their pasture for grassland birds, mowing or grazing it after the nesting season (Line 1997).
 
     A substantial unplowed section of tallgrass prairie was acquired by a private conservation organization. The Nature Conservancy obtained 30,000 acres in Oklahoma's Osage Hills, a former cattle ranch, in the early 1990s.  It plans to restore the original plant life, and 300 bison have already been released in the prairie (Madson 1993).  This sanctuary is sizeable enough to harbor a natural tallgrass ecosystem, which ecologists have calculated should encompass at least 16,500 acres, have a population of 500 bison, and a complete watershed (Madson 1993). The new preserve is being biologically inventoried prior to reintroduction of native species.


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