. Critical trends assessment program : keeping an eye on Illinois habitats. Critial trends assessment program; Habitat conservation. .allgrass prairie was once the dominant habitat type in Illinois covering 63% of the state (Fig. 14). Over the past 150 years, prairie has been converted to cropland because of its immense soil fertility. Over of our original prairie is now gone, meaning that only 1,050 hectares remain intact (Figs. 3 and 14). Similar amount of prairie losses have taken place across the midwestern Remnant patches of prai- rie are now so isolated from each other that th
. Critical trends assessment program : keeping an eye on Illinois habitats. Critial trends assessment program; Habitat conservation. .allgrass prairie was once the dominant habitat type in Illinois covering 63% of the state (Fig. 14). Over the past 150 years, prairie has been converted to cropland because of its immense soil fertility. Over of our original prairie is now gone, meaning that only 1,050 hectares remain intact (Figs. 3 and 14). Similar amount of prairie losses have taken place across the midwestern Remnant patches of prai- rie are now so isolated from each other that they function as completely unconnected islands of habitat. Additionally, the fires and large grazing mammals which used to sustain prairies by keeping them open have been eliminated from the land- scape; meaning that neglected patches today become overgrown thickets of inpenetrable woody vegetation. With the loss of this habitat, entire groups of animals associated with it have suffered similar declines or elimination (, grassland birds and bison). Simply put, this is the most human-impacted habitat in Illinois, if not the most impacted ecosystem r\'pe in the world. Nonetheless, because Illinois' tallgrass prairie has the highest plant species density of any grassland on record—a healthy 5- acre remnant typically harbors more than 100 native plant spe- cies—even small patches can be large repositories for biological diversity and are extremely valuable. To characterize and monitor the entire range of remaining Illinois' grasslands, CTAP randomly selected 128 (125 in the case of birds*) grasslands and surveyed their plants and birds. In addition to sampling these "average" grasslands, CTAP also sampled 11 minimally disturbed prairie remnants for plants and 10 large grasslands for birds. These grasslands serve as biological references by which to compare randomlv selected, average Illinois grasslands to. Overall, results show that reference sites had greater plan
Size: 1060px × 2358px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorillinoisnaturalhistorysurveydivision, bookcollectionb
