1fs. North American PrairiesWe have seen that climatic boundaries
generally coincide with vegetation boundaries, but it is noteworthy that
humans can greatly modify extant vegetation. The great prairies once
reached from the southern parts of the Canadian Plains southward to
Texas and westward to the Rocky Mountain foothills and extended to the
east into the Great Lakes region. Prairies consist primarily of grasses,
along with some herbs and shrubs and the exclusion of trees.Many
factors are involved in creating prairie environments. Large temperature
differences between summer and winter are common and precipitation is
lower than that of most woodland areas. Precipitation across North
America generally increases eastward from the foothills of the Rockies,
and natural prairie populations have reflected this by having taller
grasses eastward.Nonclimatic factors also play a role in the existence
of prairies. The existence of periodic fire is important because it
prevents the incursion of trees that, unlike prairie grasses, do not
quickly regenerate in the wake of burns. Like other ecosystems, prairies
maintain an interaction between the vegetation and animal species. In
North America bison fed on unlimited grass and at the same time helped
maintain the grass by naturally tilling the soil with their very narrow
hooves (Figure 15-2-1).The extent of this major ecosystem has been
reduced greatly in North America since the westward expansion. The
reduction has been particularly acute where the tall grass prairies once
ruled; in Illinois only an estimated 0,1 percent of the original
prairie still exists. An estimated 20 to 25 percent of the short grass
prairie still exists farther to the west.The biggest culprit in the
demise of prai-rielands is expansion by humans. Prairie soils are
particularly fertile and valuable for agriculture. Urban expansion has
also played a role. Even where people have not taken over prairielands,
fire suppression has facilitated the expansion of trees into former
grasslands. There is also a threat from the spread of nonnative
species.As we will see in Chapter 16, climates have been changing and
will continue to do so. These changes may have significant effects on
the plants and animals from all ecosystems, including North American
prairies.FIGURE 15-2-1 North American Prairies. Bison qrazinq in Custer
State Park, South Dakota....What climatic factors explain the existence
of the North American prairie? Get solution
2fs. North American PrairiesWe have seen that climatic boundaries generally coincide with vegetation boundaries, but it is noteworthy that humans can greatly modify extant vegetation. The great prairies once reached from the southern parts of the Canadian Plains southward to Texas and westward to the Rocky Mountain foothills and extended to the east into the Great Lakes region. Prairies consist primarily of grasses, along with some herbs and shrubs and the exclusion of trees.Many factors are involved in creating prairie environments. Large temperature differences between summer and winter are common and precipitation is lower than that of most woodland areas. Precipitation across North America generally increases eastward from the foothills of the Rockies, and natural prairie populations have reflected this by having taller grasses eastward.Nonclimatic factors also play a role in the existence of prairies. The existence of periodic fire is important because it prevents the incursion of trees that, unlike prairie grasses, do not quickly regenerate in the wake of burns. Like other ecosystems, prairies maintain an interaction between the vegetation and animal species. In North America bison fed on unlimited grass and at the same time helped maintain the grass by naturally tilling the soil with their very narrow hooves (Figure 15-2-1).The extent of this major ecosystem has been reduced greatly in North America since the westward expansion. The reduction has been particularly acute where the tall grass prairies once ruled; in Illinois only an estimated 0,1 percent of the original prairie still exists. An estimated 20 to 25 percent of the short grass prairie still exists farther to the west.The biggest culprit in the demise of prai-rielands is expansion by humans. Prairie soils are particularly fertile and valuable for agriculture. Urban expansion has also played a role. Even where people have not taken over prairielands, fire suppression has facilitated the expansion of trees into former grasslands. There is also a threat from the spread of nonnative species.As we will see in Chapter 16, climates have been changing and will continue to do so. These changes may have significant effects on the plants and animals from all ecosystems, including North American prairies.FIGURE 15-2-1 North American Prairies. Bison qrazinq in Custer State Park, South Dakota....Give an example of a natural factor that helped to maintain the prairie ecosystem. Get solution
2fs. North American PrairiesWe have seen that climatic boundaries generally coincide with vegetation boundaries, but it is noteworthy that humans can greatly modify extant vegetation. The great prairies once reached from the southern parts of the Canadian Plains southward to Texas and westward to the Rocky Mountain foothills and extended to the east into the Great Lakes region. Prairies consist primarily of grasses, along with some herbs and shrubs and the exclusion of trees.Many factors are involved in creating prairie environments. Large temperature differences between summer and winter are common and precipitation is lower than that of most woodland areas. Precipitation across North America generally increases eastward from the foothills of the Rockies, and natural prairie populations have reflected this by having taller grasses eastward.Nonclimatic factors also play a role in the existence of prairies. The existence of periodic fire is important because it prevents the incursion of trees that, unlike prairie grasses, do not quickly regenerate in the wake of burns. Like other ecosystems, prairies maintain an interaction between the vegetation and animal species. In North America bison fed on unlimited grass and at the same time helped maintain the grass by naturally tilling the soil with their very narrow hooves (Figure 15-2-1).The extent of this major ecosystem has been reduced greatly in North America since the westward expansion. The reduction has been particularly acute where the tall grass prairies once ruled; in Illinois only an estimated 0,1 percent of the original prairie still exists. An estimated 20 to 25 percent of the short grass prairie still exists farther to the west.The biggest culprit in the demise of prai-rielands is expansion by humans. Prairie soils are particularly fertile and valuable for agriculture. Urban expansion has also played a role. Even where people have not taken over prairielands, fire suppression has facilitated the expansion of trees into former grasslands. There is also a threat from the spread of nonnative species.As we will see in Chapter 16, climates have been changing and will continue to do so. These changes may have significant effects on the plants and animals from all ecosystems, including North American prairies.FIGURE 15-2-1 North American Prairies. Bison qrazinq in Custer State Park, South Dakota....Give an example of a natural factor that helped to maintain the prairie ecosystem. Get solution
