518
for agriculture and forestry have affected pocosins
in North Carolina.
Further details of the pocosins may be found
in Richardson ( 1983 ), Kologiski ( 1977 ), etc.
23.6.3 The Big Rivers of the South
Atlantic Coast
The Atlantic coastal plain extends from North
Carolina to Savannah River in Georgia. It is a
land dominated by forested wetlands and marshes
and cut by large rivers which drain the Piedmont
and cross the coastal plain in a NW–SE direction
to the ocean. Extensive bottomland hardwood
forests and cypress swamps line these rivers
and spread into the lowlands between them.
Interspersed amongst these forests are hundreds
of Carolina bays, small elliptical-shaped lakes of
uncertain origin, surrounded by or overgrown
with marshes and forested wetlands (Knight et al.
1984 ; Lide et al. 1995 ).
23.6.4 The Prairie Potholes
There is a signifi cant number of small wetlands,
primary FW marshes found in a 780,000-km
2
region in the States of North Dakota, South
Dakota and Minnesota and in the Canadian
provinces of Manitoba, Alberta, etc. These wetlands are called ‘prairie potholes’. These were
formed by glacial action during the Pleistocene.
This region is considered as one of the most
important wetland regions in the world. It is
because of its innumerable shallow lakes and
marshes, their rich soils and their warm summers
(Weller 1994 ). Wet and dry cycles are a natural
part of the ecology of these prairie wetlands.
Much of the region is now used for farming and
rangeland agriculture, and many of the wetlands
in the region have been preserved even though
the vegetation is often harvested for hay or grazed
by cattle. Aquifer is a signifi cant source of water
for the region and is recharged to a signifi cant
degree through dune sands and to some extent
through the wetlands. It has been estimated that
there are 558,000 ha of wetlands in the Nebraska
Sandhills. Many of these are inter-connected wet
meadows or shallow lakes which contain water
levels determined by both run-off and regional
water table levels (LaBaugh 1986 ). The wetlands
in the region have been threatened by agricultural
developments, especially pivot irrigation systems
which cause a lowering of the local water tables
despite increase wetland fl ooding in the vicinity
of the irrigation systems. The Nebraska Sandhill
wetlands are signifi cant breeding grounds of
many waterfowls, like the prairie potholes
(Novacek 1989 ).
23.6.5 The Great Kankakee Marsh
This wetland does not exist anymore for all practical purposes. However, it was one of the largest
marsh–swamp basins in the in the interior USA
until about a century ago. It is situated primarily
in NW Indiana and NE Illinois. The Kankakee
River basin is 13,700 km
2 in size including
8,100 km
2 in Indiana, where most of the original
Kankakee Marsh was located.
The Kankakee region was believed to be a
prime hunting area until the wholesale draining
of the land for crops and pasture began in 1850s.
Nevertheless, some amount of historic and scientifi c literature exists for the Great Kankakee
Marsh (Bartlett 1904 ; Meyer 1935 ; Mitsch and
Rust 1984 , etc.).
23.6.6 The Mississippi River Delta
The Mississippi River reaches the last part of
its journey to the Gulf of Mexico in SE
Louisiana. It, then, enters one of the most
wetland regions of the world. The total area of
marshes, swamps and shallow coastal lakes
covers >36,000 km
2 . Further, the forested wetlands give way to freshwater marshes and then
to salt marshes as the Mississippi River distributaries reach the sea.
The Barataria Bay estuary in Louisiana is
another frequently studied wetland area in the
delta. It is an interdistributary basin of the
Mississippi River which is now isolated from
23 Wetlands of America
for agriculture and forestry have affected pocosins
in North Carolina.
Further details of the pocosins may be found
in Richardson ( 1983 ), Kologiski ( 1977 ), etc.
23.6.3 The Big Rivers of the South
Atlantic Coast
The Atlantic coastal plain extends from North
Carolina to Savannah River in Georgia. It is a
land dominated by forested wetlands and marshes
and cut by large rivers which drain the Piedmont
and cross the coastal plain in a NW–SE direction
to the ocean. Extensive bottomland hardwood
forests and cypress swamps line these rivers
and spread into the lowlands between them.
Interspersed amongst these forests are hundreds
of Carolina bays, small elliptical-shaped lakes of
uncertain origin, surrounded by or overgrown
with marshes and forested wetlands (Knight et al.
1984 ; Lide et al. 1995 ).
23.6.4 The Prairie Potholes
There is a signifi cant number of small wetlands,
primary FW marshes found in a 780,000-km
2
region in the States of North Dakota, South
Dakota and Minnesota and in the Canadian
provinces of Manitoba, Alberta, etc. These wetlands are called ‘prairie potholes’. These were
formed by glacial action during the Pleistocene.
This region is considered as one of the most
important wetland regions in the world. It is
because of its innumerable shallow lakes and
marshes, their rich soils and their warm summers
(Weller 1994 ). Wet and dry cycles are a natural
part of the ecology of these prairie wetlands.
Much of the region is now used for farming and
rangeland agriculture, and many of the wetlands
in the region have been preserved even though
the vegetation is often harvested for hay or grazed
by cattle. Aquifer is a signifi cant source of water
for the region and is recharged to a signifi cant
degree through dune sands and to some extent
through the wetlands. It has been estimated that
there are 558,000 ha of wetlands in the Nebraska
Sandhills. Many of these are inter-connected wet
meadows or shallow lakes which contain water
levels determined by both run-off and regional
water table levels (LaBaugh 1986 ). The wetlands
in the region have been threatened by agricultural
developments, especially pivot irrigation systems
which cause a lowering of the local water tables
despite increase wetland fl ooding in the vicinity
of the irrigation systems. The Nebraska Sandhill
wetlands are signifi cant breeding grounds of
many waterfowls, like the prairie potholes
(Novacek 1989 ).
23.6.5 The Great Kankakee Marsh
This wetland does not exist anymore for all practical purposes. However, it was one of the largest
marsh–swamp basins in the in the interior USA
until about a century ago. It is situated primarily
in NW Indiana and NE Illinois. The Kankakee
River basin is 13,700 km
2 in size including
8,100 km
2 in Indiana, where most of the original
Kankakee Marsh was located.
The Kankakee region was believed to be a
prime hunting area until the wholesale draining
of the land for crops and pasture began in 1850s.
Nevertheless, some amount of historic and scientifi c literature exists for the Great Kankakee
Marsh (Bartlett 1904 ; Meyer 1935 ; Mitsch and
Rust 1984 , etc.).
23.6.6 The Mississippi River Delta
The Mississippi River reaches the last part of
its journey to the Gulf of Mexico in SE
Louisiana. It, then, enters one of the most
wetland regions of the world. The total area of
marshes, swamps and shallow coastal lakes
covers >36,000 km
2 . Further, the forested wetlands give way to freshwater marshes and then
to salt marshes as the Mississippi River distributaries reach the sea.
The Barataria Bay estuary in Louisiana is
another frequently studied wetland area in the
delta. It is an interdistributary basin of the
Mississippi River which is now isolated from
23 Wetlands of America