275
model of food chain in a newly constructed
wetland in Central Ohio. This model had predicted that the general development of the fi sh
community in constructed wetlands with and
without river infl ows was very sensitive to certain environmental variables.
18.7 Peatlands
Bogs and fens are the peatlands which are distributed primarily in the cool boreal zones of the
world where excess moisture is abundant. Bogs
and fens may be formed in various ways. They
may originate either from aquatic systems (as
infl ow through succession or quaking bogs) or
from terrestrial systems (as with blanket bogs).
Many types of peatlands are identifi able. But
classifi cation according to the chemical conditions usually defi nes three types.
18.8 FW Swamps
‘Swamps’ are forested wetlands. A freshwater
(FW) deep swamp is a FW with woody communities and retains water throughout or most or all
of the growing season. The cypress ( Taxodium
sp.) swamps are the major deepwater forested
wetlands in the SE USA with permanent or nearpermanent standing water. There have been much
works on the freshwater swamps (Lugo et al.
1990; Laderman 1998; Golet et al. 1993).
18.8.1 Geographical Extent
Bald cypress swamps are found as far north as
southern Illinois and western Kentucky in the
Mississippi River embayment and southern New
Jersey along the Atlantic coastal plain. Shepard
et al . (1998) had estimated that there are 11.4
million ha of ‘oak–gum–cypress’ or about 14.5 %
of all of the timberland (78.5 million ha) in the
sub-eastern USA.
18.8.2 White Cedar Swamps
These swamps are dominated by Atlantic white
cedar. They are found along the Atlantic and Gulf
of Mexico coastlines of the USA as far north as
SE Maine.
18.8.3 Red Maple Swamps
This is one of the most common of the broadleaved deciduous forested wetlands in the NE
USA. However, the red maple swamps are replaced
by swamps dominated by trees, e.g. ash (Fraxinus
spp.), towards the west into Pennsylvania and
Ohio. However, the presence of red maple
swamps does not always indicate wetlands as
would the presence of cypress, tupelo or white
cedar.
18.8.4 Cypress Swamps
The cypress–tupelo swamps of the southern USA
generally occur under a diversity of geologic and
hydrologic conditions. They range from the
extremely nutrient-poor dwarf cypress communities of the southern Florida to the rich fl oodplain
swamps along many tributaries of the Mississippi
River basin.
18.8.5 White Cedar Swamps
This kind of swamps generally occupy a narrow
hydrologic niche between deepwater cypress–
tupelo swamps and moist-soil red maple swamps.
18.8.6 Biogeochemistry
The biogeochemistry of forested wetlands is
considered as one of the most complex and diffi cult to study amongst the different types of
forest ecosystems (Lockaby and Walbridge
18.8 FW Swamps
model of food chain in a newly constructed
wetland in Central Ohio. This model had predicted that the general development of the fi sh
community in constructed wetlands with and
without river infl ows was very sensitive to certain environmental variables.
18.7 Peatlands
Bogs and fens are the peatlands which are distributed primarily in the cool boreal zones of the
world where excess moisture is abundant. Bogs
and fens may be formed in various ways. They
may originate either from aquatic systems (as
infl ow through succession or quaking bogs) or
from terrestrial systems (as with blanket bogs).
Many types of peatlands are identifi able. But
classifi cation according to the chemical conditions usually defi nes three types.
18.8 FW Swamps
‘Swamps’ are forested wetlands. A freshwater
(FW) deep swamp is a FW with woody communities and retains water throughout or most or all
of the growing season. The cypress ( Taxodium
sp.) swamps are the major deepwater forested
wetlands in the SE USA with permanent or nearpermanent standing water. There have been much
works on the freshwater swamps (Lugo et al.
1990; Laderman 1998; Golet et al. 1993).
18.8.1 Geographical Extent
Bald cypress swamps are found as far north as
southern Illinois and western Kentucky in the
Mississippi River embayment and southern New
Jersey along the Atlantic coastal plain. Shepard
et al . (1998) had estimated that there are 11.4
million ha of ‘oak–gum–cypress’ or about 14.5 %
of all of the timberland (78.5 million ha) in the
sub-eastern USA.
18.8.2 White Cedar Swamps
These swamps are dominated by Atlantic white
cedar. They are found along the Atlantic and Gulf
of Mexico coastlines of the USA as far north as
SE Maine.
18.8.3 Red Maple Swamps
This is one of the most common of the broadleaved deciduous forested wetlands in the NE
USA. However, the red maple swamps are replaced
by swamps dominated by trees, e.g. ash (Fraxinus
spp.), towards the west into Pennsylvania and
Ohio. However, the presence of red maple
swamps does not always indicate wetlands as
would the presence of cypress, tupelo or white
cedar.
18.8.4 Cypress Swamps
The cypress–tupelo swamps of the southern USA
generally occur under a diversity of geologic and
hydrologic conditions. They range from the
extremely nutrient-poor dwarf cypress communities of the southern Florida to the rich fl oodplain
swamps along many tributaries of the Mississippi
River basin.
18.8.5 White Cedar Swamps
This kind of swamps generally occupy a narrow
hydrologic niche between deepwater cypress–
tupelo swamps and moist-soil red maple swamps.
18.8.6 Biogeochemistry
The biogeochemistry of forested wetlands is
considered as one of the most complex and diffi cult to study amongst the different types of
forest ecosystems (Lockaby and Walbridge
18.8 FW Swamps