Geoscience Reference
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accelerated since the Industrial Revolution in
the eighteenth century.
Dugan (2005) emphasized the distinction
between “hydraulic” and “aquatic” civilizations
in terms of how they utilized wetland resources.
Hydraulic civilizations usually developed in
upstream or inland settings in which water
resources were seasonal or limited. Storage and
distribution of water were controlled via engi-
neering structures such as dams, levees, reser-
voirs and canals for irrigating farm land, all of
which degrade or eliminate wetlands. Aquatic
civilizations, in contrast, were situated in down-
stream or coastal settings where water was gen-
erally abundant. These civilizations utilized the
annual l ood cycle to farm deltas and alluvial
plains, which had lesser impacts on wetlands.
During the European period of exploration
and colonization, beginning in the late i fteenth
century, the hydraulic approach ruled at home
and was exported throughout the world.
It is generally agreed that worldwide at least
half of all pre-development wetlands have been
lost to human activities (Mitsch and Gosselink
2007). This global loss of wetland habitats may
be attributed primarily to the hydraulic empha-
sis of the past i ve centuries (Dugan 2005). The
same holds true for the coterminous United
States since the birth of the country. The 20
northeastern states are representative of this
trend (Table 1-2). In general, the relatively rocky
New England states (Maine, New Hampshire,
Vermont, Massachusetts) had lower losses,
whereas the Midwestern corn belt (Ohio,
Indiana, Illinois, Iowa, Missouri) had the great-
est conversions of wetland along with the Atlan-
tic states of Connecticut and Maryland. The
western Great Lakes and Appalachian states
experienced intermediate reductions in wet-
lands. The distribution of wetland losses from
state to state rel ects primarily the extent of
agriculture and amount of urban development.
Elsewhere around the world, similar wetland
losses range from over 90 percent in New
Zealand (Dugan 2005) to minimal impacts in
remote and little-developed regions (Table
1-3). However, oil-and-gas and diamond explo-
ration and extraction threaten once pristine
wetlands in the circumarctic region, and human
Table 1-2.
Wetland losses in the 20 northeastern states
of the United States from
c.
1780 to 1980. Areas given
in hectares; based on Dahl (1990).
State
1780
1980
% loss
Maine
2584
2080
19
New Hampshire
88
80
9
Vermont
136
88
35
Massachusetts
328
236
28
Rhode Island
42
26
37
Connecticut
268
70
74
New York
1025
410
60
Pennsylvania
450
200
56
New Jersey
600
366
39
Delaware
192
90
54
Maryland
660
176
73
West Virginia
54
40
24
Ohio
2000
194
90
Michigan
4480
2234
50
Indiana
2240
300
87
Wisconsin
3920
2132
46
Illinois
3285
502
85
Minnesota
6030
3480
42
Iowa
1600
170
89
Missouri
1938
258
87
Table 1-3.
Estimated wetland losses for selected
regions of the world. Adapted from Mitsch and
Gosselink (2007, Table 3.2).
Region
% loss
United States
53
Canada
Atlantic tidal/salt marshes
65
Lower Great Lakes/St. Lawrence
71
Prairie pothole region
71
Pacifi c coastal estuaries
80
Australia
Swan Coastal Plain
75
Coastal New South Wales
75
Victoria
33
River Murray basin
35
New Zealand
>
90
Philippine mangrove swamps
67
China
60
Europe
60
encroachment on wetlands continues apace
throughout the developing tropical world,
both inland and offshore. The 2010 BP Deep-
water Horizon oil spill in the Gulf of Mexico
demonstrates that further degradation of
wetland habitat may take place even in places
