190
books, reports, scientifi c studies and conference
proceedings, mostly in the last two decades of the
twentieth century. The citations in this treatise
could be said to be only the tip of the iceberg of
the literature on wetlands. Much of these have
been published since the mid-1980s. Two journals, namely, Wetlands and Wetlands Ecology and
Management , have been on publication. They disseminate scientifi c and management papers on
wetlands. In addition, many other scholarly journals frequently publish papers on wetlands.
Further, dozens of wetland meetings, proceedings
and special issues of journals have been published
from conferences on wetlands held throughout
the world. Moreover, books and articles on wetlands with coloured photographs and beautiful
illustrations have been developed by Niering
( 1985 ), Littlehales and Neiring ( 1991 ), Mitchell
et al. ( 1992 ), Kusler et al. ( 1994 ) and Rezendes
and Roy ( 1996 ) on North American wetlands, by
McComb and Lake ( 1990 ) on Australian wetlands
and by Finlayson and Moser ( 1991 ) and Dugan
( 1993 ) on wetlands of the world.
Notwithstanding the above, the government
agencies and NGOs around the world have been
contributing signifi cantly to the wetland literature and to our understanding of the wetland
functions and values. In the USA, the US Fish
and Wildlife Service ( USFWLS ) has been involved
in the classifi cation and inventorisation of wetlands. They have published a series of community profi les on various regional wetlands.
Concomitantly, the US Environmental Protection
Agency ( USEPA ) has been interested in the
impact of human activity on wetlands. They are
also eager to understand the role of wetlands as
possible systems for the control of water pollution. The US Army Corps of Engineers and the
USEPA have been requested by the USFWS
and Natural Resource Conservation Service ,
especially through its Offi ce of Wetlands, Oceans,
and Watersheds (OWOW), to act as the primary
wetland management agencies in the USA.
Concomitant to above, the wetland management organisations, e.g. Association of State
Wetland Managers and the Society of Wetland
Scientists , have been engaged in disseminating
information on wetlands, particularly in North
America. Moreover, the International Union for
the Conservation of Nature and Natural Resources
( IUCN ) and the Ramsar Convention ( RC ) are both
located in Switzerland. Both of them have been
developing a series of publications on wetlands of
the world. Further, it is important to note here that
Wetlands International ( WI ) is one of the leading
non-profi t organisations concerned with the conservation of wetlands and wetland species. WI
consists of a global network of governmental and
non- governmental experts who work on wetlands.
The HQ of WI for Africa, Europe and the Middle
East (AEME) is located at Wageningen, the
Netherlands. The American HQ is situated at
Montreal, Canada. WI has activities in more than
120 countries throughout the world.
11.4 Distinguishing Features
of Wetlands
(a) Wetlands are distinguished by the presence
of water, either at the surface or within the
root zone.
(b) Wetlands often have unique soil conditions
which differ from adjacent uplands.
(c) Wetlands support vegetation adapted to the
wet conditions ( hydrophytes ). Conversely,
they are characterised by an absence of
fl ooding-intolerant vegetation.
Climate and geomorphology defi ne the degree
to which wetlands can exist, but the starting point
is the hydrology . This, in turn, affects the physico -
chemical environment , including the water and
soil. This, further, determines with the hydrology,
what and how much biota , including vegetation,
is found in the wetland.
11.5 Comparison of Wetlands
with Terrestrial and Aquatic
Systems
In brief, a wetland is a lentic waterbody whose
depth does not generally exceed 6 m. Amongst
the other aquatic systems, a lake is a lentic system whose depth is generally >6 m. A river is
altogether a running (lotic) system.
11 Wetlands in the Landscape: Their History, Defi nitions, Origin and Evolution
books, reports, scientifi c studies and conference
proceedings, mostly in the last two decades of the
twentieth century. The citations in this treatise
could be said to be only the tip of the iceberg of
the literature on wetlands. Much of these have
been published since the mid-1980s. Two journals, namely, Wetlands and Wetlands Ecology and
Management , have been on publication. They disseminate scientifi c and management papers on
wetlands. In addition, many other scholarly journals frequently publish papers on wetlands.
Further, dozens of wetland meetings, proceedings
and special issues of journals have been published
from conferences on wetlands held throughout
the world. Moreover, books and articles on wetlands with coloured photographs and beautiful
illustrations have been developed by Niering
( 1985 ), Littlehales and Neiring ( 1991 ), Mitchell
et al. ( 1992 ), Kusler et al. ( 1994 ) and Rezendes
and Roy ( 1996 ) on North American wetlands, by
McComb and Lake ( 1990 ) on Australian wetlands
and by Finlayson and Moser ( 1991 ) and Dugan
( 1993 ) on wetlands of the world.
Notwithstanding the above, the government
agencies and NGOs around the world have been
contributing signifi cantly to the wetland literature and to our understanding of the wetland
functions and values. In the USA, the US Fish
and Wildlife Service ( USFWLS ) has been involved
in the classifi cation and inventorisation of wetlands. They have published a series of community profi les on various regional wetlands.
Concomitantly, the US Environmental Protection
Agency ( USEPA ) has been interested in the
impact of human activity on wetlands. They are
also eager to understand the role of wetlands as
possible systems for the control of water pollution. The US Army Corps of Engineers and the
USEPA have been requested by the USFWS
and Natural Resource Conservation Service ,
especially through its Offi ce of Wetlands, Oceans,
and Watersheds (OWOW), to act as the primary
wetland management agencies in the USA.
Concomitant to above, the wetland management organisations, e.g. Association of State
Wetland Managers and the Society of Wetland
Scientists , have been engaged in disseminating
information on wetlands, particularly in North
America. Moreover, the International Union for
the Conservation of Nature and Natural Resources
( IUCN ) and the Ramsar Convention ( RC ) are both
located in Switzerland. Both of them have been
developing a series of publications on wetlands of
the world. Further, it is important to note here that
Wetlands International ( WI ) is one of the leading
non-profi t organisations concerned with the conservation of wetlands and wetland species. WI
consists of a global network of governmental and
non- governmental experts who work on wetlands.
The HQ of WI for Africa, Europe and the Middle
East (AEME) is located at Wageningen, the
Netherlands. The American HQ is situated at
Montreal, Canada. WI has activities in more than
120 countries throughout the world.
11.4 Distinguishing Features
of Wetlands
(a) Wetlands are distinguished by the presence
of water, either at the surface or within the
root zone.
(b) Wetlands often have unique soil conditions
which differ from adjacent uplands.
(c) Wetlands support vegetation adapted to the
wet conditions ( hydrophytes ). Conversely,
they are characterised by an absence of
fl ooding-intolerant vegetation.
Climate and geomorphology defi ne the degree
to which wetlands can exist, but the starting point
is the hydrology . This, in turn, affects the physico -
chemical environment , including the water and
soil. This, further, determines with the hydrology,
what and how much biota , including vegetation,
is found in the wetland.
11.5 Comparison of Wetlands
with Terrestrial and Aquatic
Systems
In brief, a wetland is a lentic waterbody whose
depth does not generally exceed 6 m. Amongst
the other aquatic systems, a lake is a lentic system whose depth is generally >6 m. A river is
altogether a running (lotic) system.
11 Wetlands in the Landscape: Their History, Defi nitions, Origin and Evolution