Geoscience Reference
In-Depth Information
Wetland services, resources
and valuation
11
11.1 Human use of wetland ecosystems
of the Dal Lake of Srinagar, India provide a
comparable modern version. Carefully main-
tained raised earthen beds along the shallow
shores of the Dal Lake provide space for vegeta-
ble harvests. Similar l oating cultivation tech-
niques called
dhap
using l oating mats of dead
aquatic plants are seen in the wetlands and
waterlogged areas of rural Bangladesh.
The push for agricultural expansion led to
wetland conversions across various parts of
the world well into the twentieth century. The
industrial age sped up this process, as increased
population pressures led to the development of
untouched wetlands for settlement and proi t.
Policy initiatives from colonial India to North
America pursued sustained wetland conversion
strategies. Often these were not based on scien-
tii c knowledge about the role of wetlands
within the larger biosphere, so that they were
erroneously represented as wastelands (Mitsch
and Gosselink 2000).
Beginning in the second half of the twentieth
century, however, numerous studies began doc-
umenting the valuable economical, hydrological
and ecological functions provided by wetland
habitats at local, regional and global scales
(Table 11-1). Scientii c journals, such as
Wet-
lands
,
Estuaries
,
Journal of Wetlands Ecology
,
and
Wetlands Ecology and Management
among
others, were founded specii cally to study
important aspects of this ecosystem, its charac-
teristics, and its functioning. Scientists examined
Throughout history wetlands have sustained
human populations by acting as sources of food,
water, i ber, shelter and solace. Examples range
from ancient Sumerian and Egyptian cultiva-
tions of reed beds for i ber and building materi-
als, to Aztec experimentation with chinampas
wetland agricultural methods and water harvest-
ing techniques (Boule 1994). Archaeological evi-
dence also indicates that Mesopotamians valued
the aesthetics of wetland landscapes and sought
to replicate them by creating gardens that mim-
icked and incorporated wetland pools and pond
features (Boule 1994). Similar gardens indicative
of later Islamic inl uence were common across
Mughal India during the sixteenth through
eighteenth centuries. Many examples of these
still survive today and include the famous
gardens of Srinagar and those found within the
complex of the Taj Mahal in Agra, India.
Even so, early agriculturalists, like their more
modern counterparts, recognized the economic
value of modii ed wetlands as cropland. Scar-
borough (2009) documented the signii cant
alterations to wetland landscapes in the ancient
Mayan lowlands and highlands of Mexico and
other parts of Mesoamerica. Here, the construc-
tion of raised i elds and drained platform plant-
ing areas, and other engineering modii cations
such as ditches, earthen berms, and terraces,
were not uncommon. The horticultural gardens
