The Water's Edge
: A Closer Look
As
region develops, it’s natural resource availability declines and the
cumulative impacts on the environmental land social systems becomes severe.
This has resulted in contentious debates within the growing population as
global economic demands for forest, fish, water and wildlife resources
expand. Resolution of these conflicts requires new perspectives that combine
social, economic and environmental concerns with an approach to a micro-level
management where forest, agricultural, ecological and urban parcels are
treated in an integrated manner.
There is a need
to understand the interactive processes at the micro scale and to develop a
new perspective for micro level management that balances long-term ecological,
economic and social stability with cumulative environmental change.
In India, the
watershed approach to development planning has been introduced since 1987. The
advantages of this approach are, the possibility of more detailed study of
various aspects at a much smaller scale. The experiences of watershed
planning has shown that the “riparian areas” are very often not considered as
a separate ecosystem.
“Riparian” is
defined by Webster as “relating to or living on the banks of a natural
watercourse (as a stream or river, lake).....” Other definitions range from
broad to very specific, but basically riparian areas are the green lands or
zones associated with or affected by water sources. (Naiman 1990, Gregory et.
al. 1991).
Though the
actual area of a riparian zone may be very less as compared to the area of the
surrounding forest or vegetation community, it deserves special attention
because of a number of reasons. The utility of riparian zones can be
discussed in terms of their being niches for various kinds of animal life, in
terms of their nutrient recycling ability and the buffer zone function they
perform.
The production
of biomass is very high. The vegetation also tends to be structurally
diverse. This structural diversity coupled with the fact that it is a
transition zone or an “ecotone” between the aquatic and the terrestrial
ecosystems promotes more niches for animal life. Riparian forests have a high
concentration of fruits, fish and insects. The dense foliage and the humid,
more stable micro environment in a riparian area officers a classic refuge to
many of the species. Besides attracting frugivores, piscivores and
insectivores, riparian areas are also multiple use zones for human beings by
virtue of the presence of the twin resources of fertile land and watr, in
fact, river banks gave traditionally acted as nuclei for human settlements.
The riparian
areas have a higher species diversity as compared to the surrounding forest.
Studies on bird communities in Dachigam, Rajaji and Bori have shown a higher
Bird diversity in riparian areas as compared to the adjacent uplands. The
riparian areas function as a refuges for wildlife as migratory routes for many
animals. They offer roosting and resting sites for birds and animals. During
the migratory seasons, there is an extremely high turnover of bird species in
the riparian areas as they are used as stopovers. Riparian areas are also
important to amphibians and some reptiles such as the mugger, the gharial
etc.
The riparian
areas play an important part in the nutrient cycling between the land and
water ecosystems. Primary productivity by the numerous tiny life forms in the
water and the leaf litter from the waterside vegetation are the two major
contributors to the nutrient cycling of this land - water eco-tone. This
nutrient cycling is very important in determining fish and mollusc
populations. This in turn affects inland fisheries.
Riparian zones
act as buffers and this action varies in upstream and downstream areas. They
filter out most of the nitrates and phosphates from the runoff water and
ground water that ultimately drains into the rivers. The roots of the stream
side vegetation also prevent rapid erosion of the river banks. These high
levels of nitrates and phosphates are a result of fields and agriculture. The
chemical compounds are often fixed in the plant tissue of the riparian area.
Today, however,
this effective filtering mechanism is threatened. Most of the riparian areas
have been taken up either for some development activity or agriculture. Their
vegetation is relatively undisturbed only in very steep or flood prone areas
which are relatively inaccessible. The continuity of the riparian zone is
very important to help in effective buffer action.
Today, as man’s
dependency on natural resources borders on the abyss of exploitation. These
areas are subject to heavy anthropogenic pressures such as settlements,
lopping, logging, grazing, bunding and recreation. Today, one of the greatest
threats to riparian areas is the impoundment of stream side vegetation by
river engineering - the building of dams, bunds etc. Airborne pollution and
sewage inputs are the other major threats to the riparian zones. Though
change is an integral part of the riparian ecosystem, the severity of human
action can have irretrievable consequences on the riparian ecosystem and the
diversity of flora and fauna present in the area.
In India, which
is famed for its rivers, few studies have been done on riparian areas. Those
undertaken have only looked at the bird community in isolation. Possibly the
best integrated study on the subject anywhere in the world has been done in
Idaho, USA.
Today, when
environment has assumed a centre stage in all development programmes and
coastal regulation zones have been identified, very little has been done for
riparian zones apart from the ban on logging within 4m. of a riparian area.
It is time we realised the sensitiveness of the eco-tone and took suitable
measures to make amends.
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