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GIS in biodiversity conservation - The technology trend
Shirish A. Ravan
Research Scientist of
Maharashtra Remote Sensing Application Centre
VRCE Campus, South Ambazari Road,
Nagpur.
rshirish@hotmail.com
Depiction of ecosystem harbouring around
120,000 known plants and perhaps another 400,000 as yet undescribed species of
plants, microbes and animals is possible with the recent technological
advances.
Biodiversity is
receiving the attention of various scientists/planners/decision-makers due to
its importance as a natural reservoir with tremendous economic potential.
Conservationists have focussed attention on this fast depleting resource.
In-situ conservation using ecosystem approach is popular which also protects
various ecological services offered by forest ecosystem. Examples of such
services are soil and water conservation, pollutant sink, noise reduction,
shelter belts, microclimatic effects etc. Emphasis is on identifying most
valuable biodiversity spots that harbour non-timber forest species such as
endangered flora and fauna, medicinal plants and wild relatives of cultivated
crops. While identifying such spots, it is also important to take into account
the landuse and human activities around the forest.
Conservation programmes for the 21stcentury are increasingly
focused at the ecosystem level. IUCN/UNEP/WWF observe that "conserving
biological diversity equals conserving ecosystems". The key question in this
case is "Where are such ecosystems and how one is important in comparison to
another?"
Comprehensive,
quality information on the distribution, status and utilisation of India’s
biodiversity is the cornerstone for planning its conservation. While a lot of
information exists, it is dispersed widely across the subcontinent among a large
number of organisations. Moreover, some of it is not easily accessible or
available in readily usable electronic form. Also, there are significant gaps in
database in many areas.
Hence, assessing biodiversity of megadiversity country like India is enormous task.
Depiction of ecosystem harbouring around 120,000 known plants and perhaps another 400,000 as yet undescribed species of plants, microbes and animals is possible with the recent technological advances. Over the years, scientists have tried to find practical and simplified approaches to identify vegetation unit that represents unique species composition and diversity. Thus, the term "vegetation type" became popular among ecologists, which
can be defined as ‘the assemblage of dominant growth forms of plant species
sharing common habitat i.e. landform.
In early 90’s, the
efforts were focussed on supplementing field-based observations with the remote
sensing based observations. The challenge was to prove that units identified on
remote sensing data represents unique composition. In pioneer studies carried
out at Indian Institute of Remote Sensing, Dehradun, vegetation communities in
dry deciduous forests were mapped using Landsat TM data. Field data collected
using stratified random sampling was analysed statistically to identify
communities existing in the forest. The results showed vegetation units
identified on remote sensing image show total agreement with the results of
field based observations (Ravan, Roy and Sharma, 1995). The advantage of remote
sensing is that it also identifies the vegetation /landuse units which may
likely to miss during field surveys because of limitations in sampling
techniques.
Recent publications
from Centre for Ecological Sciences (Indian Institute of Science) have verified
above concept in Western Ghats forest by classifying ecological entities
differentiated in terms of their composition/configuration to which field
investigations of biodiversity can be linked (Nagendra and Gadgil, 1999). Thus,
the efforts have resulted in wide acceptance of remote sensing technology in
various studies such as wildlife ecology, biodiversity assessment, wetland
ecology, biodiversity prioritization, forest and wildlife management
etc.
The technology that has given many more dimensions to the applicability of remote sensing based vegetation type map is ‘Geographic Information System (GIS)’. To name one, Landscape Ecology is benefited most with the
availability of spatial analysis tool like GIS.
Landscape ecology
considers vegetation as a mosaic of patches of vegetation with unique landform,
species composition and disturbance gradient and focuses on parameters such as
patch sizes, patch shapes, patch isolation, interspersion (adjacency of various
landuses/landcover), juxtaposition (relative importance of adjacent patches),
fragmentation, patchiness etc. All these parameters have direct bearing on the
status of biodiversity within forest ecosystem.
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