810-RESOURCES - ... 810-RESOURCES 7.1 Importance ofBio-resource Management The bio-resources or...

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Transcript of 810-RESOURCES - ... 810-RESOURCES 7.1 Importance ofBio-resource Management The bio-resources or...

  • J

  • 810-RESOURCES

    7.1 Importance ofBio-resource Management The bio-resources or ecological resources often termed as biodiversity is

    defined as the totality of genes, species and ecosystems in a region (WRI-IUCN-

    UNEP, 1992). The wealth of life on the earth is the product of hundreds of millions

    of years of evolutionary history. During this process, speciation and extinction are

    two biological processes that have always gone hand in hand. What is worrisome

    however, is the accelerated rate at which extinction of species has occurred in

    recent times. This is primarily because of large-scale exploitation of natural

    resources and conversion/degradation of landscapes by humans in recent times.

    J'he ever-increasing loss of this biological wealth has posed serious threat to the

    very existence of humankind. Our dream of sustainable planet can only be attained

    if we protect the structure function and. diversity of the world's natural system on

    which man and other species depend. Rio-resources or ecological resources are

    generally divided into two broad categories: plant resources and animal resources.

    Green Plants occupy very important place in the ecosystem because of its higher

    biomass and its capability to convert solar energy into food energy, thus serving as

    a basis of energy flow in an ecosystem. Apart from meeting the basic needs of

    food, shelter and health, biodiversity has contributed in a variety of ways to

    conserve and enhance human utilisation. Unwise and over exploitation of bio-

    resources and destruction of natural habitats lead to environmental degradation,

    which ultimately lead to destabilisation of natural ecosystem. It is, therefore,

    necessary to pay more attention towards the preservation, conservation and

    management of bio-resources as to maintain ecological balance and ecosystem

    equilibrium in order to ensure the survival of humanity.

    Recently more interests are being shown m the preservation and

    management of ecological resources because of their intrinsic value, aesthetic

    value, social benefits, scientific value, recreational and educational significance

    and overall environmental value. Management of bio-resources includes all the

    three aspects: survey evaluation and preservation as well as conservation. Survey

    of bio-resources is the collection of more database using field survey methods and

    remote sensing techniques. On the other hand evaluation of bio- resources is

  • mainly concerned with the value judgement of habitats and species of plants and

    animals of a particular habitat. Quite often, people use the terms preservation and

    conservation as synonyms but both the terms differ significantly in their meaning

    In ecological context preservation means upkeep of rare and endangered species of

    plants and animals in specially protected areas so that their populations may

    increase to optimum level. No use of such resources is permitted. On the other

    hand conservation is a process which aims at proper use and its management in

    such a way that they are always available for judicious use by humans as well as

    ecological balance is maintained.

    7.2 Role , of Remote Sensing and GIS in Rio-resource evaluation.

    Satellite data have been found useful in providing spectral and spatial

    information pertaining to forest due to its synoptic coverage and periodicity.

    Satellite data have made a big difference in the formulation and implementation of

    national forest policy. While satellite data provide the status of forests in a cost-

    effective way, the Geographic Information System (GIS) enables planners to

    process the data in terms of the people's need as well as physical realities.

    Remote Sensing and GIS techniques are expected to be a valuable tool in

    the study of biodiversity. The techniques can be used to examine the species

    habitat relationship, which can be used to evaluate biological diversity. Species-

    habitat relationships are suitably ratings assigned by biologists to each habitat

    class, either as a binary (suitable, unsuitable), ordinal (High, Medium, Low) or

    ratio (index scoring) value. Each species distribution can thus be mapped by

    mapping environmental factors. Richness of species can then be inferred from the

    models developed in such a way.

    GIS modeling can be successfully used for mapping and monitoring

    species richness at local and regional scale based on vegetation cover (derived

    from Remote Sensing) and other habitat factors (obtained from existing maps like

    SOl toposheets or field studies). Comparison of bitemporal data : NDVI, PCs etc.

    results, is one of the most widely used methods for obtaining information on

    temporal vegetation changes. This needs following conditions to be fulfilled: (i)

    Classification scheme for both the dates should be exactly same. (ii) Identical

    126

  • classification algorithm should be employed for both the data sets. (iii) Level of

    generalization in both the classifications should be identical.

    7.3 Evaluation of Plant Biodiversity of Delhi Delhites today would react with surprise and disbelief it they would be

    told that urban Delhi was once forested and inhabited by a variety of wildlife. The

    biotic and abiotic factors, governing the type of vegetation in Delhi are rather

    adverse. The area is characterized by long periods of water deficit coupled with

    high temperature. These characteristics give the region a semi-arid climate.

    The flora of Delhi comprises nearly 1,000 species of flowering plants

    belonging to some 120 families (Khot, 1986). Sixty per cent of the species are

    either indigenous or naturalised and the remaining introduced. There is no

    endemic. More than 50 per cent of the indigenous flora represents the tropical

    species. Nearly eight per cent is from tropical Africa less than 50 per cent from the

    New World, and two per cent from-the temperate region. (Khot, 1986). Rapid pace

    of urbanisation is responsibl~Jor the loss of biodiversity in this city. Presently the

    only natural terrestrial ecosystem of Delhi is the Ridge while aquatic ecosystems

    are Yamuna River, Najafgarh drain, Bhalaswa lake etc. Various limitations

    regarding remote sensing data viz. unavailability of bitemporal multispectral data

    and use of such imagery in the study when leaf fall used to be in full swing have

    seriously affected the evaluation of plant biodiversity in the present study. In spite

    of that an attempt has been made in the present study to map the vegetation of the

    area based on satellite data and the field study. Plate 7.1 shows the Vegetation Map of Delhi. Evaluation of plant biodiversity in Delhi can be performed under

    three categories: Delhi ridge, open space and Yamuna river system.

    7.3.1 Plant Biodiversity of Delhi Ridge: A Community Structure and

    Biotic Pressure

    Delhi Ridge is defined as rocky out-crop of Aravalli ranges stretching

    from Delhi University in the north to south of the NCT boundary and beyond

    (MPD 200 1 ). It is actually such extension of the Aravalli hills that enters Gurgaon

    127

  • from south and sprawl towards Delhi in the form of tableland, some five kilometers

    across. Antique map (Plate 7.2) shows that the Delhi ridge was a continuous

    stretch but rapid urban sprawl has demolished some of its parts. Now it exists in

    four pockets with total area of about 7782 ha. Table 7.1 gives its all the sub

    division with areas.

    The Delhi Ridge and its neighbouring hilly tracts represent the

    characteristic natural flora of the state, which is a tropical thorny secondary forest

    commonly known as arid open scrub forest (Maheshwari 1963). Such forests are

    widely distributed in the arid and semi-arid zones of the earth where the total

    annual rainfall ranges from 50-100 em. In the present study dominant species of

    the Ridge have been identified by making 10 metre x 10 metre quadrants and the

    result is shown in Table 7.2. Thus the bulk of vegetation of the Ridge consists of

    co-dominant spinous shrubs and trees capable of great drought resistance.

    The tress comprising the perennial vegetation of the ridge are both

    indigenous as well as introduced. The chief indigenous species are Acacia,

    leucophloea, A. modesta, A senegal, A arabica, A catechu, Butea monosperma,

    Anogeissus pendula, Cordia dichotoma, C. rothii, Tecomela undulata, Zizyphus

    mauritiana etc. (Maheshwari, 1963). The most important exotic species of the

    ridge is Prosopis juliflora, native of the arid regions of Mexico and Central

    America introduced in 1877. Other successfully introduced tress are Azadirachta

    indica, Feronia limonia, Dalbergia sissoo, Casia fistula, Albizzia lebbeck,

    Prosopis glandulosa etc. (Maheshwari, 1963). The thorny shrubs occur in widely

    spaced clumps supporting a number of twiners and climbers. Of these Capparis

    sepiaria is very common and abundant., growing alone or associated with Grewia

    tenax, Securinega lucophyrus, Carissa spinarum, Flacourtia indica etc.

    A marked change is induced by t