Pandit Govind Ballabh Pant Memorial Lecture: II

densa associated with Rhododendron wightii, Betula utilis, juniperus wallichiana
and Pyrus aucuparia are the dominant trees. Important shrubs are Cassiope
fastigiata, Berveris spp., and Salix sikkimensis. The ground cover includes Caltha
palustris, Meconopsis simplicifolia, Primula capitata, Arisaema griffithii and
arundinaria falcata.
Alpine vegetation: This zone has no trees but it abounds in shrubs, cushion
plants and herbs. The most common species are Rhododendron nivale,
Saussurea gossypiphora, Thylacospermum rupifragrum Arenaria musciformis,
Ephendra saxatilis, Urtica hyperborea, and Leontopodum himalayanum.
Stoney Deserts: This type of vegetation is found above 4800 m on rocky
ground. It is rich in species of genera Androsace Sedum and Saxifraga.
Agro-Ecosystem
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Apart from natural ecosystems, agro-ecosystems are equally important.
These systems must also include shifting cultivation, its retinement and making it
sustainable. Agro- ecosystems have not received any attention from ecologists
eventhough these are permanent changes of the original ecosystems. These
systems have to be treated on that basis.
An agro-ecosystem is essentially a man –made ecosystem which is
geared to meeting basic human needs of food, fodder, fuel, fertilizer, fiber,
timber, medicinal and commodity crops, and also giving some economic returns.
The underlying purpose is the production of these goods and services on a
sustainable basis. Such an ecological approach to agricultural production is
based on the concept of creating productive and sustainable systems with
resource-conservation and risk-reducing aspects of traditional farming methods
appropriately blended with modern advances in biology, particularly
biotechnology. Equally important are socio-economic and other aspects like land
and tenure, farm size, pricing policy, local markets and less dependence on
sophisticated farm implements and chemicals. The system has to maintain
optimum sustainable production of food and income over long periods (Khoshoo,
1992d).
The evolution of agro-ecosystems has been necessitated by the
escalating population. From a hunter-gatherer system, humankind became
sedentary and got attached o a particular locality. Thus in essence the evolution
of agro-ecosystem became inevitable on account of a major change from food
gathering to food producing. During this process humanbeing has eliminated all
the species except those on which he depended for his food, fodde, fuel, fiber,
fertilizer, medicare and some vocations. Over the years, this change has affected
the hydrological and geochemical cycles. All in all, agro-ecosystems are a
reflection of evolution of human culture. Agro-ecosystems are there to stay and
these along with shifting cultivation have to be refined and made sustainable by
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