সেউজী ধৰণী
অতিথী চ’ৰা
Climate change
and Agricultural Biodiversity
Dr. D.N. Chakravarty
Biodiversity is the source of the
plants and animals that forms the basis of agriculture and the immense variety
within each crop and livestock species. Countless other species contribute to
the essential ecological functions upon which agriculture depends. Worldwide
there is now a huge diversity of agricultural system ranging from paddy
varieties of Asia to dryland pastoralsystems of Africa and hill farms in the
mountain of South America. Of the 27,000 species of higher plants, about 7000
are used in Agriculture. Animal and insects pollinate approximately 80% of
angiosperms which amount to about 300,000 flower visiting species.
However, the Earth’s biodiversity
is being lost at an alarming rate, putting in jeopardy the sustainability of
ecosystem services and agriculture and their ability to adapt to changing
conditions. As custodians of land and natural resources, including
biodiversity, farmers and agricultural scientist manage agricultural
biodiversity and their landscapes. They are allies in global effort to manage
biodiversity better.
According to FAO about 7000 species
of plants have been cultivated since human first began farming. To-day, only 30
crops provide an estimated 90% of the world population’s dietary energy
requirements, with wheat, rice and maize alone providing about half the dietary
energy consumed globally. Of the estimated 15,000 species of mammals and birds,
only some 30 to 40 have been domesticated for food production and less than 14
species including cattle, goats, sheep, buffalo and chickens accounts for 90%
of global livestock production. FAO data indicate that during the past six
years, a breed has been lost each month.
Many modern practices and approaches to intensification aimed at achieving high yields include use of
monocultures with reduction in cropping diversity and elimination of rotation,
use of HYV and hybrids with loss of traditional varieties and diversity
together with the need for high inputs or inorganic fertilizers, control of
weeds, pests and diseases with chemical pesticide than mechanical or biological
methods.
Land and habitat conversion to
large scale agricultural production, including drainage of land and conversion
of wetlands has also caused significant loss of biodiversity. The
homogenization of farming landscape with elimination of natural areas to
achieve large scale mechanized production has also lead to decline in
biodiversity and ecological spots.
The increased demand for animal
feed puts increased pressures on cultivated systems, with consequently an increased
demand for water and nitrogen, other fertilizers and chemical pesticides
inputs. Emphasis on modern system on quantity of yield has led to selection and
breeding for high production and loss of traditional breeds that held other
traits, qualities and adaptation, now lost.
Thus human activities
are driving the loss of biodiversity at an unprecedented rate, up to 1000 times
than natural rate of species loss. All the achievements on higher productivity
are being done without major regards to the erosion of biodiversity.
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Writer is Retd. Dean (Agri.) AAU
and presently Director, NEOLAND Technologies, Guwahati-24; Cell-94351 16605; E-mail: neoland123@gmail.com
