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AGRICULTURAL BIODIVERSITY
This includes all components of biological diversity of relevance to food and agriculture: the variety
and variability of plants, animals and micro-organisms at genetic, species and ecosystem level which
are necessary to sustain key functions in the agro-ecosystem, its structures and processes
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Agricultural biodiversity includes the following:
higher plants -crops, wild plants harvested and managed for food, trees on farms, pasture
and rangeland species;
higher animals - domestic animals, wild animals hunted for food, etc
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There are several distinctive features of agricultural biodiversity compared to other components of
biodiversity:
Agricultural biodiversity is actively managed by farmers
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Many economically-important farming systems are based on 'alien' crop species introduced
from elsewhere (maize and cassava, two most important food crops in Africa were
introduced from America); this creates a high degree of inter-dependence between countries
for the genetic resources on which our food systems are based
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Because of the degree of human management, conservation of agricultural biodiversity in
production systems is inherently linked to sustainable use - preservation through protected
areas is less relevant
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Components of Agricultural Biodiversity
Crop Diversity
Of the 27,000 species of higher plants, about 7,000 species are used in agriculture, but only three
(wheat, rice and maize) provide half of the world’s plant-derived calorie intake
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Although world food production in the aggregate relies on few crop species, many more are
important if production is disaggregated to regional, national or local levels
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6%
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Genetic diversity (variation within species) is vital for the evolution of agricultural species and their
adaptation to particular environments through a mixture of natural and human selection
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Wild Plant Biodiversity
In addition to domesticated plants, wild species are important nutritionally and culturally to many
people
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They are an important source of vitamins, minerals and other nutrients, and also
represent ready sources of income for cash-poor households
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Neighboring wild companion plants can harbor biocontrol agents useful in
agriculture
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Many wild plant populations are carefully nurtured by people although less intensively than those
cultivated in their fields
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Livestock Diversity
Of about 50,000 known mammal and bird species, only about 40 have been domesticated
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From these species, farmers and breeders have developed about 5,000 identified
breeds to fit local environmental conditions and to meet specific needs
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Genetic diversity also allows livestock to adapt to diseases, parasites and wide variations in the type
and availability of food and water
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Aquatic Diversity
Fish and other aquatic species are integral parts of several important farming systems
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More generally, aquaculture is becoming increasingly important and now supplies
about 20% of total fish production
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They physically stabilize soil structure
against erosion and soil movement on steep slopes and, in tropical systems, the contribution of
roots to soil organic matter is proportionately larger than from above-ground inputs
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But there has been little attention to the
selection of rooting traits in cultivars by crop breeders, and much less research into the production,
turnover and structure of rooting systems in tropical crops than into the above-ground components
they support
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Microbes play varied roles in plant communities and agriculture
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Seed-borne microflora are instrumental in seed transmission
of disease and thereby important in plant quarantine
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Arthropod Biodiversity
It is well known that insects, spiders and other arthropods often act as natural enemies of crop pests
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For example,
research on Javanese rice fields has shown that arthropod communities are structured in such a way
that the dynamics of seasonal succession consistently lead to high levels of pest suppression by
natural enemies, with little chance of major pest outbreaks
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Bees and other pollinating
insects are essential agents for the production of many crops
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Changing Trends in Agricultural Development and Biodiversity Links
Agricultural Biodiversity Loss: Conflicts and Effects
Increase of agricultural production and productivity, in the last 30 years, stems from both expansion
of cultivated area (extensification) and the increased output per unit of land (intensification)
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Ecosystem services provided by agricultural biodiversity have degraded and therefore undermine
ecosystem health
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Additional influential forces are the predominant
paradigms of industrial agriculture and the Green Revolution, beginning in the l960s
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Seed and agrochemical companies have also
influenced these trends
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The Food and Agriculture Organization of the United Nations (FAO-UN) figures show that:
At least one breed of traditional livestock dies out every week in the global context;
Of the 3,831 breeds of cattle, water buffalo, goats, pigs, sheep, horses and donkeys believed
to have existed in this century, 16 % have become extinct and 15 % are rare;
Some 474 of livestock breeds can be regarded as rare, and about 617 have become extinct
since 1892;
Over 80 breeds of cattle are found in Africa, and some are being replaced by exotic breeds
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As forms of biodiversity are eroded, food security can also be reduced and economic risks increased
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Loss of diversity also reduces the resources available for future adaptation
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There has also been a serious decline in soil organisms and soil nutrients
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These losses, along with fewer types of agro-ecosystems, also increase risks and can
reduce productivity
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Some insects benefit farming - for pollination, contributions to
biomass, natural nutrient production and cycling, and as natural enemies to insect pests and crop
diseases
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The global proliferation of modern agricultural systems has eroded the range of insects and fungi, a
trend that lowers productivity
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Agrochemicals generally kill natural enemies and
beneficial insects, as well as the "target" pest
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This disturbing cycle often leads farmers to apply increasing amounts of pesticides or to
change products-a strategy that is not only ineffective, but that also further disrupts the ecosystem
services and elevates costs
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Reliance
on monocultural species and the decline of natural habitat around farms also cut beneficial insects
out of the agricultural ecosystem
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Projections of food needs in the coming decades indicate probable
further expansion of cropland, which could add to this degradation
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Intensive use of pesticides and fertilizers can also disrupt and erode biodiversity in natural habitats
and ecosystem services that surround agricultural areas, particularly when these inputs are used
inappropriately
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Efforts to conserve and enhance agricultural biodiversity
Diversity Through Sustainable Agriculture: Principles and Practices
To achieve transformations for the conservation and enhancement of agricultural biodiversity, the
following strategic principles are critical:
Application of agro-ecological principles helps conserve, use and enhance biodiversity on
farms and can increase sustainable productivity and intensification, which avoids
extensification, thereby reducing pressure on off-farm biodiversity;
Participation and empowerment of farmers and indigenous peoples, and protection of their
rights, are important means of conserving agricultural biodiversity in research and
development;
Adaptation of methods to local agro-ecological and socio-economic conditions, building
upon existing successful methods and local knowledge, is essential to link biodiversity and
agriculture and to meet livelihood needs;
Conservation of plant and animal genetic resources -especially in situ efforts -- help protect
biodiversity for current livelihood security as well as future needs and ecosystem functions;
Reforming genetic research and breeding programs for agricultural biodiversity enhancement
is essential and can also have production benefits; and
Creating a supportive policy environment – including eliminating incentives for uniform
varieties and for pesticides, and implementing policies for secure tenure and local rights to
plant genetic resources – is vital for agricultural biodiversity enhancement and for food
security
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Good
examples include:
compost from crop residues, tree litter, and other plant/organic residues;
intercropping and cover crops, particularly legumes, which add nutrients, fix nitrogen, and
"pump" nutrients to the soil surface;
use of mulch and green manures (through collection and spread of crop residues, litter from
surrounding areas, and organic materials, and/or under crop);
integration of earthworms (vermiculture) or other beneficial organisms and biota into the
soil to enhance fertility, organic matter, and nutrient recycling; and
elimination or reduction of agrochemicals -especially toxic nematicides -- that destroy
diverse soil biota, organic material, and valuable soil organisms
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Experiences have shown that full
involvement of local farming practices in agricultural Research &Development- through
participation and leadership of local people -- has had beneficial outcomes
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Policy and Institutional Changes
Although many institutions are already actively involved, more coordination work is needed at all
levels to ensure effective reforms and agricultural biodiversity conservation policies that benefit the
public, especially the poor
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Ideas needing further attention include:
ensuring public participation in the development of agricultural and resource use policies;
eliminating subsidies and credit policies for high yielding varieties (HYVs);
fertilizers, and pesticides to encourage the use of more diverse seed types and farming
methods;
policy support and incentives for effective agro-ecological methods that make sustainable
intensification possible;
reform of tenure and property systems that affect the use of biological resources to ensure
that local people have rights and access to necessary resources;
regulations and incentives to make seed and agrochemical industries socially responsible;
development of markets and business opportunities for diverse organic agricultural products;
changing consumer demand to favor diverse varieties instead of uniform products
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(1998) Cultivating Diversity: Agrobiodiversity and Food Security
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, USA