Agro-biodiversity: Its Role And Conservation

Biodiversity became an important environmental issue in the early 1980s when humans became aware of its impact and danger of exhausting them. 
By Okolle N. Justin*
With this global issue, the Convention on Biological Diversity (CBD) was developed as an international biodiversity treaty with a general objective of developing national strategies for the conservation and sustainable use of biodiversity.  This CBD was opened for signature at the Earth Summit held in Rio de Janeiro on June 5, 1992 and this treaty became fully implemented on December 29, 1993.
In sum, agro-biodiversity involves the variety of plants, animals and micro-organisms necessary to sustain key functions of an agro-ecosystems (structure and processes) mainly for food production and food security.  It has been found that many people depend on agro-biodiversity for sustainable livelihoods. Furthermore, agro-biodiversity is largely shaped/maintained by human activities and management practices.
Importance of Agro-biodiversity
Important source of genetic resources for food, fibre, fuel and income. Many plants, animals and fish, as well as microbial life (fungi, bacteria) found in agro-ecosystems can be used as source of food, fibre, fuel and income. Many of these organisms can be cultivated or reared and used as food for humans and other animals or sold to provide income. In addition, biomass and wastes of some these organisms can be used as organic fertilizers for the vigorous growth of crops.
Vegetation in agro-ecosystems helps to prevent soil erosion and supply ground water. Vegetation can also help to control/prevent flooding. Ultimately, vegetation in agro-ecosystems helps to regulate local micro-climate.
Source of useful substances such as bio-pesticides. Fungi such as Beauveria bassiana can be mass-cultured to produce pesticides that are specific, and environment friendly.
Regulating the abundance of pests and diseases. In nature, there are many insects, spiders and micro-organisms that attack and kill pests as well as disease-causing organisms. For example, parasitic hymenopteran wasps use their sharp ovipositor (sting at end of abdomen) to insert eggs into the bodies of other insects. Young larvae hatching from these eggs eat the internal structures of their hosts, eventually killing and reducing their population. Apart of this natural control rendered, these natural enemies of pests can be captured, reared and released in agro-ecosystems so as to effectively search, parasitize, kill and control pests. This manipulative process is referred to as biological control or bio-control.
Some plants and micro-organisms have special mechanisms used to detoxify harmful chemicals in the environment. This is known as phytoremediation and it plays an important role in pollution reduction in agricultural ecosystems.
Many insects (butterflies, moths, bees) and flower visiting birds (sun bird) serve as pollinators for plant reproduction. For seeds and fruits to be formed, male sex gametes must leave anthers of flowers, land on the female organ (stigma), move downward and fuse with the female sex gametes in the ovary. This process is largely aided by biotic pollinating agents such as insects, birds and some mammals. In oil palm plantations, small beetles help in pollinating the plants and in the absence of these pollinators, yield of oil palm drops drastically.
Plants, animals, and lots of micro-organisms are actively involved in the cycling of matter/nutrient in agro-ecosystems. Typical nutrients cycled are carbon, phosphorus, and nitrogen. For example, in the nitrogen cycle, specialized bacteria mainly found in the nodules of leguminous plants help to convert atmospheric nitrogen to nitrates that are useful for plant growth and development. In a related process, these organisms especially trees can help maintain the hydrological (water) cycle.
With the so much talk about global warming and climate change, carbon sequestration has been encouraged as a means to mitigate these environmental concerns. Carbon sequestration is simply the removal of excess carbon dioxide from the atmosphere whose excess accumulation has been implicated as one of the major sources of greenhouse gases. Biological sequestration of carbon is when plants and microbes in the soil capture and store atmospheric carbon dioxide either as biomass or in the soil. Farming methods that support or encourage bio-sequestration of carbon (i.e. methods that return biomass and hence carbon to the soil ) include (i) use of cover crops between planting seasons, (ii) use of mulch that will protect the soil from sun, allow soil to hold more water, and be more attractive to carbon-capturing microbes, (iii) crop rotation.
Agro-tourisms: Plants in plantations or farms and animals reared in large production units usually attract tourists.
Threats to Agro-biodiversity
Like the case of biodiversity in general, certain human activities are major threats to agro-biodiversity such as pollution (air, land, water), over/illegal hunting/harvesting, and greenhouse gases emission.  Emission of certain chemicals into the agricultural environment can result to genetic erosion; disappearance of certain plant/animal species
Natural activities such as volcanic eruption, floods, earthquakes, tsunamis, hurricanes, tornadoes can to some extend cause serious loss of biodiversity.
Replacement of local varieties with high-yielding ones can also result to genetic erosion.
Conservation of Agro-biodiversity
Conservation is necessary because of the impact that certain human activities have on the biotic factors of the environment due to industrial development, modern agriculture and unwise/over-exploitation of resources.  
The purpose of conservation is for sustainable development which entails carrying out activities to supply needs of present generation and that of future generations.
Conservation approaches/methods can include (i) protection, restoration or creation of natural habitats such as wetlands.  
According scientists, wetlands and mangrove habitats are very important carbon sinks in the world, with wetlands containing about 14.5% of world soil carbon, (ii) the creation and enforcement of laws to protect endangered species, (iii) there is need to implement strict measures to control and/or manage or prevent land, air, and water pollution, (iv) provision of areas where endangered species can live and reproduce e.g. zoos, gene banks, botanic gardens, and germplasm collection.

* Dr. Okolle N. Justin
(Researcher/Lecturer)
IRAD/CARBAP/UB/AGROVISC/IBINS
Tel: +(237)74534786/95951991. E-mail: okollejustin@yahoo.com