Article 2 of the1992 convention on biological diversity defines biodiversity as the variability among living organisms from all sources including inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part and this includes diversity within species, between species and of ecosystems.
It talks about three forms of biodiversity.
- Genetic diversity-variation in the genes of an organism, the frequency and diversity of different genes and/or genomes
- Species diversity-variation of species within a region. Different sub species under a bigger group of a particular species. Example is different species of yam under the bigger specie of yams
- Ecosystem diversity- This relates to the variety of habitats, biotic communities and ecological processes in the biosphere.
Why conserve biological diversity?
The reasons for conserving nature and biodiversity are essentially in three folds.
- First biodiversity provides an actual and potential source of biological resources (including food for sustenance for both plant and animal life, pharmaceutical and other material values which support fisheries, soil conditions and parks).
- Secondly it contributes to the maintenance of biosphere in a condition which supports humans and other life.
- Thirdly, biodiversity is worth maintaining for non-scientific reasons of ethical and aesthetic value.
Other uses and importance of biodiversity are
- It provides us with the raw material base for industries
- It provides recreational value of biodiversity
- It provides natural sink for waste such as carbon
Why are we losing biological diversity?
Primarily it is because of human activities.
Human activities contributes to the destruction of nature and loss of biodiversity through direct activities (hunting, collection and persecution) and indirect activities (habitat destruction and modification from industrial, agricultural and other activities). The destruction and loss of habitats and species bring with them known and unknown ecological consequences: what is ultimately threatened is the ability of the ecosystems to purify water, regenerate soil, protect watersheds, regulate temperature, recycle nutrients and waste, and maintain the atmosphere.
Other reasons….
- Population growth and the associated resource consumption– Increased insatiable demand for resources results to land use changes hence loss to genetic diversity, species reduction and increased ecosystem changes such as random population changes, disease outcrops, habitat fragmentation among others resulting in biodiversity losses.
- The failure to account for biological diversity
- Weaknesses in the legal regulatory system
- Inequities in the global trading system. You take more from nature to get less
- Ignorance about species and ecosystems
- Poor conception and making of policies– Some institutions are created to manage biological resources. However, the institutions/policy fail to internalize the values of biodiversity within the decision making process of their Nations and individuals. Such institutions/policies in place should have a holistic approach towards biodiversity conservation rather than part conservation.
- Pollution–Chemical or thermal pollution is a threat to biodiversity. Species in habitats are increasingly being
harmed by industrial activities and pollution from excessive use of agro-chemicals such as DDT, oil spills, acid precipitation etc. - Introduced species / biological invasions– This can be intentional or accidental. Species introduced in an ecosystem will cause changes in the ecosystem. Introduced species are organisms arising in areas/ habitats in which they were previously not native. Such introduced species are usually referred to as biological pollutants. Some of the ecological impacts of the invasion include hybridization, out competition, disruption of original
ecosystem, plant pathogenic influences, disease transmission, and disruption of food webs and to some situations extinction. Species may be introduced intentionally for:
• Ornamental concerns;
• Agriculture;
• Hunting and spotting activities;
• Biotechnology for scientific research;
• Trade.
Climatic changes–This is of great concern especially when global CO2 increases in the atmosphere resulting to global warming. Most species originate within a very narrow physiological limit; hence nature has a range of
tolerance maintained for ecosystem stability. Changes may be gradual or abrupt such that if the limit is exceeded the upper or lower species suffers extinction.