Biodiversity is a term that refers to the variability of life forms or species on earth. It is the variability among all life forms from all sources including, marine, terrestrial, and other aquatic ecosystems as well as the ecological systems they are part of; including variability between species, within species, and of ecosystems (Ecological Society of America, 1997). The importance of biodiversity to humans cannot be overestimated. In agriculture for instance, crop biodiversity can lead to recovery when the main cultivar is destroyed by disease. Thanks to biodiversity, many medicines that lead to treatment of diseases have been and continue to be discovered (Corvalan et al., 2005). In the business and manufacturing industry, many raw materials of major products like rubber, oil, dyes, and fibres come from different biological sources. These are just but a few of the benefits of biodiversity. Noting the importance of biodiversity, this paper discusses the various factors that affect biodiversity.
Factors affecting biodiversity can be grouped into human and natural factors. Human factors include pollution, deforestation, overpopulation, overexploitation, hybridization, and introduction of alien invasive species which all lead to habitat alteration or removal. Natural factors affecting biodiversity include climate change, and natural disasters such as drought (Shah, 2011). Pollution as a result of human activity in the form of toxic discharges, bacterial contamination, and nutrient build-up affect biodiversity. Toxic discharges released into water bodies can kill, weaken, or affect the biological functions of biota in these ecosystems. Bacterial contamination of water through municipal effluent discharges can lead to contamination of portable water by fecal coliforms which if not treated, can cause illness in individuals. Nutrient build-up, mostly nitrogen and phosphorous, as result of run-off from fertilizers used in agricultural lands stimulate rapid growth of algae and other aquatic plants leading to limitation of amount of light and oxygen available to other living things in the water body ecosystem. This can in turn lead to their death. Chemical air pollution from industries can lead to acid rain which may lead to the death of both terrestrial and aquatic organisms. In Canada, acid rain is cited to have the most significant effect on biodiversity.
Deforestation and clearance of land for agriculture, settlement, or commercial development affects the richness of species in the ecosystem hence posing a serious threat to biodiversity. Agriculture is linked with extirpations and reductions in fauna that are characteristic of agricultural lands for instance wild pollinating insects, scrubland and grassland birds (Shah, 2011). Overpopulation leads to interruption or alteration of existing ecosystems such as forests which are cleared to pave way for agriculture and human settlement. Overpopulation also puts pressure on existing ecosystems which become overexploited to fulfil human needs. An example includes overharvesting of fish. Also affecting biodiversity is hybridization where the introduction of a non-native species leads to interbreeding with native species hence ultimately resulting to the decline or loss of the native species. Hybridization has been said to have resulted in extinction of 38 per cent of fish species in North America (Convention on Biological Diversity, 2011).
The introduction of non-native invasive species may likely cause harm (NISC, 2006) to the native species and the ecosystem hence affecting biodiversity. The introduction of a predator species in particular may cause disturbances in the food chain leading to extinction of some species. Climate change on the other hand has been known to have led to extinction of some animal species such as dinosaurs. As climate change takes place, organisms are forced to adapt. Those that fail to adapt face the danger of extinction. Natural disasters such as drought may lead to food scarcity hence the death of organisms in an ecosystem. For example, drying of rivers due to drought may lead to the death of many life forms in the rivers.
To conclude, it is very important for the above discussed factors to be considered when promoting biodiversity. Promotion of biodiversity is important because of its human benefit in agriculture, medicine, and manufacturing.