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Human Influence and Threat to Biodiversity and Sustainable              Debela Hunde

deriving forces and human influences, as well as the measures for the conservation and sustainable use of biodiversity within and between different cultures. This is sometimes referred to as cultural diversity (GBS, 1992).It recognizes the important role of sociological, ethical, and religious and ethno biological values in human activities. The magnitude of human induced environmental change at the global scale is considered to be enormous. Globally, humans are now the dominant influence on biodiversity. Recent studies have estimated that today humans use or pre-empt 40% of the terrestrial component of net primary productivity (total photosynthetic production) (GBS, 1992). Furthermore, the main force driving the global transformation of the biosphere is human population growth, together with increasing resource consumption and socio cultural change. Inevitably this raises the question of carrying capacity of the planet and whether we can continue to increase our demands on it without limits or not. Strictly speaking, no part of the world is considered truly undisturbed. The worlds’ habitats have been significantly modified by human action terms such as undisturbed or virgin forest is now days considered of little value.

Hauff (2002) in his sustainability analysis pointed out poverty forces many people to strip away too many valuable resources and biodiversity is under threat at alarming rate. Australian Museum (AM) (2005) released report state that “in the Earth’s 5.5 million years history, there have been five major mass extinctions recorded in the fossil record, the most recent of which, 65 million years ago, killed the last of the true dinosaurs.  Currently extinction rates rivaling or exceeding the rate of the prehistoric mass extinctions.  Although majority of all animals that once lived on earth are now extinct, the mass destruction

attributed to one species (our own) is apparently unique in the earth’s history”. This indicates that biodiversity loss can be attributed to the resources demands of our rapidly growing human population. In recent times, the human population has increased from about 1 billion in 1990 to almost more than 6 billion today. Like other living beings, humans use the natural resources to survive, but humans are far resourceful and destructive to other life forms than any species previously known. The major human influences which affect biodiversity can be summarized: (1) agriculture and fisheries and over harvesting of resources, (2) habitat destruction, conversion, fragmentation of habitats i.e. degradation and loss, (3) introduction of exotic or invasive organisms and diseases i.e. non- native invasive species (4) overuse of resources resulting to pollution of soil water and atmosphere, and (5) global environmental change. As the world human population increases, all the organisms on Earth including humans must have share the same limited resources (food, shelter, space, water, and others). Yet there is less and less natural habitat remaining as land is developed for humans’ habitation and activities.

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 2.1Threats to Biodiversity

Extinction is   a natural event and from geological perspective routine i.e. most species that have ever lived have gone extinct during different geological time. According to AM (2005) report the average rate over the past 200 million years is 1-2 species per million species per year. Furthermore, it has been noted that, the average duration of a species is 1-10 million years (based on last 200 million years). In modern era, due to human actions, species and ecosystems are threatened with destruction to an extent rarely seen in Earth history (AM, 2005).

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