210130103003 Global Environmental Issue.pptx

loss of biodiversity

1. Loss of biodiversity Global environmental issue Presentation by Masello Mahloane

2. What is biodiversity loss? Biodiversity loss includes the worldwide extinction of different species as well as the local reduction or loss of species in a certain habitat, resulting in loss of biological diversity. Biodiversity loss can be permanent or temporary depending on whether the environmental degradation that leads to the loss is reversible through ecological restoration or effectively permanent. Before human life, there had been 5 episodes of mass extinction (loss of a large number of species in a short time), and currently we are in the Sixth Extinction. The current rate of species extinction is 100 – 1000 times faster than pre-human times, which only shows that our activities are responsible for the faster rate.

3. Habitat loss One of the main causes of extinction. The tropical rainforests, that once covered 14% of the land surface of the earth have now been reduced to only 6% of land area. The Amazon rainforest (lungs of the planet) are cleared for cultivation of soybeans or are converted into grasslands for raising beef-cattle. It has also been a recent victim of a wildfire that broke out in 2021. Loss of habitat essentially means many animals and plants lose their “home” and face extinction. Pollution also degrades many habitats threatens the survival of many species. Sometimes a habitat is broken up into fragments and the population of mammals and birds that require large territories are badly affected.

4. Invasive species When alien species are introduced in an area, some of them become invasive and may cause extinction of indigenous species e.g. introduction of Nile Perch into Lake Victoria (Est Africa) caused extinction of more than 200 species of cichlid fish in the lake. When any new species is introduced into an ecosystem it messes up the already established balance and while some species adapt to the new addition some simply cannot adjust (weaklings) and end up dying. A simple case is whereby weeds grow on an established plot and the crops do not get enough water and minerals and therefore end up dying as the weeds are taking their nutrition. In other cases the extinction of one species leads to the extinction of another. e.g. when a host fish becomes extinct its parasites extinct.

5. over-exploitation This is when need turns to greed. The overexploitation natural resources leads to many species being extinct. In South Africa the poaching of rhinos for their horns for medicinal purposes and money has lead to them being endangered and almost extinct.

6. Pollution Wildlife and plant life struggle to adapt to life on a polluted planet. Majority of pollution will affect wildlife in a negative way either directly (breathing in toxins) or indirectly (e.g. habitat loss due to climate change caused by an increase in certain air pollutants. Types of pollution that may affect wildlife include air pollution, water pollution, land pollution, light pollution and even noise pollution.

7. Climate change due to global warming The earth’s climate has been changing since the dawn of time, with variations in solar activity and other events causing natural fluctuations in temperatures. However, this recent human-induced change is occurring much more rapidly and extremely. This mean plants and animals can not adapt quickly enough and this is impacting biodiversity. As a result animals are physically moving to cooler areas, the ocean temperatures are rising and causing coral reefs to ‘bleach’ thus leaving them likely to die. Ice glaciers melting also means rising sea levels and imbalance of the food chain as seen in the already melting Antarctic glaciers.

8. Biodiversity conservation Reasons for biodiversity Narrowly Utilitarian Reasons Human beings get economic benefits and materials from nature. Human beings get traditional medicine (about 25% and 2500 species of plant are used by native people. Broadly Utilitarian Reasons Production of oxygen Pollination of plants Aesthetic pleasure Ethical Reasons Every species has intrinsic value We all have a moral duty to care for the environment for future generations.

9. references Innovate Eco. 2022. How does pollution affect biodiversity?/Innovate Eco 2022 [online] Available at: https://www.innovate-eco.com/how-does-pollution-affect-biodiversity/ > [accessed 15 May 2022] Slideshare.net. 2022. Biodiversity loss. [online] Available at: https:// www.slideshare.net/SyedAliRaza6/biodiversity-loss > [accessed 15 May 2022 ] Slideshare.net. 2022. Biodiversity value and threats. [online] Available at: https://www.slideshare.net/kangdali/biodiversity-value-and-threats [accessed 15 May 2022]