4.2 Evaluating Diversity and Vulnerability
4.2.1 Identify factors that lead to loss of diversity.
There are different factors that lead to loss of biodiversity. Here are some of them:
EXAMPLE: Cane Toads
Excessive number of cane toads in Australia is an example of exotic specie’s introduction to the new environment. Hypothesis of the experiment outlined that the cane toads would be able to predate and balance populations of some species in lower trophic levels but it didn’t work. Cane toads were introduced to Australia from Hawaii in June 1935 by the Bureau of Sugar Experiment Stations in an attempt to control the native cane beetle population. Population of cane toads is rapidly increasing. This species is eating lots of grass and damaging biodiversity.
ANIMATION showing the spread of Cane Toads
- Natural hazards
- Loss of habitat
- Fragmentation by human impact pollution
- Overexploitation (non-sustainable harvesting)
- Introducing Non-native (exotic) species to the new environment
- Spread of disease and modern agricultural practices which basically means commercial farming and destroying the land.
EXAMPLE: Cane Toads
Excessive number of cane toads in Australia is an example of exotic specie’s introduction to the new environment. Hypothesis of the experiment outlined that the cane toads would be able to predate and balance populations of some species in lower trophic levels but it didn’t work. Cane toads were introduced to Australia from Hawaii in June 1935 by the Bureau of Sugar Experiment Stations in an attempt to control the native cane beetle population. Population of cane toads is rapidly increasing. This species is eating lots of grass and damaging biodiversity.
ANIMATION showing the spread of Cane Toads
4.2.2 Discuss the perceived vulnerability of tropical rainforests and their relative value in contributing to global biodiversity.
Biodiversity is crucial for the earth and the world’s over half of the species are represented tropical rainforests, there are several details that prove the vulnerability of tropical rainforests. The benefits of Rainforests are:
Despite the importance of tropical rainforests, human factors affect rainforests seriously, as a result of huge usage of wood and paper the natural organisms of tropical rainforests such as trees being cut down and deforested. Global deforestation mainly harms tropical rainforests and the species that are found in tropical rainforests. Statistics clearly show that tropical rainforests are in progress of reducing and damaging by humans and natural disasters. Unfortunately rainforests cover only 6% of the land area of the planet. Rainforests produce about 40% of the oxygen that animals use. As a result of massive deforestation within last 50 years tropical rainforests now only cover 6% where 50 years ago they covered 14% of the world’s surface. As mentioned above the main reason of reducing rainforests is deforestation for timber business, but the main harmer of rainforests is individual human. A low density of human population is sustainable as they clear a small area of forests, grow crops for two or three years then move on to the next area as long as there is enough time for the forest to regenerate before the same area is cleared again. It is called Shifting Cultivaton |
4.2.3 Discuss current estimates of numbers of species and past and present rates of species extinction.
4.2.4 Describe and explain the factors that may make species more or less prone to extinction.
4.2.5 Outline the factors used to determine a species’ Red List conservation status.
4.2.6 Describe the case histories of three different species: one that has become extinct, another that is critically endangered, and a third species whose conservation status has been improved by intervention.
EXTINCT SPECIES
Gazelle The last Gazelle was killed in Georgia in the second half of the 20th century. Main reason was hunting in the areas of Borjomi. Locals always complained the decrease of this animal as it was clearing environment from fallen leaves. From 19th to 20th century there has been rapid decrease in population which was estimated as 60%. Government didn’t seem to respond. Gazelle was hunted down by hunters from civilized cities of Georgia and also by the misbalance in lower trophic levels which was caused by deforestation and hunting again. Domba. In Georgia since the past human activities harm seriously animals. In Georgia years ago hunting was not prohibited and that caused massive lose of animals. In the 20th Century last Domba was killed by human beings. |
CRITICALLY ENDANGERED SPECIES
Wolf Wolf is one of the endemic species of Georgia. Some say that reason for that is climate change and deforestation in the northern parts of the country. Statistics show 0.6% decrease in the population once, every two years. Many wolfs are killed by the means of protection, when they are attacking a village. Auroch Another horned animal has been killed massively in Georgia, Aurochs has being very useful because by its horn has been used for different things. |
SPECIES IMPROVED BY HUMAN INTERVENTION
Brown Bear Bear population shows a recovery over the last 30 years. Borjomi national park has displayed satisfactory numbers. The result was achieved by the protection of the park and rapid decrease in hunting rates. Borjomi forest has good environment which fits the bear adaptations. Bears show approximate increase of 4.75% over last ten years. |
4.2.7 Describe the case history of a natural area of biological significance that is threatened by human activities.
Algeti National Park
This park has suffered a lot. Especially in the 20th century, when people cut down trees, hunted and nobody even asked them anything. Starting from the 1980’s, governments slowly intervened and limited accessibility to the park. Now the park displays a beautiful environment. 6% growth in total the biodiversity has been displayed from the 90s. |
Borjomi-Kharagauli National Park
One of the largest national park in Europe, it includes six administrative districts stretching from the resort of Borjomi to the town of Kharagauli. The total area of the park is 5, 3 thousand square kilometers, i.e., 7.6% of the total territory of Georgia. The park was founded in 1995 and officially inaugurated in 2001. |