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Biodiversity;, Both result in low biodiversity. - Coggle Diagram
Biodiversity;
Climate change;
In 2007, the Intergovernmental Panel on Climate Change (IPCC) released a report based on the findings, conclusions and recommendations of 2500 scientists, after 6 years of work.
The warming trend over the last 50 years (about 0.13' per decade) is nearly twice that of the previous 100 years.
The average amount of water vapour in the atmosphere has increased since the 1980s, consistent with the moisture holding capacity of warmer air.
Since 1961, the average temperature of the global ocean down to depths of 3km has increased. It has been absorbing more than 80% of the heat added to the climate system, causing seawater to expand, and contributing to a rise in sea levels.
The global average sea level rose by an average 1.8mm a year from 1961 to 2003. There is a high confidence that the sea level rise increased from the 19th to the 20th century.
Average arctic temperatures have increased at almost twice the global average in the past 100 years.
Mountain glaciers and snow cover have declined in both hemispheres. Contributing to a rise in sea levels.
Long-term upward trends in the amount of precipitation have been observed in many areas from 1990 to 2005.
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If global warming continues, biodiversity will be affected. Examples;
- The melting of the polar ice caps could lead to the extinction of the few plant and animal species living in these regions. Some species of animals present in the Arctic are migrating further and further north to find favourable conditions as their habitat shrinks. Increasing global temperatures would allow temperature plant and animal species to live further north than currently.
- Rising sea levels from melting ice caps and thermal expansions of oceans could flood low-lying land, reducing the available terrestrial habitats. Seawater would flow further up rivers, reducing the habitats of freshwater plants and animals living in the river and surrounding areas.
- High temperatures and less rainfall would result in some plant species (xerophytes) becoming more dominant. The loss of non-drought resistant species of plants would lead to the loss of some animal species dependent on them as a food source. These would be replaced by other species that feed on xerophytes.
- Insect life cycles and populations will change as they adapt to climate change. Insects are key pollinators of many plants, so if the range of as insect changes, it could affect the lives of the plants leaves behind, causing extinction. As insects carry many plant and and animal pathogens, if tropical insects spread, this in turn could lead to the spread of tropical diseases towards the poles.
If climate change is slow, species may have time to adapt (eg; by eating a different food source) or to migrate. This will lead to a loss of native species, but in turn other species may movie into that area - so biodiversity may not be lost.
Deforestation;
Can occur naturally eg; forest fires caused by lightening or extreme heat after a period of dry weather. However, it is mainly due to human action.
Some forests have been destroyed due to acid rain, caused by release of sulphur dioxides and nitrogen oxides into the atmosphere.
The majority of deforestation is the permanent removal, by cutting down, large areas of trees or forests to provide wood for building or fuel to create space for agriculture, roads and buildings. This is a major example of humans reducing biodiversity by changing the land.
- It reduces the number of trees in an area.
- If only a specific type of tree is required (eg; rosewood) and only these are felled, species diversity is reduced.
- It reduces the number of species in an area due to habitat destruction, loss of home and food source, therefore reducing the number of other species in the area by reducing or removing their habitat.
- Animals are forced to migrate to another area, impacting that area positively or negatively.
Forests, are also a carbon sink because they remove CO2 from the atmosphere and trap it through photosynthesis.
Agriculture;
In general, farmers grow or rear a limited number of species of crop or livestock. They will select the most profitable crop or livestock for their conditions, eg; the highest milk yielding cow or grain yielding cereal.
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- Deforestation - mostly happens in tropical areas where it is used to clear land to; increase available land for agriculture, provide land for farming such as cattle (cattle also produce methane, a greenhouse gas), grow crops for food and biofules.
- Hedgerow removal - to facilitate the use of machinery across large areas of land for crop; planting, treating (pesticides and fertilisers), harvesting and preparing the land, as well as increasing the arable land area. This removes habitats of many organisms; range of plants, invertebrates, birds and small mammals.
- Chemical application - pesticides and fertilisers. Insecticides directly reduce the biodiversity of the species killed and indirectly their predators. Herbicides directly reduce the plant species and indirectly the species that consume them or their nectar. Non-judicious use of fertilisers may lead to eutrophication of nearby water, reducing their biodiversity.
- Mono culture - many acres of land are used to grow only one species of crop. As only one species is present, there is very low biodiversity. One crop species will support very few animal species, enhanced by a uniform growth stage of the crop, eg; palm oil is currently one of the main reasons for deforestation. Jungles are cut down to clear space to plant palm trees.The palm oil is sold for use in foods, beauty products and to make biofules. This has led to a loss of habitat for critically endangered species like the rhino.
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Definition;
The variety of plant and animal life in the world or in a particular habitat, a high level of which is usually considered to be important or desirable.
The measure of the variety of all species on earth, or in a particular ecosystem or habitat. Local (small eg; pond) or global (large eg; amazon rainforest).
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