factors affecting biodiversity
climate change
human influence
agriculture
climate change
release of carbon dioxide and other pollutants into the atmosphere from burning of fossil fuels is increasing global temperatures
deforestation
permanent removal of large areas of forest to provide wood for building and fuel, and to create space for roads, building and agriculture
increasing amount of land has to be farmed in order to feed growing population - resulted in large amounts of land being cleared - many fields planted with a single crop (monoculture)
deforestation
directly reduces number of trees present in an area
if only a specific type of tree is felled, species diversity is reduced
reduces number of animal species present in an area as it destroys their habitat, including their food source and home
animals are forced to migrate to other areas to ensure their survival - can result in biodiversity of neighbouring areas increasing
techniques used in agriculture
deforestation - increase area of land available for growing crops or rearing animals
removal of hedgerows
mechanisation - farmers remove hedgerows to enable them to use large machinery to plant, fertilise and harvest crops
frees extra land for crop growing
reduces number of plant species present in an area
destroys habitat of animals e.g. blackbirds, hedgehogs, mice and invertebrates
use of chemicals - pesticides and herbicides
reduces species diversity directly - destroys pest species and indirectly destroys food source of other organisms
weeds destroyed - plant diversity reduced directly - animal diversity can be reduced by removal of an important food source
monoculture
lowers biodiversity - only one plant species is present
very few animal species will be supported by only one type of plant - low overall biodiversity levels
rising sea levels from melting ice caps
high temperatures and less rainfall - some plant species being unable to survive
melting of polar ice caps
changing insect life cycles and populations
could lead to extinction of the few plant and animal species living in these regions
species of animals in the Arctic migrating further north to find favourable conditions as their habitat shrinks
low-lying land could flood - reduce available terrestrial habitats
saltwater would flow further up rivers - reduce habitats of freshwater plants and animals living in surrounding areas
xerophytes (drought-resistant species) become dominant
loss of non-drought-resistant species of plants - lead to loss of some animal species dependent on them as a food source
replaced by other species that feed on xerophytes
insects are key pollinators of plants - range of insects changes - affect lives of plants left behind - can cause extinction
slow climate change - species can have time to adapt or migrate to new areas
loss of native species - other species may move into the area
biodiversity would not be lost - species mix would change