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9.3 Science Natural and Human Impacts - Coggle Diagram
9.3 Science Natural and Human Impacts
Natural events such as fires, floods, and droughts can damage ecosystems but also benefit them. Humans also affect ecosystems in positive and negative ways.
Change Due to Natural Events
Season changes affect organisms because they are influenced by abiotic factors such as rainfall etc.
Bushfires
Bushfires are common in Australia. Some are lit accidentally, some are started purposefully and some come about because of lightning.
Fire has a major impact on ecosystems because it promotes the germination of many plant species.
After fire much of the bush regenerates through germination.
Many plants species either are adapted to or benefit from fires.
Affects on animals from fire vary. Slow-moving animals may be killed cause they can't escape. The dead are replaced by surrounding populations expanding back into the burnt out areas after the fire.
Droughts
Australia suffer from regular droughts, often lasting five years or more.
A drought is a period of no rain or low rainfall. They can change ecosystems by increasing the death rate of plants and animals.
Entire ecosystem can be destroyed.
Loss of plant cover = erosion by wind. When rain returns, water erosion can further damage the land by washing away the soil.
Flooding
Heavy rains can result in floods where rivers overflow their banks to cover normally dry areas of land.
The flooding also greatly affected natural ecosystems and there were high death rates among native plants and animals.
Animals and plants die from lack of oxygen. Plants: to roots. Animals: to breathe.
Change Due to Human Impact
Humans can affect ecosystems in a negative way. Disposing of toxic waste, destroying ecosystems, and clearing land all negatively affect ecosystems. Humans also try to make positive contrubutions.
Habitat Destruction
Damage done to the environmental factors an organism depends on for survival. E.g. land clearing, mining and logging.
Numbers of some animals have declined because of agricultural development.
However, some animal populations have increased because of food supply.
Introduced Species
Animals and plants brought to Australia from other countries are known as introduced species.
Introduced animals that adapt to the new environment and become established are known as feral animals.
Many introduced plants have become weeds and now successfully compete with native plants for limited resources.
Overcropping
Of animal population means killing more animals than can be replaced by the normal breeding cycle. This can result in a decrease of population.
One of the important roles of ecologists is to find out how many animals can be removed from an environment without endangering the survival of species.
Regulations control how many animals may be taken.