9 4 human influences on the environment

Fish farming is the practice of raising large numbers of fish in confined enclosures for commercial purposes, primarily to provide food for human consumption.

Fish farming helps to address overfishing by providing an alternative source of fish protein that reduces the need for wild-caught fish and so reduces the pressure on wild fish populations.

Environmental impacts of fish farming include:

A non-indigenous species is one which is not native to a particular area.

Non-indigenous species can be introduced to an area as follows:

The negative effects of introducing non-indigenous species include:

False. Introducing non-indigenous species usually results in a decrease in the biodiversity of a habitat.

Eutrophication is the process by which increased nutrient availability in a body of water leads to a decrease in dissolved oxygen levels.

Human activities that can lead to eutrophication include:

The process of eutrophication is as follows:

An indicator species is an organism that is particularly sensitive to certain environmental changes and can be studied to determine the effect of human activities on a habitat or ecosystem.

False. ** Indicator species can be used to determine levels of water and air pollution**.

The presence of stonefly larvae in a stream indicates that the water is not polluted and has high dissolved oxygen levels.

Two invertebrate species that indicate high levels of water pollution are bloodworms and sludgeworms.

Lichens are particularly sensitive to sulfur dioxide pollution in the air.

False. A high abundance of bushy lichen indicates very clean air.

The presence of blackspot fungus on rose leaves indicates clean air.

Disadvantages of using indicator species to assess pollution levels are:

Maintaining biodiversity is key in maintaining the stability of ecosystems and avoiding disruption which could lead to the loss of species.

False. The loss of one species would have knock-on effects that would impact other species within the ecosystem.

Conservation is the protection of species or habitats.

Animal species can be conserved as follows:

Reforestation is the planting of trees to recreate diverse woodland habitat.

False. ** Reforestation helps maintain the global carbon balance **by planting trees that remove carbon dioxide from the atmosphere for photosynthesis.