How do human activities cause changes in ecosystems?

Question 1

drainage of wetlands

Answer 1

lower water tables and alters habitats

Question 2

trampling

Answer 2

light trampling increases species diversity, but heavy pressure damages plants. some species are more resistant to trampling than others, which is why tolerant plants are often found along footpaths

Question 3

fertiliser application by farmers

Answer 3

nitrate and phosphate fertilisers increase crop yield, but excess fertilisers not taken up by the plant find their way into ditches and lakes causing nutrient enrichment or eutrophication

Question 4

species removal

Answer 4

could be removed as a threat to other species (e.g. elk, grey wolves yellowstone).

Question 5

introduction of alien plants an animals

Answer 5

Hawaii, introduction of mongoose and the rat has posed major threat to flightless, ground-nesting birds
Fireweed, a plant introduced in the Canary Islands has also displaced native species on volcanic soils

Question 6

burning of fossil fuels

Answer 6

creates acid rain, which affects lakes and coniferous forests. acid rain that falls on already acid soils develeped under coniferous woodland, leaches nutrients e.g. potassium and magnesium form the soil. heavy metals e..g mercury kill sensitive species e.g. trout in lakes