6.6.6 controlling effects of human activities Flashcards
name 4 areas where humans have strived to control their effects on the environment
1) galapagos islands
2) antarctic
3) lake district
4) snowdonia national park
1) galapagos islands - habitat disturbance
- population increase = demands of water, energy & sanitation services
- more waste & pollution
- increased oil demand (eg. oil spill in 2001)
- building & conversion of land for agriculture = destruction & fragmentation of habitats
- forests of scalesia trees/shrubs almost eradicated on santa cruz & san christobal
1) galapagos islands - over-exploitation of resources
- (19th C) whaling boats/fur traders killed 200,000 tortoises
- Charles Darwin Research Station has captive breeding programme to supplement tortoise numbers
- increase in fishing for exotic species = depleted populations
- depletion of sea cucumber populations = drastic effect on underwater ecology
- market for sea fin = 150,000 shark deaths each year incl. 14 endangered species
1) galapagos islands - effects of introduced species
- outcompete local species
- eat native species
- destroy native species habitat
- bring disease
eg. goats feed on galapagos rock-purslane (unique to island) & trample/feed upon giant tortoises food supply & disrupt nesting site
- (northern isabela island) goats transformed forest into grassland = soil erosion
eg. red quinine - aggressively invasive species on santa cruz & occupies highland w/ wind-dispersed seeds
- ecosystem in highlands changed from low shrubs/grassland to closed forest canopy = native cacaotillo shrub almost eradicated & galapagos petrel lost nesting sites
- out-competes native scalesia trees
1) galapagos islands - managing effects of human activity
1999, charles darwin research station adopted 2 strategies:
1) prevent introduction/dispersion of introduced species
2) treat problems caused by such species
- search incoming boats/tourists for foreign species
- exploit natural predators to reduce damage by pest populations
- culling successful against feral goats (isabela island) & pigs (santiago island)
- at least 36% of coast = ‘no-take’ zones (no extraction allowed & communities left undisturbed)
2) antarctic - krill
- tiny shrimp-like organisms
- food for whales, seals, penguins, albatrosses & squid
- used to make nutritional supplements & animal feed
- recent changes in technology means lots can be caught quickly & easily so boats congregate in 1 area
- predators can’t adapt easily to find krill elsewhere
to avoid over-exploitation:
- there’s a trigger-level catch size in certain areas
- if reached, fishing must be conducted equally across all areas up to total catch limit
2) antarctic - protected areas
= protect whales/marine environment
- southern ocean whale sanctuary established in 1994
- covering summer feeding grounds of 80-90% of worlds whales
- illegal to kill/hunt
- monitoring of whaling activity still needs to maintained to ensure sanctuary is effective
2) antarctic - albatrosses & petrels
- threatened by pollution, hunting/poaching for eggs, habitat destruction & introduction of non-native predators
- biggest threat = long line fishing
to reduce deaths, boats can:
- use bird scaring lines & streamers
- weighted lines which sink more quickly out of reach of birds
- use lines at night to avoid albatross & petrel feeding times
- avoid breeding & nesting time
what’s long line fishing
- fisherman trail long fishing line behind boat (up to 130km)
- attached to line = hundreds of baited hooks
- bird try to eat prey & swallow hooks
lake district - name a solution for this threat to biodiversity:
1) spruce/pine in conifer plantations support limited biodiversity
- recent initiatives generated more varied planting/felling patterns
- gives mosaic of smaller stands of diff. aged trees
lake district - name a solution for this threat to biodiversity:
2) invasive species (eg. rhododendron, laurel) escaped from gardens & spread into woodland outcompeting native species - also have dense canopy so reduce light reaching floor & roots produce toxic chemicals stopping other plants growing (allelopathy)
physically removed by conservation workers
lake district - name a solution for this threat to biodiversity:
3) limestone pavement - rare ferns grow in fissures & rare butterflies thrive
pavement legally protected through ‘limestone pavement orders’
lake district - name a solution for this threat to biodiversity:
4) hay meadows support rich diversity of flowers/grasses & under threat due to preference of silage production, involving use of artificial fertiliser & earlier cut - caused loss of species diversity in grasslands/pastures
farmers paid to maintain hay meadows
lake district - name a solution for this threat to biodiversity:
5) heathland is an open habitat w/ small shrubs important for butterflies, moths, spiders, beetles, birds & reptiles
- burning strips of vegetation promotes new shoot growth which maintains areas of diff. ages fostering a larger variety of animals
- ensures constant food supply for red grouse/merlin
- area managed by grazing
- financial incentives provided to farmers to prevent overgrazing
lake district - name a solution for this threat to biodiversity:
6) mires are internationally scarce nutrient-poor, waterlogged ecosystems where mosses, liverworts, lichens & sedges flourish as well as breeding ground for moorland birds - under threat from burning, grazing, drainage (all intensive agriculture) & peat extraction
- managed more sympathetically
- some being rewetted w/ artificially controlled water levels
- areas w/ rare plants (eg. bog orchid) = grazing controlled
