How humans threaten wildlife Flashcards
3 main threats
Unsustainable exploitation
Purposeful eradication
Climate change
Food
Dodo, Passenger pigeon, Cod, Tuna, and Sharks are going or are extinct due to too much human consumption
Fashion
Crocodiles, Alligators, Turtles, Rhino, Shellfish, Elephants, and Wild cats are going or are extinct so people can have clothes and accessories
Case study- Snow leopard
Threats= habitat loss, loss of prey species, POACHING. 1 snow leopard skin coat= 10 skins and would cost $44082
Pets and entertainment
Tortoise, Tropical fish, Parrots, Lizards, and Snakes have been collected from the wild for the illegal pet trade
Case study- Yellow headed parrot
very social animals that are easy to tame and mimic voices well. While protected by CITES appendix 1, they are poached. eggs are smashed and trees cut down. the population has fallen by 95% since 1970
Furniture and ornaments
Mahogany, Teak, Ivory, Ebony, Coral, and shells from Turtles and Tortoises are going or have gone extinct due to human greed
Traditional medicines
Tigers, Snakes, and Bears are being taken from the wild because some people believe parts of their bodies can cure various ailments and illnesses
Case study- Rhinoceros horn
Rhino horns have been used to treat a range of ailments from nosebleeds to smallpox as well as ornamental dagger handles. Rhinos are protected under CITES appendix 1, but are still hunted illegally
Other products
Some oils can be extracted from animal parts such as whale blubber. these oils have been replaced with others since the 1970’s
Eradication of predators and competitiors
Sharks and poisonous snakes threaten humans
Wolves, Lions, Birds of Prey, Herons threaten livestock
Insects, Fungi, Molluscs are considered agriculture pests
Malaria mosquitoes, Tsetse flies are disease risks
Wood boring insects, Deer, Beavers are forestry pests
Rabbits, Deer compete with livestock
Unintentional deaths from human activities
Dolphins, Albatrosses caught in tuna nets
Roadkill
Case study- Barn owl
Barn owl hunt on roadside verges. their lack of weight gets them pulled into the airstream of moving vehicles. Some councils cut verges very short to prevent this from happening
Introduced species
Competitive advantage of an introduced species
Isolated evolution so indigenous species are not able to cope with new predators
Predators
Water voles are eaten by introduced American Mink
Cane toads introduced to Australia from South America threaten lizards, insects, small marsupials, ground nesting birds
Small asian mongoose introduced to Hawaii have devastated Endemic bird species
Ground nesting birds on oceanic islands such as New Zealand are threatened by introduced dogs, cats, rats, and pigs
Introduced herbivores such as rabbits and goats have seriously damaged vegetation in places such as Round Island
Case study- Nile perch
Introduced to Lake Victoria during the 1950’s as a new source of food, it ate the native cichlids, driving some to extinction. the introduction has increased demand for wood so the perch can be smoked, increasing deforestation and soil erosion
Competitiors
Grey squirrel introduced to the UK from America out competed the red squirrel
Rhododendrons introduced to the UK from Asia as coverage for game birds outcompeted native plants in regards to sunlight
Harlequin ladybirds introduced to Europe from Asia prey on other ladybird species and outcompete them for food
Disease
Elm trees killed by an Asian fungus spread by a bark beetle
Pigs, snakes, cats, rats, mongooses, malaria mosquitoes have been introduced to Hawaii, leading to the endangerment or extinction of over half of the native bird species
Signal crayfish introduced to UK from North America carried a fungal disease that killed the native white clawed crayfish
Changes in abiotic factors
Straightening rivers removes habitat for fish eggs
Hydroelectric plants flood nests of lizards and turtles
Acid rain denatures the enzymes in fish eggs and gills, and dissolves the exoskeletons of species like crayfish
farming/mining increases turbidity which prevents aquatic plants from photosynthesising
Drainage schemes aerate the soil better, allowing colonisation of a wider range of competitiors
Habitat destruction
Deforestation for timber/farmland
Flooding caused by reservoir construction
Mining
Urbanisation
