Module 9 Flashcards
4 threats to biodiversity
- Habitat loss/ destruction
- Over exploitation/ over harvesting
- Intro new species
- Global changes
Causes habitat loss/ destruction
- deforestation
- habitat fragmentation
- forest fires
- mining
Dodo
Overexploitation: Over hunted by sailors
Passenger pigeon
- 40% overhunted
- habitat destruction
- Martha died 1914
Giant tortoise
Lonesome George died 2014
Overfishing Atlantic cod
-1992 collapse
Lead to fishery collapse
- exploitation
- disturbance
- insufficient productivity
- no other profitable species
Long line fishing
Super trawlers: 25-30 tons
Trophic cascade
Change of eco systems
Moratorium
Fishing for cod
Invasive species
Deliberate/accidental movement of species causing greater risk local extinction
Argentinian ant
Linepithema humile
- low intraspecific competition
- large colonies
- Dominant
Red fox
Vulpes vulpes
- sport to pest
- over 7 billion
- threat biodiversity
- extinction small mammals/birds
- threaten livestock
European rabbit
Oryctolagus cuniculus
- 1778 brought to Australia
- 1859 Thomas Austin released 13
- 150 million feral
- pest: crop damage
- increase impact drought/fire
Cane toad
Rhinella marina (Bufo marinus)
- diverse diet
- native south Central America
- 1935 unsuccessfully introduced for cane beetles (insufficient shelter, bad climbers, eat other stuff)
- poisonous skin: decline native reptiles
Stephen’s island wren
Xenicus lvalli
- 10 flightless pairs
- eaten by Tibbles the cat
Global changes
- release toxins
- gh gas
- global warming
Toxins
Pesticides
- decrease biodiversity
- impact water, soil, air
Phosphorus in Great Lakes
- Runoff = eutrophication (enrichment minerals/nutrients in water)
- nuisance algae leads to hypoxia (oxygen depletion)
Habitat loss example
Ex. 93% coral reefs damaged by humans (50% disappear 30-40 years)
Effects global warming
- changes species distribution
- affects arthropod metabolism, reproduction, survival
Endangered species example
Tasmanian devil (Sarcophilus harrissi)
- largest carnivorous marsupial
- nocturnal
- scavenger
- consumes bones (returns N,P to soil)
- wiped from mainland by dongoes (Canis lupus dingo) now endemic to Tasmania
- endangered by DFTG killed 90%
- eat less often = small impact on small mammals
Effect of population decline
Restructures food webs
Conservation biodiversity ex
Aussie ark
- 390 devils born
- released in sanctuary 2020
Extinction opposite to speciation
