Biology 1229 Extinction

 “the cessation of existence of a species”

IUCN categories  Extinct No reasonable doubt that the taxon is gone.  717 animal and 87 plant species since 1500

Lytta mirifica huia Labrador duck Stead’s Bush Wren Great Auk Thylacine Steller’s Sea Cow Passenger Pigeon dodo Quagga

IUCN categories  Extinct in the wild Species only exists in captivity or cultivation  37 animals and 28 plants

Extinct in the wild St Helena Redwood Wood’s Cycad Hawaiian Crow Redtail Shark Black-footed ferret Partula snails

IUCN categories  Critically endangered Extremely high risk of extinction in the wild  3240 species (up from 3124 in 2007 and 3071 in 2006)  Includes 6 species of fungi

Baiji North American Burying beetle Southern Bluefin Tuna Black Rhino Kakapo

IUCN categories  Endangered Very high risk of extinction in the wild  4768 species

IUCN categories  Vulnerable High risk of extinction in the wild  8911 species

IUCN categories  Near Threatened Ongoing conservation measures required to prevent risk of extinction 3513  Least concern Widespread, abundant & safe  Data deficient No assessment possible 5561

Gaps in knowledge  Almost all invertebrates Apart from ‘showy’ ones  Collected beetles  Butterflies  Dragonflies  Poor knowledge of tropics, esp. in Africa  The vast majority of described species are known from only a few specimens

A Global Extinction Crisis  >33% of frogs threatened  ¼ of Mammals face extinction  15-37% of species extinct by 2050  70% of Butterfly species in decline

Why should we care?  The sadness of losing biodiversity  Our moral responsibilities  Ecosystem services

Ecosystem services  All the free stuff we get from nature Water purification, decomposition, dung removal, pollination, O2 repletion, CO2 absorption, food, pharmaceutical products etc.  $16-54 Trillion (i.e. $ ) per year… in 1997!

Why do species go extinct I?  Natural extinctions Population changes Natural disasters Evolution, migration and habitat change

Why do species go extinct II?  Anthropogenic influence

Habitat destruction Invasive species Overkill Climate Change

The four horsemen of the extinction crisis I: Habitat destruction

The four horsemen of the extinction crisis II: Overkill

The four horsemen of the extinction crisis III: Invasive species Stoat (NZ) House Mouse (Many places!) Red Fox (Australia) Brush-tailed possum (NZ) Rhododendron (Scotland) Emerald Ash Borer (SW ON) NZ Flatworm (Ireland) Zebra Mussel (Great Lakes) European Starling (Many places!)

The four horsemen of the extinction crisis IV: Climate change