Biology 1229

Extinction 3: Good News Stories

The four horsemen of the extinction crisis I: Habitat destruction

Formation of parks and reservesSLOSS?

Blue and John Crow Mountains National Park800 km2 of habitat protectedOngoing surveys to establish

basic population biology of species

Moapa DaceMoapa coriaceaUpper headwaters of the Muddy

River, Clark County, Nevada

Moapa Dace Once widespread throughout Muddy River

tributaries Requires thermal springs (~30 °C) for

breeding Habitat destruction

Hot springs resorts! Swimming pools in hot springs

(treated with Chlorine!) Dams Planting of exotic species Water sucked out of aquifer for developments Also invasive species (aquarium species) & Tilapia

3800 in 1994; 850 in 2003

Moapa Valley national Wildlife Refuge106 acres (= 43 ha)Restoration of streamBreeding habitat produces 95%

of Moapa Dace recruited into population

SLoSSSingle Large or several small?The great debate in reserve

design! Risk vs habitat Amount of habitat required Many or one population?

The four horsemen of the extinction crisis II: Overkill

Antarctic fur seal

Antarctic Fur SealArctocephalus gazellaBreeds on islands around the

AntarcticSexually dimorphic

Males: 200 kg Females: 40 kg

Eat Krill

Hunted for fur Intensively in late 18th/early 19th

CenturiesPartial recovery in 19th Century

Followed by more huntingCommercially extinct in early 20th

centuryBetween 1 & 3 remaining

colonies remaining <1000 animals total

Hunting ceasesFirstly for commercial reasonsFollowed by legal protection

CCAMLR CITES IUCN

Current populations (as of 2004)All around sub-Antarctic11/14 populations increasing2.7-6.2 MILLION seals on South

Georgia alone Doing well out of whale decline?

IUCN: Least Concern

The four horsemen of the extinction crisis III: Invasive species

Mainland islands and eradications in New Zealand

Rats (etc)

No (or fewer) rats, etc

Lots of space and habitat

Finite space and habitat

Many species extinct

Many species hanging on

Two strategiesMake more of the islands useful

for conservation Eradication of predators

Make the mainland more like an island The ‘Mainland Island’ concept

Predator eradicationPigs (Adams Island)Cats (Macquarie; Marion)Rats

The biggest baddie for birds!

How to eradicate rats?By hand

Breaksea Island (26 ha) – 1986By Air

Codfish Island (1800 ha) – 1998 Kapiti Island (2200 ha) – 1996 Several others in this size range

Scaling it up Campbell Island (11300 ha) - 2001

Aerial poison drops Use mammal-specific

poison Useful mainly in

places where there shouldn’t be any mammals…

Need to know about biology of target Get correct rates &

densities of poison spread etc.

ProblemsPutting an awful lot of poison

into the environment 12 tonnes on Campbell Island!

‘collateral damage’Dangerous

ResultsSignificant recovery of many

species Seabirds, landbirds, endangered

insects, even plants!New habitat for reintroductionsFew reinvasions

Exporting the revolution“There’s no island in the world

from which we can’t eradicate rats” Pete McClelland, Rat eradication

guru

But…There are only so many islandsOnly so much habitatSome important habitat simply

won’t grow on islands

Mainland IslandsAll the rage in New Zealand

conservationBuild a fence, eradicate the

predators and re-introduce the species you want

Karori Wildlife Sanctuary (Almost) downtown Wellington,

New ZealandFormer reservoir for drinking

water252 ha8.6 km of predator-proof fence

erected in 1999

Reintroduced12 species of birds

6 IUCN red-listedTuataraGiant Weta

The four horsemen of the extinction crisis IV: Climate change

Problems with climate changeExtreme weather events (see

natural disasters)Changes in habitat zone

Northward shifts in climatic zones Plants and animals can’t keep up…

Assisted migration to help deal with climate change?Give the species a helping

hand?!Serious ethical issues with

introducing new speciesSerious ethical issues with

standing by and watching species go extinct…