View
219
Download
0
Category
Tags:
Preview:
Citation preview
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…
Recommended