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Climate Change & Biodiversity

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CO2 and global temperature

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Carbon dioxide and temperature last 1000 years

200

250

300

350

02004006008001000years before 2000 AD

CO

2 (

pp

m)

-0.5

0.0

0.5

1.0te

mp

era

ture

(o C

) Cape Grim and South PoleLaw Dome ice corestemperature change

• CO2 increased 35% since industrial revolution• Exceeds natural range over past 650,000 yrs• 0.8oC increase in global average temperature since 1906• Rate of warming doubled in past 50 years

• 1990s warmest decade, 1980s second warmest

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Northern Hemisphere Ice

• Arctic ice: shrinking 7.8% per decade (3 x faster than GCM projections), historic low in 2007, 20% below previous record (2005)

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Muir Glacier, Alaska

1941 2004

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What about the future?

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But:

• CO2 has almost tripled since the 1990s from 1.1% pa to 3.1% in the 2000s

• Sea levels also rising faster than IPCC projections

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Global Temperature Projections

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• Temperatures increased 0.9oC since 1950• Frequency of hot days and nights increased• Recent droughts hotter

Australian trends

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2005: Warmest year on record (>1oC above long-term average)

2007: Warmest year on record in southern Australia, 6th warmest overall

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• Rainfall very variable• Decreased along east coast and SW WA• Increased in north west• Snow depth declined 40% since 1960s

Australian trends

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• Temperature will increase:+ 1oC by 2030+ 0.8-2.8oC by 2050+ 1-5oC by 2070

• Rainfall will change– Little change in north– Decrease of 2-5% elsewhere by 2030

• Further declines in snow• Increased drought, especially in SW• Increase in fires• Sea level will rise

What do we expect in Australia?

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Natural ecosystems and biodiversity

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1. Directly:

TemperatureRainfallCO2

Extreme events

2. Indirectly:

Interactions with other species

Species & communities will be affected

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Increased temperature

Will affect:• Photosynthesis• Respiration• Decomposition

• Metabolic rate• Survivorship• Timing of life cycles

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Indirect Impacts

e.g. Herbivory

Reduced C:N

• Increased consumption• Reduced survival & reproduction• Increased development time

Increased CO2

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Winners

• Short generation times• Good dispersal• Broad climatic tolerances• Generalists• Opportunists

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Losers

• Long generation times• Poorly dispersed• Narrow climatic tolerances• Specialists• Large home ranges• Isolated populations• Genetically impoverished

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What do we expect?

Some species will move: eg.• away from current cold boundary• south• up

BUT:Some species will lose much of their current habitat

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• Southward range expansions observed for several bird species

eg: Figbird, Channel-billed cuckoo, Black-necked Stork and Pied Heron, Noisy Pitta, Pacific Baza, Beach Thick Knee, Hooded Plover

Observed changes

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+ 1 deg.

86%

+ 3.5 deg.

7%

Grey-headed Robin

Present

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+ 1 deg.

46%

+ 3.5 deg.

0%

Lemuroid Ringtail Possum

Present

(Williams et al. 2003)

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What do we expect? (cont)

Advances in life cycles

eg earlier flowering, fruiting, egg laying, migration

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Since 1960:

Migratory birds arriving 3.5 days per decade earlier & departing 5.1 days per decade later

Beaumont et al. 2006

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• Alpine zone• Coastal wetlands• Freshwater wetlands & rivers• North QLD Wet Tropics• South-west WA • Coral reefs

Most at risk..

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Alpine zone

• < 0.15% of land surface

• Low altitudinal relief

• Many species already threatened

• 40% reduction in snow cover and duration since 1960s

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Duration of snow cover, Australian Alps

Modelled current

Moderate climate change : 0.3oC

increase

More severe climate change : +1.3oC increase, -8% precipitation

www.greenhouse.gov.au

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Predicted impacts

eg Burramys parvus, mountain pygmy possum, < 500 individuals, confined to 10 km2 habitat

• Dependent on snow cover for hibernation

• Bioclimate projected to disappear with 1oC warming

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Coastal wetlands

• Already experienced major losses in area

• Vulnerable to sea level rise, tidal surges and changes in precipitation

• Ongoing reductions in saltmarsh communities (up to 80% area in some locations)

• Some mangrove communities extending landwards

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• Mangroves encroaching on freshwater wetlands- associated with sea level and rainfall changes- 17,000 ha freshwater wetlands replaced by 4 km intrusion of mangroves in Mary River system, since 1940s

Northern Territory rivers

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Freshwater wetlands & riverine environments

• Already severely degraded

• Will be affected by further reductions in flows if rainfall declines concurrently with warming

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Wet Tropics World Heritage Area

Temperature increase (oC)

No. species losing core climatic habitat

1 1

3.5 30

5 57

7 65

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Coral Reefs• 1998: highest SSTs on record

• Feb-April 1998: most severe & widespread bleaching onGBR so far

• Unmatched in period 1903-1999

• By 2030, bleaching may occur annually

• Potential replacement of coral by algal communities

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Conclusions

• Climate change is already here• Plants and animals are already responding• We need to:

• Drastically reduce our greenhouse gas emissions

• Think about how to help species and ecosystems adapt to inevitable change

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