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The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology

Marine Climate Change Impacts & Adaptation Report Card: Seabirds

Dr Lynda E. Chambers1

B. Congdon2, N. Dunlop3, P. Dann4, C. Devney2

www.cawcr.gov.au

1 Centre for Australian Climate and Weather Research 2 James Cook University 3 Conservation Council (WA) 4 Phillip Island Nature Park

N Valez


Marine Climate Change and Adaptation Report Card for Australia

Assessment of state of knowledge of known and expected impacts of climate variability and change on Australian seabirds; Knowledge gaps; Adaptation options

Published November 2009

Sections:

Marine Climate

Temperature, Sea Level, EAC, Leeuwin

Current, ENSO, Ocean Acidification

Impacts on Marine Biodiversity

Tidal Wetlands, Seagrass,

Macroalgae, Phytoplankton

Zooplankton, Coral Reefs

Tropical Fish, Temperate Fish

Pelagic Fish, Marine Reptiles

Seabirds


Seabirds

•  Consume significant amounts of marine resources

•  Important role in marine ecosystems •  Nutrient transfer from pelagic and offshore regions to islands, reef and coasts •  Seed dispersal

•  Movement of organic matter through soil layers (esp. burrow nesters)

•  Upper trophic level predators

•  Demography and reproduction often related to changes in trophic and oceanographic conditions

Photo: LE Chambers


Seabirds in the Australian Region

•  ~110 species (including external territories) from 12 families

•  69% breed in region

•  Many environmental and anthropogenic threats, including climate change


Climate and Seabirds

•  Variation and changes in marine environment affect seabirds, influencing •  Prey density •  Seabird abundance •  Distribution •  Productivity •  Behaviour

•  Particularly true in regions of upwelling & boundary currents •  Any change in availability of prey items has flow on effects to seabird abundance,

distribution, migration patterns and community structure at higher trophic levels


Impacts: Sea Surface Temperature

Observed: •  Southward expansion of tropical seabirds (WA); •  Later breeding in ENSO years (WA) & in cooler years (Little Penguins, Vic) •  Reduced breeding participation and success in ENSO years (WA) and warm SST

years (GBR) •  Increased survival of first year L. Penguins (Vic) in warmer years & decreased adult

survival

Expect: southward expansion or shifts, altered reproductive success & timing, foraging areas & possibly prey species

SSTs & laying date in Little Penguins


Increased land temperatures can increase heat stress and mortality, leading to reduced

breeding success (esp. surface dwelling birds)

Many seabirds (e.g. LP) unable to withstand prolonged exposure to surface air temperatures > 35 ºC, which lead to dangerously high body temperatures and heat stress

Impacts: Air Temperature


Alterations in currents, mixed layer depth & ocean stratification have potential to impact seabird

distributions, migration and foraging through impacts on supply of nutrients and light and, therefore,

prey species and subsurface predators that force and maintain prey at the surface

•  Negative relationship between number breeding Sooty Terns (GBR) and precursor changes in

depth of 20 ºC thermocline

•  Foraging and breeding success in Little Penguins linked to ocean stratification (prey more

dispersed in poorly stratified waters)

Impacts: Ocean currents, mixed layer depth, ocean stratification


•  Strong winds and cyclones reduce breeding success, foraging and nesting habitats in northern Australia

•  Cyclones can cause catastrophic damage of breeding colonies and deaths of individuals •  Indirect effects include: wave inundation, erosion, storm tides and intensified currents

•  Cyclonic activity can affect timing of breeding (e.g. Sooty Tern – GBR)

A composite weather satellite image from MTSAT-1R, 19 March 2006, 4.15pm (eastern standard time), showing Tropical Cyclone Larry over the Queensland coast, near Cairns and Innisfail. Image processed by the Bureau of Meteorology.

Copyright Commonwealth of Australia and Japan Meteorological Agency, 2006

Impacts: Winds, storms and cyclones


•  Non-cyclonic storms and strong winds influence breeding success by reducing foraging success, increasing juvenile mortality and flooding nests (e.g. Roseate Terns)

•  Storms associated with mass mortality of seabirds along Victorian coast

•  Strong westerly winds (Jan-Mar) & later breeding in LP (Vic)

Impacts: Winds, storms and cyclones

Angela Wylie


Precipitation, floods and terrestrial runoff

•  Few direct effects on survival or breeding success •  Occasional heavy rain may flood burrows •  Indirect (potential effects) include: impact on prey availability, quality of breeding habitat, fire risk •  Anchovy productivity (important prey of LP) associated with streamflow in coastal areas

Sea level rise •  No known quantitative links between observed SLR & changes in the distribution & abundance

of seabirds – future impact will vary with breeding habitat (Torres Strait, GBR)

Ocean Acidification •  No known direct or indirect effects


Other extreme events (including fire)

•  Prolonged periods of hot dry conditions increase risk of fire, including power-pole fires

•  Synchronised breeding in seabirds increase vulnerability, esp. burrow nesting species

•  Little Penguin maladapted fire response


Future changes

•  Many uncertainties •  Rising SST projected to decrease prey availability to many seabirds at current breeding

sites •  Background rises in SSTs may foster persistence of tropical seabirds at more southern

latitudes •  Potential for seabirds to shift breeding locations as result of inundation and/or degradation

of breeding sites is unclear & highly dependent on resilience of coral reef ecosystems and other breeding locations to CC

•  Any increase in fire risk potential to severely impact some colony nesting seabirds •  Increased surface temperatures likely to increase heat stress related mortality


Knowledge gaps

•  Understanding drivers of change in seabird populations, including relative role of natural variability and CC

•  Understanding factors determining resilience and adaptive capacity of marine ecosystems. E.g. How do seabirds respond to climatic changes: gradual vs trigger vs thresholds

•  Knowledge of existing non-climatic threats and how these will interact with CC

•  Which species and systems are more vulnerable? When can we make generalisations?

•  Information on seabird movement and diet

•  What is manageable, what are we managing for, and minimum amount of information needed for managers to differentiate particular actions

•  Economic and social impacts of climate-related changes to seabirds? •  Limits to current modelling of CC impacts on marine systems


Adaptation Responses

Many aspects of climate’s impacts on seabirds little known, vary by location and species, suggesting regional or colony by colony assessments of resilience or adaptive capacity may be required.

However, general principles:

•  Reduce existing (non-climate) threats to increase resilience and chance of autonomous adaptation, e.g.

•  Marine protected areas •  Exclusionary fences limiting tourist access to colonies

•  Feral/pest animal control

•  Buffering potential negative effects of CC through habitat management


Adaptation Responses

•  Monitoring and research – to improve adaptation responses

•  Ex situ conservation or translocation

•  Other species and site specific options

•  Nest shading

•  Signage at colonies

•  Powerlines underground •  Decoys to encourage new colonies


Conclusions

•  Changes in oceanographic and climatic processes are impacting on Australian seabirds, across many foraging guilds

•  Changes in distribution, success & timing of breeding, chick growth and survival of adult & immature birds

•  Some uncertainty in future impacts •  Southward expansion limited by available habitat & distribution of prey species

•  SLR likely to reduce existing breeding habitat


•  For many seabirds & regions we have limited information on prey distributions, foraging & movement patterns & ability of species to alter prey species or life-cycle timing

•  Further research & monitoring of key species required

•  Determine which species and systems more vulnerable to CC •  Where generalisations about impacts & adaptation can be made •  Which species are most effective indicators of climate impacts on higher trophic predators

Conclusions


Dr Lynda Chambers

Email: [email protected] Web: www.cawcr.gov.au

Thank you www.cawcr.gov.au

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