Heather Gibbs
I hope
to address questions such as:
· What climatic and geographic factors influence breeding date in Australian birds?
· Has there been an overall trend in breeding dates over the last 30 years?
· Does breeding date track annual variability in climate?
· Are the bioclimatic profiles of birds related to their observed response to climate?
· Does the bioclimate in which a species breeds differ from that of its overall distribution?
· Can climatic factors that limit bird breeding in Australia be identified?
Biological climate change research in Australia
has recently been reviewed (Hughes
in press), revealing substantial gaps
in our knowledge. There has been little study relating to birds, although
migratory bird species apparently arrived earlier in the alpine zone in the
1980s and 1990s, compared to the 1970s (Green
& Pickering in press)
cited by (Hughes
in press). However, the types of
analyses of long-term national bird databases performed internationally have
not been done in Australia. This may be because the broad geographic scale and relatively low
number of observers in Australia make it more difficult to pick up climate-related
trends here. Also, because of the large difference in climate between Australia
and Europe / North America, the trends are likely to be quite different. For
instance, where extremely cold conditions occur during winter, birds are often
limited by temperature (Wuethrich 2000), but in Australia, especially in arid regions, it is thought that
rainfall may be more significant (Barrett et al. 2002). Although changes in
temperature would affect Australian birds, it cannot be assumed that these
effects would parallel those reported in the northern hemisphere. To study the
effects of climate change on Australian birds, it is first necessary to extend
our understanding of the effects of climate – for example, to extend the work
done in the Handbook of Australian, New Zealand and Antarctic Birds (Higgins & Peter 2002) by summarizing bird breeding seasons across the continent and
attempting to explain the observed patterns in relation to climatic and
geographic factors.
Biological climate change research in Australia
has recently been reviewed (Hughes
in press), revealing substantial gaps
in our knowledge. There has been little study relating to birds, although
migratory bird species apparently arrived earlier in the alpine zone in the
1980s and 1990s, compared to the 1970s (Green
& Pickering in press)
cited by (Hughes
in press). However, the types of
analyses of long-term national bird databases performed internationally have
not been done in Australia. This may be because the broad geographic scale and relatively low
number of observers in Australia make it more difficult to pick up
climate-related trends here. Also, because of the large difference in climate
between Australia and Europe / North America, the trends are likely to be quite
different. For instance, where extremely cold conditions occur during winter,
birds are often limited by temperature (Wuethrich 2000), but in Australia, especially in arid regions, it is thought that
rainfall may be more significant (Barrett et al. 2002). Although changes in
temperature would affect Australian birds, it cannot be assumed that these
effects would parallel those reported in the northern hemisphere. To study the
effects of climate change on Australian birds, it is first necessary to extend
our understanding of the effects of climate – for example, to extend the work
done in the Handbook of Australian, New Zealand and Antarctic Birds (Higgins & Peter 2002) by summarizing bird breeding seasons across the continent and
attempting to explain the observed patterns in relation to climatic and
geographic factors.
Analysis of British Nest
Record Scheme (NRS) data shows a long-term trend towards earlier egg-laying
over 25 years in 20 of 65 species analysed, across taxonomic and ecological
groups (waterbirds, resident insectivores, migrant insectivores, corvids and seed-eaters). Later laying
was observed only once (Crick et al.
1997). Analysing 36 species with at least 1000 records over
56 years, Crick and Sparks (1999) found that 19 species laid earlier, and in 17
of these species (89%), temperature and rainfall explained a significant amount
of the variation, while other factors (e.g. large-scale changes in land use)
may be responsible for the remaining variation (Crick & Sparks 1999). Only one study has documented earlier laying at
a continental scale, after controlling for the effects of latitude, longitude,
breeding density and elevation: Tree Swallows Tachycineta bicolor have advanced laying by around 9 days across
North America over the last 40 years (Dunn & Winkler 1999). Detailed studies of individual species at single
locations have yielded similar results, e.g. a study of the Mexican Jay Aphelocoma ultramarina in se. Arizona
showed that the date of the first clutch had advanced by about 10 days between
1971 and 1998 (Brown et al.
1999). In both swallows and jays, the observed trends
paralleled changes in minimum temperatures. However, a study using NRS data
from the Czech Republic found no evidence that laying dates or clutch size in
nine species had changed at the regional scale over the past decades (Weidinger 2001).
Proposed research
I aim to study the effects of climate and geography on
the distribution, abundance and breeding of Australian avifauna, using bird
Atlas and Nest Record Scheme data and bioclimatic modelling. This is relevant to biodiversity conservation,
particularly in relation to climate change, and could inform management at a
regional level and policy at the national level. This will help ensure that the
needs of Australia’s avifauna are properly accounted for during the critical
early stages of adaptation to climate change.
Barrett, G., A. Silcocks, R. Cunningham, and R. Poulter. 2002. Comparison of Atlas 1 (1977-1981) and Atlas 2 (1998-2001): Supplementary Report No. 1. Unpublished Report to Natural Heritage Trust.
Brown, J.L., S.-H. Li, and N. Bhagabati. 1999. Long-term trend toward earlier breeding in an American bird: A response to global warming? Proc. Natl Acad. Sci. USA 96: 5565-5569.
Caughley, Short, Grigg, and H.A. Nix. 1987. Kangaroos and climate: an analysis of distribution. J. Anim. Ecol. 56: 751-761.
Crick, H.Q.P., C. Dudley, D.E. Glue, and D.L. Thomson. 1997. UK birds are laying eggs earlier. Nature 388: 526.
Crick, H.Q.P., and T.H. Sparks. 1999. Climate change related to egg-laying trends. Nature 399: 423-424.
Dunn, P.O., and D.W. Winkler. 1999. Climate change has affected the breeding date of tree swallows throughout North America. Proc. R. Soc. Lond. B 266: 2487-2490.
Green, K., and C.M. Pickering. in press. A potential scenario for mammal and bird diversity in the Snowy Mountains of Australia in relation to climate changein Global Mountain Biodiversity: changes and threats (E. Spehn, ed.).
Higgins, P.J., and J.M. Peter. 2002. Handbook of Australian, New Zealand and Antarctic Birds. Volume 6. Pardalotes to Spangled Drongo. Oxford University Press, Melbourne.
Hughes, L. in press. Climate change and Australia: trends, scenarios and impacts.
Weidinger, K. 2001. Laying dates and clutch size of open-nesting passerines in the Czech Republic: A comparison of systematically and incidentally collected data. Bird Study. 48: 38-47.
Wuethrich, B. 2000. How climate change alters rhythms of the wild. Science 287: 793-795.
1. Determine which climatic and geographic factors seem to have the most influence on breeding date and clutch size
Nest Record Scheme data for
common species e.g. Willie Wagtail, Grey Fantail
+
Elevation information from a
Digital Elevation Model (DEM)
+
Long-term climatic averages
from BIOCLIM
¯
2. Determine which climatic and geographic factors seem to influence distribution
¯
¯
Relate climatic parameters
to patterns of species distribution, as has been done for kangaroos (Caughley et al. 1987).
3. Attempt to document the influence of year-to-year climatic variation
¯
See whether year-to-year
variation in temperature, rainfall patterns or biological productivity can be
related to timing of breeding or distribution
4. Can long-term trends relating to climate change be detected?
Using
the above techniques, see if any trends relating to climate change (like those
reported internationally) can be
detected