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Deakin
plays major role in Darwin celebrations
 Deakin
University has sponsored a major symposium to celebrate
the 200th birthday of Charles Darwin and also the 150th
anniversary of the publication of his landmark On
The Origin of Species.
“Our symposium has attracted a range of experts on
the evolution of birds from around the world,” said
Dr Kate Buchanan from Deakin’s School of Life and
Environmental Sciences who helped organise the symposium
and also presented her own paper.
“The Deakin symposium celebrated the impact of evolution
on avian biodiversity. The vast array of bird forms, in
terms of appearance and behaviour, is due to evolutionary
selection for the genes that determine individual fitness.
“The processes first identified by Darwin over 150
years ago are now recognised as responsible for radiation
in avian molecular sequences, morphologies, behaviour and
physiology.
“Within the field of avian biology, the wide interests
of the symposium speakers reflect the scale and diversity
of the adaptive radiation seen in avian evolution. The themes
of the symposium include the processes giving rise to evolutionary
adaptation, speciation, morphological changes, influence of
environmental change and the evolution of adaptive behavioural
strategies.
“The aim is to publish a group of papers which celebrates
avian biodiversity and the impact of natural and sexual selection
processes, by reviewing past work and highlighting new and
exciting areas for future research.
“A number of papers to be published later this year
in Emu Austral Ornithology, the premier ornithological journal
for the southern hemisphere, as a result of the symposium.
“This special issue is a fair indication of the quality
of those speakers involved, and the importance of their research.”
Below are the abstracts of the participants, plus short biographies.
Professor John Endler
Title: Testing hypotheses about Elaboration, Innovation and
Speciation in Bowerbirds using principles of visual physiology.
Abstract: Male bowerbirds construct and decorate bowers with
coloured objects in order to attract and mate with females
and are found only in Australia and New Guinea. Their visual
signal consists of their own plumage plus the bower and the
bower decorations. It is assumed in the literature that males
select ornaments which elaborate their plumage. We can use
known visual physiology parameters to make and test hypothesis
about visual signals even though birds have much better colour
vision than humans. This reveals that the elaboration hypothesis
is an artifact of human appraisal of bird colours, bowerbirds
do not elaborate their plumage but in fact select ornaments
which are a different as possible from their own plumage as
well as that of the visual background. The same calculations
successfully predict hybridization and suggest that visual
species recognition may be much simpler than we originally
thought.
Prof. John A. Endler received his Ph.D. in 1973 from the University
of Edinburgh where he studied the population genetics of geographic
differentiation and speciation. From then he spent time at
Princeton University, University of Utah and the University
of California Santa Barbara, working on the interaction between
predation and sexual selection in determining geographic variation
in guppy colour patterns, and the occurrence and strength
of natural and sexual selection in natural populations. This
work resulted in two well known books, Geographic Variation,
Speciation and Clines (1977) and Natural Selection in the
Wild (1986). He started working on Australian birds in 1988
and Bowerbirds in 1996 because they allow experimental manipulation
of colour patterns in unrestrained wild birds and unparalleled
opportunities to explore the relationship between signal design,
colour vision and sexual selection. In 2006 he moved to the
University of Exeter to set up an undergraduate, postgraduate,
and research group in Animal Behaviour and Sensory Ecology,
and continues to work on Australian Bowerbirds. He is widely
known for his work on natural and sexual selection and visual
contrast, and the function of sensory processes in sexual
selection.
Dr Katherine Buchanan
Abstract
Environmental and genetic control of the avian song system
Buchanan, KL, School of Life and Environmental Sciences, Deakin
University
Sexual selection is a powerful evolutionary force which acts
directly to shape avian song production, both in terms of
output and song structure. Species which show a strong influence
of sexual selection on song output tend to produce conspicuous
songs which have complex structures. The morphology of the
avian song system, the neural mechanism determining song production,
is under strong evolutionary selection. In particular, the
size of the high vocal centre (HVC) has been shown to relate
to song complexity, both across and within species. However,
the avian song system is also vulnerable to change during
development, according to early developmental conditions.
This can be clearly seen from our recent finding that exposure
of male birds to estrogenic pollutants enhances song complexity
of European starlings, through changes in neural development,
with consequences for male attractiveness and reproductive
success. Here, I go onto review the evidence for the heritability
of the song system and show that whilst studies show a strong
genetic component to the development of the song system, they
have failed to control environmental conditions sufficiently
to quantify heritability accurately. I present data from our
own experiments which go some way to quantifying the heritability
of the morphology of the avian song system.
Kate Buchanan received her first degree from Glasgow University
and her Ph.D. from Royal Holloway, University of London,
U.K.. Her Ph.D. was conducted on the influence of sexual
selection in shaping song structure in the sedge warbler
(Acrocephalus schoenobaenus). Kate conducted 2 postdoctoral
appointments working with Prof Matthew Evans at University
of Stirling UK. The first tested the evolutionary forces
shaping tail shape in hirundines, examining the tail of
the barn swallow (Hirundo rustica) which had been regarded
as the classic example of a sexually selected trait. The
results showed that tail shape is actually a trade-off between
the competing forces of both natural and sexual selection.
The second postdoctoral position focussed on the influence
of hormone levels on signalling behaviour and immunocompetence
in the house sparrow (Passer domesticus). In 2001 Kate moved
to Cardiff University to take up a research fellowship from
the Royal Commission for the Exhibition of 1851, together
with a proleptic lectureship. Throughout her career she
has worked on the evolution of avian signals, with a strong
interest in condition-dependence, physiological mechanisms
and cost-benefit trade-offs. She moved to take up as position
as Senior Lecturer at Deakin University in 2008 and at the
same time took on the position as Editor of Emu.
Austral Ornithology. Assoc Prof Simon Griffiths
Title: Supermodels, molecules and biodiversity in birds:
the impact of the molecular revolution on our understanding
of avian evolution. Our understanding of avian mating systems
has been revolutionised over the past 21 years through the
application of molecular markers that have revealed levels
of sexual conflict between social partners that had hitherto
been unimagined. Alternative mating strategies such as extrapair
paternity are a major driving force of sexual selection
and biodiversity in birds and yet, although we now have
a good set of comparative data on over one hundred species,
we still know remarkably little about the functional significance
of such strategies. Australia is particularly well placed
to lead significant advances towards a greater understanding
of the evolutionary biology of avian life-histories and
biodiversity given the model systems available locally.
Foremost amongst these is the zebra finch (Taeniopygia guttata)
a widely used captive model system throughout the world
and the first non-agricultural avian species to have its
genome sequenced. The completion and publication of the
zebra finch genome will further increase the significance
of this species as the most important avian model system
for evolutionary biologists and will revolutionise research
fields investigating questions that underpin biodiversity
such as communication, pigmentation, and reproductive biology.
A/Prof Simon Griffith completed his doctorate at the University
of Leicester (UK) in the Burke Laboratory that pioneered the
use of DNA fingerprinting to study mating systems in animals.
He has worked on the classic passerine model systems in Europe
(e.g blue tit, great tit, house sparrow and collared flycatcher)
through postdoctoral positions in Uppsala, Oxford and Imperial
College, London. Currently an ARC QEII Fellow, he is based
at the Centre for the Integrative Study of Animal Behaviour
at Macquarie University where his research combines behavioural
and molecular techniques to study the evolutionary ecology
of a number of Australian bird species in the wild and captivity,
with a particular focus on the effect of the genetic landscape
on individual reproductive decisions.
Leo Joseph and Gaynor Dolman
Title From Molecules to Populations: Insights from DNA into
the Evolution of Australian Birds at the Species Level
Australian National Wildlife Collection, CSIRO Sustainable
Ecosystems, GPO Box 284, Canberra, ACT 2601, Australia
Complementing the revolution that DNA data have brought to
understanding the origins of Australian birds, especially
passerines, this talk reviews insights from DNA into the
evolution of Australian birds over the last two million years.
Molecular phylogeography and population genetics of Australian
birds have now spanned a range of species and biomes. The
power of integrating contemporary and historical perspectives,
though becoming axiomatic, is emphasized. Another theme of
the presentation will focus on the wealth of hypotheses provided
by the study of species-level systematics of Australian birds
during the 20th Century. Some of these hypotheses
that have been examined at the DNA level concern putative
zones of intergradation such as that hypothesized to occur
across the Flinders Ranges, or the origins of birds narrowly
endemic to areas such as the Wet Tropics or south-west Western
Australia. Molecular data, it seems, always yield some unexpected
insight that cannot be gained solely from analysis of contemporary
ecological and distributional data. Here lies the real message
of the talk: evolution of Australian birds, like any group
of organisms, is best understood with an integrated approach
to the rich diversity of biological knowledge that Darwin’s
theory of evolution unified.
Leo Joseph is Director of the Australian National Wildlife
Collection at CSIRO Sustainable Ecosystems, Canberra. He holds
a PhD from the University of Queensland and undertook earlier
studies at the University of Adelaide. After postdoctoral
research in Uruguay where he explored phylogenetic and climatic
approaches to understanding bird movements across South America,
he worked from 1997 to 2005 as a curator of birds at the Academy
of Natural Sciences, Philadelphia. On returning to Australia,
he has expanded his research theme of integrating present-day
ecological diversity with evolutionary history and has developed
a program of research into the evolution of arid zone birds.
Conducting this work in the environment of a modern museum
collection, he is developing insights complementary to those
emerging from research elsewhere on the deeper history of
the Australo-Papuan avifauna.
Assistant Prof Irwin
Title: The Greenish Warbler ring species: lessons for the
study of avian speciation.
Ring species, in which two coexisting and reproductively isolated
forms are connected by a long chain of interbreeding populations,
provide a rare opportunity to reconstruct the process of divergence
of two species from one. One example is provided by the greenish
warblers (Phylloscopus trochiloides / P. plumbeitarsus), in
which two divergent Siberian forms are connected by a chain
of intermediate populations encircling the Tibetan Plateau
to the south. I present patterns of variation in a wide variety
of traits, with the goal of inferring the changes that occurred
during speciation. There is a pattern of gradual variation
around the ring in molecular markers, songs, calls, and migratory
behavior, with the two Siberian forms being the most divergent
in each of these traits. In contrast, habitat as well as body
shape and size are extremely similar between the Siberian
forms, which together differ strongly from the presumably
ancestral southern populations. These results suggest that
divergence in behavioral traits has played an important role
in speciation and that speciation has occurred during parallel
rather than divergent ecological shifts. Other examples of
speciation in Asia and North America show similar patterns
of trait variation, suggesting that greenish warblers serve
as a widely applicable model for avian speciation on continents.
Assistant Prof Darren Irwin is an Assistant Professor of Zoology
at the University of British Columbia, Canada, after receiving
his B.S. with Honors and Distinction from Stanford University
and his Ph.D. from the University of California, San Diego.
His research is directed toward understanding how new species
arise, using both empirical and theoretical approaches. He
studies carefully chosen model systems using an integrative
approach, employing techniques such as DNA sequencing, analysis
of vocalizations, observation and experimentation in the field,
and computer simulation. Research systems have included greenish
warblers in Asia, willow warblers in Europe, and winter wrens
and yellow-rumped warblers in North America. He has published
in journals such as Nature, Science, Proceedings of the Royal
Society of London, Evolution, and Molecular Ecology, and his
work on speciation in greenish warblers and winter wrens has
been covered widely in the popular press. He now leads an
active team of researchers who are studying geographic variation
and speciation in birds and salamanders of the boreal forests
of North America.
Les Christidis
The Australasian Bird Fauna- a Remarkable Laboratory for Investigating
Evolutionary Radiations and Speciation.
Les Christidis and Janette A. Norman
DNA analyses have revolutionised our understanding of the
origin and evolution of the world’s avifauna and the
central role of the Australasian region in the 85 million
year history of this group. It is now established that the
ancient supercontinent Gondwana was the centre of origin
for a number of bird orders including the perching birds(Passeriformes),
Anseriformes (waterfowl), Galliformes (megapodes, pheasants
and allies), and Psittaciformes (parrots) with many of the
basal lineages of these groups restricted to the Australasian
region. DNA analyses have also revealed intricate links between
bird lineages across the Indo-Pacific region. These studies
have shown that dispersal has played a major role in speciation
across the island archipelagos, whereas biogeographical barriers
and vicariance have been more important in shaping diversity
within the continental landmass. The regional avifauna has
also been instrumental in the development of key speciation
concepts and DNA studies are providing new insights into
the veracity of these models. As the Australasian region
supports one of the oldest bird faunas it also provides an
excellent opportunity to investigate how lineages radiate
and adapt through long term major changes in climatic and
environmental conditions. Comparative studies of other continental
avifaunas should also provide new insights into the mode
and tempo of avian speciation.
Dr Les Christidis completed a Bachelor
of Science (Honours) degree at the University of Melbourne
in 1980, then undertook a Ph.D. at the Australian National
University where he focused on the evolutionary genetics
of Australian finches. He went on to conduct research on
the origins of Australia’s
songbirds, first as a CSIRO post-doctoral fellow and then
as the recipient of Queen Elizabeth II fellowship. During
this period he was able to demonstrate that Australia was
the centre of origin for the world’s 4500 songbirds.
From 1987 to 1996, Les was Senior Curator of Ornithology at
Museum Victoria and in 1997 he became Science Program Director
and later Head of Sciences. From 1997 to 2004 he led teams
that produced major exhibitions for Melbourne Museum and the
development of Australia’s first digital planetarium
at Scienceworks. Les Christidis has published over 100 scientific
papers and books on the systematic and evolutionary genetics
of birds, bats, marsupials, bryozoans and more recently on
cultural intangible heritage. In 2005 he was a recipient
of the inaugural W. Roy Wheeler medallion for excellence
in field ornithology. Since 2004, he has been Head of the
Division of Research and Collections, and Assistant Director
of the Australian Museum in Sydney.
Dr Anthony Herrel
Title Biting, mechanical constraints, and trade-offs in Darwin’s
finch beaks: a recipe for ecological speciation?
Anthony Herrel, Joris Soons, Joris Dirckx, Bieke Vanhooydonck,
Peter Aerts and Jeff Podos.
Studies of Darwin’s finches of the Galápagos
Islands have provided pivotal insights into the interplay
of ecological variation, natural selection, and morphological
evolution. Beak morphology in Darwin’s finches has been
shown to evolve via natural selection as a response to variation
in food type, food availability, and interspecific competition
for food. From a mechanical perspective, however, beak size
and shape are only indirectly related to a bird’s ability
to crack seeds, and beak form is hypothesized to evolve mainly
under selection for fracture-avoidance. We show that birds
specializing on large seeds have higher bite forces, larger
jaw muscles and bigger heads as expected if selection operates
on seed crushing capacity. Moreover, mechanical models show
that across species mechanical loading approaches reported
values of bone strength, suggesting pervasive selection on
fracture-avoidance. Additionally, deep and wide beaks are
better suited in dissipating stress than more elongate beaks.
However, the larger jaw muscles needed to crack large seed
also constrain jaw movement velocity both within and across
species. Adaptations to varying food types thus appear to
drive divergence not only in beak size, head size, and bite
force, but also in jaw closing velocity and vocal performance
capacity. These results support a biomechanical link between
adaptive divergence and mating signal divergence, the two
key features thought to have driven this radiation.
Dr. Anthony Herrel studied zoology
at the Universities of Ghent and Antwerp in Belgium and
completed his PhD at the University of Antwerp. He took
up a postdoctoral position at the fund for scientific research,
Flanders and spent several years in the United States (Northern
Arizona University &
Tulane University). Recently, he took a postdoctoral position
at Harvard University working with Dr. Jonathan Losos, and
from January 2009 onwards he will be working as a full time
researcher at the French CNRS based at the Museum of Natural
History in Paris. His research interests broadly encompass
the evolution of complex integrated systems such as the vertebrate
cranial and locomotor systems. In pursuing his research interests
he uses tools from functional morphology, biomechanics and
ecological morphology to understand the functional implications
of morphological differences between animals. These approaches
are combined with analyses of whole-animal performance and
field studies of ecology and behavior. Integration of these
data with insights obtained from developmental and genetic/genomic
studies are used to understand the evolution functional diversity
in vertebrates.
Dr Naomi Langmore
Coevolution between Australian cuckoos and their hosts: an
escalating arms race
Birds exhibit a striking diversity of breeding strategies,
but arguably the most unusual of all is employed by brood-parasitic
cuckoos. Cuckoos lay their eggs in the nests of other birds
and thereafter abandon their young entirely to the host’s
care. In most species the cuckoo nestling, still naked and
blind, evicts the host eggs and chicks from the nest, thereby
becoming the sole occupant of the nest. The high cost of
parasitism to hosts provokes an evolutionary arms race in
which hosts evolve defences against cuckoos, and cuckoos
evolve ever more cunning tricks to fool their hosts. In Australia,
the arms race between bronze-cuckoos (Chalcites spp.) and
their hosts has reached the most advanced level yet recorded.
Whereas cuckoos elsewhere lay mimetic eggs, in Australia
host discrimination of bronze-cuckoo chicks has led to the
evolution of mimetic nestling cuckoos. Selection for mimicry
of host nestlings in cuckoos has led to remarkable phenotypic
plasticity, in which cuckoo nestlings can modify their behaviour
according to which host species is rearing them, and may
even be driving speciation of Australian bronze-cuckoos.
Naomi Langmore completed her PhD at the University of Cambridge,
UK, and then took up a Research Fellowship at Peterhouse,
Cambridge. In 1999 she returned to Australia to take up an
ARC Post-doctoral Fellowship at the Australian National University.
Currently, Naomi is based at the ANU as an ARC Australian
Research Fellow. Her research interests, which take her to
field sites from the mountains of the French Pyrénées
to the mangrove swamps of Darwin, span several areas of behaviour,
including bird song, breeding systems, and coevolution between
cuckoos and their hosts.
Bird population responses to fire: insights from species’
ecological traits
Simon Watson1*, Rick Taylor2, Luke Kelly1, Dale Nimmo1, Mike
Clarke2 and Andrew Bennett1
1 Landscape Ecology Research Group, School of Life and Environmental
Science, Deakin University, Burwood Campus
2 Department of Zoology, Faculty of Science and Technology,
La Trobe University, Bundoora Campus
* Corresponding Author: sjwat@deakin.edu.au
Fire is recognised as a major disturbance shaping Australian
ecosystems, with many plant species having evolved specialized
adaptations to cope with fire. Fire provides an important
source of vegetation heterogeneity and is a determinant of
habitat structure and suitability for animal species. Altered
fire regimes have been implicated as a contributing factor
to the decline of many bird species in Australia. In light
of this, understanding how different species’ populations
respond to fire, and which of their ecological traits are
linked to these responses, are important ecological questions
directly relevant to maintaining avian biodiversity. We studied
the post-fire responses of birds in the Murray Mallee region
of Victoria, New South Wales and South Australia. Mallee
vegetation has evolved a range of adaptations that allow
survival and recovery from wildfire, yet little is known
about the way that bird populations respond to wildfire.
The species encountered in this study represent a wide range
of ecological traits, in relation to body size, movement
patterns, dispersal ability, dietary types, habitat specialism,
foraging techniques and foraging zones used. Bird species
displayed a range of population response patterns to time-since-fire.
Some species show a population increase from low density
immediately post-fire to a peak in numbers in long-unburnt
vegetation; whereas other species erupt immediately post-fire
and decline in local abundance over time. Here we outline
the range in types of responses to time-since-fire and examine
how ecological traits of species give insights into the way
their populations respond.
Landscape-level benefits of revegetation to birds in an agricultural
system
Rohan H. Clarke1,2, Greg Holland1, Alistair Stewart1, James
Radford1, Andrew F. Bennett1
1 School of Life and Environmental Sciences, Deakin University,
221 Burwood Hwy, Burwood, 3125 Vic.
2 Present address: School of Biological Sciences, Monash University,
Clayton 3800 Vic.
Email: rohan.clarke@sci.monash.edu.au
Restoration of agricultural environments is a major issue
across southern Australia. Protection and management of existing
native vegetation, and revegetation to expand and create
new habitats, are important aspects of restoration. While
the planting of woody vegetation is undertaken to achieve
a number of goals (e.g. stock shelter, land protection),
there is an underlying assumption that revegetation will
also benefit the conservation of biodiversity. Using birds
as indicators, we sought to identify and measure the landscape-level
biodiversity benefits of revegetation in an agricultural
region in south-western Victoria. We employed a design based
on study landscapes of 8 km2. Landscapes were selected to
provide a gradient from no wooded vegetation cover (0-1%)
through to higher revegetation cover (~20%). Additional landscapes
containing only remnant vegetation and a mixed cover of remnants
and revegetation were also selected to provide similar gradients
of cover. Survey results were pooled to provide a ‘snapshot’
of the response of woodland-dependant birds to landscape-level
changes along a gradient of farmland restoration. Here we
summarize changes in the diversity and composition of avifaunal
communities as a) the amount of remnant vegetation declines
within production landscapes and, b) the amount of restored
vegetation within production landscapes increases. The results
of multivariate modelling demonstrate that revegetation at
individual sites on farms has cumulative benefits at the
landscape-scale that help to reverse the detrimental effects
of native vegetation loss.
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