Impacts of Climate Change on Endemics PDF Print E-mail

Using genetics to understand the impacts of climate change on Australian endemics

 

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Project overview

 

Understanding how and why organisms respond to climate change is key to predicting the effects of future climates and acting to preserve biological diversity. It is well known that climate fluctuations during evolutionary history have had dramatic impacts on biodiversity, although most major climatic shifts are old enough that it is difficult to perform detailed analyses of the effects on species distribution and genetic diversity. Much of our knowledge comes from studies of organismal response to the late Pleistocene glacial phases in the Northern Hemisphere, In contrast, the impacts and species responses in arid regions such as Australia remain poorly understood. This is a critical gap in our knowledge because environmental conditions in Australia during glacial phases are not dissimilar to those predicted under future climate change models. Specifically, a “dusty world” with significant expansion of arid and semi-arid zones, contraction of mesic environments, desiccation of lakes, increased dune activity, and loss of vegetation cover over inland Australia. Existing genetic data indicate a massive negative impact across a wide range of Australian terrestrial animals during this period, and provide a picture of species and ecosystem responses, and former refugia. This information forms critical baseline data for models predicting the future under increasingly arid regimes.

Our working group of national and international scientific experts will hold two workshops to:

i) synthesise and analyse existing genetic data from a wide range of Australian animals to determine patterns of genetic diversity and distribution, and reveal responses to previous periods of climatic change,

ii) produce high-profile publications on the impacts of recent climate change on the paleoecology of Australia.

iii) Identify the knowledge gaps that need to be addressed to build a comprehensive and Australia-wide picture of impact/response, and prepare a funding application to generate this data.

iv) Provide environmental managers with empirical evidence of past responses to climate change, and usable models for different species and ecosystems.

An inter-disciplinary, international working group will reconstruct the impacts of past climate change on Australian native animals using genetic data from 100 species of vertebrates. The study will focus on previous periods of hyper-arid conditions, including the last two glacial cycles in Australia. The group will bring together relevant scientific experts in conservation and landscape genetics, and paleoecological modellers, and will initiate an on-going multi-disciplinary research program to build comprehensive pictures of past impact/responses to aridity

We will hold two workshops to bring the group together and synthesise results and plans. In the first workshop we will focus on collating, synthesising, and contrasting existing genetic datasets to identify patterns amongst species and areas. This data will be used for landscape genetics analyses, and population genetic analyses. In the second workshop we will present the results of these studies, determine the implications of the results and prepare the initial papers. The key aims of the second workshop will be locate the timing and nature of past glacial refugia, identify species/areas requiring further data, and initiate modelling of responses to future climate changes. This workshop will also be used to start the application process for a future ARC application.

Our current lack of knowledge about how Australian environments changed during previous glacial cycles is a major strategic gap because current models predict future environmental conditions in large parts of Australia with aridity levels last seen during glacial phases. We know that Australia was a "dusty world" during these periods, with significant expansion of arid and semi-arid zones, contraction of mesic environments, desiccation of lakes, increased dune activity, and the loss of vegetation cover. The dominant "Northern Hemisphere" models of biotic response to major climate change (large scale contraction to/expansion from a small number of refugia) are unlikely to suit Australia. Studies of certain Australian plant species have identified alternative models (eg local persistence via very low levels of individuals in a geographically broad meta-populations2) but it is unclear how applicable these models are within different groups. These mechanisms are important – as future climate predictions differ from glacial phases because they are characterised not just by aridity but also higher temperatures, and this combination may make previous low-level metapopulation mechanisms unviable.

We will:

1. Use existing genetic, paleovegetation and paleoecological data to build models of biotic response of a broad range ofspecies to the cold, dry conditions of glacial Australia. Key issues to be addressed include the response of different species/ecosystems, and correlations with ecological characteristics.

2. Use the distribution of modern genetic diversity across the range of taxa to identify the location of putative glacial refugia, and the species/groups which shared them. Common areas may represent important long-term biodiversity "hotspots" for conserving biodiversity.

3. Include the past impacts of arid phases, and current levels of genetic diversity, in climatechange models to predict future population viability.

 

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Pairwise mismatch distributions - 100spp. endemic fauna

 

 

For further information about the activities of this group, please contact the Principal Investigator This e-mail address is being protected from spambots. You need JavaScript enabled to view it

 

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Workshop Reports

 

 

 

Workshop 1 Report (21–25 May 2012)

 

The Working Group held its first meeting at the Linnaeus Estate in May 2012. Attendees included population geneticists, theoretical ecologists, mathematical biologists and landscape scientists.

During the first meeting the Group assembled genetic datasets for over 200 species of Australian animals and plants - an impressive effort given that the primary data is spread over 15 years and more than 100 different publications and with widely varying amounts of metadata. All DNA sequences in all datasets were coded with two important pieces of metadata - a geocode identifying which of ~20 biogeographic regions the sample came from and a "clade" code identifying which of one or more genetic groups the sample was associated with within species. The coding provides options for subsequent analyses of the subsets of the data by biogeographic region or evolutionary depth. The dataset now represents the most comprehensive, standardized collection of genetic data of any continent in the world.  A data collation and preliminary analysis computational pipeline was also built to streamline and standardise the data formatting and analysis.

 

With the data collection and collation phase now complete, the Group will spend the next 4-6 months running a number of analyses to identify taxa and groups with signals of past population bottlenecks and subsequent expansion, and explore the taxonomic, geographic and ecological features of these groups.

 

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Left to right: Leo Joseph, Steve Donnellan, Gabriele Cybis, Jeremy Austin, Vicki Thompson, Alan Cooper, Craig Moritz, Xander Xue, Tania Laity and Julien Soubrier. Absent: Margaret Byrne and Julien Soubrier

 

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Workshop 2 Report (28–22 March 2013)

 

The second working group meeting was held at the Moreton Bay Research Station on North Stradbroke Island, Queensland, Australia. Since the first meeting in May 2012, the team had pulled together a very large dataset of published and unpublished DNA sequence data from over 200 species of Australian mammals, birds, reptiles, frogs and plants. The dataset itself represents a significant output of the working group: data format has been standardised and includes both phylogenetic clade (“clade code”) and geographic locality (“geocode”) information. A data analysis pipeline has been produced to efficiently generate summary statistics for particular groups of taxa, geographic regions and/or phylogenetic clades.

 

During the workshop a considerable amount of time was spent discussing how best to synthesise the large amounts of data and to address the main aims of the project – to identify taxa and regions that have experienced common histories of contraction/expansion or persistence, to identify congruent patterns in the timing of population contraction/expansion and to identify ecological/biological features of taxa/regions showing congruent patterns.

 

The final stages of data analysis are now underway and progress has been boosted by funding from an ARC Discovery Project. Our group now has funding for three years and a dedicated post-doctoral research associate to finalise the analysis of the current data and to gather additional high resolution genetic information.

 

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Impacts of Climate Change on Endemics WS2 Left to right: Mike Hickerson (City College of New York, USA), Steve Donnellan (South Australian Museum), Alan Cooper (University of Adelaide), Marc Suchard (University of California, Los Angeles, USA), Jeremy Austin and Vicki Thompson (both University of Adelaide), Margaret Byrne (WA Department of Environment and Conservation) and Julian Soubrier (University of Adelaide).
Absent from photo: Corey Bradshaw (University of Adelaide) and Craig Moritz (Australian National University).

 

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Last Updated on Sunday, 08 February 2015 15:46