The Environment Institute
                    Where ideas grow




   Dr Melanie Lancaster
   Pines and paddocks: Socioeco...
Pines and paddocks: Socio-ecology and
   population genetics of marsupials
in fragmented south-eastern Australia

        ...
Molecular Ecology
        INDIVIDUAL            POPULATION                SPECIES


      Use of genetic tools to answer e...
Background (mine)
                       PhD research
• Small population of fur seals on Macquarie Island
• Suspected inte...
PhD research – species identification
                                                Genetic screening of individuals =>
...
PhD research – mating systems




      Genetic analysis of paternity =>
         identify fitness cost to
               ...
Molecular Ecology
          INDIVIDUAL              POPULATION                     SPECIES

    Use of genetic tools to an...
Forest Fragmentation
         • Deforestation as old as the human
         occupation of the earth (Williams 2003)

      ...
Fragmentation in Australia




  Source: http://adl.brs.gov.au/anrdl/metadata/overviews/alccdr9ab__004/alccdr9ab__00411a10...
SA - the Lower South-East
           Pre-European Settlement
           • Flora diverse
           • E. baxteri and E. vim...
Study site
The “Greater Green Triangle” region…when green is bad

• Largest wood fibre producing region in Australia
• Dry...
Mammal species

Arboreal and terrestrial
   Sugar gliders, yellow-bellied gliders, Common brushtail and
     ringtail poss...
Consequences of fragmentation
Populations may become isolated if:
•   Distances between fragments too great to traverse
• ...
ARC Linkage
Conservation genetics and socio-ecology of marsupials
   in fragmented populations of south-eastern South
    ...
Fragmentation case studies
Factors affecting population connectivity in fragmented
   landscapes:
       •   Age of regrow...
Common ringtail possum
• Nocturnal arboreal marsupial
• Broad distribution, abundant in a variety of forest habitats
• Gen...
Study site


                                    10             23

                         11
                          ...
Data collection
      Site selection based on:

      • patch size
      • distance to neighbouring patch (0.5-
      >10 ...
1. Genetic Diversity
Have possums in patches retained
   genetic diversity?




                                   •   HH ...
2. Population structure
    Do possums move through the pine?

•    Five distinct clusters identified from 8 populations
 ...
2. Population structure
Do possums move through paddocks
   and roadside vegetation?



  8 distinct genetic clusters
  id...
Pop Differentiation
      HH          HS          L           P          REN      SG          W          WD
HH
HS         ...
Dispersal patterns

• Mammalian patterns of dispersal
   – Sex-biased
   – Males disperse as juveniles or young adults
   ...
PINE                                                                      PADDOCKS
                                       ...
Summary
• Intervening matrices appear to hinder dispersal and gene flow of
  possums
   – Less problematic in larger patch...
Recommendations and What next?

    – Modelling – which factors affect connectivity – position/distance/
      size of pat...
Acknowledgements

Field volunteers for valuable       Australian Research Council Linkage
assistance with possuming       ...
The Environment Institute
                        Where ideas grow




   Next Seminar: 27 November

   Professor Kym Ande...
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Pines and paddocks: socioecology and population genetics of marsupials in fragmented systems

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The eleventh installment of the 2009 Science Seminar Series presented by Doctor Melanie Lancaster. The presentation is entitled "Pines and paddocks: socioecology and population genetics of marsupials in fragmented systems?"

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Pines and paddocks: socioecology and population genetics of marsupials in fragmented systems

  1. 1. The Environment Institute Where ideas grow Dr Melanie Lancaster Pines and paddocks: Socioecology and population genetics of marsupials in fragmented systems
  2. 2. Pines and paddocks: Socio-ecology and population genetics of marsupials in fragmented south-eastern Australia Melanie Lancaster Earth and Environmental Sciences The University of Adelaide Steven J.B. Cooper, Susan Carthew, Andrea C. Taylor
  3. 3. Molecular Ecology INDIVIDUAL POPULATION SPECIES Use of genetic tools to answer ecologically important questions Identification of individuals to a source population Population processes: migration, dispersal (ie. juvenile, sex-biased), GENE FLOW Social structure: Mating systems, site fidelity, mate fidelity Predict species responses to environmental changes, human impacts, etc.
  4. 4. Background (mine) PhD research • Small population of fur seals on Macquarie Island • Suspected interbreeding among three species – Different recolonisation histories • Tissue samples collected from entire pup cohorts between 1992 and 2003 • Extensive observational data – territory locations, pupping sites • Species composition of the population • Hybrids? • Costs of hybridisation?
  5. 5. PhD research – species identification Genetic screening of individuals => 70 identification to a source species or hybrid class 60 50 % PUPS 40 30 20 10 0 1992 1994 1996 1998 2000 2002 YEAR Lancaster et al. (2006) Molecular Ecology
  6. 6. PhD research – mating systems Genetic analysis of paternity => identify fitness cost to hybridisation Lancaster et al. (2007) Molecular Ecology
  7. 7. Molecular Ecology INDIVIDUAL POPULATION SPECIES Use of genetic tools to answer ecologically important questions Identification of individuals to a source population Population processes: migration, dispersal (ie. juvenile, sex-biased), GENE FLOW Social structure: Mating systems, site fidelity, mate fidelity Predict species responses to environmental changes, human impacts, etc.
  8. 8. Forest Fragmentation • Deforestation as old as the human occupation of the earth (Williams 2003) • Process has affected more of the earth’s surface Laurance and Beirregaard 1997: • Preserve what we have • Plan the future landscape • Manage what is left Species ecology Multi-species approaches
  9. 9. Fragmentation in Australia Source: http://adl.brs.gov.au/anrdl/metadata/overviews/alccdr9ab__004/alccdr9ab__00411a10b.pdf
  10. 10. SA - the Lower South-East Pre-European Settlement • Flora diverse • E. baxteri and E. viminalis forests and woodlands dominated Post-Settlement • Large areas cleared after WWII for softwood and agricultural land • 13 % native vegetation remains • Vegetation community composition changed • Remaining veg adapted to poor soils and poor drainage, incomplete representation • Remnants surrounded by cropland, pastures, pines • Habitats that once supported native fauna may no longer be present
  11. 11. Study site The “Greater Green Triangle” region…when green is bad • Largest wood fibre producing region in Australia • Dry, sclerophyll forests isolated by pine stands of various ages
  12. 12. Mammal species Arboreal and terrestrial Sugar gliders, yellow-bellied gliders, Common brushtail and ringtail possums, microbats Native rats, mice, southern brown bandicoot, yellow-footed Antechinus, wallabies (swamp, red-necked), kangaroos, wombats, echidnas
  13. 13. Consequences of fragmentation Populations may become isolated if: • Distances between fragments too great to traverse • Surrounding habitat too difficult to move through, acts as a barrier to dispersal Individuals within populations do not move out of patch • Populations become isolated over time and genetically differentiated from each other • Within patches, results in increased relatedness, inbreeding, loss of genetic diversity Dispersal = ?gene flow No dispersal = NO gene flow To assess the impacts of forest fragmentation on population processes in key marsupial species
  14. 14. ARC Linkage Conservation genetics and socio-ecology of marsupials in fragmented populations of south-eastern South Australia: towards a regional biodiversity management plan A/Prof Sue Carthew, Dr Steve Cooper, Dr Andrea Taylor PARTNERS: To assess the impacts of forest fragmentation on population processes in key marsupial species
  15. 15. Fragmentation case studies Factors affecting population connectivity in fragmented landscapes: • Age of regrowth forest • Surrounding matrix • Habitat shape, edge effects • Lemurs, bird spp., gorillas, pademelons, bats, reptiles, frogs Sugar gliders (Mansoureh Malekien) • Restricted gene flow among some patches • Effects greater in small patches isolated by pine • Evidence for inbreeding in one patch from parentage analysis Yellow-footed antechinus (Amanda McLean) • Some evidence of differentiation between populations • Higher relatedness among females within patches than in continuous forest
  16. 16. Common ringtail possum • Nocturnal arboreal marsupial • Broad distribution, abundant in a variety of forest habitats • Generalist herbivore – leaves, flowers, seeds of eucalypt spp., acacia spp. • Can build dreys • Survives in degraded habitats, found in fragmented landscapes
  17. 17. Study site 10 23 11 21 18 30 10 35 23 20 47 7 23 15 78 43 74
  18. 18. Data collection Site selection based on: • patch size • distance to neighbouring patch (0.5- >10 km) • 3 sites within continuous forest (distances between sites comparable) • 251 possums patches within pine • 189 possums patches within agriculture • 48 from 3 continuous forest sites • Genotyped at 15 microsatellites • Analysed for genetic diversity and genetic differentiation
  19. 19. 1. Genetic Diversity Have possums in patches retained genetic diversity? • HH and L sig. Lower allelic richness and heterozygosity • Larger patches levels comparable to continuous forest • Trend towards lower H and AR in ag patches YES for some, NO for others, not related to patch size alone
  20. 20. 2. Population structure Do possums move through the pine? • Five distinct clusters identified from 8 populations sampled  • No sub-structure within continuous forest  • HH and L genetically isolated  • P a subset of continuous forest  • SG, W and HS virtually same cluster membership  Yes, but pine hinders dispersal and gene flow Less dispersal into small, isolated patches
  21. 21. 2. Population structure Do possums move through paddocks and roadside vegetation? 8 distinct genetic clusters identified Significant pop structure and isolation Limited evidence of gene flow/dispersal
  22. 22. Pop Differentiation HH HS L P REN SG W WD HH HS 0.05 L 0.19 0.12 P 0.11 0.03 0.17 REN 0.10 0.03 0.13 0.00 SG 0.08 0.03 0.12 0.03 0.04 W 0.06 0.04 0.14 0.05 0.07 0.04 WD 0.09 0.02 0.13 0.02 0.02 0.03 0.05 BG G HC M PS RR SQ REN BG G 0.08 HC 0.08 0.07 Population pair-wise FST shows all M 0.06 0.04 0.08 pops except P and R as significantly PS 0.04 0.08 0.11 0.05 RR 0.08 0.11 0.09 0.08 0.09 different (most p < 0.0001) SQ 0.07 0.05 0.07 0.02 0.06 0.07 REN 0.03 0.04 0.06 0.03 0.04 0.05 0.03 Patches vs Continuous R1 R2 R3 No sig difference between R1 and R2 R1 0.12 <0.0001 (2.5 km) R2 0.007 <0.01 Sig. Differentiation of R3 from other R3 0.038 0.033 patches (3 km)
  23. 23. Dispersal patterns • Mammalian patterns of dispersal – Sex-biased – Males disperse as juveniles or young adults – Females philopatric • In fragmented landscapes these patterns may be disrupted if movement is inhibited • Use genetic relatedness to look at patterns
  24. 24. PINE PADDOCKS P and SG not sig Males Males 0.600 0.300 0.400 0.200 0.100 0.200 Mean 0.000 r 0.000 U -0.100 -0.200 L -0.200 -0.400 BG G HC M PS RR SQ HH HS L P SG W WD Females Females 0.800 0.300 0.600 0.200 0.400 0.100 r 0.200 0.000 0.000 -0.100 -0.200 -0.200 HH HS L P SG W WD BG G HC Patch M PS RR SQ Patch Continuous Forest All others sig. higher relatedness than 0.300 0.200 expected by chance 0.100 Mean Both sexes show this trend r 0.000 U -0.100 L -0.200 R1 M R2 M R3 M R1 F R2 F R3 F cf continuous forest neither females or Patch males show this pattern
  25. 25. Summary • Intervening matrices appear to hinder dispersal and gene flow of possums – Less problematic in larger patches than smaller ones – Larger patches have comparable genetic diversity to continuous forest – Smaller patches HH and L show signatures of genetic isolation through low heterozygosity and lower allelic diversity. • Findings of lower dispersal in both sexes in fragments important implications for social structure and mating system • Pastoral land has greater impact on ringtail possums – Depend on several factors • Patch size • Age of pine • Distance to neighbouring patch • Time since isolation
  26. 26. Recommendations and What next? – Modelling – which factors affect connectivity – position/distance/ size of patch but need to quantify – Incorporate landscape features – roadside vegetation, plantations, grazed remnant vegetation. Circuitscape (uses algorithms from electronic circuit theory to predict patterns of dispersal) – Incorporate more species • Corridors to join patches on the periphery of landscapes • Multiple potential sources of immigration important for genetic diversity • Continued conservation of large patches that can support viable populations to maintain remaining communities
  27. 27. Acknowledgements Field volunteers for valuable Australian Research Council Linkage assistance with possuming Grants Scheme, with partners: • Department for the Environment and Heritage Martin Pepper for providing • Forestry SA photographs • Hancock Victorian Plantations • Nature Foundation of South Kathy Saint for assistance Australia with microsatellite development • South Australian Museum
  28. 28. The Environment Institute Where ideas grow Next Seminar: 27 November Professor Kym Anderson Regional implications of climate change for the Australian wine industry

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