Spatial and temporal synchrony in small mammal populations: the role of intrinsic and extrinsic

factors

Aaron C. Greenville, Glenda M. Wardle and Chris R. DickmanDesert Ecology Research Group

School of Biological SciencesUniversity of Sydney

@AarontheEcolog

Spatial dynamics

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i = growth rate

Time

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Introduction Methods Results Conclusion

Moran effect

Introduction Methods Results Conclusion

Aims

1. Spatial structure of small mammal populations

– Moran effect?

2. Density dependence and extrinsic factors

Introduction Methods Results Conclusion

Study species

Photo by Bobby Tamayo

Sandy inland mouse, Ps. hermannsburgensis, 12 g

Lesser hairy-footed dunnart, Sminthopsis youngsoni, 10 g

Mulgara, Dasycercus blythi, 100 g

Ningaui, Ningaui ridei, 8 g

Dasyurid marsupials:

Rodents:

Introduction Methods Results Conclusion

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• Asynchronous• Oasis• Wildfire• Productivity• Synchronous

• Multivariate autoregressive state-space (MARSS) models

1. Spatial structure

Introduction Methods Results Conclusion

2. Covariates

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Introduction Methods Results Conclusion

Results:

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Results:

Introduction Methods Results Conclusion

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01234

0 20 40 60 80 100 120

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Trips

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log)

Photo by Bobby Tamayo

Sandy inland mouse, Ps. hermannsburgensis, 12 g

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Results:

Introduction Methods Results Conclusion

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Introduction Methods Results Conclusion

0 40 80 120

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Main Camp

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Carlo

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0.0

1.5

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Field River South

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0.0

1.5

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South Site

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0.0

1.5

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Kunnamuka Swamp East

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0.0

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Shitty Site

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Tobermorey East

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Field River North

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Tobermorey West

Trips

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Introduction Methods Results Conclusion

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0 20 60 100

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Main Camp

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0.0

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Carlo

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2.0

Field River South

0 20 60 100

0.0

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South Site

0 20 60 100

0.0

1.0

2.0

Kunnamuka Swamp East

0 20 60 100

0.0

1.0

2.0

Shitty Site

0 20 60 100

0.0

1.0

2.0

Tobermorey East

0 20 60 100

0.0

1.0

2.0

Field River North

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0.0

1.0

2.0

Tobermorey West

Trips

Abun

danc

e (lo

g)

Photo by Bobby Tamayo

Sandy inland mouse, Ps. hermannsburgensis, 12 g

0.29 (0.07, 0.5)

0.25 (0.07, 0.44)

0.53 (0.28, 0.77)

0.23 (0.05, 0.42)

0.38 (0.13, 0.63)

0.16 (0.29, 0.03)

0.27 (0.44, 0.1)

Introduction Methods Results Conclusion

Extrinsic factors:

0.19 (0.05, 0.33)

0.26 (0.11, 0.41)

1.79 (0.46, 3.12)

0.05 (0.002, 0.09)

0.1 (0.01, 0.05)

Introduction Methods Results Conclusion

Extrinsic factors:

Conclusion• Moran effect present for rodents -synchronous

– Landscape-scale– Density dependency

• Mulgara similar to their prey + wildfire– Landscape-scale– Density dependency

• Insectivorous dasyurids – asynchronous– Local-scale– Weak density dependency

• ManagementIntroduction Methods Results Conclusion

Acknowledgements• Bobby Tamayo and the DERG team.• All our volunteers.• Bush Heritage Australia.• Bedourie Hotel.• ARC, APA and Paddy Pallin Science Grant.

Volunteer info: http://bit.ly/1fxVOhH

For more: www.AarontheEcolog.wordpress.com

@AarontheEcolog