Using a possum’s parentage to predict possible pathways across landscapes

SCHOOL OF ENVIRONMENT

Using a possum’s parentage to predict possible pathways across landscapes

Thomas R. Etherington

SCHOOL OF ENVIRONMENT · Geography

Invasive spread in New Zealand

adapted from King (2005)

Red Deer(Cervus elaphus)

Brushtail Possum(Trichosurus vulpecula)

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Patch-matrix landscape dispersal

?

?

?

?

?

?

?

?

Year 1Year 2Year 3Year 4

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Matrix compositionHomogenous

Heterogeneous

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Friction surface

Forest

Grass

Rock

Water

Landscape

1

10

100

1000

Cost

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Least-cost paths

1

10

100

1000

Cost

Start point

End point

Least-cost pathway

a b

c

cd bc = D bc ×C b + C c

2

cd ab = D ab × C a + C b

2

LCP ac = cd ab + cd bc

(D = distance, C = cost)

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Least-cost spread

from Lockwood et al. (2007)

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Connectivity and Relatedness

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?

?

?

??

?

?

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Hawke’s Bay Possum Genetics

from Cowan et al. (2006)

Geneti

c d

ista

nce

Geneti

c d

ista

nce

Euclidean distance (m)

Euclidean distance (m)

Separated by a river

Not separated by

a river

SCHOOL OF ENVIRONMENT · Geography

Hawke’s Bay Possum Genetics

10 Kilometres

N

Wide river

Genetic distance

High

Low

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Acknowledgements