Bovine TB Persistence in Low-Density Possum Populations – The Patchiness Problem

Reasons for the maintenance of bovine Tb in post-control brushtail possum populations are unclear, although crowding of residual possums on a local scale is frequently correlated with higher prevalence of the disease. Three key density characteristics of post-control possum populations that may contribute to Tb persistence are (1) the threshold density above which Tb will be maintained if the population is uniformly distributed within a controlled area, (2) the variation between patchiness across the landscape of survivors and the low-density, uniform distribution required for Tb to die out, and (3) the changes in patchiness over time, as patches of survivors increase to exceed the density threshold more rapidly than the wider population. We investigated the hypothesis that persistence of Tb in residual possum populations is influenced by their non-random (patchy) distribution. Our investigation confirmed that Tb in post-control possum populations is typically associated with patches of higher-than-average residual possum density, and provided some support for two of the three density characteristics argued to contribute to Tb persisting in residual possum populations.

Author Coleman, J. and Fraser, W.
Date 2005-05-02
Year 2005
Secondary title 13th Australasian Vertebrate Pest Conference
Place published Wellington, NZ
Publisher Landcare Research
Pages 81-87
Region NZ
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