Invasive species adaptation and hybrid speciation

Andrew Lowe | Peter Prentis | Eleanor Dormontt 

As invasive weeds affect both agricultural and native ecosystems equally, research to understand the mechanisms of weed invasion is critical.  Only a small proportion of introduced plants become significant weeds and why this should be is unclear.

Current Research Projects

Using the important east-coast weed, Senecio madagascariensis (fireweed), as our model, we are testing different demographic and genetic hypotheses as to why some plants become weeds. This project specifically tests alternative hypotheses about how weeds have become invasive. 

Four hypotheses are being formally tested as part of the project

1. the influence of admixture of source ranges on invasion potential is being tested by ascertaining the geographic and temporal introduction sequence of South African source(s) of fireweed into Australia.
2. the potential influence of hybridisation with Australian native species as a an evolutionary fast-track mechanism to introduce adaptive variation.
3. the potential for regulatory and rapid genomic adaptation and selective changes between invasive and native range material.
4. the potential for a demographic expansion only scenario and the potential for recent bioclimatic adaptive shift is being tested.

Funding:
Richardson DM; Lowe AJ, and 6 others (2007) Research for integrated management of invasive alien species; Using genetic techniques to improve understanding and management of invasive alien plant species in South Africa. Working for Water Programme, South African Government (South African R 1.4 M ~ $200K).

Lowe AJ, et al (2006) Why do some exotics become invasive? Using ecological and genomic approaches to test alternative hypotheses in an Australian weed, fireweed. ARC Discovery ($561K).

Lowe AJ (2006) Phylogeography and genetic identity of bEleanorache bush in its native and introduced ranges. Department of Natural Resources, Mines and Water ($50 K).

Relevant publications:
Wilson JRU, Dormontt EE, Prentis PJ, Lowe AJ, Richardson DM (2009) Something in the way you move: dispersal pathways affect invasion success. Trends in Ecology & Evolution 24: 136-144.

Prentis P, Dormontt E, Wilson A, Richardson D, Lowe AJ (2008) Adaptive evolution in invasive species. Trends in Plant Sciences 13: 288-294.

Kang M, Buckley Y, Lowe AJ (2007) Testing the role of genetic factors across multiple independent invasions of the shrub Scotch broom (Cytisus scoparius). Molecular Ecology. 16: 4662-4673.

Prentis P, White EM, Lowe AJ, Clarke AR. (2007) Can hybridization cause local extinction: a case for demographic swamping of the Australian native Senecio pinnatifolius by the invasive Senecio madagascariensis? New Phytologist 176: 902-912.

Abbott RJ, Lowe AJ (2004) Origins, establishment and evolution of two new polyploid species of Senecio in the British Isles. Biological Journal of the Linnean Society. 82: 467-474.

Lowe AJ, Abbott RJ (2004) Reproductive isolation of a new hybrid species, Senecio eboracensis. Heredity. 92: 386-395.