PROF Roger Cousens

PROF Roger Cousens


  • Application of ecology to management decisions
  • Historic botanic gardens of Victoria
  • Invasions & Biosecurity (coastal weeds, alpine weeds)
  • Plant Ecology (weeds, population dynamics, dispersal)
  • Plant invasions
  • Plant population biology



  • As a plant population ecologist, I am interested in the processes that determine abundance and distribution of plant species and genotypes. Through experimentation, survey, sampling, laboratory analysis and modelling, we are able to predict how abundance and distribution change under different conditions and hence what action we might take to manage populations. This same research philosophy applies to rare species requiring conservation, to invasive species requiring eradication or containment, or to abundant weeds that require control. I have written academic books on Population Dynamics of Weeds (with Martin Mortimer) and Dispersal in Plants: A Population Perspective (with Calvin Dytham and Richard Law); I was also part of the team that wrote the identification book Western Weeds: A Guide to The Weeds of Western Australia. Over 35+ years, my interests have moved from seaweeds, to weeds of agricultural systems and now to the geographic and local dynamics of alien plants and their post-invasion adaptation.

    The main focus of my research group is currently the invasion of Australian coastlines by two sea rockets, one from Europe and N. Africa (Cakile maritima), the other from eastern N. America (C. edentula). In a way analogous to the spread of modern man into regions occupied by Neanderthals, the European species has spread into parts of Australia pre-invaded by the N. American species. As the European species spread, C. edentula was eliminated. Sara Ohadi (PhD student, with Peter Ades and Josquin Tibbits) has uncovered multiple introductions of the European species and bi-directional hybridisation between the two species and introgression from C. edentula into C. maritima. There is still much to do to determine why C. edentula is being displaced, but we have lots of hypotheses to test! Our early work on the two species led to the hypothesis that an obligately out-breeding species (such as C. maritima) could overcome this handicap a   


Member of

  • Ecological Society of Australia. Ordinary 1992 -
  • British Ecological Society. Ordinary 1980 -


Selected publications


Investigator on


Education and training

  • BSc, Dalhousie University 1981
  • PhD, Wales 1978

Awards and honors

  • Honorary member, Weed Science Society of America, 2011



Available for supervision

  • Y

Supervision Statement

  • I am always looking for students with good ideas, numeracy, logic, writing ability , passion for ecology/evolution and a sense of humour, even if they have not studied invasions before.  In my research group we have fun while working hard and at high standards.  A population ecology, evolutionary ecology or bioinformatics background is desirable.  

    I need postgraduate students to work on the pollination ecology of invasive sea rockets, evolution of adaptation to climate in invasive species and their physiological ecology in relation to climate.  Or other ideas that overlap with my interests.