Current Research in the Comparative Ecology Group, Macquarie University

Much of the research in the lab is funded by ARC grants to Mark Westoby. In general, we are identifying leading dimensions of ecological variation among plant species and working towards understanding the basis for them. Four dimensions are of particular interest. Since the early 1990s, much of our work has centred around seed mass. The seed mass-seed output dimension is an important predictor of dispersal to establishment opportunities (seed output), and of establishment success in face of hazards (seed mass). Angela Moles (PhD 2000-2003) is studying seed mass distributions and factors shaping it at a community level.

The leaf mass per area - leaf lifespan (LMA-LL) dimension describes variation in the rate of turnover of plant parts, length of nutrient residence times and rate of response to favorable growth conditions. Since 1996 we have examined various aspects of leaf economics in eastern Australia, i.e. on the costs and benefits of higher vs lower LL and LMA, on their correlation with other plant traits, and with variation between and within vegetation types. Ian Wright (post-doc from 2001) has been extending this work to global scale by compiling multi-species datasets to test whether leaf trait combinations shift predictably with environmental factors. This project is known as "GloPNet" (Global Plant Trait Network). It is a collaborative project with Peter Reich (U. Minnesota) and others.

The twig size-leaf size spectrum has obvious consequences for the texture of canopies, but the costs and benefits of large vs small leaf and twig size remain unclear. Since 2000 we have begun looking at various aspects of this spectrum (see our publication list).

Another, rather complex, dimension of variation is plant height. Daniel Falster has been investigating the relationship between species maximum height and properties of the stem and leaves, asking whether height is correlated with other growth-traits of species, namely the pace of height growth, stem persistence and shade tolerance.

Other members of the group are also working in areas related to comparative ecology. Huw Morgan (PhD from 2000 on) studies plant responses to rainfall, comparing root and shoot traits and how they fit together to describe a 'response strategy'. Barbara Rice works on the spinifexes or hummock grasses (Triodia and Plectrachne) that dominate much of inland Australia. She is interested in regeneration after fire and pollination biology. She has also been setting up a public access phenology database for Australia, called Biowatch.

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(Last updated May 2003)