Research

Animal Behaviour - The New Zealand robin is one of only a few food hoarding birds in the Southern Hemisphere. Although this behaviour may seem inconsequential, experiments on food hoarding animals in the Northern Hemisphere have played a pivotal role in what we know about how animal think. New Zealand robins are also unique because they are fearlessness of humans and wild birds can be fed by hand. In collaboration with Jason Low (School of Psychology, Victoria University) we are conducting long-term field experiments on a colour banded population in the Karori Wildlife Sanctuary to better understand their spatial memory and numerical sense.

Plant Form and Function - Most research on biological diversity focuses on species number. However, there are many other types of biological diversity. For example, leaves come in a bewildering array of sizes, shapes and colours. Plant morphological diversity is especially pronounced in New Zealand, where many native plants exhibit radical changes in morphology during ontogeny, which is referred to as heteroblasty. We are currently testing whether heteroblasty is a common feature of other isolated islands and if plants evolve in repeated ways after colonising New Zealand’s satellite islands. I have also been following the masting cycles of Dysoxylem spectabile in Otari-Wilton’s Bush since 2002, in an attempt to better understand the adaptive significance of inter-annual variability in reproductive effort.

Plant-Animal Interactions - Many New Zealand birds interact with plants as both pollinators and seed dispersers. In 2005, I began bi-weekly foraging observations of New Zealand birds in the Karori Sanctuary to investigate: 1) the architecture of pollination and seed dispersal networks, 2) how the colours of flowers and fruits help attract pollinators and frugivores and 3) long-term phenological cycles of flowers and fruits. We are also investigating the evolutionary consequences of seed dispersal by weta, which are group of giant, flightless crickets that are endemic to New Zealand.

Island Biology - Since 2004, I have been censusing plant communities on small islands offshore of the Wellington coast, to investigate species turnover (i.e. successive colonisation and extinction of island populations). Using a network approach I am also investigating the distribution of epiphytes and mistletoes among isolated host trees, which are function as ‘islands’ to arboreal plants.