While climate change is expected to be the leading cause of extinctions globally into the future, most extinctions will be driven by climate change working synergistically with other ecosystem changes, such as invasion. My research projects broadly circle one theme: how will two independent drivers of global environmental change- climate change and plant invasion- interact, and what impact will this have on the way native ecosystems look and function?
My field work is based in Tongariro National Park, in New Zealand. The park harbours a variety of indigenous plant species, and many subspecies which occur exclusively within the Central Volcanic Plateau region. This unique and charismatic landscape is undergoing change as a result of a warming climate. Simultaneously, European heather (Calluna vulgaris) is aggressively invading the Park. Management strategies targeted at conserving species are likely to under-represent risk if they fail to incorporate the complex interactive effects of these two drivers of environmental change. I hope that my research will contribute to both global ecological knowledge and provide applied information towards the conservation of this treasured landscape.
Species distribution models are increasingly used as a management tool: they great potential to show us where species will be limited by the climate as global temperatures soar. However, these models often do not include species interaction, like those with invaders. The vigour of invasive plants, as well as the geographic space they occupy, is likely to change with the climate. This affects the persistence of the indigenous species they coexist with. How do invasion and climate change work together to affect species' distributions in the landscape? I use elevational gradients, which I feed into climate envelope models to investigate this question.
Our species distribution modelling project is being done in collaboration with local iwi and government, to ensure the conservation of not only ecologically, but also culturally important species. For more about this project take a look at "The Future of Our Taonga Tipu"
Invasions of novel plant species can endanger the reproduction of indigenous plant species. Particularly in alpine ecosystems, pollinators are limited and plants often compete with one another for crucial pollination services. Invasive plant species, particularly high flower bearing ones with easily accessible rewards for pollinators can interrupt native plant-pollinator mutualisms. Such invasive plants can cause landscape-scale re-distributions of insect activity. Decreased pollination resulting from competition for pollination with invasives may result in reduced sexual reproduction for the native community. Simultaneously, changing temperatures change the phenology of both invasive and native species. Under future climatic warming, different species will contemporaneously flower. This means that some plant species which currently do not compete for pollinators with heather will do so in the future. What effect will the climate induced competition for pollination with a novel species affect sexual reproduction of natives?
In an experiment I run with Julie Deslippe and Aimee Classen, I use open top chambers to manipulate temperatures and probe species' phenological changes. I match this work with pollen limitation studies to investigate pollination in a changing world.
School of Biological Sciences
Room KK 507
New Kirk Building
Victoria University of Wellington