Dr Melanie Massaro - Research
A. Evolutionary changes in behavioural and life-history traits in native New Zealand birds since the introduction of mammalian predators
 |
The introduction of predatory mammals, such as rats, cats and stoats, to oceanic islands has led to the extinction of many endemic island birds, and exotic predators continue to threaten the survival of 25% of all globally, endangered bird species. The impact of exotic predators on the native birds of oceanic islands is particularly profound because island birds evolved largely in the absence of these predators and appear naïve towards newly introduced mammals. In addition, introduced predators must be exerting intense selective pressure on remnant native bird populations in areas where native birds are still exposed to these predators. Such intense selective pressure is expected to favour the emergence and spread of behavioural and life-history traits that confer protection from predation.
 |
For my post-doctoral research, which is funded by the Foundation for Research, Science and Technology (http://www.frst.govt.nz), I investigate whether the novel predation risk imposed by introduced mammalian predators has altered parental behaviour and life history traits of endemic New Zealand birds by comparing populations in several native forest sites that differ in predation risk due to the presence or absence of exotic predators. In collaboration with Assoc. Prof. Jim Briskie (University of Canterbury) and Prof. Tom Martin (University of Montana), I am also comparing behavioural and life history traits of New Zealand birds with those of closely related species in Tasmania, Australia that evolved with native nest predators. This research is aimed at understanding to what extent and how rapidly these behavioural and life-history traits can change due to the selective pressure of mammalian predation and, ultimately, at integrating evolutionary concepts into management and conservation efforts.
 |
In a recent study on the endemic New Zealand bellbird (see publications for more details), my colleagues and I have shown for the first time that a previously naïve species of island bird has the ability to change its nesting behaviour in response to the introduction of a large suite of exotic mammalian predators to New Zealand. It demonstrates that such species are not necessarily “trapped” by their evolutionary history as is generally considered to be the case, but they, in fact, have the ability to change their behaviours in ways that appear adaptive. More importantly, this study demonstrates that such a change can occur over an ecologically relevant time-scale of years and not centuries.
 |
B. Plasticity in foraging behaviour of Adélie penguins: are they able to cope with climate-induced changes to the marine environment
 |
Most studies addressing the impact of climate change on marine vertebrates have focused almost exclusively on links between climate variability and demographic parameters of species. While these studies have demonstrated that climate factors importantly affect population trends, the biological mechanisms underlying such declines occur on an individual level, as it is the individual animal that must deal with changing environmental conditions. The inability of an individual to adjust to changes in resource availability caused by climate variability will proximately lead to low reproductive success and/or low adult survival. Thus, studying inter-individual differences in physiological parameters in relation to foraging behaviour and breeding success is the key to understanding plasticity of behaviour that might allow these marine predators to cope with environmental changes.
 |
This NSF-funded research on Adélie penguins is conducted in collaboration with Dr Amélie Lescroël (Centre d'Etudes Biologiques de Chizé, France), Dr David Ainley (HT Harvey & Associates,USA, www.penguinscience.com) and Dr Phil Lyver (Landcare Research, New Zealand). In the 2007/2008 Antarctic season, I studied Adélie penguins at Cape Bird on Ross Island to investigate the physiological constraints that might impact foraging success of Adélie penguins in Antarctica in years of low food availability.