Until recently, it was widely believed that individual’s in the wild died before they aged and did not senesce. However, over the last decade it has become apparent that senescence is widespread in the animal kingdom and that senescence rates (including magnitude and fitness consequences) vary among species, populations and individuals (e.g. Jones et al. 2014; Jones et al. 2008; Nussey et al. 2013). Both survival and reproduction decrease with age in birds and mammals. Senescence can therefore have a negative impact on the vital rates that influence population growth and persistence. Management can play a role in regulating some of the effects of senescence in populations of conservation concern by mitigating some of the factors that play a role in mortality in wild populations. For example, via predator and disease control and the provision of food and shelter. There is also strong evidence that conservation management can have a strong impact on senescence dynamics, with captive populations of threatened species having significantly different senescence profiles than their wild counterparts (Lemaître et al. 2013). Despite this, it is only now that the impact of senescence on populations of conservation concern is being explored. A comparative study by Robert et al. (2015) has shown that senescence can negatively impact the dynamics of threatened wild mammal populations and increase the risk of extinction. However, empirical evidence on identity and mechanisms of factors that drive this variation in senescence patterns in threatened populations, and the role of conservation management in regulating this effect are still to emerge.
The proposed project aims to combine environmental, demographic, genetic and life-history data on the long-term reintroduction programme for the New Zealand hihi (Notiomystis cincta) to determine the factors that drive senescence patterns in this species and test, using the establishment history and variation in management strategies, the effects that conservation management has on senescence and its long-term repercussions on population viability. The project will involve field work in New Zealand, lab work in the UK and Bayesian modelling in Denmark.
Policy Impact of Research:
The proposed project will help bridge the gap between evolutionary theory and conservation practice by providing insight into how to incorporate senescence patterns into the management programmes of threatened species to reduce the bias in extinction risk prediction.