Climate change is widely accepted as one of the worst threat to the world’s biodiversity. A
recently proposed solution to help species survive climate change is “assisted colonisation”,
i.e. translocations of species to more suitable sites. Although assisted colonisation could be
a powerful conservation tool, translocations are known to have a low success rate despite
being commonly-used. Before promoting assisted colonisation as a solution, we need to
make two major advances: first, understand how translocated species will respond to a
changing climate and if their population viability will be compromised and, second, develop
a quantitative framework to improve the success rates of conservation translocation under
global environmental change. Those were the two aims of my thesis. The hihi (stitchbird;
Notiomystis cincta ) was used as a study species. It has been the subject of several
translocations in the past few decades and every translocated population is intensely
monitored, yielding long-term demographic datasets.
Climate was found to be a key factor in the dynamics of translocated population, and thus
viability. However, it may also interact with other intrinsic factors like density and age to
influence species’ long-term persistence. A stochastic population model built to quantify the
potential impacts of future climate change on translocated populations’ long-term
persistence showed the importance of taking into account the impact of longer and more
frequent extreme weather on translocated population’s viability. Moreover, MaxEnt was
found to be a good habitat suitability model for translocated populations and used to
identify future translocation sites for the hihi under climate change. Finally, quantitative
guidelines for the planning and implementation of assisted colonisations were developed.
They address the known issues impeding translocation success, and, if used, will maximise
the success of assisted colonisations.