Consistency, continuity and creativity: long-term studies of population dynamics on Tiritiri Matangi Island

One of the quandaries faced by ecological researchers is whether they should continue to invest in ongoing projects or whether they should shift their attention to new species or systems that may have received less attention. While research on Tiritiri Matangi has touched on a wide range of species and topics, the long-term projects on the reintroduced robin population (20 years) and hihi population (17 years) have accounted for the bulk of the published research, with 57 papers featuring these populations published to the end of 2009. This literature has made contributions to several disciplines (wildlife management, population ecology, behavioural ecology, conservation genetics, ornithology and wildlife disease) at both the local and international level. However, most of these published papers use <5 years of data, so most of the results made possible from the long-term data sets have yet to be published. We illustrate how long-term monitoring has allowed us to continually improve our understanding of the dynamics of these populations, and how this has allowed us to interpret and predict the effects of management. This management includes the 1993 poison drop, follow-up translocations to both populations, food provisioning and mite control for hihi, and most importantly, the ongoing harvesting of both populations for reintroduction to other locations. We are now able to detect complex and subtle processes that required many years of data, and present information on the number of years required to obtain various results. These results are now allowing us to develop long-term models integrating factors such as density-dependent regulation, demographic and environmental stochasticity. These models are not only relevant to the long-term viability and management of Tiritiri Matangi populations, but to small populations worldwide.