Can dietary specialization be used for conservation? Foraging and ecological restoration by hihi (Notiomystis cincta)

Abstract

While it is now widely acknowledged that individuals within species behave differently even when faced with similar environmental challenges, few studies have identified how this variation arises and what impacts it has on the environment itself. This is critical to consider given that the ecosystems species inhabit are often under threat. The hihi (Notiomystis cincta), a threatened New Zealand passerine and important pollinator of native plants, provides an excellent model for investigating the causes and consequences of specialization through the lens of foraging. Following near-extinction around 1890, hihi have been reintroduced to several island and mainland sites, but habitat suitability has proved a major barrier to establishing self-sustaining populations. Here, we consider how we can increase the restorative effects of translocations by selecting individuals based on foraging traits that will i) increase their likelihood of survival and ii) promote ecosystem processes such as pollination. We tested these ideas by tracking a hihi cohort as individuals either remained on their natal island or were translocated to a novel site with more mature forest structure and less intense competition. As a whole, the translocated group broadened its diet, but individuals differed in their dietary shifts. We examine the consequences of preexisting dietary preferences for these individuals and use preliminary data on pollination-related trait variation among hihi to discuss the lasting effects a founder population can have on its habitat.