Partitioning of nectar resources by New Zealand honeyeaters

Evaluating the success of functional restoration after reintroduction of a lost avian pollinator

Conservation translocation is a common method for species recovery, for which one increasingly frequent objective is restoring lost ecological functions to promote ecosystem recovery. However, few conservation translocation programs explicitly state or monitor function as an objective, limiting the ability to test assumptions, learn from past efforts, and improve management. We evaluated whether translocations of hihi (Notiomystis cincta), a threatened New Zealand passerine, achieved their implicit objective of restoring lost pollination function. Through a pollinator-exclusion experiment, we quantified, with log response ratios (lnR), the effects of birds on fruit set and seed quality in hangehange (Geniostoma ligustrifolium), a native flowering shrub. We isolated the contributions of hihi by making comparisons across sites with and without hihi. Birds improved fruit set more at sites without hihi (lnR = 1.27) than sites with hihi (lnR = 0.50), suggesting other avian pollinators compensated for and even exceeded hihi contributions to fruit set. Although birds improved seed germination only at hihi sites (lnR = 0.22-0.41), plants at sites without hihi had germination rates similar to hihi sites because they produced 26% more filled seeds, regardless of pollination condition. Therefore, although our results showed hihi improved seed quality, they also highlighted the complexity of ecological functions. When an important species is lost, ecosystems may be able to achieve similar function through different means. Our results underscore the importance of stating and monitoring the ecological benefits of conservation translocations when functional restoration is a motivation to ensure these programs are achieving their objectives.

Floater males gain reproductive success through extrapair fertilizations in the stitchbird

We used minisatellite DNA profiling to assign parentage to stitchbird, Notiomystis cincta, chicks from a breeding population on Tiritiri Matangi Island off the coast of the North Island of New Zealand. The small population size allowed samples to be collected from all potential parents and nearly (33/34 nestlings) complete assignment of paternity. Analysis revealed that 35% of nestlings (12/34) were the result of extrapair copulation and that extrapair young were present in 80% of nests (8/10). About half of the extrapair nestlings were the offspring of unpaired males. This is substantially higher than predicted from the literature, which suggests that extrapair paternity is typically gained by paired males. Copyright 1999 The Association for the Study of Animal Behaviour.