European hedgehogs rear young and enter hibernation in New Zealand’s alpine zones

Abstract

There is increasing interest in restoring native predators in order to regulate ecosystems and maintain biodiversity, but predator reintroductions are still controversial for complex social and ecological reasons. Few studies have examined predator restoration on islands or in ecosanctuaries, where highly endemic faunas have typically undergone precipitous declines and extinctions due to novel invasive predators, and translocations are used to restore species. Currently in New Zealand, discussions regarding predators typically focus on introduced mammalian pests, and the importance of native predators is frequently overlooked. We present a case study of the mesopredatory New Zealand weka (Gallirallus australis), a threatened flightless rail that provokes controversy among restoration practitioners due to concerns that it may decrease populations of other threatened species. We (1) review studies of weka diet and impacts on native and exotic fauna; (2) contrast prehistoric and contemporary predation webs focused on weka; and (3) consider the role of biocultural approaches in the management and restoration of socio-ecological systems with weka. Weka are opportunistic omnivores that can include vertebrates in their diet, and on small islands where weka can reach high densities there is some evidence that they may limit some prey populations. However, very few manipulative experimental studies measuring effects of weka on native species have been carried out, and such studies would be extremely valuable. Weka also consume invasive rodents and, if they obtain a sufficiently high density, may provide benefits in ecosanctuaries by limiting invasive mice populations. Māori historically harvested weka, and such harvest may now valuably limit weka numbers at certain island or ecosanctuary sites, perhaps replacing the effect of extinct avian competitors and apex predators. How weka and other native predators should be managed on islands depends on the value placed on ecosystem restoration, species-focused conservation, or biocultural enrichment.

Anyone Can Get Old—All You Have to Do Is Live Long Enough: Understanding Mortality and Life Expectancy in European Hedgehogs (Erinaceus europaeus)

“…This statement is supported by Morris [41], who noted that a young hedgehog kept active and well-fed throughout winter, and which did not hibernate, failed to form any growth line in the bone. This means that the assessment of periosteal growth lines is not appropriate for age determination in hedgehogs that do not hibernate, such as many individuals in New Zealand [75]. This problem may be increasingly relevant in other populations too.…”

Time-lapse cameras improve our understanding of invertebrate activity in the alpine zone

“…Furthermore, future warming scenarios project a significant reduction in alpine habitat (Dirnböck et al 2011;Parida et al 2015;Barredo et al 2020;Chinn & Chinn 2020;Koot et al 2022). As temperatures increase, the elevational range of introduced pests, mammals, invertebrates, and plants is likely to rise, which will increase pressure on alpine invertebrates in the years to come (Christie et al 2017;O'Donnell et al 2017;Foster et al 2021b;Macinnis-Ng et al 2021). With additional threats looming, improving our understanding of how invertebrates respond to predation and management efforts will become more critical.…”

High-elevation landforms limit the movement of invasive small mammal species

“…Small GPS backpacks were made from i-gotU GT120 GPS travel loggers (Mobile Action Technology, Taipei, Taiwan) and 11 g VHF transmitters (Lotek V2G 152 C) and were attached to spines on the backs of hedgehogs with hot-melt adhesive. Stationary tests revealed these devices to have a mean location error of 4.17 m (± 0.10) on bare ground, and 5.28 m (± 0.17) in dense tussock (Foster et al 2021b). GPS movement tracks of 26 individual hedgehogs were acquired across two 6-month periods (December-June).…”