Enhancing conservation outcomes for New Zealand’s coastal ecosystems through knowledge of hedgehog (Erinaceus europaeus) spatial ecology : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Conservation Biology at Massey University, Albany, New Zealand
Loading...
Date
2024
DOI
Open Access Location
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Massey University
Rights
The author
Abstract
Aotearoa New Zealand has experienced significant biodiversity loss from the impacts of invasive species. This thesis has applied spatial ecology principles to conservation biology, focusing on invasive hedgehogs (Erinaceus europaeus) in a duneland ecosystem in northern New Zealand. Due to its generally milder climate compared to Europe and the absence of natural predators that hedgehogs face in their native habitats, hedgehogs have thrived as an invasive species in numerous ecosystems across New Zealand. Reliable estimates of home range sizes for hedgehogs in duneland ecosystems are critical as less than 30 percent of New Zealand’s natural duneland systems remain for native species such as the New Zealand dotterel (Charadrius obscurus aquilonius) and the critically endangered New Zealand fairy tern (Sternula nereis). My research aimed to quantify and understand hedgehog spatial ecology and habitat use in Northland’s duneland coastal ecosystems and provide insights that can guide more effective control measures of hedgehogs. My study was conducted at Tara Iti Ecological Sanctuary (Tara Iti), located in Mangawhai, Northland, New Zealand, from Spring 2022 to late Autumn 2023. Eleven hedgehogs (four males and five females during November 2022 and two males during May 2023) were live captured and fitted with Lotek Pinpoint VHF-75 tags for a maximum of seven days. GPS data were used to estimate the home range and nightly distances travelled by hedgehogs. Trail camera sampling was carried out to indicate the presence of pest species and six years of hedgehog trapping data from the study areas were analysed. Hedgehogs occupy a small core area of their home range intensively while covering its entirety over several foraging nights. Home ranges overlap significantly between individuals of either sex, but core ranges are more independent. The overall mean home range size was 7.1 ha ± 1.6 ha. The average home range was higher for males (8.1 ± 2.3 ha) than for females (5.6 ± 2.1 ha), but the difference was not statistically significant due to small sample sizes and high variation between individuals. The mean nightly home range was similar for males (3.4 ha) and females (3.6 ha). The average nightly distance travelled by female hedgehogs (2054 m ± 580 m) was higher than male hedgehogs (1632 m ± 237 m). One female hedgehog travelled over 4 km in one sampling night, this is the highest distance that has ever been recorded by a European hedgehog in a single night. It is suspected that this was a dispersal event given the linearity of the trip. This hedgehog covered the full width of Tara Iti from the neighbouring farmland to the edge of the golf course, indicating that hedgehogs can travel from the neighbouring farmland to shorebird nesting areas in one night of activity. I found a strong seasonal trend in the hedgehog trapping data, with peaks in January, February (austral summer), and May (austral autumn) and a low in July (austral winter). Based on my results, DOC250 are more effective traps for targeting hedgehogs and roads and habitat edges should be utilized. To control hedgehogs in vulnerable areas, a trap density of 100 m by 100 m, with one DOC250 trap per hectare, should be used. An intensive trapping program, primarily in early spring and summer, should target hedgehogs to impact the adult population and protect breeding shorebirds. Secondary intensive control should be undertaken in late autumn to primarily target females and juvenile hedgehogs while they are preparing for hibernation. My findings support the need for specific home range estimates for vulnerable ecosystems due to variability and plasticity in hedgehog behaviour based on habitat and climate factors. Trapping regimes should consider home range estimates, average nightly distances travelled, recorded dispersal distances, and habitat preferences when planning hedgehog control programs.