Spatially explicit capture-recapture estimate of hedgehog population density in exotic grassland, New Zealand

Abstract

European hedgehogs (Erinaceus europaeus) in New Zealand are considered a pest species due to their impacts on native species and are targeted in trapping programmes. A robust estimate of hedgehog population density using spatially explicit capture-recapture (SECR) is lacking and can provide the parameters σ (the spatial decay parameter for a half-normal home-range kernel to model the decline in encounter probability with distance between the home-range centre and trap) and ɡ 0 (the nightly probability of capture by a trap placed at the animal's home-range centre) needed to model optimal trapping or detection arrays. We estimated the density of hedgehogs in pasture habitat on the Otago Peninsula, South Island, New Zealand, using SECR during late February/early March as 0.46 ha −1 (95% confidence interval 0.26-0.82 ha −1 ; ɡ 0 = 0.02; σ = 85.7). The mean body mass of captured hedgehogs (482 g, range: 180-890g, n = 32) indicated a mix of adults and juveniles. Future research should evaluate prey availability as well as hedgehog density to develop a better understanding of the relationship between hedgehog abundance, prey availability, habitat and climate.