Researchers from the University of Otago, Dunedin, New Zealand have been tracking hedgehogs' movements using global positioning systems (GPS) to understand more about the introduced species' impact on native fauna.
Hedgehogs were introduced to New Zealand when Europeans settled on the islands in the 19th century. Although considered cute by many, conservationists argue that the prickly mammals pose a considerable threat.
Without any natural predators on the islands, hedgehog populations have rapidly expanded causing concern amongst those trying to protect endemic insects, lizards and ground-nesting birds.
Having previously lived on the islands without the pressure of predation, species such as black stilts, black-fronted terns, grand skinks and weta lack natural defences to the voracious mammals.
For their study, scientists recorded 28 hedgehogs. "GPS devices offer the possibility to collect animal positions at short intervals, at any time, location and season," said researcher Mariano Rodriguez Recio.
The lightweight GPS "backpacks" were designed not to impede natural behaviour including movement through vegetation, defensive rolling and nesting. Hedgehogs are the smallest mammals to have been tracked this way.
The GPS units recorded positions every five minutes for five days. Researchers found that hedgehogs could travel as far as 1.5km in one direction but that they usually foraged around specific locations or "hotspots".
The study focused on the Godley Valley area of New Zealand's South Island. Using the data collected, scientists were able to create distribution maps of hedgehog populations to help future management efforts.
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