Biodiversity in urban gardens: Assessing the accuracy of citizen science data on garden hedgehogs

Abstract

Urban gardens provide a rich habitat for species that are declining in rural areas. However, collecting data in gardens can be logistically-challenging, time-consuming and intrusive to residents. This study examines the potential of citizen scientists to record hedgehog sightings and collect habitat data within their own gardens using an online questionnaire. Focussing on a charismatic species meant that the number of responses was high (516 responses were obtained in 6 weeks, with a ~ 50:50% split between gardens with and without hedgehog sightings). While many factors commonly thought to influence hedgehog presence (e.g. compost heaps) were present in many hedgehog-frequented gardens, they were not discriminatory as they were also found in gardens where hedgehogs were not seen. Respondents were most likely to have seen hedgehogs in their garden if they had also seen hedgehogs elsewhere in their neighbourhood. However, primary fieldwork using hedgehog 'footprint tunnels' showed that hedgehogs were found to be just as prevalent in gardens in which hedgehogs had previously been reported as gardens where they had not been reported. Combining these results indicates that hedgehogs may be more common in urban and semi-urban gardens than previously believed, and that casual volunteer records of hedgehogs may be influenced more by the observer than by habitat preferences of the animal.When verified, volunteer records can provide useful information, but care is needed in interpreting these data.

Patterns of Feeding by Householders Affect Activity of Hedgehogs (Erinaceus europaeus) during the Hibernation Period

“…Gardens were surveyed using footprint tunnels, which have been used previously to survey hedgehogs in both rural and urban environments (e.g., [ 19 , 26 , 54 , 55 , 56 ]). Each householder was given one footprint tunnel and instructed to place the tunnel in their rear garden in a position where they thought hedgehogs would be likely to encounter it (e.g., parallel to fences at points where animals could enter the garden).…”

An assessment of a conservation strategy to increase garden connectivity for hedgehogs that requires cooperation between immediate neighbours: A barrier too far?

“…Furthermore, the fact that hedgehogs were already visiting their garden was the most cited reason for respondents not having created a highway. Overall, only 5% of respondents thought their back garden was completely inaccessible to hedgehogs, although this may be an over-estimate as Williams et al [66] reported a 70-80% discrepancy in the number of gardens considered inaccessible based on householder perceptions versus surveys performed by the researchers themselves. Nonetheless, these data do suggest that the fragmentation effect of garden boundaries in preventing access to gardens in the UK may not be as big a problem as has previously been supposed.…”

Using citizen science to understand and map habitat suitability for a synurbic mammal in an urban landscape: the hedgehog Erinaceus europaeus

“…Individual decisions therefore have a large impact on habitat quality and connectivity for species such as hedgehogs, impeding cohesive conservation (Aronson et al 2017). Furthermore, previous studies have suggested that householders are often not aware of hedgehogs' usage of their gardens (Williams et al 2015(Williams et al , 2018b, so decisions may be made without realisation of the potential impact on hedgehog populations. Schemes to promote awareness of hedgehogs in gardens therefore are an important component of urban hedgehog conservation, particularly as the species is generally well-liked by householders (Baker & Harris 2007).…”