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

Abstract

Urban environments are important for west European hedgehogs Erinaceus europaeus. The species has been recorded in 73% of large urban areas throughout its geographic range. However, the environmental relationships determining hedgehog distribution within these landscapes are not well understood. Taking a city‐wide perspective, this study identifies hedgehogs’ habitat relationships with urban environmental characteristics and predicts habitat suitability in a major urban centre, Greater London, UK. We use a collated citizen science dataset of 3012 hedgehog occurrence records from Greater London, and pseudoabsences inferred from other mammal taxa, to construct a multiscale generalised linear model identifying the influence of 10 variables representing urban greenspace, built infrastructure, and the presence of the European badger Meles meles (as a predator or competitor) on hedgehog distribution. We find a positive association of hedgehog presence with availability of gardens, parks, allotments, percentage of terraced housing, traffic, and intermediate impervious cover (roads and buildings, peaking at 31%). High impervious cover, woodland, water, human densities (above 2262 people km−2), and badger presence were negatively related to hedgehog presence. Predicted habitat suitability was high across much of Greater London but declined towards the centre and in some locations around the outskirts of the study region. Our results emphasise the importance of public and private greenspaces for urban hedgehogs, and suggest that loss of garden, park, and allotment habitats and disturbance associated with high human densities may restrict hedgehog distribution. Despite the inherent complexity of urban environments, this study shows that citizen science is useful for developing an understanding of large‐scale species–habitat relationships in diverse urban landscapes.

Habitat suitability as an indicator of urbanisation potential in four UK mammals

“…Background species were included to use as inferred absence points, so minimise the effects of spatial bias in the dataset due to opportunistically collected citizen science data, such as the overrepresentation of records in easily accessible public parks (Phillips et al 2009). These four background species were chosen because they are commonly seen mammals in urban London, with similar body sizes as the target species and so expected to be easily observable by the public in a similar way (Turner et al 2021).…”

“…We overlaid a 100 m × 100 m grid onto the study area using QGIS to compare the presence and absence of mammals in different parts of Greater London (Turner et al 2021). As environmental features in London can differ drastically within a small area, a 100 m × 100 m grid cell size is chosen to take into account environmental differences at fine spatial scales (Turner et al 2021).…”

“…Urban greenspace, such as gardens, parks and allotments, can become strongholds for mammals (Harris 1984, Scott et al 2014, Gurnell et al 2017, Lovell et al 2022). These man-made greenspaces consist of dense and structurally complex plant cover, suitable for concealment, foraging and nesting , Hubert et al 2011, Turner et al 2021. They are also managed independently with varying levels of human disturbance, thus may be preferred by different mammals.…”

“…The overall habitat suitability was estimated to be high across much of Greater London, except with lower suitability in central and sections of the periphery. Building upon the work by Turner et al (2021), this study further investigated the habitat suitability of three other urban mammals in Greater London using environmental data from 2005 to 2021. We aim to 1) re-evaluate the habitat suitability model developed by Turner et al for hedgehogs using updated environmental data; 2) predict the habitat suitability for three other urban species (fox, badger, grey squirrel) and 3) investigate their urbanisation potential by examining the similarities and differences in the habitats exploited by different species.…”

“…Records were filtered using R (ver 4.1.2) (R Core Team 2021), keeping only records between 2005 and 2021, from within greater London. Using records spanning 16 years maximises the number of mammal occurrence data available while minimising extreme variation caused by extreme weather or the COVID pandemic (Turner et al 2021). Duplicate records with the same coordinates, year and source dataset, and records with a coordinate uncertainty of over 100 m were also removed.…”