Hof et al (2012) hedgehog predation risk edge refuging
Title: Food of fear? Predation risk mediates edge refuging in an insectivorous mammal, Animal Behaviour 83; 1099-1106. 2012
Authors: A.R. Hof, J. Snellenberg & P.W. Bright
Background to study
An investigation into how badger abundance and food availability influences the movement patterns of hedgehogs in rural arable-dominated landscapes.
- 88 hedgehogs were collared and radio-tracked in four rural-arable dominated areas of the UK which consisted of primarily arable fields with some set aside, pastures, woodlands and village habitat. Hedgerows (2-3m high and wide) and ~6m wide grassy margins bordered the majority of fields.
- Camera trapping, sign surveys and spot light surveys were used to identify badger absence in two of the four study sites and presence in the other two study sites.
- Hedgehogs were radio-tracked for a minimum of 10 days and fixes per hour were obtained where possible. Locations, distance to nearest edge habitat, behaviour (foraging, courtship, meeting with other hedgehogs or stationary), habitat use and height of crop in utilised habitat (if applicable) were recorded for each hedgehog between May and June 2008 (for one study site) and between June and August for the remaining three sites.
- Food availability was measured by sampling 1 m, 10 m and 20 m from hedgerows for earthworms (using 15 cm soil cores), beetles (using 0.5 m2 quadrangles) and beetles (using 14 cm diameter pitfall traps) in 35 arable fields, 3 pastures and 4 set-aside fields. Five samples per method and at each distance class (from hedgerow) were employed and the abundance (direct count) and biomass was recorded.
- Hedgehogs were assigned to food availability estimates obtained from the nearest sampling location to their recorded home range.
- Hedgehogs were more frequently located (65% of cases) in village habitat where badgers were present and in one of the two badger occupied sites, hedgehogs were only located within the boundaries of village.
- Total food availability was significantly higher in sites unoccupied by badgers and did not differ across all sites when accounting for distance from hedgerow.
- Earthworm abundance was higher and beetle abundance lower in sites occupied by badgers.
- The use of field margins by hedgehogs significantly increased in the presence of badgers and where badgers were absent or when the crop height was high, hedgehogs were found further from edge habitat.
- The behaviour of hedgehogs did not vary significantly with distance from edge habitat; however they were most frequently in locomotion when far from edge cover.
- In arable fields, hedgehogs were found significantly further from edge cover (42 +8 m) in the absence of badgers when compared to sites where badgers were present (4 + 1.1 m from edge cover).
- Food availability in arable fields had a significant influence on the spatial use of hedgehogs.
Key messages to landowners and managers derived from these results
- Establishing and/or maintaining >6 m grassy field margins and incorporating conservation headlands in arable dominated landscapes is recommended and supported by agri-environment schemes to provide refuge and foraging habitat for hedgehogs, particularly in areas where badgers are present.
- Reinstating and maintaining well connected hedgerows in rural areas and increasing undergrowth and dense shrubby habitats in gardens and amenity grassland is recommended to provide greater foraging opportunities, refuge habitat and nest sites for hedgehogs. This is particularly relevant in areas of high badger abundance where hedgehogs may be displaced from farmland into urban and rural environments.