Haigh et al (2013) hedgehog habitat selection philopatry spatial segregation
Title: Habitat selection, philopatry and spatial segregation in rural Irish hedgehogs (Erinaceous europaeus), Mammalia DOI 10.1515. 2013
Authors: A. Haigh, R. M. O’Riordon & F. Butler
Background to study
An investigation into ecological and environmental factors that may regulate hedgehog numbers in a rural landscape.
- Hedgehog movements were monitored within a 97 ha site consisting of 23% arable, 64% pasture, 7% residential garden, 1% scrub, 1% marsh and 4% wood in Ratharoon area of County Cork, Ireland.
- Hedgehogs were captured and uniquely marked using both heat-shrink plastic tubes and by PIT tagging. Individuals were fitted with a radio-transmitter and tracked from September 2008 and from March – November 2009 including six hedgehogs monitored through hibernation.
- Hedgehogs were located using radio-telemetry between 6 and 21 times/night. Eight individuals were monitored continuously for 33 nights in 2008. Ten hedgehogs were periodically tracked for 2 and 3 years.
- Home range sizes were calculating using minimum convex polygons and their spatial distribution mapped within ArcGIS.
- Habitat selection was investigated using compositional analysis which determines whether habitats utilised were random or selected for based on randomisation tests and the proportion of each habitat available within the calculated home range area of each individual.
- The mean annual (April – October) home range size for adult male hedgehogs was 56 ha which was significantly larger than adult females whose mean home range size was 16.5 ha.
- Male home range sizes changed seasonally, increasing from a mean of 4.5 ha outside of breeding season to 15.9 ha within the breeding season (April – July).
- Females maintained similar monthly home ranges throughout the year, but an increase from 4.05 ha to 5.8 ha was observed in June towards the end of the breeding season.
- Female home ranges showed little overlap and occupied mutually exclusive home areas, whilst male home ranges overlapped each other and encompassed other female ranges.
- Each night, hedgehogs occupied small specific areas and rarely crossed the path of another individual.
- Site philopatry was observed in both male and females who were tracked from 2008 till 2010.
- Adult hedgehogs selected for garden and arable land in which they were used in a proportion greater than their availability.
- Seasonal changes in habitat use were observed across the study years;
- Gardens and scrub were used after emergence from hibernation as this was close to hibernacula sites.
- Pasture was used most between May and July.
- Garden land was preferred in August.
- Arable land, once harvested was permanently occupied between September and October and coincided with an increase in invertebrate abundance which was likely to be influenced by the well-established hedgerows, winter stubble and mosaic of gardens and pasture in the surrounding area.
- Scrub was favoured in October/November when hedgehogs were constructing hibernacula.
- Seasonal changes in activity were also observed with 66% of time being spent foraging in autumn compared with 29% of time during the breeding season when 35% of time was spent engaged in courtship behaviour.
Key messages to landowners and managers derived from these results
- Long-term studies that incorporate seasonal changes in habitat use, ranging and behaviours are recommended for both ecological research and for mitigation purposes.
- Traditional farming methods that include mosaic of pasture and arable, well connected hedgerows and over-winter stubble are recommended to increase the suitability of arable land for hedgehogs.
- Maintaining well connected hedgerows and buffer strips in rural landscapes is recommended to maintain connectivity between populations and to facilitate movement between selected habitat types.