Estimating social group size of Eurasian badgers Meles meles by genotyping remotely plucked single hairs
Thomas L. J. Scheppers, Alain C. Frantz, Michel Schaul, Edmée Engel, Peter Breyne, Laurent Schley & Timothy J. Roper
Scheppers, T.L.J., Frantz, A.C., Schaul, M., Engel, E., Breyne, P., Schley, L. & Roper, T.J. 2007: Estimating social group size of Eurasian badgers Meles meles by genotyping remotely plucked single hairs. - Wildl. Biol. 13: 195-207.
Owing to the Eurasian badger’s Meles meles role as an agricultural pest, its potential role in the transmission of bovine tuberculosis and other management problems, accurate estimation of badger abundance is required. At present, no censusing method exists that is accurate, cost-effective and relatively non-invasive. In this article, we test the feasibility of estimating badger social group and population size by genotyping DNA extracted from remotely plucked hair, obtained using unbaited barbed-wire traps suspended above runs and main sett entrances. Social group size was independently estimated by direct observation. The study was performed on 11 social groups in a population in Luxembourg, and hair samples were collected on alternate days during a four-week period. A total of 332 hair samples was collected, from which 303 single-hair extracts gave rise to a complete genetic profile after a single round of amplification. Of 48 multiple-hair extracts, 23% gave rise to a mixed profile from multiple contributors. Of samples collected from different barbs of the same trap on the same collection day, 53% originated from different individuals. After applying two error-checking protocols, an extended singles filter and a mismatch filter, 55 unique profiles were obtained. Mark-recapture analysis estimated the population to contain 61 badgers, whereas direct observation suggested a population of 49 badgers. By comparison with direct observation, hair-trapping yielded a higher estimate for six social groups, an equal estimate for four groups and a lower estimate for one group. We conclude that hair-trapping by means of unbaited barbed-wire traps, placed at sett entrances and well-used runs, offers a method of censusing badgers that is relatively accurate and precise, comparatively non-invasive, potentially applicable in a variety of habitats and at different population densities, and not prohibitively expensive. We suggest that DNA should be extracted from single hairs, rather than from hairs pooled from a single barb or a single trap in order to avoid mixed profiles.
Key words: hair DNA, Meles meles, molecular ecology, non-invasive DNA, population size, remote censusing
Thomas L.J. Scheppers & Timothy J. Roper, Department of Biology and Environmental Science, John Maynard Smith Building, University of Sussex, Brighton BN1 9QG, UK - e-mail addresses: thomas.scheppers@telenet.be (Thomas L.J. Scheppers); t.j.roper@sussex.ac.uk (Timothy J. Roper)
Alain C. Frantz, Michel Schaul& Edmée Engel, Musée National d’Histoire Naturelle, 25 rue Münster, L-2160 Luxembourg, Luxembourg - e-mail addresses: alainfrantz@yahoo.co.uk (Alain C. Frantz); michel.schaul@education.lu (Michel Schaul); eengel@mnhn.lu (Edmée Engel)
Peter Breyne, Research Institute for Nature and Forest, Gaverstraat 4, B-9500 Geraardsbergen, Belgium - e-mail: peter.breyne@inbo.be
Laurent Schley, Service de la Conservation de la Nature, Direction des Eaux et Forêts, 16 rue Eugène Ruppert, L-2453 Luxembourg, Luxembourg - e-mail: laurent.schley@ef.etat.lu
Corresponding author: Thomas L. J. Scheppers
Received 20 September 2005, accepted 21 March 2006
Associate Editor: Lisette Waits