DNA genotypes reveal red fox (Vulpes vulpes) abundance, response to lethal control and limitations of contemporary survey techniques

Article

Next >>

Contents Vol 36(8)

doi:10.1071/WR08109

DNA genotypes reveal red fox (Vulpes vulpes) abundance, response to lethal control and limitations of contemporary survey techniques

Clive A. Marks ^A ^F, Frank Gigliotti ^B, Steve McPhee ^C, Maxine P. Piggott ^D, Andrea Taylor ^D, Al. S. Glen ^E

^A Nocturnal Wildlife Research Pty Ltd, PO Box 2126, Wattletree Road Post Office, East Malvern, Vic. 3145, Australia.
^B Vertebrate Pest Research Department, Victorian Institute of Animal Science, PO Box 48, Frankston, Vic. 3199, Australia.
^C Agricultural Technical Services, 177 Ballan Rd, Werribee, Vic. 3030, Australia.
^D Australian Centre for Biodiversity, Analysis, Policy and Management, School of Biological Sciences, Monash University, Clayton, Vic. 3800, Australia.
^E Department of Environment and Conservation and Invasive Animals CRC, Dwellingup Research Centre, Banksiadale Rd, Dwellingup, WA 6213, Australia.
^F Corresponding author. Email: camarks@attglobal.net





	PDF (359 KB) $25



	Export Citation

Print

Wildlife Research 36(8) 647–658 http://dx.doi.org/10.1071/WR08109
Submitted: 14 July 2008 Accepted: 25 August 2009 Published online: 16 December 2009

Abstract

Context. Scat genotyping has not been routinely used to measure fox (Vulpes vulpes) abundance and our study sought to provide a benchmark for further technique development and assessment of field methods.

Aims. This study sought to provide a comparative assessment of some common methods used to determine fox density and contrast their success with scat DNA genotyping.

Methods. DNA recovered from fox scats was used to genotype individual red foxes and determine their abundance at four transects. Population indices were also developed from bait take, scat counts and sand plot tracks using index-manipulation-index (IMI) procedures on the same transects. Known samples of foxes were taken from two treatment transects using cyanide delivered in the M-44 ejector to manipulate the population and to recover foxes at the end of the trial.

Key results. Replicated counts on a 41-km-spotlight transect at the field site before and after the population manipulation had low variance and good correlation (r² = 0.79, P < 0.01). Scat genotypes revealed 54 foxes in eight days and, when combined with biopsy DNA from recovered foxes, a minimum known to be alive (KTBA) density of between 1.6 and 5 foxes km^–1 was calculated for the transects. Overall, 15/30 (50%) of all recovered foxes had not been detected by scat genotyping, 23/53 (49%) of KTBA genotypes were detected only once and 5/54 (9.5%) of foxes were found to have moved between two transects.

Conclusions. At transects where population manipulation occurred, surviving individuals contributed significantly more scats than at the control transects and some individuals were detected at bait stations at a much greater frequency. This strongly suggested that they had contributed disproportionately to some IMI density estimates that were probably influenced by a change in the activity of some individuals rather than changes in population density alone. At one transect, eight foxes were confirmed to be present by spotlight surveys and were detected by scat and KTBA genotypes, yet were undetected by scat, bait station and sand plot indices.

Implications. Scat and other DNA-based survey techniques provide a great deal of information about the identification and movement of individuals and if DNA sampling methods can be made more efficient they have the potential to provide accurate abundance estimates that are independent of the control technique.