Population biology of the woodland dormouse Graphiurus murinus in a riverine Combretum forest, South Africa

Abstract

Until recently, very little was known of the biology and ecology of the woodland dormouse Graphiurus murinus, a nocturnal and arboreal rodent belonging to the family Gliridae. Here, we aimed to increase our knowledge on its population biology in a riverine Combretum forest of the Albany Thicket Biome, South Africa. Data were collected between February 2006 and June 2007 by means of a monthly live-trapping and nest-box monitoring programme, but complementary information on reproduction was opportunistically obtained in 2008–2011 and 2017. During the main study period, the dormouse population showed a steady increase from winter to spring, and a peak of 16 ind. ha⁻¹ in summer, as a result of the influx of juveniles. Winter mortality and/or spring dispersal accounted for the disappearance of 55% of subadults. The annual adult:juvenile ratio was 1.08, whereas the overall sex ratio was 1.94 females per one male. In females, reproductive activity was observed from September to end January (spring–summer). The pattern observed in males was similar, because dormice with descended testes were exclusively found from October to end January. Parturition occurred from the second half of October to the beginning of December, but observations made in 2009 and 2011 indicated that births can take place as late as mid-February. Litters (n = 15) consisted of an average (± SD) of 3.88 ± 0.81 young. We provide evidence that some females can give birth to two litters during the same breeding period, with a 5- to 6-week interval, hence indicating the occurrence of post-partum mating in woodland dormice. Multi-year data from different habitat types are needed in order to confirm and advance our knowledge on this species’ population biology and dynamics.

Keywords: age structure, breeding period, capture–mark–recapture, Gliridae, litter size, live trapping, MNA, nest box, population dynamics