The maintenance of genetic variation is a general conservation concern for endangered
species, such as the British hazel dormouse (Muscardinus avellanarius). The structuring
of genetic variation at multiple hierarchical levels, from individual through to the total
population, can provide insights into within-population processes, such as inbreeding
and social behaviour, and help understand the causes of population partitioning,
both current and historical. Investigating the processes that shape and alter levels of
genetic variation within hazel dormouse populations will highlight any factors that may
influence their continued persistence and inform on appropriate management strategies.
The current thesis aimed to address whether a) microbial-mediated odour could be
a mechanism for kin discrimination, inbreeding avoidance and social cooperation; b)
the hazel dormouse displays social structuring and, as a result, evidence for inbreeding
avoidance; c) there is within and among population structuring, resulting from identified
physical features that restrict gene flow and d) current patterns of genetic variation
inform us about historic dispersal.
Captive bred individuals of known pedigree were used to assess the relationship
between bacterial community composition and relatedness. Microsatellite markers were
used to generate relatedness estimates and analyse levels of genetic variation at the
individual, social group and sub-population levels on samples obtained from Sussex
and the Isle of Wight. Mitochondrial markers were used to infer patterns of genetic
variation at the total population level, including samples obtained from all over the
species range. F-statistics were then used to infer any deviations from Hardy-Weinberg
equilibrium that could imply for example inbreeding or gene flow.
The main findings of the thesis are that 1) microbial composition correlates with
genetic relatedness in the hazel dormouse, indicating that microbial-mediated odour
could be a mechanism for kin discrimination; 2) inbreeding levels are not significantly
high, even though both male and female close relatives are in close proximity, with
neither sex exclusively practising natal philopatry or dispersal; 3) no identified habitat
features appeared to influence gene flow and levels of genetic variation did not differ
between sites, regardless of the habitat features; 4) on the basis of mtDNA, the British dormouse population is likely to have been founded by a relatively recent colonisation
event, rather than be a remnant of a more ancient indigenous species.
The results of this study contribute to our understanding of how social and dispersal
mechanisms determine a population’s composition and hence provide some indicators of
how the species has evolved. It is intended that knowledge of the species’ social structure
and, in particular, details of their inbreeding avoidance behaviour and tolerance of close
relatives, will help optimise population survival in future reintroduction programs.
|Date of Award||2017|
The Social Structure of the Hazel
Glass, D. (Author). 2017
Student thesis: Doctoral Thesis