Cardiff University | Prifysgol Caerdydd ORCA
Online Research @ Cardiff 
WelshClear Cookie - decide language by browser settings

Dynamics of demographic expansion and population structure in the otter (Lutra lutra)

Thomas, Nia 2021. Dynamics of demographic expansion and population structure in the otter (Lutra lutra). PhD Thesis, Cardiff University.
Item availability restricted.

[thumbnail of PhDThesis]
PDF (PhDThesis) - Accepted Post-Print Version
Download (5MB) | Preview
[thumbnail of Publication form] PDF (Publication form) - Supplemental Material
Restricted to Repository staff only

Download (142kB)


Genetic diversity is considered one of the three main pillars of biodiversity, yet to date conservation policy has largely overlooked monitoring and protecting it in favour of species and ecosystem-based targets. Populations may experience considerable genetic erosion without extinction, and this loss can take considerably longer to recover from than population size alone. Low genetic diversity can have detrimental effects on the evolutionary potential of species and the viability of populations, yet population recovery at the genetic level remains poorly understood in the wild. In this thesis, I use large scale spatio-temporal sampling to explore the recovery of the otter population across the UK at a genetic level, after a well-documented decline in the latter half of the 20th century. Successive national surveys have documented increased occupancy rates, from small fragmented stronghold areas to a near continuous distribution in the 21st century. Firstly, I show that despite increased gene flow between sub-populations over the last 20 years, significant population structure persists, and intra-regional genetic diversity has not increased. Secondly, I use a landscape genetics approach, finding that favourable habitat is the most significant environmental factor affecting functional connectivity of otters across the Wales and Borders region, with implications for conservation management. Thirdly, I show that despite a near contiguous distribution and assumed population recovery, effective population sizes remain significantly below those required for long-term population viability in regional otter populations, and in some cases even raise concerns over short-term viability. This thesis serves as an important demonstration of the practical value of genetic data, even for populations where a significant (non-genetic) monitoring program has existed for several decades. The differing conclusions regarding population status, when based on genetic data rather than occupancy data, highlight the inherent dangers in assuming that spatial connectivity is an indicator of genetic connectivity.

Item Type: Thesis (PhD)
Date Type: Completion
Status: Unpublished
Schools: Biosciences
Date of First Compliant Deposit: 31 January 2022
Date of Acceptance: 31 January 2022
Last Modified: 15 Feb 2022 13:48

Actions (repository staff only)

Edit Item Edit Item


Downloads per month over past year

View more statistics