Immigrants to the rescue! How can immigration help save threatened wildlife populations?

Threatened species have invariably small and frequently isolated populations, and are thus characterized by increased inbreeding and depleted genetic variation.  Increased inbreeding could lead to a reduction in reproduction and survival (inbreeding depression), which causes an immediate risk of extinction. 

Depleted genetic variation could compromise the ability of a species to adapt to an ever-changing environment, threatening its long-term survival.  How to mitigate these adverse effects of small populations, and maintain a threatened species for short- and long-term survival, is a major task for conservation science.

Supplementing genetically impoverished populations with external unrelated individuals (immigrants) can be a valuable strategy to counteract the negative effects of isolation.  This ‘genetic rescue’ effect occurs because the addition of unrelated genomes increases diversity in the recipient population, reducing inbreeding and inbreeding depression. 

Genetic rescue has the added benefit of increasing population size and larger populations are less vulnerable to random events, such as a natural disaster or disease outbreak. 

Despite the potential benefits of genetic rescue for the management of threatened species, there have been fewer than twenty published studies of genetic rescue/restoration for conservation purposes.  Why has there been such a low uptake? 

At this event, the speakers described the hurdles, and illustrated how genetic rescue can be expedited through reintroduction and conservation programmes.



Emeritus Professor Richard Frankham is one of the leading international figures in conservation genetics, having been a pioneer in the field and senior author on the first textbooks in the field (3 textbooks that have been subject to 6 translations). In 2005 he was awarded a DSc by Macquarie University, based upon his published work (now ~ 170 publications).  His background is in agriculture, having received BScAgr [Hons 1] and PhD from the University of Sydney. He worked for Agriculture Canada, followed by a postdoctoral fellowship at the University of Chicago, before spending 31 years at Macquarie University, beginning as a lecturer and ending as a Professor. He officially retired in 2002, but continues to work full-time, sharing his time between Macquarie University and the Australian Museum. In 2004, he was Hrdy Visiting Professor in conservation biology at Harvard University, USA.  

Mike Bruford is Professor of Biodiversity at the School of Biosciences, Cardiff University. After gaining his PhD in DNA profiling in animals from the University of Leicester in 1990, Mike worked for the Zoological Society of London as a conservation biologist for nine years, before moving in Cardiff in 1999. Mike’s research focuses on the population biology of endangered species, with a special focus on those found in fragmented habitat. He uses DNA profiling to gain information about elusive animal species, which helps to build a picture about their population size and distribution, often in inhospitable habitats where direct observation is impossible.

Jane's research spans the fields of population, evolutionary and conservation ecology. Specifically, she uses long-term field studies of marked individuals (birds) to understand the genetic and environmental causes of individual variation in life-history, and to understand the consequences of emerging demographic variation for population dynamics and evolution. She is also a diehard field ecologist.  Jane completed her Undergraduate degree in Natural Sciences at the University of Cambridge, followed by a PhD in behavioural ecology at Glasgow University and Killam Postdoctoral Fellowship at the University of British Columbia, and a Junior Research Fellowship at Jesus College, University of Cambridge.  She was appointed Royal Society University Research Fellowship at University of Aberdeen starting 2006 and since 2014 works on an ERC-funded research programme in population & evolutionary ecology.  In 2013 Jane was awarded the ZSL Scientific Medal for her work.

  • Chaired by Dr Patricia Brekke, ZSL

Patricia is a Research Fellow at ZSL, with research interests in ecology, evolution and conservation of small and fragmented populations. She applies molecular genetics and genomics to understand the role that changes in genetic diversity and inbreeding have on a species' risk of extinction. She is particularly interested in understanding how small populations cope and adapt to conservation management interventions to predict their long-term effects.

Download full talk abstracts: PDF icon Agenda and Abstracts Genetic Rescue 14 March 2017 (536.67 KB)



  • Contact Jennifer Howes, Scientific Events Coordinator; 0207 449 6227

  • For press enquiries please contact the ZSL Press Office:

  • Sign up to receive email updates about forthcoming ZSL Science and Conservation Events

More Events