Genetic Management of Fragmented Animal and Plant Populations

10 12 2016

logoThat is the title of a new textbook that will be available mid-2017.

After almost 6 years work, authors Dick Frankham, Jonathan Ballou, Katherine Ralls, Mark Eldridge, Michele Dudash, Charles Fenster, Bob Lacy & Paul Sunnucks have produced an advanced textbook/research monograph that aims to provoke a paradigm shift in the management of small, isolated population fragments of animals and plants.

One of the greatest unmet challenges in conservation biology is the genetic management of fragmented populations of threatened animal and plant species. More than a million small, isolated, population fragments of threatened species are likely suffering inbreeding depression, loss of evolutionary potential, and elevated extinction risks (genetic erosion). Re-establishing gene flow between populations is required to reverse these effects, but managers very rarely do this. On the contrary, molecular genetic methods are mainly being used to document genetic differentiation among populations, with most studies concluding that genetically differentiated populations should be managed separately (i.e., kept isolated), thereby dooming many populations to eventual extinction.

The need for a paradigm shift in genetic management of fragmented populations has been highlighted as a major issue in conservation. The rapidly advancing field of molecular genetics is continually providing new tools to measure the extent of population fragmentation and its genetic consequences. However, adequate guidance on how to use these data for effective conservation is still lacking, and many populations are going extinct principally for genetic reasons. Consequently, there is now urgent need for an authoritative textbook on the subject.

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50/500 or 100/1000 debate not about time frame

26 06 2014

Not enough individualsAs you might recall, Dick Frankham, Barry Brook and I recently wrote a review in Biological Conservation challenging the status quo regarding the famous 50/500 ‘rule’ in conservation management (effective population size [Ne] = 50 to avoid inbreeding depression in the short-term, and Ne = 500 to retain the ability to evolve in perpetuity). Well, it inevitably led to some comments arising in the same journal, but we were only permitted by Biological Conservation to respond to one of them. In our opinion, the other comment was just as problematic, and only further muddied the waters, so it too required a response. In a first for me, we have therefore decided to publish our response on the arXiv pre-print server as well as here on

50/500 or 100/1000 debate is not about the time frame – Reply to Rosenfeld

cite as: Frankham, R, Bradshaw CJA, Brook BW. 2014. 50/500 or 100/1000 debate is not about the time frame – Reply to Rosenfeld. arXiv: 1406.6424 [q-bio.PE] 25 June 2014.

The Letter from Rosenfeld (2014) in response to Jamieson and Allendorf (2012) and Frankham et al. (2014) and related papers is misleading in places and requires clarification and correction, as follows: Read the rest of this entry »