What We’re Reading- Feb 3, 2017

Finding management solutions for species that are threatened in their home ranges but introduced pests elsewhere
Wildlife conservation and invasive species management are rarely straightforward. In some cases, a species that is an introduced pest in one place may be threatened in its native range. This creates a dilemma for managers: control them or conserve them? In this paper, the authors provide some examples of introduced threatened species, and suggest some creative solutions to such management dilemmas. If actions to control an introduced population can simultaneously help to conserve the species in its native range, that is surely a win-win scenario. Depending on context, appropriate management actions might include translocating individuals from the introduced population for use in captive breeding, or for reintroduction to their native range, using individuals from the introduced population to relieve human pressures on native populations (e.g. where there is a commercial demand for the species, such as in the pet trade), or conducting research on the introduced population to improve conservation of native populations.

Using genetics to guide conservation when different genes tell different stories
Genetics can provide valuable insight for conservation programs, but the answers genetics provides aren’t always clear cut. Until recently, most conservation genetic studies have relied upon variation at very small numbers of genetic markers to delineate populations or even species, to determine the best approaches to managing wildlife. More recently, genomic methods have made a lot more data available for many species of conservation concern. But these data don’t always make the jobs of conservation managers easier… especially when different genetic markers tell different stories.

In this preprint (which has not yet been peer-reviewed) the authors describe how to date Galapagos tortoises have been managed as several distinct species, with these species definitions based on variation in mitochondrial DNA and a small number of microsatellite markers (which may not be representative of the whole genome). Conservationists have acted to protect the genetic integrity of these different species, for example by removing hybrid tortoises, which have mixed genetic ancestry, from breeding programs. However, more recent data (which include many more genetic markers but only small numbers of individuals) do not provide any evidence of differentiation between the different Galapagos tortoise species.  Instead these results suggest that all Galapagos tortoises are members of a single species, which means that current management strategies may actually be promoting harmful inbreeding. Further,  by excluding “hybrids” managers may be reducing local fitness. So, how to proceed given these conflicting data and confusion about species definitions? The authors suggest delaying further interventions that may affect the genetic makeup of future populations until more comprehensive genomic analyses can be conducted. These would combine the higher resolution of large numbers of markers with a much more comprehensive sampling strategy.

Side photo by Mark Jones via ARKive


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