What’s the end-game for biodiversity: is it time for conservation evolution?
- Environmental Science and Monitoring Group, Marlborough District Council, PO Box 443, Blenheim 7240, New Zealand
Conservation biology emerged in the 1980s to prevent extinctions by intervention and adaptive management. Despite many successes worldwide, the goal of self-sustaining populations of many threatened species without ongoing human assistance remains elusive. This is in part due to novel selection pressures overwhelming the ability of species to adapt to changing ecological circumstances. Evolution was also not considered to occur sufficiently fast to induce the recovery of many species. Recently, however, evolution has been observed in contemporary time frames, often in decades. This has stimulated discussion that evolutionary rescue could be possible for some species, leading to populations becoming self-sustaining. Evolutionary rescue is the ability of species to respond to novel selection pressures by adaptation via natural selection.
In this article, I ask whether it is possible to manipulate natural selection to facilitate the ongoing survival of some New Zealand indigenous forest bird species in the presence of introduced predators, using existing management techniques. I suggest that existing management could be reconfigured so that existing and new safe sites, which safeguard evolutionary potential, have adjoining transition zones where predator abundance is suppressed, to provide the conditions for selection of adaptive phenotypic plasticity. Natural selection is theorised to favour phenotypes with plastic behaviour or genetic mutations that enhance survival and reproduction in the face of changing selection pressures, such as introduced predators. The aim is to facilitate the long-term coexistence of some forest bird species with introduced predators, so that populations eventually require little or no human intervention, in the event a predator-free country proves to be insurmountable. I suggest this conservation evolution approach is complementary to, and extends, the current conservation predator control paradigm. This is because it remains essential to continue to protect species that are substantially maladapted to novel selection pressures for evolutionary rescue to occur.