Interspecific hybridization between narrowly endemic alpine plants and widely distributed lowland plants might lead to the genetic extinction of the endemic species.
Most global-warming models predict an altitudinal movement of plants. This upward migration of lowland species will surely result in contact with related species inhabiting high-mountain ecosystems. We propose that an overlooked consequence of this upland movement is the possibility for interspecific hybridization between narrowly endemic alpine plants and widely distributed lowland plants. Genetic swamping due to introgressive hybridization might even lead to the genetic extinction of the endemic species, without any apparent detrimental demographic effect. Unfortunately, this phenomenon has long been ignored in the ecological literature, probably because is widely assumed that the ecological effects of climate change are more detrimental than its genetic effects. We tested our idea by searching for human-induced hybridization in a worldwide hotspot biodiversity, the high-mountains of the Sierra Nevada (south-eastern Spain). About 25 % of the endemic flora is already hybridizing in these mountains, mostly with widespread lowland congeners. Some species are even already threatened due to genetic swamping. It is thereby urgent including in future conservation agendas a protocol for detecting and monitoring positive and negative effects of genetic swamping mediated by climate change in high mountains and other sensitive ecosystems
Gómez JM, González-Mejias A, Lorite J, Abdelaziz M, Perfectti F. 2015
Climate change and the potential for hybridization-mediated extinction of endemic high-mountain plants: the silent extinction
Biodiversity and Conservation 24: 1843-1857