The Red List of Nothofagus (trees more commonly known as ‘false beech’ or ‘southern beech’), recently published by BGCI and Royal Botanic Gardens, Kew, identifies 11 species at risk of extinction in the wild, including three Critically Endangered species. The report contains assessments for all 37 species of Nothofagus and identifies major threats to the genus from wood harvesting, deforestation and the impact of globally rising temperatures on the ecology of species.
Nothofagus are deciduous and evergreen forest trees only found in the Southern Hemisphere. They are the major component of forests in parts of Chile, Argentina, Papua New Guinea, Indonesia, New Zealand, New Caledonia and Australia, and play a vital role in supporting the ecology and biodiversity of these forests. The island of New Guinea, a biodiversity hotspot, holds the greatest diversity of Nothofagus, being home to 14 species.
The genus is well understood compared to other tree groups, owing to a rich fossil record dating back to the break-up of the Gondwana supercontinent, the historical use of the species for timber and the dominance of the species in forests across their range. This has led to no Data Deficient assessments for Nothofagus. Due to the information available for the group and the long lived nature of some species, with individuals recorded to be over 500 years old, it is possible to see how threats to trees have changed across time. Historically, Nothofagus were more threatened by harvest for timber, but currently the species are exposed to pressures of land use change. In the future populations are predicted to decline due to the effects of climate change.
Due to these threats, 30% of Nothofagus have been assessed as threatened with extinction in the wild. The report finds three species to be Critically Endangered, the most threatened category on the IUCN Red List, three species are Endangered and five species are assessed as Vulnerable. Conservation action should now be prioritised for these threatened species, particularly to bring the three Critically Endangered species (N. nuda, N. stylosa, N. womersleyi) into ex situ collections. Fortunately, 20 species of Nothofagus are currently held in ex situ collections including the Endangered Nothofagus alessandrii, from Chile, which is grown across a network of UK botanic gardens and arboreta.
Although the majority of Nothofagus species (26 species) were found not to be experiencing major threats, they may still be exposed to risk from habitat loss and exploitation. These Least Concern and Near Threatened species still require monitoring to ensure they do not become more threatened. As Nothofagus are exposed to a variety of threats across their range, there is a need for a holistic range of of conservation actions to protect the species. This should consider in situ methods, such as protecting large stands of Nothofagus forest in the wild, to maintain populations of both threatened and not threatened species.
The Red List of Nothofagus contributes to the Global Tree Assessment, an initiative to produce conservation assessments for all of the world’s tree species by 2020. This work is identifying the tree species most in need of conservation, helping to prioritise GTC work.
Read the full report here.