A Systematic Review of 65 Years of Research on Nothofagus: An Iconic Southern Hemisphere Genus

Nothofagus is a genus of 37 species of tree distributed across the Southern Hemisphere and has long been considered a taxon of fundamental importance for understanding the evolution and ecology of the forest ecosystems of the Southern Hemisphere. Using quantitative text analysis, we evaluated 65 years of research on this iconic genus. Since 1960, research publications about the Nothofagus have steadily increased. Network analysis and structural topic models indicate that over this period, research activity has been concentrated on three broad themes: (i) long-term vegetation history and palaeoecology, (ii) forest ecology and management, with the latter becoming more prevalent over time, and (iii) the taxonomy and ecology of species associated with Nothofagus. Efforts to understand the long-term evolution, dispersal, and history of the group continue to inform debates about the biogeography of the Southern Hemisphere. Over time, there have been changes in the geographic patterns of research activity, with it becoming increasingly concentrated in South America since around 2000, with a commensurate decline in Australia and Aotearoa-New Zealand. This change in geographic activity is also associated with a shift in focus. Research in South America has increasingly addressed applied questions, including the potential response of forests with a Nothofagus component to climate change and questions associated with the silvicultural use of the group. Some outstanding research gaps remain, especially regarding our understanding of the ecology of the 19 tropical members of the genus, most of which are scarcely mentioned in the literature. A number of these tropical Nothofagus are of conservation concern, making this lack of basic ecological and distributional information alarming.