The fate of Holoregmia, a monospecific genus endemic to the Brazilian Caatinga, under different future climate scenarios.

– Climatic fluctuations during the Pleistocene altered the distribution of many species and even entire biomes, allowing some species to increase their range while others underwent reductions. Recent and ongoing anthropogenic climate change is altering climatic patterns very rapidly and is likely to impact species’ distributions over shorter timescales than previous natural fluctuations. Therefore, we aimed to understand how Pleistocene and Holocene climatic fluctuations might have shaped the current distribution of and explore its expected distribution under future climate scenarios. – We modelled the potential distribution of (Martyniaceae), a monospecific plant genus endemic to the semi-arid Caatinga Domain in Brazil. We used an ensemble approach to model suitable areas for under present conditions, Paleoclimatic scenarios, and global warming scenarios in 2050 and 2090. – Holocene climates in most Caatinga were too humid for , which restricted its suitable areas to the southern Caatinga, similar to its current distribution. However, under global warming scenarios, the Caatinga is expected to become too dry for this lineage, resulting in a steady decline in the area suitable for and even its possible extinction under the most pessimistic scenario modelled. – The predicted extinction of the ancient and highly specialized highlights the possible consequences of climate change for some species of endemic Caatinga flora. Invaluable phylogenetic diversity may be lost in the coming decades, representing millions of years of unique evolutionary history and consequent loss of evolutionary potential to adapt to future environmental changes in semi-arid environments.

Funder

Funder name	Awards
Science and Technology Facilities Council, United Kingdom
Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brazil	PhD grant nº 140278/2020-6