Search

The biogeographic history and the degree of environmental niche conservatism provide essential clues to decipher the underlying macroevolutionary processes of species diversification and to understand contemporary patterns of biodiversity. The genus Helianthemum constitutes an excellent case study to investigate the impact of the geo-climatic changes and the environmental niche shifts on the origins of plant species diversity in the Mediterranean hotspot. It is a palearctic species-rich lineage with c. 140 species and subspecies mostly belonging to three distinct evolutionary radiations, almost confined to the Mediterranean region and occurring across varied environmental conditions. In this work, we studied the ample and rapid diversification of the genus Helianthemum across its whole distribution range by performing phylogenetic reconstructions of ancestral ranges and environmental niche evolution. We observed a striking synchrony of biogeographic movements with niche shifts between the three major clades of the genus Helianthemum, likely related to the geo-climatic events occurred in the Mediterranean Basin since the Upper Miocene. In particular, Late Miocene and Early Pliocene were dominated by episodes of range expansions, the Late Pliocene by range contraction and vicariance events, and Pleistocene by most intense environmental niche shifts and in-situ diversification. Our study also provides evidence for four main environmental niches in Helianthemum (i.e., Mediterranean, subdesert, humid-montane and subtropical-insular) and a tendency toward environmental niche conservatism within different subclades, with few niche shifts mostly occurring from Mediterranean ancestors. The relative longer time spent in Mediterranean areas by the ancestors of Helianthemum suggests that the larger species diversity observed in the Mediterranean (i.e. Northern Africa and Southern Europe) may have been generated by a time-for-speciation effect reinforced by environmental niche c

Societal Impact Statement Plant and fungal specimens provide the auditable evidence that a particular organism occurred at a particular place, and at a particular point in time, verifying past occurrence and distribution. They also document the aspects of human exploration and culture. Collectively specimens form a global asset with significant potential for new uses to help address societal and environmental challenges. Collections also serve as a platform to engage and educate a broad range of stakeholders from the academic to the public, strengthening engagement and understanding of plant and fungal diversity—the basis of life on Earth. Summary We provide a global review of the current state of plant and fungal collections including herbaria and fungaria, botanic gardens, fungal culture collections, and biobanks. The review focuses on the numbers of collections, major taxonomic group and species level coverage, geographical representation and the extent to which the data from collections are digitally accessible. We identify the major gaps in these collections and in digital data. We also consider what collection types need to be further developed to support research, such as environmental DNA and cryopreservation of desiccation-sensitive seeds. Around 31% of vascular plant species are represented in botanic gardens, and 17% of known fungal species are held in culture collections, both these living collections showing a bias toward northern temperate taxa. Only 21% of preserved collections are available via the Global Biodiversity Information Facility (GBIF) with Asia, central and north Africa and Amazonia being relatively under-represented. Supporting long-term collection facilities in biodiverse areas should be considered by governmental and international aid agencies, in addition to short-term project funding. Institutions should consider how best to speed up digitization of collections and to disseminate all data via aggregators such as GBIF, which will great