What drives diversification in a pantropical plant lineage with extraordinary capacity for long-distance dispersal and colonisation?

Aim: Colonisation of new areas may entail shifts in diversification rates linked to biogeographic movement (dispersification), which may involve niche evolution if species were not pre-adapted to the new environments. Scleria (Cyperaceae) includes c. 250 species and has a pantropical distribution suggesting an extraordinary capacity for long-distance dispersal and colonisation. We investigate patterns of diversification in Scleria, and whether they are coupled with colonisation events, climate niche shifts or both.

Location: Tropics and subtropics.

Taxon: Nutrushes Scleria (Cyperaceae).

Methods: We used molecular data from three DNA regions sequenced for 278 accessions representing 140 Scleria taxa (53% of species) to develop a chronogram, model ancestral ranges, and measure rates of diversification. Integrating data from 12,978 digitised and georeferenced herbarium records, we investigated niche evolution.

Results: High dispersal rates in Scleria, a genus with multiple disp...