How the temperate world was colonised by bindweeds: biogeography of the Convolvuleae (Convolvulaceae). Issue 1 (December 2016)

• Record Type: Journal Article
• Authors: Mitchell, Thomas; Williams, Bethany; Wood, John; Harris, David.; Scotland, Robert; Carine, Mark
• Is Part Of: BMC evolutionary biology. Volume 16:Issue 1(2016)
• Page Start: 1
• Page End: 12
• Publication Date: 2016-12
• Subjects: Amphitropical -- Calystegia -- Convolvulus -- Disjunction -- Diversification rates -- Polymeria -- Temperate -- Transoceanic; Evolution (Biology) -- Periodicals; 576.805
• DOI: 10.1186/s12862-016-0591-6
• Languages: English
• ISSNs: 1471-2148

Abstract

Abstract Background At a global scale, the temperate zone is highly fragmented both between and within hemispheres. This paper aims to investigate how the world's disjunct temperate zones have been colonised by the pan-temperate plant group Convolvuleae, sampling 148 of thec . 225 known species. We specifically determine the number and timing of amphitropical and transoceanic disjunctions, investigate the extent to which disjunctions in Convolvuleae are spatio-temporally congruent with those in other temperate plant groups and determine the impact of long-distance dispersal events on diversification rates. Results Eight major disjunctions are observed in Convolvuleae: two Northern Hemisphere, two Southern Hemisphere and four amphitropical. Diversity in the Southern Hemisphere is largely the result of a single colonisation of Africa 3.1–6.4 Ma, and subsequent dispersals from Africa to both Australasia and South America. Speciation rates within this monophyletic, largely Southern Hemisphere group (1.38 species Myr−1 ) are found to be over twice those of the tribe as a whole (0.64 species Myr-1) . Increased speciation rates are also observed inCalystegia (1.65 species Myr−1 ). Conclusions The Convolvuleae has colonised every continent of the world with a temperate biome inc . 18 Myr and eight major range disjunctions underlie this broad distribution. In keeping with other temperate lineages exhibiting disjunct distributions, long-distance dispersal is inferred as the main process explaining the patterns observed although for one American-Eurasian disjunction we cannot exclude vicariance. The colonisation of the temperate zones of the three southern continents within the lastc . 4 Myr is likely to have stimulated high rates of diversification recovered in this group, with lineage accumulation rates comparable to those reported for adaptive radiations.