BackgroundThe Ampelopsis clade (Ampelopsis and its close allies) of the grape family Vitaceae contains ca. 43 species disjunctly distributed in Asia, Europe, North America, South America, Africa, and Australia, and is a rare example to study both the Northern and the Southern Hemisphere intercontinental disjunctions. We reconstruct the temporal and spatial diversification of the Ampelopsis clade to explore the evolutionary processes that have resulted in their intercontinental disjunctions in six continents.ResultsThe Bayesian molecular clock dating and the likelihood ancestral area analyses suggest that the Ampelopsis clade most likely originated in North America with its crown group dated at 41.2 Ma (95% HPD 23.4 - 61.0 Ma) in the middle Eocene. Two independent Laurasian migrations into Eurasia are inferred to have occurred in the early Miocene via the North Atlantic land bridges. The ancestor of the Southern Hemisphere lineage migrated from North America to South America in the early Oligocene. The Gondwanan-like pattern of intercontinental disjunction is best explained by two long-distance dispersals: once from South America to Africa estimated at 30.5 Ma (95% HPD 16.9 - 45.9 Ma), and the other from South America to Australia dated to 19.2 Ma (95% HPD 6.7 - 22.3 Ma).ConclusionsThe global disjunctions in the Ampelopsis clade are best explained by a diversification model of North American origin, two Laurasian migrations, one migration into South America, and two post-Gondwanan long-distance dispersals. These findings highlight the importance of both vicariance and long distance dispersal in shaping intercontinental disjunctions of flowering plants.

The phylogeny of Vitaceae was reconstructed sampling 114 accessions of Vitaceae and the outgroup Leea of Leeaceae, using three noncoding plastid markers: trnC-petN, trnH-psbA, and trnL-F. Six 5-merous genera including Parthenocissus, Yua, Ampelocissus, Vitis, Nothocissus, and Pterisanthes form a well-supported clade. Ampelopsis, Rhoicissus, and the Cissus striata complex form a clade sister to the clade containing all the other taxa of Vitaceae. The core Cissus clade is resolved to be sister to the Cayratia-Tetrastigma-Cyphostemma clade, forming a clade of taxa with 4-merous flowers. The Parthenocissus-Yua clade is sister to the Ampelocissus-Vitis-Nothocissus-Pterisanthes clade. The Old World Cissus is paraphyletic, with the New World core Cissus nested within it. The intercontinental disjunction between Africa and Asia may have evolved at least twice in Cissus. Cayratia is paraphyletic with four Asian species sampled grouping with Tetrastigma and the African species forming another clade.

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Background and aims -The Coastal Forests of Eastern Africa, stretching along the Indian Ocean coastline from Somalia to Mozambique, are considered by Conservation International to be a global biodiversity hotspot -an area of high diversity and endemism under increasing threat. Although the largest remaining extent of these forests is reported to be found in Mozambique, very little is known on their extent, condition and composition here. In addition, the term 'coastal forest' has been used in different ways by different authors. This paper defines and characterises coastal dry forests found in northern Mozambique and assesses their present extent, botanical composition, conservation importance and the threats to these forests. Methods -The study area of 18,150 km 2 lies in Cabo Delgado Province in north-east Mozambique, adjacent to Tanzania. Its limits are determined primarily by geological substrate and landform. Four smaller study sites were chosen covering a range of landforms. Manual interpretation of satellite imagery dating from 1999-2002 was used to calculate possible previous and present extent of 'dense vegetation'. Extensive field collecting was used in determining botanical composition and distribution patterns. IUCN Red List assessments were carried out on selected species using distributional criteria. Results -Dry forests similar to those in southern Tanzania are found widely scattered across coastal Cabo Delgado, sitting in a matrix of miombo woodland and other vegetation types. However, forest cover is not as extensive was believed. We calculate that the original extent of 'dense vegetation cover', which includes coastal dry forest, was 6087 km 2 . Owing to clearance over the last 150 years this is now only 1182 km 2 , of which perhaps only 400 km 2 is moderately-intact dry forest. In this southern part of their range such forests are essentially dry, not moist and mesic, and dominated by a high proportion of deciduous or sclerophyllous evergreen trees. The plant species composition differs significantly from that of the surrounding woodlands. There is a marked change in species composition between forest patches along the coast, and they contain numerous species with restricted global distribution. Since 2003, 68 species new to Mozambique have been recorded from Cabo Delgado in addition to 36 possible new species. Many new records are of species previously only known from south-eastern Tanzania. Previously recorded patterns of restricted distribution and high species turnover between forest patches in Kenya and Tanzania are confirmed. Seven coastal forest species were assessed as Endangered. Regional context and conservation -Coastal dry forests are discussed in relation to the more widespread 'sand forests' of the continental interior of south-central Africa, and shown to have similarities in ecology, species composition, soils and ecology. Very little of the present extent of coastal forests in Mozambique lies within protected areas. The threats to their continued existence in the face of explo...