Exploring the floristic diversity of tropical Africa

Abstract

BackgroundUnderstanding the patterns of biodiversity distribution and what influences them is a fundamental pre-requisite for effective conservation and sustainable utilisation of biodiversity. Such knowledge is increasingly urgent as biodiversity responds to the ongoing effects of global climate change. Nowhere is this more acute than in species-rich tropical Africa, where so little is known about plant diversity and its distribution. In this paper, we use RAINBIO – one of the largest mega-databases of tropical African vascular plant species distributions ever compiled – to address questions about plant and growth form diversity across tropical Africa.ResultsThe filtered RAINBIO dataset contains 609,776 georeferenced records representing 22,577 species. Growth form data are recorded for 97% of all species. Records are well distributed, but heterogeneous across the continent. Overall, tropical Africa remains poorly sampled. When using sampling units (SU) of 0.5°, just 21 reach appropriate collection density and sampling completeness, and the average number of records per species per SU is only 1.84. Species richness (observed and estimated) and endemism figures per country are provided. Benin, Cameroon, Gabon, Ivory Coast and Liberia appear as the botanically best-explored countries, but none are optimally explored. Forests in the region contain 15,387 vascular plant species, of which 3013 are trees, representing 5–7% of the estimated world’s tropical tree flora. The central African forests have the highest endemism rate across Africa, with approximately 30% of species being endemic.ConclusionsThe botanical exploration of tropical Africa is far from complete, underlining the need for intensified inventories and digitization. We propose priority target areas for future sampling efforts, mainly focused on Tanzania, Atlantic Central Africa and West Africa. The observed number of tree species for African forests is smaller than those estimated from global tree data, suggesting that a significant number of species are yet to be discovered. Our data provide a solid basis for a more sustainable management and improved conservation of tropical Africa’s unique flora, and is important for achieving Objective 1 of the Global Strategy for Plant Conservation 2011–2020. In turn, RAINBIO provides a solid basis for a more sustainable management and improved conservation of tropical Africa’s unique flora.Electronic supplementary materialThe online version of this article (doi:10.1186/s12915-017-0356-8) contains supplementary material, which is available to authorized users.

A revision of the Old World Black Nightshades (Morelloid clade of Solanum L., Solanaceae)

“…Smith et al (2000) found only weak relationships between populations of two bird species along the Cameroon line, suggesting they evolved by allopatry. Plant diversity in this area is amongst the highest in tropical Africa (Sosef et al 2017), but despite having within it some well-sampled units (e.g. Mount Cameroon), the northern extent of the escarpment is very poorly sampled (Sosef et al 2017: 12, fig.…”

“…Plant diversity in this area is amongst the highest in tropical Africa (Sosef et al 2017), but despite having within it some well-sampled units (e.g. Mount Cameroon), the northern extent of the escarpment is very poorly sampled (Sosef et al 2017: 12, fig. 7).…”

Amazon plant diversity revealed by a taxonomically verified species list

“…Our study highlights the importance of taxonomically verified checklists as baseline infrastructures for engaging in accurate science. Checklists and floras, when vouchered and verified taxonomically, provide a falsifiable list of names on which further knowledge can be built (16,24,25,62). Until now, no taxonomically verified checklist of seed plants or trees has been available for the Amazon rain forest.…”

“…Although in theory this data mining approach enables rapid construction of preliminary regional and continental lists, it cannot be a substitute for expertly vetted checklists (62). To emphasize the perils of scientifically unsound and taxonomically unverified lists as the basis of ecological analyses, previous aggregated checklists including many non-Amazonian species, such as species from the high-elevation Andes, temperate Chile, and the Old World, would lead to extremely misleading conclusions on the phylogenetic community structure of lowland Amazonian forests.…”

Big data of tree species distributions: how big and how good?

“…4, Inset 3). These differences result from colonial history, but also from incomplete digitization of existing records (Figueiredo et al 2009;Sosef 2016;Gilles et al 2016;Sosef et al 2017). In addition, important conflicts in such biodiverse regions make ongoing data collections difficult (Hanson 2011).…”