Evidence of constant diversification punctuated by a mass extinction in the African cycads

The recent evidence that extant cycads are not living fossils triggered a renewed search for a better understanding of their evolutionary history. In this study, we investigated the evolutionary diversification history of the genus Encephalartos, a monophyletic cycad endemic to Africa. We found an antisigmoidal pattern with a plateau and punctual explosive radiation. This pattern is typical of a constant radiation with mass extinction. The rate shift that we found may therefore be a result of a rapid recolonization of niches that have been emptied owing to mass extinction. Because the explosive radiation occurred during the transition Pliocene–Pleistocene, we argued that the processes might have been climatically mediated

Unravelling the evolutionary origins of biogeographic assemblages

AIM : Floristic and faunal diversity fall within species assemblages that can be grouped into distinct biomes or ecoregions. Understanding the origins of such biogeographic assemblages helps illuminate the processes shaping present‐day diversity patterns and identifies regions with unique or distinct histories. While the fossil record is often sparse, dated phylogenies can provide a window into the evolutionary past of these regions. Here, we present a novel phylogenetic approach to investigate the evolutionary origins of present‐day biogeographic assemblages and highlight their conservation value. LOCATION : Southern Africa. METHODS : We evaluate the evolutionary turnover separating species clusters in space at different time slices to determine the phylogenetic depth at which the signal for their present‐day structure emerges. We suggest present‐day assemblages with distinct evolutionary histories might represent important units for conservation. We apply our method to the vegetation of southern Africa using a dated phylogeny of the woody flora of the region and explore how the evolutionary history of vegetation types compares to common conservation currencies, including species richness, endemism and threat. RESULTS : We show the differentiation of most present‐day vegetation types can be traced back to evolutionary splits in the Miocene. The woody flora of the Fynbos is the most evolutionarily distinct, and thus has deeper evolutionary roots, whereas the Savanna and Miombo Woodland show close phylogenetic affinities and likely represent a more recent separation. However, evolutionarily distinct phyloregions do not necessarily capture the most unique phylogenetic diversity, nor are they the most species‐rich or threatened. MAIN CONCLUSIONS : Our approach complements analyses of the fossil record and serves as a link to the history of diversification, migration and extinction of lineages within biogeographic assemblages that is separate from patterns of species richness and endemism. Our analysis reveals how phyloregions capture conservation value not represented by traditional biodiversity metrics.The Government of Canada through Genome Canada and Ontario Genomics Institute (2008‐OGI‐ICI‐03), International Development Research Centre (IDRC) and University of Johannesburg.http://wileyonlinelibrary.com/journal/ddi2019-03-01hj2018Plant Production and Soil Scienc

Report of the multidisciplinary investigation of differentiation and potential hybridisation between two Yellowfish species Labeobarbus Kimberleyensis and L. Aeneus from the Orange-Vaal system

From the executive summary]: The relationships within and between two yellowfish species, Labeobarbus aeneus (smallmouth yellowfish) and L. kimberleyensis (largemouth yellowfish) from the Orange-Vaal system were investigated through three independently conducted studies of the same material collected from the Sak River (the type locality of L. aeneus), the upper Orange River at Aliwal North and the lower Orange River at Pella and Onseepkans

Testing the reliability of standard and complementary DNA barcodes for the monocot subfamily Alooideae from South Africa

Although a standard DNA barcode has been identified for plants, it does not always provide species-level specimen identifications for investigating important ecological questions. In this study, we assessed the species-level discriminatory power of standard (rbcLa + matK) and complementary barcodes (ITS1 and trnH-psbA) within the subfamily Alooideae (Asphodelaceae), a large and recent plant radiation, whose species are important in horticulture yet are threatened. Alooideae has its centre of endemism in southern Africa, with some outlier species occurring elsewhere in Africa and Madagascar. We sampled 360 specimens representing 235 species within all 11 genera of the subfamily. With three distance-based methods, all markers performed poorly for our combined data set, with the highest proportion of correct species-level specimen identifications (30%) found for ITS1. However, when performance was assessed across genera, the discriminatory power varied from 0% for all single markers and combinations in Gasteria to 63% in Haworthiopsis, again for ITS1, suggesting that DNA barcoding success may be related to the evolutionary history of the lineage considered. Although ITS1 could be a good barcode for Haworthiopsis, the generally poor performance of all markers suggests that Alooideae remains a challenge. As species boundaries within Alooideae remain controversial, we call for continued search for suitable markers or the use of genomics approaches to further explore species discrimination in the group.The University of Johannesburg, the Royal Society of London, and the National Research Foundation of South Africa. Part of this project was also funded by the Government of Canada through Genome Canada and the Ontario Genomics Institute (2008-OGI-ICI-03).http://www.nrcresearchpress.com/journal/genPlant Scienc

Molecular and morphological analysis of subfamily Alooideae (Asphodelaceae) and the inclusion of chortolirion in aloe

Asphodelaceae subfam. Alooideae (Asparagales) currently comprises five genera, four of which are endemic to southern Africa. Despite their importance in commercial horticulture the evolutionary relationships among the genera are still incompletely understood. This study examines phylogenetic relationships in the subfamily using an expanded molecular sequence dataset from three plastid regions (matK, rbcLa, trnH-psbA) and the first subunit of the nuclear ribosomal internal transcribed spacer (ITS1). Sequence data were analysed using maximum parsimony and Bayesian statistics, and selected morphological traits were mapped onto the molecular phylogeny. Haworthia is confirmed as being polyphyletic, comprising three main clades that largely correlate with current subgeneric circumscriptions. Astroloba and Gasteria are evidently each monophyletic and sister respectively to Astroloba and H. subg. Robustipedunculares. Chortolirion is shown to be deeply nested within Aloe and is formally included in that genus. Aloe itself is clearly polyphyletic, with the dwarf species A. aristata allied to Haworthia subg. Robustipedunculares. The taxonomic implications of these findings are examined but branch support at critical lower nodes is insufficient at this stage to justify implementing major taxonomic changes

DNA barcodes reveal microevolutionary signals in fire response trait in two legume genera

Large-scale DNA barcoding provides a new technique for species identification and evaluation of relationships across various levels (populations and species) and may reveal fundamental processes in recently diverged species. Here, we analysed DNA sequence variation in the recently diverged legumes from the Psoraleeae (Fabaceae) occurring in the Cape Floristic Region (CFR) of southern Africa to test the utility of DNA barcodes in species identification and discrimination. We further explored the phylogenetic signal on fire response trait (reseeding and resprouting) at species and generic levels. We showed that Psoraleoid legumes of the CFR exhibit a barcoding gap yielding the combination of matK and rbcLa (matK + rbcLa) dataset as a better barcode than single regions. We found a high score (100%) of correct identification of individuals to their respective genera but very low score (<50%) in identifying them to species. We found a considerable match (54%) between genetic species and morphologicallydelimited species. We also found that different lineages showed a weak but significant phylogenetic conservatism in their response to fire as reseeders or resprouters, with more clustering of resprouters than would be expected by chance. These novel microevolutionary patterns might be acting continuously over time to produce multi-scale regularities of biodiversity. This study provides the first insight into the DNA barcoding campaign of land plants in species identification and detection of phylogenetic signal in recently diverged lineages of the CFR.The South African National Research Foundation (NRF; AMM); Nigeria Tertiary Education Trust Fund (NTETF) / Umaru Musa Yar’adua University Katsina, Nigeria (Fellowship Grant; A. Bello); and University of Cape Town, J. W. Jagger Centenary Gift Scholarship (to A. Bello).http://aobpla.oxfordjournals.orgam2016Physiotherap

Modelling the Impact of World Bank Policy-Based Lending: The Case of Malawi's Agricultural Sector

This article uses a multi-market agricultural pricing model to analyse the impact of the World Bank's three structural adjustment loans (SALs) to Malawi on the smallholder agricultural sector. Three price policy scenarios are simulated on the model representing zero, partial and full compliance with the Bank's SAL price policy conditionality. These scenarios are analysed in terms of their impact on: the government budget; smallholder real incomes; maize production; exportable cash crop production; and the balance of payments. Critiques of the Bank's programme and the government and Bank bargaining strategies are assessed in the light of the modelling results.

A novel phylogenetic regionalization of phytogeographical zones of southern Africa reveals their hidden evolutionary affinities

AIM : Although existing bioregional classification schemes often consider the compositional affinities within regional biotas, they do not typically incorporate phylogenetic information explicitly. Because phylogeny captures information on the evolutionary history of taxa, it provides a powerful tool for delineating biogeographical boundaries and for establishing relationships among them. Here, we present the first vegetation delineation of the woody flora of southern Africa based upon evolutionary relationships. LOCATION : Southern Africa. METHODS : We used a published time-calibrated phylogenetic tree for 1400 woody plant species along with their geographical distributions and a metric of phylogenetic beta diversity to generate a phylogenetic delineation of the woody vegetation of southern Africa. We then explored environmental correlates of phylogenetic turnover between them, and the evolutionary distinctiveness of the taxa within them. RESULTS : We identified 15 phylogenetically distinct biogeographical units, here referred to as phyloregions. The largest phyloregion broadly overlaps with Savanna vegetation, while the phyloregion overlapping with the south-western portion of the Fynbos biome is the most evolutionarily distinct. Potential evapotranspiration and mean annual temperature differ significantly among phyloregions and correlate with patterns of phylogenetic beta diversity between them. Our phylogeny-based delimitation of southern Africa’s woody vegetation broadly matches currently recognized phytogeographical classifications, but also highlights parts of the Namib Karoo and Greater Limpopo Transfrontier Park as distinct, but previously under-recognized biogeographical units. MAIN CONCLUSIONS : Our analysis provides new insights into the structure and phylogenetic relationships among the woody flora of southern Africa. We show that evolutionary affinities differentiate phyloregions closely resembling existing vegetation classifications, yet also identify ‘cryptic’ phyloregions that are as evolutionarily distinct as some of the recognized African vegetation types.Government of Canada through Genome Canada and the Ontario Genomics Institute (2008-OGI-ICI-03), the International Development Research Centre (IDRC) Canada, the University of Johannesburg and the South African National Research Foundation (NRF).http://onlinelibrary.wiley.com/doi/10.1111/jbi.126192017-01-31hb201

Baseline projections for Latin America: base-year assumptions, key drivers and greenhouse emissions

This paper provides an overview of the base-year assumptions and baseline projections for the set of models participating in the LAMP and CLIMACAP projects. We present the range in baseline projections for Latin America, and identify key differences between model projections including how these projections compare to historic trends. We find relatively large differences across models in base year assumptions related to population, GDP, energy and CO2 emissions due to the use of different data sources, but also conclude that this does not influence the range of projections. We find that population and GDP projections across models span a broad range, comparable to the range represented by the set of Shared Socioeconomic Pathways (SSPs). Kaya-factor decomposition indicates that the set of baseline scenarios mirrors trends experienced over the past decades. Emissions in Latin America are projected to rise as a result of GDP and population growth and a minor shift in the energy mix toward fossil fuels. Most scenarios assume a somewhat higher GDP growth than historically observed and continued decline of population growth. Minor changes in energy intensity or energy mix are projected over the next few decades

Financing SME growth in the UK: meeting the challenges after the global financial crisis

In the aftermath of the Global Financial Crisis new forms of SME finance are emerging in the place of traditional banking and equity finance sources. This Special Issue has its origins in a conference organised in June 2014 by the Centre for Enterprise and Economic Development Research (CEEDR) at Middlesex University Business School, where all but the final two papers were presented. The Conference was designed to provide a timely forum for leading academics, practitioners and policy makers to disseminate current research and practitioner knowledge exploring finance gaps and how best to address the financing needs of small high growth potential businesses