A global trend towards the loss of evolutionarily unique species in mangrove ecosystems
- Authors: Daru, Barnabas H. , Yessoufou, Kowiyou , Mankga, Ledile T. , Davies, T. Jonathan
- Date: 2013
- Subjects: Mangrove ecology , Threatened species , Biodiversity conservation
- Type: Article
- Identifier: uj:5984 , http://hdl.handle.net/10210/8604
- Description: The mangrove biome stands out as a distinct forest type at the interface between terrestrial, estuarine, and near-shore marine ecosystems. However, mangrove species are increasingly threatened and experiencing range contraction across the globe that requires urgent conservation action. Here, we assess the spatial distribution of mangrove species richness and evolutionary diversity, and evaluate potential predictors of global declines and risk of extinction. We found that human pressure, measured as the number of different uses associated with mangroves, correlated strongly, but negatively, with extinction probability, whereas species ages were the best predictor of global decline, explaining 15% of variation in extinction risk. Although the majority of mangrove species are categorised by the IUCN as Least Concern, our finding that the more threatened species also tend to be those that are more evolutionarily unique is of concern because their extinction would result in a greater loss of phylogenetic diversity. Finally, we identified biogeographic regions that are relatively species-poor but rich in evolutionary history, and suggest these regions deserve greater conservation priority. Our study provides phylogenetic information that is important for developing a unified management plan for mangrove ecosystems worldwide.
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The first initiative of DNA barcoding of ornamental plants from Egypt and potential applications in horticulture industry
- Authors: Elansary, Hosam O. , Ashfaq, Muhammad , Ali, Hayssam M. , Yessoufou, Kowiyou
- Date: 2017
- Language: English
- Type: Articles
- Identifier: http://hdl.handle.net/10210/241494 , uj:24863 , Citation: O. Elansary H, Ashfaq M, Ali HM, Yessoufou K (2017) The first initiative of DNA barcoding of ornamental plants from Egypt and potential applications in horticulture industry. PLoS ONE 12(2): e0172170. doi:10.1371/journal. pone.0172170
- Description: Abstract: DNA barcoding relies on short and standardized gene regions to identify species. The agricultural and horticultural applications of barcoding such as for marketplace regulation and copyright protection remain poorly explored. This study examines the effectiveness of the standard plant barcode markers (matK and rbcL) for the identification of plant species in private and public nurseries in northern Egypt. These two markers were sequenced from 225 specimens of 161 species and 62 plant families of horticultural importance. The sequence recovery was similar for rbcL (96.4%) and matK (84%), but the number of specimens assigned correctly to the respective genera and species was lower for rbcL (75% and 29%) than matK (85% and 40%). The combination of rbcL and matK brought the number of correct generic and species assignments to 83.4% and 40%, respectively. Individually, the efficiency of both markers varied among different plant families; for example, all palm specimens (Arecaceae) were correctly assigned to species while only one individual of Asteraceae was correctly assigned to species. Further, barcodes reliably assigned ornamental horticultural and medicinal plants correctly to genus while they showed a lower or no success in assigning these plants to species and cultivars. For future, we recommend the combination of a complementary barcode (e.g. ITS or trnH-psbA) with rbcL + matK to increase the performance of taxa identification. By aiding species identification of horticultural crops and ornamental palms, the analysis of the barcode regions will have large impact on horticultural industry.
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Temporal analysis of electricity consumption for prepaid metered low and high income households in Soweto, South Africa
- Authors: Kambule, Njabulo , Yessoufou, Kowiyou , Nwulu, Nnamdi , Mbohwa, Charles
- Date: 2019
- Subjects: Electricity consumption , High income household , Low income household
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/404639 , uj:33942 , Citation : Kambule, N. et al. 2019: Temporal analysis of electricity consumption for prepaid metered low and high income households in Soweto, South Africa. , https://doi.org/10.1080/20421338.2018.1527983
- Description: Abstract : This study explores the temporal trend in electricity consumption since the introduction of prepaid meters in low income households of Soweto, and compares the findings with high income households. Monthly electricity consumption data (over 96 months: 2007-2014) on 4427 households in Soweto, for both low and high income households, was collected from Eskom. Using a simple linear model to analyse consumption trends in low income households, we ascertain that electricity consumption has decreased by 48% since the inception of prepaid meters. Nonetheless, it is noted that 60% of household incomes are spent on electricity bills, which is way above the threshold set for energy poverty. Comparatively, high income households consume lower electricity than low income households do. Overall, the prepaid meter programme is producing expected results for Eskom but remains a challenge for low income households, which are still entrenched in energy poverty. We call for an energy policy that is tailored for each income groups and the formulation of laws and policies to protect the energy vulnerable households.
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Exploring the driving factor on prepaid electricity meter rejecting the largest township of South Africa
- Authors: Kambule, Njabulo , Yessoufou, Kowiyou , Nwulu, Nnamdi , Mbohwa, Charles
- Date: 2019
- Subjects: Electricity consumption , Education , Prepaid electricity meter
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/406836 , uj:34221 , Citation: Kambule, N. et al. 2019. Exploring the driving factor on prepaid electricity meter rejecting the largest township of South Africa.
- Description: Abstract: Technology rejection phenomenon manifests itself differently across different societies. Over the past two decades, low income households in Soweto have persistently rejected prepaid electricity meters. Until now, the basis of the rejection in the region remains scientifically underexplored. We therefore conduct an exploratory study of pertaining prepaid meter rejection in Soweto. Through triangulation research and survey approach, 88 households based in Orlando East and Diepkloof were interviewed by means of a questionnaire. Our findings show that three aspects contributing to this phenomenon, namely: lack of quality consultation and education, the high levels of electricity consumption, and unattainable politically motivated promises are the main reasons that currently fuel prepaid meter rejection. We emphasise that the current state of the Free Basic Electricity (FBE) (2003) policy also fuels rejection, as it remains socio-economically inadequate and irrelevant for indigent households. We therefore note the need for an FBE policy review and update as well as the establishment of a policy monitoring committee to ensure implementation and enforcement.
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Revisiting species delimitation within the genus Oxystele using DNA barcoding approach
- Authors: Van Der Bank, Herman , Herbert, Dai , Greenfield, Richard , Yessoufou, Kowiyou
- Date: 2013
- Subjects: Oxystele , Trochoidea , DNA barcoding
- Type: Article
- Identifier: uj:5415 , http://hdl.handle.net/10210/10962
- Description: The genus Oxystele, a member of the highly diverse marine gastropod super-family Trochoidea, is endemic to southern Africa. Members of the genus include some of the most abundant molluscs on southern African shores and are important components of littoral biodiversity in rocky intertidal habitats. Species delimitation within the genus is still controversial, especially regarding the complex O. impervia/ O. variegata. Here, we assessed species boundaries within the genus using DNA barcoding and phylogenetic tree reconstruction. We analysed 56 specimens using the mitochondrial gene COI. Our analysis delimits five molecular operational taxonomic units (MOTUs), and distinguishes O. impervia from O. variegata. However, we reveal important discrepancies between MOTUs and morphology-based species identification and discuss alternative hypotheses that can account for this. Finally, we indicate the need for future study that includes additional genes, and the combination of both morphology and genetic techniques (e.g. AFLP or microsatellites) to get deeper insight into species delimitation within the genus.
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Phylogenetic analysis of plant community assemblages in the Kruger National Park, South Africa
- Authors: Yessoufou, Kowiyou
- Date: 2012-08-16
- Subjects: Plant communities , Kruger National Park (South Africa) , Cladistic analysis , Savanna ecology , Herbivores
- Type: Thesis
- Identifier: uj:9574 , http://hdl.handle.net/10210/5998
- Description: D.Phil. , What underlies species distribution and species coexistence has long been of key interest in community ecology. Several methods and theories have been used to address this question. However, it still remains a controversial debate. The recent development of plant DNA barcodes with possibility of merging phylogeny with ecology brings high expectation in uncovering the processes underlying community assemblages. Previous works that used molecular approach in community ecology focused mainly on rainforests. Using a phylogenetic approach, this study brings novel understandings about savanna ecology, especially regarding how megaherbivores impact plant community composition. The Kruger National Park (KNP) is one of the world’s largest reserves, but less studied from a phylogenetic perspective. A DNA database of 445 DNA sequences (plant DNA barcodes, rbcLa + matK) was generated for the woody plants of the KNP. This database proves reliable in reconstructing the phylogeny of Angiosperms of the park. Based on this phylogeny, the present study characterised plant community composition, and investigated how megaherbivores influence this composition. Results indicate that plant communities in the KNP are not neutral, i.e. they are more clustered than expected under various null models. This suggests that ecological forces, most likely habitat filtering may be playing key role in dictating community structure in the KNP. The KNP is well-known for its richness in megaherbivores. The contribution of these animals to the current shape of plant community structures was therefore further investigated. Where megaherbivores have been excluded, plant diversity decreases, but shifts in plant community structure are contingent upon the initial community composition, suggesting that herbivory might be important filter that drives the clustering pattern observed.
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Phylogenetic patterns of extinction risk in the Eastern Arc Ecosystems, an African biodiversity hotspot
- Authors: Yessoufou, Kowiyou , Daru, Barnabas H. , Davies, T. Jonathan
- Date: 2012
- Subjects: African biodiversity , Biodiversity , Ecosystems , Climate change , Phylogenetics , Eatern Arc Mountains
- Type: Article
- Identifier: uj:5853 , ISSN 1932-6203 , http://hdl.handle.net/10210/7950
- Description: There is an urgent need to reduce drastically the rate at which biodiversity is declining worldwide. Phylogenetic methods are increasingly being recognised as providing a useful framework for predicting future losses, and guiding efforts for preemptive conservation actions. In this study, we used a reconstructed phylogenetic tree of angiosperm species of the Eastern Arc Mountains – an important African biodiversity hotspot – and described the distribution of extinction risk across taxonomic ranks and phylogeny. We provide evidence for both taxonomic and phylogenetic selectivity in extinction risk. However, we found that selectivity varies with IUCN extinction risk category. Vulnerable species are more closely related than expected by chance, whereas endangered and critically endangered species are not significantly clustered on the phylogeny. We suggest that the general observation for taxonomic and phylogenetic selectivity (i.e. phylogenetic signal, the tendency of closely related species to share similar traits) in extinction risks is therefore largely driven by vulnerable species, and not necessarily the most highly threatened. We also used information on altitudinal distribution and climate to generate a predictive model of at-risk species richness, and found that greater threatened species richness is found at higher altitude, allowing for more informed conservation decision making. Our results indicate that evolutionary history can help predict plant susceptibility to extinction threats in the hyper-diverse but woefully-understudied Eastern Arc Mountains, and illustrate the contribution of phylogenetic approaches in conserving African floristic biodiversity where detailed ecological and evolutionary data are often lacking.
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Evidence of constant diversification punctuated by a mass extinction in the African cycads
- Authors: Yessoufou, Kowiyou , Bamigboye, Samuel O. , Daru, Barnabas H. , Van der Bank, Michelle
- Date: 2013
- Subjects: Encephalartos , Cycads - Africa , Extinction (Biology)
- Type: Article
- Identifier: uj:5410 , ISSN 2045-8827 , http://hdl.handle.net/10210/10051
- Description: 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.
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