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Prof. Nigel Barker
University of Pretoria, Pretoria 0002, South Africa

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0 Biogeography
0 Conservation
0 Phylogenetics
0 phylogeography
0 Mountain Ecology

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Journal article
Published: 30 July 2021 in Sustainability
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The Maloti-Drakensberg (MD) is the largest and highest-elevation mountain system in southern Africa. Covering 40,000 km2 and reaching 3500 m, the MD provides a range of ecosystem services (ES) to the entire southern African region—benefitting diverse users and extending well beyond the mountains. Rapid socioecological change threatens the provision of ES and presents multidimensional challenges to sustainable development. However, the continued land degradation and persisting socioeconomic problems indicate that development policy has not been effective in tackling these issues. In this paper, a multidisciplinary literature review forms the basis of a discussion which takes an ES framing to scrutinise the multidimensional social, political, economic and cultural issues in the study area. Three critical management systems are presented, and their associated ES are discussed, namely, water transfer, rangelands and conservation and tourism. In particular, the diversity of ES uses and values in the MD is considered. The results reveal the main drivers of continued unsustainable development and highlight important information gaps.

ACS Style

Jess Delves; V. Clark; Stefan Schneiderbauer; Nigel Barker; Jörg Szarzynski; Stefano Tondini; João Vidal; Andrea Membretti. Scrutinising Multidimensional Challenges in the Maloti-Drakensberg (Lesotho/South Africa). Sustainability 2021, 13, 8511 .

AMA Style

Jess Delves, V. Clark, Stefan Schneiderbauer, Nigel Barker, Jörg Szarzynski, Stefano Tondini, João Vidal, Andrea Membretti. Scrutinising Multidimensional Challenges in the Maloti-Drakensberg (Lesotho/South Africa). Sustainability. 2021; 13 (15):8511.

Chicago/Turabian Style

Jess Delves; V. Clark; Stefan Schneiderbauer; Nigel Barker; Jörg Szarzynski; Stefano Tondini; João Vidal; Andrea Membretti. 2021. "Scrutinising Multidimensional Challenges in the Maloti-Drakensberg (Lesotho/South Africa)." Sustainability 13, no. 15: 8511.

Research article
Published: 19 March 2021 in Journal of Natural History
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A new phytoseiids species, Typhlodromus (Anthoseius) uhoneae sp.n. is described from plants with domatia. In addition, 8 known phytoseiid species also associated with plants with domatia are discussed. A key to all the South African species of the subgenus Anthoseius is given. LSIDurn:lsid:zoobank.org:pub:F933C219-C363-49D5-8CA2-706013CF540C

ACS Style

E. A. Ueckermann; Sivuyisiwe Situngu; Nigel P. Barker. Checklist of Phytoseiidae (Acari: Mesostigmata) species from plants bearing leaf domatia, from the Eastern Cape Province, South Africa, with the description of a new species. Journal of Natural History 2021, 55, 683 -697.

AMA Style

E. A. Ueckermann, Sivuyisiwe Situngu, Nigel P. Barker. Checklist of Phytoseiidae (Acari: Mesostigmata) species from plants bearing leaf domatia, from the Eastern Cape Province, South Africa, with the description of a new species. Journal of Natural History. 2021; 55 (11-12):683-697.

Chicago/Turabian Style

E. A. Ueckermann; Sivuyisiwe Situngu; Nigel P. Barker. 2021. "Checklist of Phytoseiidae (Acari: Mesostigmata) species from plants bearing leaf domatia, from the Eastern Cape Province, South Africa, with the description of a new species." Journal of Natural History 55, no. 11-12: 683-697.

Journal article
Published: 03 March 2021 in African Journal of Range & Forage Science
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Rangeland conditions in the Lesotho highland dam catchment areas is important for local livelihoods and regional water supply. We investigated changes in land cover and condition from 1991 (before construction) to 2013, using Landsat imagery. The Normalised Difference Vegetation Index (NDVI) decreased in the catchment areas, while increasing within two protected areas. NDVI decreases were greatest close to the dams and in the high altitude summer grazing areas. Land cover maps were generated for 1993, 2005 and 2013, using structural vegetation classes, as well as categories of grassland based on NDVI. High altitude areas were characterised by grasslands changing to lower NDVI categories, indicating overgrazing in climax sourveld grasslands. Mid-altitude areas were characterised by grasslands changing to higher NDVI categories and increases in woody vegetation, indicating overgrazing in Sweetveld. At lower altitudes, the increase in cultivated areas suggested disproportionately high population growth in the catchment areas. The results suggest that there has been widespread degradation that appears to be more as a result of overgrazing than climate change. The study demonstrates the importance of using a combination of land cover, NDVI and field data in assessing degradation. Natural capital accounting methods provide a useful framework for documenting, monitoring and understanding changes in ecosystem condition.

ACS Style

Jane Turpie; Grant Benn; Mark Thompson; Nigel Barker. Accounting for land cover changes and degradation in the Katse and Mohale Dam catchments of the Lesotho highlands. African Journal of Range & Forage Science 2021, 38, 53 -66.

AMA Style

Jane Turpie, Grant Benn, Mark Thompson, Nigel Barker. Accounting for land cover changes and degradation in the Katse and Mohale Dam catchments of the Lesotho highlands. African Journal of Range & Forage Science. 2021; 38 (1):53-66.

Chicago/Turabian Style

Jane Turpie; Grant Benn; Mark Thompson; Nigel Barker. 2021. "Accounting for land cover changes and degradation in the Katse and Mohale Dam catchments of the Lesotho highlands." African Journal of Range & Forage Science 38, no. 1: 53-66.

Preprint content
Published: 01 April 2020
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Mitochondrial DNA (mtDNA) has long been used to date the divergence between species, and to explore the time when species’ effective population sizes changed. The idea that mitochondrial DNA is useful for molecular dating rests on the premise that its evolution is neutral. This premise was questionable to begin with, and even though it has long been challenged, the evidence against clock-like evolution of mtDNA is usually ignored. Here, we present a particularly clear and simple example to illustrate the implications of violations of the assumption of selective neutrality. DNA sequences were generated for the mtDNA COI gene and the nuclear 28S rRNA of two closely related and widely distributed rocky shore snails whose geographical ranges are defined by different thermal preferences. To our knowledge, this is the first study to use nuclear rRNA sequence for studying species-level genealogies instead of phylogenetics, presumably because this marker is considered to be uninformative at this taxonomic level. Even though the COI gene evolves at least an order of magnitude faster, which was reflected in high inter-specific divergence, intraspecific genetic variation was similar for both markers. As a result, estimates of population expansion times based on mismatch distributions were completely different for the two markers. Assuming that 28S evolves effectively clock-like, these findings likely illustrate variation-reducing purifying selection in mtDNA at the species level, and an elevated divergence rate caused by divergent selection between the two species. Although these two selective forces together make mtDNA suitable as a DNA barcoding marker because they create a ‘barcoding gap’, estimates of demographic change can be expected to be highly unreliable. Our study contributes to the growing evidence that the utility of mtDNA beyond DNA barcoding is limited.

ACS Style

Tshifhiwa Given Matumba; Jody Oliver; Nigel P. Barker; Christopher D. McQuaid; Peter R. Teske. Purifying selection can reduce intraspecific mitochondrial gene variation to that of nuclear rRNA. 2020, 1 .

AMA Style

Tshifhiwa Given Matumba, Jody Oliver, Nigel P. Barker, Christopher D. McQuaid, Peter R. Teske. Purifying selection can reduce intraspecific mitochondrial gene variation to that of nuclear rRNA. . 2020; ():1.

Chicago/Turabian Style

Tshifhiwa Given Matumba; Jody Oliver; Nigel P. Barker; Christopher D. McQuaid; Peter R. Teske. 2020. "Purifying selection can reduce intraspecific mitochondrial gene variation to that of nuclear rRNA." , no. : 1.

Journal article
Published: 18 February 2020 in Diversity
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Some plant species possess structures known as leaf domatia, which house mites. The association between domatia-bearing plants and mites has been proposed to be mutualistic, and has been found to be important in species of economic value, such as grapes, cotton, avocado and coffee. This is because leaf domatia affect the distribution, diversity and abundance of predatory and mycophagous mites found on the leaf surface. As a result, plants are thought to benefit from increased defence against pathogens and small arthropod herbivores. This study assesses the relative diversity and composition of mites on an economically important plant host (Coffea aribica) in comparison to mites found in a neighbouring indigenous forest in South Africa. Our results showed that the coffee plantations were associated with only predatory mites, some of which are indigenous to South Africa. This indicates that coffee plantations are able to be successfully colonised by indigenous beneficial mites. We also found an “edge effect”, in that coffee trees at the edge of the plantation hosted fewer mite species. These results are a snap-shot from a single sampling period. Nonetheless, they highlight the potential importance of this mutualism in commercial crop species and the possible role of faunal exchanges between indigenous and exotic crop species. This study expands our understanding of the mite–plant mutualism in Southern Africa, a region where acarological studies are sparse.

ACS Style

Sivuyisiwe Situngu; Nigel P. Barker; Susanne Vetter. A Snap-Shot of Domatial Mite Diversity of Coffea arabica in Comparison to the Adjacent Umtamvuna Forest in South Africa. Diversity 2020, 12, 79 .

AMA Style

Sivuyisiwe Situngu, Nigel P. Barker, Susanne Vetter. A Snap-Shot of Domatial Mite Diversity of Coffea arabica in Comparison to the Adjacent Umtamvuna Forest in South Africa. Diversity. 2020; 12 (2):79.

Chicago/Turabian Style

Sivuyisiwe Situngu; Nigel P. Barker; Susanne Vetter. 2020. "A Snap-Shot of Domatial Mite Diversity of Coffea arabica in Comparison to the Adjacent Umtamvuna Forest in South Africa." Diversity 12, no. 2: 79.

Journal article
Published: 21 January 2020 in Phytotaxa
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Veltheimia is a genus of two species of bulbous flowering angiosperms restricted to southern Africa. Both parsimony and Bayesian analysis of 1829 nucleotides of DNA sequence data, from three non-coding chloroplast regions from multiple samples of both species, indicates that specimens of V. bracteata form a monophyletic clade together with three specimens named as V. capensis. This clade receives low support and is embedded within a paraphyletic grade of specimens of V. capensis. A Median Joining Network analysis of a subset of samples revealed nine haplotypes, the relationships of which mirrored the relationships resolved by the Bayesian analysis. With the exception of the V. capensis members of the V. bracteata clade, the remaining specimens are from the summer rainfall thicket and coastal forests. The samples of the basal V. capensis grade are found in the winter rainfall regions of southern Africa. These results indicate that there is limited genetic diversity within the genus, and there is no clear distinction between these two species based on plastid non-coding DNA data. This may be due to their recent divergence and incomplete lineage sorting, or recent or ongoing hybridisation and / or introgression.

ACS Style

Nigel P. Barker; Tamika Fellows; Ntombifikile Phaliso; John Rourke. Genetic diversity and species limits in Veltheimia (Asparagaceae: Scilloideae): insights from noncoding cpDNA sequence data. Phytotaxa 2020, 429, 239 -247.

AMA Style

Nigel P. Barker, Tamika Fellows, Ntombifikile Phaliso, John Rourke. Genetic diversity and species limits in Veltheimia (Asparagaceae: Scilloideae): insights from noncoding cpDNA sequence data. Phytotaxa. 2020; 429 (3):239-247.

Chicago/Turabian Style

Nigel P. Barker; Tamika Fellows; Ntombifikile Phaliso; John Rourke. 2020. "Genetic diversity and species limits in Veltheimia (Asparagaceae: Scilloideae): insights from noncoding cpDNA sequence data." Phytotaxa 429, no. 3: 239-247.

Journal article
Published: 25 November 2019 in Zoological Journal of the Linnean Society
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Mitochondrial DNA sequences (1137 bp) of the cytochrome b gene and craniodental and craniometric data were used to investigate the evolutionary relationships of six putative rodent taxa of Otomys (family Muridae: subfamily Murinae: tribe Otomyini) co-occurring in the Western Cape and Eastern Cape provinces of South Africa. Phylogenetic analysis of 20 new sequences together with craniodental and craniometric characters of 94 adult skulls reveal the existence of a unique lineage of Otomys cf. karoensis (named herein Otomys willani sp. nov.) from the Sneeuberg Centre of Floristic Endemism in the southern Drakensberg Mountain Range. Craniometric analysis distinguished O. karoensis from O. willani and identified a further four localities in the range of the latter species. We document southern range extensions of both Sloggett’s ice rat, Otomys sloggetti, and the vlei rat Otomys auratus to the Sneeuberg Mountain Range, in addition to appreciable genetic divergence between Sneeuberg and southern and central Drakensberg populations of O. sloggetti. Our results demonstrate parallel patterns of cryptic speciation in two co-occurring species complexes (Otomys irroratus s.l. and O. karoensis s.l.) associated closely with the boundaries of biomes (fynbos vs. grassland biomes) and geological formations (Cape Fold Belt vs. Great Escarpment).

ACS Style

Peter John Taylor; Teresa Kearney; Desire Lee Dalton; Gamuchirai Chakona; Christopher M R Kelly; Nigel P Barker. Biomes, geology and past climate drive speciation of laminate-toothed rats on South African mountains (Murinae: Otomys). Zoological Journal of the Linnean Society 2019, 189, 1046 -1066.

AMA Style

Peter John Taylor, Teresa Kearney, Desire Lee Dalton, Gamuchirai Chakona, Christopher M R Kelly, Nigel P Barker. Biomes, geology and past climate drive speciation of laminate-toothed rats on South African mountains (Murinae: Otomys). Zoological Journal of the Linnean Society. 2019; 189 (3):1046-1066.

Chicago/Turabian Style

Peter John Taylor; Teresa Kearney; Desire Lee Dalton; Gamuchirai Chakona; Christopher M R Kelly; Nigel P Barker. 2019. "Biomes, geology and past climate drive speciation of laminate-toothed rats on South African mountains (Murinae: Otomys)." Zoological Journal of the Linnean Society 189, no. 3: 1046-1066.

Review article
Published: 17 September 2019 in Ecosystem Services
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Southern African mountains remain poorly studied as social-ecological systems (SES) and are poorly represented in the global mountain discourse. However, these mountains provide essential ecosystem services (ES) that underpin local and regional development. Quantitative data on ES, their representation in policy, and the political will for sustainable management are limited. We demonstrate this using the Manica Highlands (MH; Zimbabwe—Mozambique): benefiting one million immediate and five million downstream beneficiaries, the seven identified ES are supported in the literature but lack recent quantitative data needed to persuade policymakers for action to promote sustainability. The ES are most at risk from mining, alien invasive species, rapid land transformation, and climate change – yet fine-scale quantitative data to inform mountain-specific policy on these are also lacking. We recommend a ‘science to policy to action’ agenda for the MH, but highlight that the greatest challenge to achieving sustainability is a lack of effective governance; therefore it may be difficult to change ‘immediate benefits’-thinking to higher ideals that would render the ES of the MH sustainable. As a result, academics, civic society, policy makers and governance instruments should work closely together to quantify the value of the MH, and to formulate specific policy for the MH.

ACS Style

V. Ralph Clark; João De Deus Vidal; Isla M. Grundy; Togarasei Fakarayi; Susan L. Childes; Nigel P. Barker; H. Peter Linder. Bridging the divide between intuitive social-ecological value and sustainability in the Manica Highlands of southern Africa (Zimbabwe-Mozambique). Ecosystem Services 2019, 39, 100999 .

AMA Style

V. Ralph Clark, João De Deus Vidal, Isla M. Grundy, Togarasei Fakarayi, Susan L. Childes, Nigel P. Barker, H. Peter Linder. Bridging the divide between intuitive social-ecological value and sustainability in the Manica Highlands of southern Africa (Zimbabwe-Mozambique). Ecosystem Services. 2019; 39 ():100999.

Chicago/Turabian Style

V. Ralph Clark; João De Deus Vidal; Isla M. Grundy; Togarasei Fakarayi; Susan L. Childes; Nigel P. Barker; H. Peter Linder. 2019. "Bridging the divide between intuitive social-ecological value and sustainability in the Manica Highlands of southern Africa (Zimbabwe-Mozambique)." Ecosystem Services 39, no. : 100999.

Journal article
Published: 27 November 2018 in PhytoKeys
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This paper aims to provide a baseline for conservation planning by documenting patterns of plant diversity and vegetation in the upper catchment of the Cuito River. 417 species are recorded from this region. Nine of these are species potentially new to science. Ten species are newly recorded from Angola, with an additional species only recorded previously within Angola from the northern enclave of Cabinda. The 108 new provincial records for Moxico clearly indicate the lack of collections from Angola’s largest province. We note the existence of extensive peat deposits in the Cuito river system for the first time and suggest that one of Barbosa’s vegetation types in the area needs to be reassessed.

ACS Style

David J. Goyder; Nigel Barker; Stoffel P. Bester; Arnold Frisby; Matt Janks; Francisco M.P. Gonçalves. The Cuito catchment of the Okavango system: a vascular plant checklist for the Angolan headwaters. PhytoKeys 2018, 113, 1 -31.

AMA Style

David J. Goyder, Nigel Barker, Stoffel P. Bester, Arnold Frisby, Matt Janks, Francisco M.P. Gonçalves. The Cuito catchment of the Okavango system: a vascular plant checklist for the Angolan headwaters. PhytoKeys. 2018; 113 (113):1-31.

Chicago/Turabian Style

David J. Goyder; Nigel Barker; Stoffel P. Bester; Arnold Frisby; Matt Janks; Francisco M.P. Gonçalves. 2018. "The Cuito catchment of the Okavango system: a vascular plant checklist for the Angolan headwaters." PhytoKeys 113, no. 113: 1-31.

Original paper
Published: 05 October 2018 in Biodiversity and Conservation
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Global climate change is a major challenge for the future with serious potential impacts on biodiversity. Biodiversity in mountains is particularly vulnerable as many montane species are adapted to narrow microhabitats, making them less able to adjust to a climatic change. It is considered important to investigate range changes in the South African Great Escarpment because of the high levels of biodiversity in these mountains, as well as their importance for water provision in South Africa. The current and future ranges of 46 montane plant species in South Africa and Lesotho were therefore modelled using biomod in R, using presence points and predictor variables which included rainfall and temperature worldclim layers. The performance of distribution models produced was evaluated using the Area Under the receiver operating Curve (AUC), True Skill Statistic (TSS), Sensitivity and Specificity. We calculated beta diversity and species richness changes between current and future climates for the group of 46 species, as well as shifts of the predicted presence region boundaries and centroids. We also analysed shifts in minimum, median and maximum elevations. Results show a contraction in species’ ranges towards higher elevation as has been documented from other mountain regions around the world. These results are a cause for concern as a warming climate is decreasing the potential regions of occurrence of montane species in South Africa and Lesotho’s mountainous regions of high biodiversity. This region is under a diverse range of conservation and land use management practises, and our results suggest a coordinated response to climate change is needed.

ACS Style

Luke K. Bentley; Mark P. Robertson; Nigel P. Barker. Range contraction to a higher elevation: the likely future of the montane vegetation in South Africa and Lesotho. Biodiversity and Conservation 2018, 28, 131 -153.

AMA Style

Luke K. Bentley, Mark P. Robertson, Nigel P. Barker. Range contraction to a higher elevation: the likely future of the montane vegetation in South Africa and Lesotho. Biodiversity and Conservation. 2018; 28 (1):131-153.

Chicago/Turabian Style

Luke K. Bentley; Mark P. Robertson; Nigel P. Barker. 2018. "Range contraction to a higher elevation: the likely future of the montane vegetation in South Africa and Lesotho." Biodiversity and Conservation 28, no. 1: 131-153.

Journal article
Published: 12 September 2018 in Journal of Crustacean Biology
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The need for highly-variable, nuclear microsatellite markers to accurately determine population genetic structure and infer patterns of gene flow and dispersal in true freshwater crabs of the genus PotamonautesMacLeay, 1838 (Potamonautidae) was raised more than a decade ago. The present study uses a shotgun genomic approach, next-generation sequencing and a bioinformatics pipeline designed for isolating microsatellites from Illumina sequence read data to isolate di- and tetra-nucleotide repeat microsatellites for Potamonautes danielsiPeer, Gouws, Lazo-Wasem, Perissinotto & Miranda, 2017 from data produced by a fraction of a MiSeq run. Twelve loci were initially identified, with reproducible amplification of eight loci in the target species. Compiled in two multiplex reactions, all eight loci were polymorphic with between three and 15 alleles. Evaluated according to PIC, three loci were considered to be highly informative and four as reasonably informative. Cross-amplification success was evaluated by screening loci for three species (P. lividusGouws, Stewart & Reavell, 2001, P. principeCumberlidge, Clark & Baillie, 2002 and P. sidneyi (Rathbun, 1904)) representing varying degrees of phylogenetic relatedness to P. danielsi. Cross-amplification attenuated along with relatedness, with seven loci being successfully amplified P. lividus and P. sidneyi, and four in P. principe. The number of polymorphic loci was further reduced and, for P. sidneyi at least, individual amplification success was low. Nonetheless, the present study does present a microsatellite panel that can be applied to population genetic studies of the widespread P. danielsi and has some potential for closely-related species. This is only the third microsatellite panel to be developed for the true freshwater crabs.

ACS Style

Gavin Gouws; Savel R Daniels; Angus H Macdonald; Albert Chakona; Nigel P Barker. Development and characterization of a microsatellite library for the freshwater crab Potamonautes danielsi Peer, Gouws, Lazo-Wasem, Perissinotto & Miranda, 2017 (Brachyura: Potamonautidae) and its transferability across three congeneric species. Journal of Crustacean Biology 2018, 1 .

AMA Style

Gavin Gouws, Savel R Daniels, Angus H Macdonald, Albert Chakona, Nigel P Barker. Development and characterization of a microsatellite library for the freshwater crab Potamonautes danielsi Peer, Gouws, Lazo-Wasem, Perissinotto & Miranda, 2017 (Brachyura: Potamonautidae) and its transferability across three congeneric species. Journal of Crustacean Biology. 2018; ():1.

Chicago/Turabian Style

Gavin Gouws; Savel R Daniels; Angus H Macdonald; Albert Chakona; Nigel P Barker. 2018. "Development and characterization of a microsatellite library for the freshwater crab Potamonautes danielsi Peer, Gouws, Lazo-Wasem, Perissinotto & Miranda, 2017 (Brachyura: Potamonautidae) and its transferability across three congeneric species." Journal of Crustacean Biology , no. : 1.

Mini review article
Published: 15 August 2018 in Frontiers in Plant Science
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Plants have developed morphological, physiological, biochemical, cellular, and molecular mechanisms to survive in drought-stricken environments with little or no water caused by below-average precipitation. In this mini-review, we highlight the characteristics that allows marama bean [Tylosema esculentum (Burchell) Schreiber], an example of an orphan legume native to arid regions of southwestern Southern Africa, to flourish under an inhospitable climate and dry soil conditions where no other agricultural crop competes in this agro-ecological zone. Orphan legumes are often better suited to withstand such harsh growth environments due to development of survival strategies using a combination of different traits and responses. Recent findings on questions on marama bean speciation, hybridization, population dynamics, and the evolutionary history of the bean and mechanisms by which the bean is able to extract and conserve water and nutrients from its environment as well as aspects of morphological and physiological adaptation will be reviewed. The importance of the soil microbiome and the genetic diversity in this species, and their interplay, as a reservoir for improvement will also be considered. In particular, the application of the newly established marama bean genome sequence will facilitate both the identification of important genes involved in the interaction with the soil microbiome and the identification of the diversity within the wild germplasm for genes involved drought tolerance. Since predicted future changes in climatic conditions, with less water availability for plant growth, will severely affect agricultural productivity, an understanding of the mechanisms of unique adaptations in marama bean to such conditions may also provide insights as to how to improve the performance of the major crops.

ACS Style

Christopher Cullis; Percy Chimwamurombe; Nigel Barker; Karl Kunert; Juan Vorster. Orphan Legumes Growing in Dry Environments: Marama Bean as a Case Study. Frontiers in Plant Science 2018, 9, 1 .

AMA Style

Christopher Cullis, Percy Chimwamurombe, Nigel Barker, Karl Kunert, Juan Vorster. Orphan Legumes Growing in Dry Environments: Marama Bean as a Case Study. Frontiers in Plant Science. 2018; 9 ():1.

Chicago/Turabian Style

Christopher Cullis; Percy Chimwamurombe; Nigel Barker; Karl Kunert; Juan Vorster. 2018. "Orphan Legumes Growing in Dry Environments: Marama Bean as a Case Study." Frontiers in Plant Science 9, no. : 1.

Original paper
Published: 17 February 2018 in Biodiversity and Conservation
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This study evaluates how a modelling approach to determine areas of suitable habitat for the Critically Endangered Albany cycad Encephalartos latifrons can assist in systematic conservation planning for this and other rare and threatened cycads. A map distinguishing suitable from unsuitable habitat for E. latifrons was produced and important environmental predictors (climate, geology, topography and vegetation) influencing the suitable habitat were estimated. The maximum entropy (MaxEnt) modelling technique was chosen for this study as it has consistently performed well compared with alternative modelling methods and is also an appropriate model choice when the sample size is small and locality records are relatively few. Predicted habitat suitability showed that some locations chosen for translocation and restoration of E. latifrons specimens are not suitable. This revealed that modelling suitable habitat can guide relocation and regeneration of E. latifrons and perhaps other threatened cycads with restricted distributions and few locality records. The species distribution model constructed for E. latifrons is the first reported habitat model for a Critically Endangered cycad in South Africa. The results may be incorporated into conservation planning and structured decision-making about translocations and restoration programmes involving vulnerable cycads, which are among the most threatened organisms globally.

ACS Style

Carin Swart; John Donaldson; Nigel Barker. Predicting the distribution of Encephalartos latifrons, a critically endangered cycad in South Africa. Biodiversity and Conservation 2018, 27, 1961 -1980.

AMA Style

Carin Swart, John Donaldson, Nigel Barker. Predicting the distribution of Encephalartos latifrons, a critically endangered cycad in South Africa. Biodiversity and Conservation. 2018; 27 (8):1961-1980.

Chicago/Turabian Style

Carin Swart; John Donaldson; Nigel Barker. 2018. "Predicting the distribution of Encephalartos latifrons, a critically endangered cycad in South Africa." Biodiversity and Conservation 27, no. 8: 1961-1980.

Journal article
Published: 01 December 2017 in Molecular Phylogenetics and Evolution
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Southern Africa is a biodiversity hotspot of patellid limpets, with three genera (Helcion, Cymbula and Scutellastra) identified and described in the region. Scutellastra is the most diverse and most frequently studied of these and, along with Cymbula, includes species with territorial and non-territorial foraging behaviours. We used three mitochondrial markers (12S rRNA, 16S rRNA and COI) and one nuclear marker (ATPSβ intron) to assess evolutionary relationships among species of Cymbula and Scutellastra with these two foraging behaviours and to identify which foraging mode is the more ancient. Maximum Likelihood and Bayesian Inference phylogenetic analyses revealed that the species sharing a foraging type are monophyletic in both genera. Territoriality is a derived character, as the clades with this foraging type are nested within a tree that otherwise comprises non-territorial taxa. These include Helcion, which was recovered as sister to the Cymbula/Scutellastra clade, and the next basal genus, Patella, which is ancestral to all southern African patellogastropods. Deep genetic divergence between the two foraging traits reflects strong adaptive effects of resource partitioning in the evolution of southern African patellid limpets.

ACS Style

Kolobe L. Mmonwa; Peter Teske; Christopher McQuaid; Nigel Barker. Evolution of foraging behaviour: Deep intra-generic genetic divergence between territorial and non-territorial southern African patellid limpets. Molecular Phylogenetics and Evolution 2017, 117, 95 -101.

AMA Style

Kolobe L. Mmonwa, Peter Teske, Christopher McQuaid, Nigel Barker. Evolution of foraging behaviour: Deep intra-generic genetic divergence between territorial and non-territorial southern African patellid limpets. Molecular Phylogenetics and Evolution. 2017; 117 ():95-101.

Chicago/Turabian Style

Kolobe L. Mmonwa; Peter Teske; Christopher McQuaid; Nigel Barker. 2017. "Evolution of foraging behaviour: Deep intra-generic genetic divergence between territorial and non-territorial southern African patellid limpets." Molecular Phylogenetics and Evolution 117, no. : 95-101.

Journal article
Published: 01 January 2017 in South African Journal of Botany
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Leaf domatia are plant-produced cavities usually found in the axils of major veins on the abaxial side of leaves. These structures are found in many woody dicotyledonous plants and mediate a mutualistic relationships between predacious and Fungivorous mites and the host plants they protect. Mites inhabit leaf domatia for shelter and to reproduce and develop. In turn, the plants are hypothesized to benefit from increased defense against pathogens and small arthropod herbivores. Here we assess the distribution of mites throughout the tree canopy to determine if certain regions of the canopy are preferred. Our results suggests that mites prefer leaves found in the lower regions of the tree canopy and avoid leaves at the top, where they may be exposed to harsher climatic conditions. This study is one of the first to document aspects of the plant – mite mutualism from African species.The National Research Foundation (NRF) of South Africa and the Department of Science and technology Centre of Excellence in Tree Health Biotechnology (CTHB). The first author also acknowledges financial support from the Canon Collins Trust and GreenMatter.http://www.elsevier.com/locate/sajb2018-01-31hb2016Plant Scienc

ACS Style

Sivuyisiwe Situngu; Nigel Barker. Position, position, position: Mites occupying leaf domatia are not uniformly distributed in the tree canopy. South African Journal of Botany 2017, 108, 23 -28.

AMA Style

Sivuyisiwe Situngu, Nigel Barker. Position, position, position: Mites occupying leaf domatia are not uniformly distributed in the tree canopy. South African Journal of Botany. 2017; 108 ():23-28.

Chicago/Turabian Style

Sivuyisiwe Situngu; Nigel Barker. 2017. "Position, position, position: Mites occupying leaf domatia are not uniformly distributed in the tree canopy." South African Journal of Botany 108, no. : 23-28.

Journal article
Published: 12 May 2016 in Hydrobiologia
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Marine geographical and ecological barriers often reflect intraspecific genetic discontinuities among populations which may experience different selective pressures and undergo evolutionary divergence. While the phylogeography of marine intertidal invertebrates across the Atlantic/Indian Ocean transition received more attention, the population genetic structures of supralittoral direct developers across such transition area have been poorly investigated. Sandhoppers are supralittoral invertebrates characterised by a direct developmental mode (low dispersal ability), and (Amphipoda, Talitridae) represents the most abundant species of sandhoppers along the South African coasts. To define population structure of , we used a mitochondrial marker (the cytochrome oxidase subunit I gene, COX1). showed a clean population structure with three main haplogroups genetically well separated, although this separation is not perfectly in line with geographical boundaries described for this area. The presence of separate evolutionary significant units is also confirmed by the shape of mismatch distribution, as well as the p distance values among groups. The overall results confirm the importance of mtDNA to retrieve information on the evolutionary history of species. This study suggests the evidence of a complex-species for this sandhoppers, which have never been considered before, providing fundamental basis for further studies.

ACS Style

Simone Baldanzi; Gavin Gouws; Nigel P. Barker; Sara Fratini. Molecular evidence of distinct evolutionary units in the sandhopper Talorchestia capensis (Amphipoda, Talitridae) along South African coasts. Hydrobiologia 2016, 779, 35 -46.

AMA Style

Simone Baldanzi, Gavin Gouws, Nigel P. Barker, Sara Fratini. Molecular evidence of distinct evolutionary units in the sandhopper Talorchestia capensis (Amphipoda, Talitridae) along South African coasts. Hydrobiologia. 2016; 779 (1):35-46.

Chicago/Turabian Style

Simone Baldanzi; Gavin Gouws; Nigel P. Barker; Sara Fratini. 2016. "Molecular evidence of distinct evolutionary units in the sandhopper Talorchestia capensis (Amphipoda, Talitridae) along South African coasts." Hydrobiologia 779, no. 1: 35-46.

Journal article
Published: 15 April 2016 in PhytoKeys
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South Africa’s 800 km-long southern Great Escarpment hosts numerous endemic plant species only known from their type specimens or from very few records. This is a legacy of a 100–150 year lag between the pioneer work of 19th century botanists and repeat fieldwork in the 21st century. As a result, population and ecological data are lacking for many local endemic species. Here we report on the rediscovery of Lotononis harveyi B.–E.van Wyk 147 years after its original description, and provide the first detailed ecological notes on the poorly known shrub Macowania revoluta Oliv. Both species are locally endemic to the Great Winterberg–Amatholes (Eastern Cape Province). With only six known individuals, Lotononis harveyi is recommended the conservation status of Critically Endangered, with fire (and potentially grazing) being the main population constraints. Macowania revoluta is locally abundant, and it is surprising that it has been so poorly collected in recent decades. It occupies an important local niche as a keystone montane wetland species, and its narrow distribution range – combined with pressure from woody alien invasive species – suggests that its conservation status should be Rare. The research further highlights the need for continued biodiversity field research along South Africa’s poorly explored Great Escarpment.

ACS Style

Vincent Ralph Clark; Joanne Bentley; Anthony P. Dold; Vathiswa Zikishe; Nigel P. Barker. The rediscovery of the Great Winterberg endemic Lotononis harveyi B.–E.van Wyk after 147 years, and notes on the poorly known Amathole endemic Macowania revoluta Oliv. (southern Great Escarpment, South Africa). PhytoKeys 2016, 62, 113 -124.

AMA Style

Vincent Ralph Clark, Joanne Bentley, Anthony P. Dold, Vathiswa Zikishe, Nigel P. Barker. The rediscovery of the Great Winterberg endemic Lotononis harveyi B.–E.van Wyk after 147 years, and notes on the poorly known Amathole endemic Macowania revoluta Oliv. (southern Great Escarpment, South Africa). PhytoKeys. 2016; 62 (62):113-124.

Chicago/Turabian Style

Vincent Ralph Clark; Joanne Bentley; Anthony P. Dold; Vathiswa Zikishe; Nigel P. Barker. 2016. "The rediscovery of the Great Winterberg endemic Lotononis harveyi B.–E.van Wyk after 147 years, and notes on the poorly known Amathole endemic Macowania revoluta Oliv. (southern Great Escarpment, South Africa)." PhytoKeys 62, no. 62: 113-124.

Journal article
Published: 05 February 2016 in Phytotaxa
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The genus Berkheya is paraphyletic with the related genera Cullumia, Cuspidia, Didelta and Heterorhachis embedded within a broader clade termed the ‘Berkheya clade’. As a contribution towards reassessment of species relationships and delimitation of species groupings within the clade, the utility of external achene morphology for supporting natural species groups within the clade was evaluated. Achenes from 67 species and 10 infraspecific taxa were examined, including representatives of each genus currently recognised in the Berkheya clade. Achene pubescence and pappus characteristics (e.g., scale shape and number of scales within a series) were indicated to be particularly variable and thus less reliable for assessment of species relationships. Of the currently recognised genera, only segregation of Cullumia was supported by achene and pappus characteristics. Species groupings implicit in Roessler’s infrageneric classification of eight series within Berkheya were to a large extent supported. However, in particular, series Speciosae was indicated to be a disparate species grouping and the distinction of series Angustae and Cruciatae is not supported by achene and pappus morphology. Achene and pappus characteristics suggest several novel species groupings (e.g. an affinity between Berkheya cuneata, B. ferox and B. spinosa). Although the taxonomic sampling in published molecular phylogenetic analyses is limited, achene and pappus morphology partially supports clades resolved in prevailing phylogenetic reconstructions for the clade. More complete sampling in future molecular phylogenetic analyses is required to test novel species affinities suggested in the present study and to explore the evolution of the achene and pappus in the Berkheya clade.

ACS Style

Ntombifikile Phaliso; Robert James McKenzie; Noluthando C Netnou-Nkoana; Per Ola Karis; Nigel P Barker. Reassessing taxonomic relationships in the Berkheya clade (Asteraceae, Arctotideae–Gorteriinae): the utility of achene morphology. Phytotaxa 2016, 246, 1 .

AMA Style

Ntombifikile Phaliso, Robert James McKenzie, Noluthando C Netnou-Nkoana, Per Ola Karis, Nigel P Barker. Reassessing taxonomic relationships in the Berkheya clade (Asteraceae, Arctotideae–Gorteriinae): the utility of achene morphology. Phytotaxa. 2016; 246 (1):1.

Chicago/Turabian Style

Ntombifikile Phaliso; Robert James McKenzie; Noluthando C Netnou-Nkoana; Per Ola Karis; Nigel P Barker. 2016. "Reassessing taxonomic relationships in the Berkheya clade (Asteraceae, Arctotideae–Gorteriinae): the utility of achene morphology." Phytotaxa 246, no. 1: 1.

Book chapter
Published: 01 January 2016 in Developments in Earth Surface Processes
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ACS Style

S.J. Taylor; J.W.H. Ferguson; F.A. Engelbrecht; V.R. Clark; Susan Janse van Rensburg; Nigel Barker. The Drakensberg Escarpment as the Great Supplier of Water to South Africa. Developments in Earth Surface Processes 2016, 1 -46.

AMA Style

S.J. Taylor, J.W.H. Ferguson, F.A. Engelbrecht, V.R. Clark, Susan Janse van Rensburg, Nigel Barker. The Drakensberg Escarpment as the Great Supplier of Water to South Africa. Developments in Earth Surface Processes. 2016; ():1-46.

Chicago/Turabian Style

S.J. Taylor; J.W.H. Ferguson; F.A. Engelbrecht; V.R. Clark; Susan Janse van Rensburg; Nigel Barker. 2016. "The Drakensberg Escarpment as the Great Supplier of Water to South Africa." Developments in Earth Surface Processes , no. : 1-46.

Journal article
Published: 01 August 2015 in Biochemical Systematics and Ecology
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ACS Style

Nigel P. Barker; Iain Paterson; Seranne Howis. “Barcoding” and ISSR data illuminate a problematic infraspecific taxonomy for Chrysanthemoides monilifera (Calenduleae; Asteraceae): Lessons for biocontrol of a noxious weed. Biochemical Systematics and Ecology 2015, 61, 541 -551.

AMA Style

Nigel P. Barker, Iain Paterson, Seranne Howis. “Barcoding” and ISSR data illuminate a problematic infraspecific taxonomy for Chrysanthemoides monilifera (Calenduleae; Asteraceae): Lessons for biocontrol of a noxious weed. Biochemical Systematics and Ecology. 2015; 61 ():541-551.

Chicago/Turabian Style

Nigel P. Barker; Iain Paterson; Seranne Howis. 2015. "“Barcoding” and ISSR data illuminate a problematic infraspecific taxonomy for Chrysanthemoides monilifera (Calenduleae; Asteraceae): Lessons for biocontrol of a noxious weed." Biochemical Systematics and Ecology 61, no. : 541-551.