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Salt intake and regulation in two passerine nectar drinkers : whitebellied sunbirds and New Holland honeyeaters
10 Apr 2013Avian nectarivores face the dilemma of having to conserve salts while consuming large volumes of a dilute, electrolyte-deficient diet. This study evaluates the responses to salt solutions and the regulation of salt intake in whitebellied sunbirds (Cinnyris talatala) and New Holland honeyeaters (Phylidonyris novaehollandiae). Birds were first offered a choice of four sucrose diets, containing …
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New plant records for Tankwa Karoo National Park, South Africa
22 Apr 2013The Tankwa Karoo National Park has been enlarged from 27 064 ha to 143 600 ha. This whole area is severely under-collected for plants in general and therefore it was an obvious target for the South African National Parks (SANParks) Programme, a component of the Pretoria National Herbarium (PRE) Plant Collecting Programme. This programme not only aims to survey national parks that have been poorly…
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16 S rDNA primers and the unbiased assessment of thermophile diversity
21 Sep 2010Our understanding of thermophile diversity is based predominantly on PCR studies of community DNA. ‘Universal’ and domain-specific rRNA gene PCR primers have historically been used for the assessment of microbial diversity without adequate regard to the degree of specificity of primer pairs to different prokaryotic groups. In a reassessment of the published primers commonly used for ‘universal…
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PCR-based detection of non-indigenous microorganisms in ‘pristine’ environments
27 Sep 2010PCR-based technologies are widely employed for the detection of specific microorganisms, and may be applied to the identification of non-indigenous microorganisms in ‘pristine’ environments. For ‘pristine’ environments such as those found on the Antarctic continent, the application of these methods to the assessment of environmental contamination from human activities must be treated with caution…
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Praktykillustrasie van die vorming en terminering van n terapeutiese sisteem volgens ekosistemiese denke
28 Aug 2014This article presents an illustration of how an ecosystemic perspective was used in a family therapy case study. Two ecosystemic concepts were used to discuss the case study. They are: the language determination of the therapeutic system as described by Anderson & Goolishian 1988; and the therapeutic formula: stability/ change/meaningful noise as used by Keeney & Ross 1985. The value of the lang…
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Scale insects on ericas : an apparently natural, unnoticeable threat to local biodiversity
28 Jan 2014Introduction: An excursion into the Limietberg Nature Reserve in the Bain's Kloof Mountains during the winter of 2006, one that I have undertaken regularly over the past ten years or so, had revealed a noticeably high number of dead and apparently dying individuals of Erica species.
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Active Principles of Tetradenia riparia; II. Antispasmodic Activity of 8(14), 15-Sandaracopimaradiene-7α, 18-diol
02 Sep 2014Tetradenia riparia is one of the most popular medicinal plants in Rwanda. Previously, several new substances have been isolated from the leaves, including a new diterpenediol, i.e. 8(14),15-sandaracopimaradiene-7α,18-diol. This new diterpenediol exhibits a papaverine-like antispasmodic activity on the contractions of the guinea pig ileum provoked by methacholine, histamine, and barium chloride an…
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Reconstructing the deep-branching relationships of the papilionoid legumes
13 Sep 2017Resolving the phylogenetic relationships of the deep nodes of papilionoid legumes (Papilionoideae) is essential to understanding the evolutionary history and diversification of this economically and ecologically important legume subfamily. The early-branching papilionoids include mostly Neotropical trees traditionally circumscribed in the tribes Sophoreae and Swartzieae. They are more highly dive…
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Phylogeny of Southern African and Australasian Wahlenbergioids (Campanulaceae) based on ITS and trnL-F sequence data: implications for a reclassification
19 Oct 2017The Campanulaceae: Wahlenbergioideae currently comprises 15 genera, one of which, Wahlenbergia, is widespread over the southern continents. Southern Africa is the region with maximum wahlenbergioid diversity with 12 genera and approximately 252 species. A second center is Australasia with 38 Wahlenbergia species. This study used a broad sample of wahlenbergioid diversity from South Africa, Aus…
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Hitting the right target: taxonomic challenges for, and of, plant invasions
12 Dec 2017This paper explores how a lack of taxonomic expertise, and by implication a dearth of taxonomic products such as identification tools, has hindered progress in understanding andmanaging biological invasions. It also explores how the taxonomic endeavour could benefit from studies of invasive species. We review the literature on the current situation in taxonomy with a focus on the challenges of…