The plant communities of the Roodeplaat Experimental Farm, Gauteng, South Africa and the importance of classification verification

Panagos, M. D.; Westfall, R. H.; Staden, J.M. van; Zacharias, Peter

doi:10.1016/s0254-6299(15)30826-7

Cited by 19 publications

(10 citation statements)

References 5 publications

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“…The aim of classification is defined as the orderly arrangement of objects according to their differences and similarities (Gabriel and Talbot 1984) and thus, for this study, to ascertain whether floristic links between leguminochoria existed. The method of classification is based on minimum entropy (Westfall et al 1997) and aims to obtain a cluster sequence where cluster-groups can be formed based on floristic similarities and sequenced according to floristic similarities, delimit cluster-groups and to obtain a species sequence where the cluster-groups and their relations are emphasised (Panagos 1995). This program allows the user to decide on the number of groups classified where the accepted minimum percentage difference between groups is 33%.…”

Section: Methodsmentioning

confidence: 99%

Diversity and biogeographical patterns of legumes (Leguminosae) indigenous to southern Africa

Trytsman¹,

Westfall²,

Breytenbach³

et al. 2016

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The principal aim of this study was to establish biogeographical patterns in the legume flora of southern Africa so as to facilitate the selection of species with agricultural potential. Plant collection data from the National Herbarium, South Africa, were analysed to establish the diversity and areas covered by legumes (Leguminosae/Fabaceae) indigenous to South Africa, Lesotho and Swaziland. A total of 27,322 records from 1,619 quarter degree grid cells, representing 1,580 species, 122 genera and 24 tribes were included in the analyses. Agglomerative hierarchical clustering was applied to the presence or absence of legume species in quarter degree grid cells, the resultant natural biogeographical regions (choria) being referred to as leguminochoria. The description of the 16 uniquely formed leguminochoria focuses on defining the associated bioregions and biomes, as well as on the key climate and soil properties. Legume species with a high occurrence in a leguminochorion are listed as key species. The dominant growth form of key species, species richness and range within each leguminochorion is discussed. Floristic links between the leguminochoria are established, by examining and comparing key species common to clusters, using a vegetation classification program. Soil pH and mean annual minimum temperature were found to be the main drivers for distinguishing among legume assemblages. This is the first time that distribution data for legumes has been used to identify biogeographical areas covered by leguminochoria on the subcontinent. One potential application of the results of this study is to assist in the selection of legumes for pasture breeding and soil conservation programs, especially in arid and semi-arid environments.

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Section: Methodsmentioning

confidence: 99%

Diversity and biogeographical patterns of legumes (Leguminosae) indigenous to southern Africa

Trytsman¹,

Westfall²,

Breytenbach³

et al. 2016

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“…We carried out a field experiment at the Roodeplaat Experimental Farm located in Pretoria, South Africa (25°20´-25°40´E; 28°17´-28°25´S). The climate is semi-arid with a mean annual rainfall of 646 mm and mean daily maximum temperatures between 20–29°C in January and 2–16°C in July [ 38 ]. The main wet season occurs from November to April, and the dry season starts in May and reaches its peak in July.…”

Section: Methodsmentioning

confidence: 99%

Seasonal regulation of condensed tannin consumption by free-ranging goats in a semi-arid savanna

et al. 2018

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Although condensed tannins (CTs) are known to reduce forage intake by mammalian herbivores in controlled experiments, few studies have tested these effects in the field. Thus the role of CTs on foraging ecology of free-ranging herbivores is inadequately understood. To investigate the effects of CTs under natural savanna conditions, we pre-dosed groups of goats with polyethylene glycol (PEG, a CT-neutralising chemical), CT powder or water before observing their foraging behaviour. While accounting for the effects of season and time of the day, we tested the hypothesis that herbivores forage in ways that reduce the intake rate (g DM per minute) of CTs. We expected pre-dosing goats with CTs to reduce CT intake rates by (1) consuming diets low in CTs, (2) reducing bite rates, (3) increasing the number of foraging bouts, or (4) reducing the length of foraging bouts. Lastly, (5) expected CT to have no influence the number of dietary forage species. In both wet and dry seasons, pre-dosing goats with CTs resulted in lower CT consumption rates compared to PEG goats which seemed relieved from the stress associated with CT consumption. During dry season, the number of dietary forage species was similar across treatments, although goats that were dosed with PEG significantly increased this number in the wet season. Dosing goats with PEG increased the number and length of browsing bouts compared to goats from the other treatments. Pre-loading goats with PEG also tended to increase bite rates on browse forages, which contributed to increased consumption rates of CTs. Based on the behavioural adjustments made by goats in this study and within the constraints imposed by chemical complexity in savanna systems, we concluded that herbivores under natural conditions foraged in ways that minimised CTs consumption. More research should further elucidate the mechanism through which CTs regulated feeding behaviour.

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“…A recent (1996) monochrome 1:60 000 aerial photograph was used to construct a photographic mosaic that was then enlarged to a scale of approximately 1:13 000. The photographic mosaic was stratified into eight relatively homogeneous areas using a method that involved the recognition of pattern based on texture and grey values (Cronje 2004;Panagos et al 1998). The number of sampling quadrats positioned in each homogeneous unit depended on the size of 4 6 2 1 1 8 7 1 2 5 3 1 2 1 2 1 1 4 3 2 2 5 7 3 6 2 3 7 6 5 3 1 7 4 4 3 7 6 2 3 3 4 5 7 2 3 2 6 1 4 4 4 4 1 3 6 6 7 4 7 8 8 5 5 8 7 5 5 5 6 8 7 6 5 6 8 8 8 8 species group a: Diagnostic species of the Strychnos madagascariensis -Aristida stipitata var.…”

Section: Methodsmentioning

confidence: 99%

The plant communities of the Andover Game Reserve, South Africa

Cronje¹,

Panagos

Reilly

2008

Koedoe

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Floristic characteristics of the Andover Game Reserve (AGR) were surveyed using an area-based survey technique and classified according to the data recorded from 88 relevés, using the PHYTOTAB-PC software package. Three plant communities, of which two each contain two variants, were described and mapped. The plant communities and their causative environmental factors were validated through detrended- and canonical correspondence multivariate analyses. The plant communities of the AGR were found to typify the floristics associated with the catenal sequences located in undulating areas on granite. Broad-leaved savanna is located at the crest and upper mid-slopes while fine-leaved savanna occurs along the footslopes of the AGR. Seeplines, a characteristic occurrence along catenas, are found at the transitional zone between the upper broad- and lower fine-leaved savanna plant communities. This study forms the basis for the compilation of a revised ecological management plan for the Andover Game Reserve

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The plant communities of the Roodeplaat Experimental Farm, Gauteng, South Africa and the importance of classification verification

Cited by 19 publications

References 5 publications

Diversity and biogeographical patterns of legumes (Leguminosae) indigenous to southern Africa

Diversity and biogeographical patterns of legumes (Leguminosae) indigenous to southern Africa

Seasonal regulation of condensed tannin consumption by free-ranging goats in a semi-arid savanna

The plant communities of the Andover Game Reserve, South Africa

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