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Adaptation of a decreaser and an increaser grass species to defoliation in semi‐arid grassveld
Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa • Authors: J.E. Danckwerts --- Department of Agriculture (Eastern Cape Region), G.C. Stuart‐Hill --- Department of Agriculture (Eastern Cape Region),Grasses have developed through natural selection to deter, escape and tolerate herbivory, and to escape and tolerate fire. In the semi‐arid grassveld of the Eastern Cape, the species Themeda triandra and Sporobolus fimbriatus have been classified as Decreaser and Increaser... -
Determinants of herbaceous plant species composition on a number of ranches in the north‐western Transvaal
Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa • Authors: M.J.S. Peel --- Department of Agricultural Development, Republic of South Africa D. Grossman --- Department of Agricultural Development, Republic of South Africa N. van Rooyen --- Department of Botany, Republic of South AfricaHerbaceous plant species composition was measured on ranches in the Thabazimbi district, Transvaal, to obtain veld composition scores and to quantify the relations between such scores and certain determinants considered important in influencing species composition. Determinants investigated were mean annual... -
Effects of rainfall, competition and grazing on flowering of Osteospermum sinuatum (Asteraceae) in arid Karoo rangeland
Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa • Authors: S.J. Milton --- FitzPatrick Institute, Republic of South AfricaThe shrub Osteospermum sinuatum, an important fodder plant in Karoo rangelands, flowered after heavy rain in autumn, winter and spring. The number of flowers produced per bush was positively conelated with basal stem diameter and rainfall in the 12 weeks... -
Patterns of seed production and shrub association in two palatable Karoo shrub species under contrasting land use intensities
Item type: Journal Article • Journal: African Journal of Range & Forage Science • Authors: S.W. ToddSeed production and shrub association patterns of the two palatable shrubs. Tripteris sinuatum and Tetragoma froticosa were investigated on heavily grazed communal and lightly grazed commercial rangeland in the succulent karoo, Namaqualand. Seed production in both these species was substantially... -
Browsing of Grewia occidentalis by domestic stock in a South African savanna: the influence of bush clumps
Item type: Journal Article • Journal: African Journal of Range & Forage Science • Authors: L.H. Watson D.H. BrownIn South African karoo categorised by multi-species bush clumps, skirted shrub species appear to physically defend the palatable shrub Grewia occidentalis against browsing by eland (Taurotragus oryx). Skirted shrubs appear to defend G. occidentalis by preventing access to plants and... -
Patterns of thorn length, density, type and colour in African Acacias
Item type: Journal Article • Journal: African Journal of Range & Forage Science • Authors: JJ Midgley MA Botha D BalfourIn Acacia no trade-off occurs between thorn length and thorn density and no correlation exists between thorn length and leaf length. By relating thorn length and density to leaf length it is clear that some species are better defended than... -
Variable community responses to herbivory in fire-altered landscapes of northern Patagonia, Argentina
Item type: Journal Article • Journal: African Journal of Range & Forage Science • Authors: T Kitzberger E Raffaele T VeblenLandscapes in northern Patagonia have undergone dramatic changes in fire regimes over the last century. Superimposed on this changing vegetation mosaic are impacts from introduced herbivores. In this paper we identify synergistic interactions developing into positive fire-herbivory feedbacks that maximise... -
Cattle diet selection during the hot-dry season in a semi-arid region of Namibia
Item type: Journal Article • Journal: African Journal of Range & Forage Science • Authors: MLJ Katjiua D WardThe northern Kalahari Desert is dominated by Terminalia sericea savanna woodland and a sparse herbaceous layer. Range ecologists regard T. sericea as a major encroaching species and that such encroachment represents a cost to cattle production. In contrast, pastoralists regard... -
An evaluation of diet quality in two desert ungulates exposed to hyper-arid conditions
Item type: Journal Article • Journal: African Journal of Range & Forage Science • Authors: SR Henley D WardDesert-dwelling ungulates are frequently exposed to plant communities of poor nutritional quality and low abundance. We assessed the diet quality of a large-bodied non-ruminant, the Asiatic wild ass (Equus hemionus) and that of a small-bodied ruminant, the dorcas gazelle (Gazella... -
Effects of herbivore exclosures on variation in quality and quantity of plants among management and habitat types in a semiarid savanna
Item type: Journal Article • Journal: African Journal of Range & Forage Science • Authors: KR Mbatha --- Department of Conservation Ecology, South Africa D Ward --- School of Biological and Conservation Sciences, South AfricaThe effects of grazing on plant biomass, plant quality, species evenness, species diversity and species composition were determined among management types (communal, commercial and game) and among habitat types (open savanna, rocky and pan) in a semiarid savanna in South... -
The application of state‐and‐transition models to rangeland research and management in arid succulent and semi‐arid grassy Karoo, South Africa
Item type: Journal Article • Journal: African Journal of Range & Forage Science • Authors: S.J. Milton --- FitzPatrick Institute, Republic of South Africa M.T. Hoffman --- Stress Ecology Research Programme, Republic of South AfricaWe evaluate the ability of existing models of vegetation dynamics to explain how drought and herbivory by domestic livestock can change Karoo vegetation, and why the vegetation does not always return to its original composition when livestock are withdrawn. Using... -
Condensed tannin in Eragrostis chloromelas leaves deters feeding by a generalist grasshopper
Item type: Journal Article • Journal: African Journal of Range & Forage Science • Authors: J. Dini --- Department of Zoology, Republic of South Africa N. Owen‐Smith --- Department of Zoology, Republic of South AfricaWe investigated the feeding responses of a generalist grasshopper, the brown locust (Locusta pardalina), to leaves of the grass Eragrostis chloromelas differing in polyphenol content. For three specimens of E. chloromelas, the presence of condensed tannin in epidermal cells was... -
Effects of herbivore grazing on the physiognomy of the coralline alga Spongites yendoi and on associated competitive interactions
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: GW Maneveldt DW KeatsThe territorial gardening limpet Scutellastra cochlear occurs along the south and southern west coasts of South Africa, whereas one of its primary food items, the encrusting coralline alga Spongites yendoi, extends much farther north along the West Coast. A combined... -
Effects of long-term exclusion of the limpet Cymbula oculus (Born) on the distribution of intertidal organisms on a rocky shore
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: GW Maneveldt --- Department of Biodiversity and Conservation Biology, South Africa RC Eager --- Department of Biodiversity and Conservation Biology, South Africa A Bassier --- Department of Biodiversity and Conservation Biology, South AfricaZonation patterns on rocky shores are typically as a result of both physical factors and biological interactions. Physical factors generally set the upper limits of species distributions whereas biological interactions generally set their lower limits. However, recent research has shown... -
Dynamics of woody vegetation in a semi-arid savanna, with a focus on bush encroachment
Item type: Journal Article • Journal: African Journal of Range & Forage Science • Authors: M-L Britz D WardIncreases in the tree: grass ratio with accompanying changes in herbaceous composition, called bush or shrub encroachment, is a worldwide phenomenon in savanna regions. Although heavy grazing by livestock is often believed to be the cause, it is clear that... -
Induced chemical defences in Colophospermum mopane trees
Item type: Journal Article • Journal: African Journal of Range & Forage Science • Authors: DCJ Wessels C van der Waal WF de BoerA field experiment was conducted in which Mopane (Colophospermum mopane) trees were subjected to three different canopy treatments:felling of trees at a mean height of 0.7m above ground level, felling at a height of 2m, or pruning of selected branches... -
Herbaceous biomass–species diversity relationships in nutrient hotspots of a semi-arid African riparian ecosystem
Item type: Journal Article • Journal: African Journal of Range & Forage Science • Authors: Helga van Coller --- Unit of Environmental Sciences and Management, South Africa Frances Siebert --- Unit of Environmental Sciences and Management, South AfricaThe hump-back relationship between species diversity and productivity predicts highest species richness at intermediate levels of biomass, and low species numbers in least and most productive habitats. Sodic patches of semi-arid savannas are considered ‘nutrient hotspots’ by producing high-quality forage... -
Different drivers create spatial vegetation cover and vertical structure in semi-arid African savannas
Item type: Journal Article • Journal: African Journal of Range & Forage Science • Authors: Rheinhardt Scholtz --- Scientific Services, South African National Parks, South Africa Gregory A Kiker --- Department of Agricultural and Biological Engineering, USA Gregory D Duckworth --- Department of Statistics, South Africa Ursula M Scharler --- School of Life Sciences, South Africa Henry G Mwambi --- School of Mathematics, Statistics and Computer Science, South Africa Frederick J Venter --- Conservation Management, South AfricaImportant drivers of woody cover in African savannas are rainfall, soil and nutrients, and disturbance factors, such as fire and herbivory. However, very little is known about how these drivers influence woody cover at specific height classes. The main aim... -
Is there a trade-off in resource allocation to condensed tannins and thorn defences in Vachellia (Acacia) species?
Item type: Journal Article • Journal: African Journal of Range & Forage Science • Authors: Allan Sebata --- Department of Forest Resources and Wildlife Management, ZimbabweAcacia species invest in condensed tannins (CT) and thorn defences among others. Plant defences are considered costly because they use resources that would otherwise be available for growth and reproduction. To reduce plant defence costs it has been argued that... -
Suppression of the aquatic weed Hydrilla verticillata (L.f.) Royle (Hydrocharitaceae) by a leaf-cutting moth Parapoynx diminutalis Snellen (Lepidoptera: Crambidae) in Jozini Dam, South Africa
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: A Bownes --- Agricultural Research Council Plant-Protection Research Institute (ARC-PPRI), South AfricaA classical biological control programme against Hydrilla verticillata (L.f.) Royle (Hydrocharitaceae) was initiated in South Africa following the discovery of extensive mats in Jozini Dam in northern KwaZulu-Natal (KZN) in 2006. However, in mid-2008, high densities of a phytophagous insect,... -
Long-term impacts of livestock grazing and browsing in the Succulent Karoo: a 20-year study of vegetation change under different grazing regimes in Namaqualand
Item type: Journal Article • Journal: African Journal of Range & Forage Science • Authors: Elelwani Nenzhelele --- Department of Biological Sciences, South Africa Simon W Todd --- South African Environmental Observation Network (SAEON): Arid Lands Node, South Africa M Timm Hoffman --- Plant Conservation Unit, Department of Biological Sciences, South AfricaThis study used a fence-line contrast approach to investigate the long-term impact of high grazing pressure on the vegetation at a site in Namaqualand, South Africa. Forty pairs of permanently marked plots were surveyed in 1996, 2006 and 2016. The... -
Forb community responses to an extensive drought in two contrasting land-use types of a semi-arid Lowveld savanna
Item type: Journal Article • Journal: African Journal of Range & Forage Science • Authors: F Siebert --- , South Africa J Klem --- , South Africa H Van Coller --- , South AfricaProjected increases in the frequency and severity of drought events are expected to impose changes in the ecology of native forb communities in semi-arid ecosystems. We examined the state of forb communities during, and directly after an extreme drought event... -
Determining the post-herbivore-exclusion effect on an intertidal community by the recovery response of a known dominant herbivore
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: DC van den Berg --- , South Africa K Sethebe --- , South Africa GW Maneveldt --- , South AfricaFollowing a long-term herbivore-exclusion study (2003-2008) in the mid-eulittoral zone at Kalk Bay, Cape Town, South Africa, the post-herbivore-exclusion effect (12 years later) of the limpet Cymbula oculus, the dominant herbivore in the community, was examined after it had recolonised... -
Fire and herbivory shape belowground bud banks in a semi-arid African savanna
Item type: Journal Article • Journal: African Journal of Range & Forage Science • Authors: AB Bombo --- , Brazil F Siebert --- , South Africa A Fidelis --- , BrazilFire and herbivory are major drivers in tropical savanna ecosystems and they selected a flora composed of species able to cope with recurrent aboveground biomass removal. Renewal of the herbaceous stratum is made possible by resprouting, mostly through a belowground... -
Occurrence of Dalbergia obovata in grasslands of urban nature reserves within a metropolitan municipality: Is it an encroaching woody species?
Item type: Journal Article • Journal: African Journal of Range & Forage Science • Authors: Terry Stewart --- , South Africa Peter F Scogings --- , South Africa Himansu Baijnath --- , South AfricaThe occurrence of Dalbergia obovata, which is typically associated with forests, in grasslands within conservation areas in a metropolitan municipality was investigated to assess whether it was encroaching and what the possible causes might be. Relevant legislation has not regarded... -
Influence of burning and defoliation on Festuca costata (Nees) in the Drakensberg
Item type: Journal Article • Journal: African Journal of Range & Forage Science • Authors: Kabemba Mwambilwa --- , South Africa Kevin P Kirkman --- , South Africa Zivanai Tsvuura --- , South AfricaFire occurs naturally in grasslands and savannas and it is commonly used as a management tool to influence structure and composition. The ability of a grass plant to recover from fire may be influenced by the fire frequency and intensity... -
The chemistry of the pedoderm – part 1: grasslands and savannas in the central Kruger National Park, South Africa
Item type: Journal Article • Journal: African Journal of Range & Forage Science • Authors: Anthony J Mills --- , South Africa Tercia Strydom --- , South Africa Jessica L Allen --- , South Africa Julia Baum --- ,Treeless grasslands occur within landscapes that are predominantly wooded savannas in the central Kruger National Park, South Africa. As a first step in identifying soil properties potentially underpinning differences in vegetation structure in these landscapes, we analysed the soil chemistry... -
Food choice of an Algerian population of the spur‐thighed tortoise, Testudo graeca
Item type: Journal Article • Journal: The Journal of the Herpetological Association of Africa • Authors: Rachid Rouag --- Centre universitaire d'El Tarf, Algerie Chahira Ferrah --- Université Badji Mokhtar, Algérie Luca Luiselli --- Centre of Environmental Studies Demetra s.r.l, Italia Ghoulem Tiar --- Université Badji Mokhtar, Algérie Slim Benyacoub --- Université Badji Mokhtar, Algérie Nadia Ziane --- Université Badji Mokhtar, Algérie El Hassan El Mouden --- Université Cadi Ayyad, MarocThe diet of an Algerian population of spur‐thighed tortoise (Testudo graeca) was studied with the aims of exploring: (i) the variation in diet among males, females and juveniles, (ii) the relationships between consumption and relative availability of the plant species,... -
Threshold changes in the production potential of bush clumps along piosphere gradients in arid thicket mosaics
Item type: Journal Article • Journal: African Journal of Range & Forage Science • Authors: Anton Schmidt --- Nelson Mandela University, South Africa Graham Kerley --- Nelson Mandela University, South Africa Munyaradzi Manjoro --- Sol Plaatje University, South AfricaVarious studies have noted threshold changes in vegetation composition and structure and soil physical and chemical properties in the Albany Thicket biome of South Africa. The aim of this study is to assess if these changes to the environment have... -
The grazer Cymbula oculus (Patellogastropoda: Patellidae) serves as an important settlement substrate for several of its macroalgal prey
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: W Moosa --- University of the Western Cape, South Africa J Phillips --- University of the Western Cape, South Africa GW Maneveldt --- University of the Western Cape, South AfricaIntertidal communities are predictably affected by both physical and biological factors, with herbivory as a particularly important factor. Instead of dense beds of macroalgae, which typically characterise the mid-eulittoral zone along the south coast of South Africa, at Kalk Bay... -
Frequent defoliation rapidly and progressively reduces the vigour of a perennial mesic grassland forb, Thunbergia atriplicifolia
Item type: Journal Article • Journal: African Journal of Range & Forage Science • Authors: Craig D Morris --- University of KwaZulu-Natal, South Africa Sindiso Nkuna --- University of KwaZulu-Natal, South AfricaForbs in South African mesic grasslands are ancient, numerous, and diverse, thriving with fires and light herbivory but declining under chronic, severe grazing and trampling. This study tested the hypothesis that repeated herbivory progressively weakens forbs by reducing their underground... -
Seasonal consumption of Thamnochortus spicigerus (Restionaceae) by eland is associated with plant sex and nutrient status
Item type: Journal Article • Journal: African Zoology • Authors: Petro Botha --- Department of Botany and Zoology, Stellenbosch University, South Africa Bruce Anderson --- Department of Botany and Zoology, Stellenbosch University, South AfricaHistoric distributions of large herbivores in the Fynbos Biome remain poorly described and, despite ongoing reintroductions, their dietary strategies and forage selection in the Fynbos Biome are understudied. We monitored an introduction of eland into Cape Flats Dune Strandveld vegetation,...