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Fire 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 (influenced by seasonal weather conditions and fuel load), defoliation and competition from neighbouring plants. This study sought to investigate factors influencing the fire and herbivore dynamics of an evergreen C3 grass, Festuca costata, in a high-altitude C4 dominated grassland in the Drakensberg Mountains of South Africa. We experimentally examined the effect of fire frequency, defoliation and competition from neighbours on the growth dynamics of F. costata. Annual burning significantly decreased aboveground biomass production, number of tillers and tuft circumference of F. costata. Defoliation similarly reduced aboveground biomass production, number of tillers, tuft circumference and specific leaf area of F. costata. Competition from neighbouring plants reduced aboveground biomass production, number of tillers and tuft circumference of F. costata. Given the expected variable impacts of increasing CO2 levels and temperature on C3 and C4 grasses, these results provide insights for managing the matrix of C3 and C4 grasses in the Drakensberg grasslands in a changing climate. Keywords: biodiversity; climate change; herbivory

Commercial seed mixes and various mechanical planting methods have been implemented to overcome barriers to successful restoration of degraded grasslands but their effectiveness in aiding the restoration process has been understudied. Harvested seed must be cleaned of chaff to allow mechanical planting, which can exclude small seeds. We propose that fluid seed drilling techniques (suspending uncleaned harvested seed in a cellulose-based gel matrix, which may then be injected into the soil with a mechanical planter) may overcome these challenges. As a preliminary investigation of the proposed method we designed a greenhouse pot trial experiment aimed at quantifying restoration success through the measurement of seedling recruitment, biomass production and composition responses of commercial and harvested seed mixes under simulated fluid seed drilling and smoke water priming (collectively termed application method). These data were analysed using generalised linear modelling and multivariate analyses. Commercial mixed seed resulted in greater recruitment, whereas harvested seed produced the greatest biomass production. There was large multivariate separation between seed types and seed type × application method centroids for recruitment responses and only seed type for biomass responses. Application method had minimal effects on restoration measurements whilst seed type greatly affected these measurements. Careful selection of the restoration seed mix is advised.Keywords: biomass, cellulose gel planting method, germination, multivariate diversity, restoration seed mixes, smoke water seed priming

With the rapid expansion of wildlife ranching and conservation in South African savannas and the resultant increase in multi-species grazing and browsing systems, information on browse production potential is essential for determination of carrying capacity. This study, conducted on three game reserves in the northern Zululand coastal plains of KwaZulu-Natal, explored the biotic (measurable tree dimensions, and tree species) and abiotic (climatic and soil) factors influencing the rate and quantity of quarterly browse production of seven key savanna tree species (Acacia nilotica [Vachellia nilotica], Carissa bispinosa, Dichrostachys cinerea, Euclea divinorum, Gymnosporia senegalensis, Spirostachys africana and Ziziphus mucronata). Available canopy volume, mean maximum daily temperature and tree species were the most significant determinants of browse production. Available canopy volume proved to be the most reliable predictor of browse production per species and per tree, with quarterly browse production being greater on trees with larger available canopy volumes (up to a threshold). Browse production differed significantly between quarters. Growing season onset occurred during the sampling period prior to the rainy season when mean maximum daily temperatures peaked. Quarterly browse production was greatest in evergreen E. divinorum, followed by the semi-deciduous species, S. africana and Z. mucronata.Keywords: available canopy volume, browser carrying capacity, CART, growing season, tree guildAfrican Journal of Range & Forage Science 2014, 31(1): 13–24

Browsing herbivores are generally highly selective feeders, selecting for new shoots and young plant material. Determinations of browser carrying capacity are then greatly inflated when based on available browse biomass estimates. Our study was initiated with the aim of modelling browse production rates of key savanna tree species in the northern Zululand region of KwaZulu-Natal, with the assumption that browse production equates to utilised browse biomass. Predictive models for the production of browse, at different game feeding levels, on deciduous, semi-deciduous and evergreen trees were developed using multivariate adaptive regression spline functions. The most significant predictors of the production of browse were measurable plant dimensions, namely available canopy volume, stem diameter and foliage density, and climatic variables, namely maximum and minimum daily temperatures and cumulative daily rainfall for each quarter. Comparing the browse production figures of consecutive years supplies land managers with valuable insight whether the browse component of the system is under stress, is maintaining, or is encroaching, as well as the impact of browsers on the system.Keywords: browser carrying capacity, growing season, multivariate adaptive regression splines, predictive modelsAfrican Journal of Range & Forage Science 2014, 31(1): 25–36

Interactions between mature grass plants and grass seedlings have been found to be both facilitative and competitive. To examine the effects of aboveground and belowground competition on seedling biomass and the effects of soil depth on competitive interactions, seedlings of three locally common grass species ( Eragrostis racemosa , Themeda triandra and Panicum maximum ) were planted into a natural grass sward on three different parts of the landscape varying in soil depth. Three aboveground treatments (full light competition, no light competition and clipping to simulate grazing), and two belowground treatments (full belowground competition and belowground competition excluded by a root tube), were used. On all soil depths the three grass species differed in mean mass, with E. racemosa having the least mass and T. triandra having the greatest mass. Simulated grazing by clipping the surrounding sward created niches for seedling establishment. This highlights the importance of maintaining stocking rates at a level that promotes seedling establishment. Keywords : competition, grass seedling, soil depth African Journal of Range & Forage Science 2011, 28 (2): 79–85

The relative benefit of different grazing management practices for maintaining grassland biodiversity integrity was assessed. Practices considered were grazing system, stocking rate, animal type, grazing season, fire–grazing interaction, plus burning regime. Sparse empirical data indicated that stocking rate, cattle-to-sheep ratio, and increased fire intervals can affect plant diversity. Certain species behave as increaser or decreaser species in response to stocking rate or cattle-to-sheep ratio. Plant diversity appears robust in the face of variation in fire regime except for preclusion of fire. Multicriteria analysis was used to assess the relative impact of grazing systems (continuous, conventional, or high-intensity grazing by sheep, cattle, or sheep plus cattle) on grassland biodiversity integrity. Selected indicators covered landscape composition, structure and functioning. High-intensity systems and continuous sheep grazing have the most, and continuous grazing with beef the least, negative impact, depending on stocking rate. The relation between veld condition and plant diversity needs to be tested further before veld condition is used as a management tool for maintaining biodiversity. Proposed research priorities include inventory of management systems used, rapid expansion of the empirical data base, an improved understanding of patterns of plant diversity across the biome, and evaluation of the pyro–grazing diversity paradigm.African Journal of Range & Forage Science 2010, 27(2): 67–76

The quantification of defoliation effects on grass vigour is important in understanding veld response to differential management. Effect on grazing on vigour can be determined by measuring regrowth during the season following grazing and comparing treatments with an undefoliated control. In this study, veld was defoliated at varying intensities and frequencies. During the following season, regrowth was measured on all treatments to quantify any residual treatment effects on vigour. Comparisons between measuring yield per tuft and yield per unit tuft basal area of this regrowth revealed marked discrepancies between the methods. These findings were in agreement with previously reported studies. In addition, differences between the mean tuft basal areas were found between treatments. Differences in vigour may reflect a change in tuft area as well as amount of growth per unit tuft area. Quantification of residual effects of grazing on plant vigour should thus logically be done using techniques based on plant yields, rather than on the basis of yield per unit tuft basal area. Techniques are available for the measurement of regrowth of all species present using quadrats, and this measure, expressed as species yield per unit land area, gives extra significance to the results.Keywords: botany; defoliation; effects; Ermelo district; grass; grass productivity; grazing; Nooitgedacht Agricultural Development Centre; productivity; regrowth; South AfricaAfrican Journal of Range and Forage Science 1995, 12(2): 89–91