The Zandvlei Nature Reserve is to be expanded to form the Greater Zandvlei Estuary Nature Reserve and will encorporate a much greater area (250 more hectares). The Greater Zandvlei area was classified by means of Zurich Montpellier (Braun Blanquet) procedures. 60 relevés were used to create a hierarchical phytosociology using TWINSPAN and DCA-ordination analyses. 3 major community types were identified, which were then subdivided to reveal 6 community types important to future management: Moist Grassland/Wetland Disturbed Parkland, Dune Asteraceous Fynbos, Thicket/Shrub Mosaic, Rhus-Euclea Dune Thicket and Homogenous Patches. CCA-ordination indicates that the abiotic soil factors sampled (texture composition, pH, carbon content and visible disturbance) explain very little of the variation between the communities (r²=0.002). This phytosociology is provided as a tool for future research in the area, and it is hoped to assist in future management decisions regarding the newly founded GZENR.

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No description available.

No description available.

This thesis investigates the influence of hedges and roads (linear landscape features) on the patch-to-patch foraging movements of insect pollinators and consequent pollen- mediated gene flow in white clover, Trifolium repens. Experimental arrays were located within the lowland UK agricultural landscape incorporating a range of patch separation distances from 25m to 250m (using both artificial and natural linear features). Mark-re-sight, “residence” (the number of visits per foraging bout) and pollen transport observations were used to observe pollinator movement characteristics between experimental patches and re-parameterise an existing model of patch-to-patch gene flow. Levels and directions of plant gene flow were observed with phenotypic and isozyme markers, allowing validation of model predictions. Harmonic radar technology was used for the first time to track butterfly flight paths; data support the hypothesis of a 150 to 200m perceptual range, and non-random flight direction but limited association to wind direction, hedges, tracks or fence lines. Mark-re-sight observations indicated similar levels of patch visitation regardless of patch location, and trap-lining by Bombus spp. only between patches 50m or less apart. A single track road significantly enhanced gene flow between connected patches and was not a barrier to gene flow across it. In contrast, a hedge did not facilitate enhanced gene flow between connected patches and was a partial barrier where it occurred between patches. Model predictions of gene flow (1.3%, range 0.8 to 2.5%) agreed well with observed levels (ranging from 0.2 to 31.4%). It is proposed that pollinator movement observations alone could not provide an accurate means of estimating low level gene flow unless the variables of residence and pollen carryover were also considered. The possible influence of spatial and temporal variables including the role of hetero-specific forage on pollinator foraging movements and consequent plant gene flow from the local to landscape scale is also discussed

published_or_final_version / Botany / Master / Master of Science

9 pp. / Principles of obtaining and interpreting utilization data on rangelands / Rangeland monitoring is essential for making sound management decisions. Monitoring requires repeated measurements of the same attributes over time. Perhaps the earliest and most widespread rangeland management monitoring data collection protocol was the development and establishment of the Parker 3-step Method on U. S. Forest Service rangelands, beginning in 1948. This method collected both objective and subjective data and provided a scoring technique for assessment purposes. This paper describes the development of the Method and suggests ways to summarize the ecological attributes collected on Parker transects, analyze the data and reinterpret them based on trends in plant species abundance, composition and soil cover.

This study represents a continuation of the historical trend in the analysis of the relationships between climate and vegetation. The focus of the work is on an examination of the association of functioning plants and climatic processes and on the interaction of structured vegetation communities with their environment. Satellite observations and remote sensing technology provide new opportunities for studying the geo-biosphere at high temporal frequencies and for large geographic areas. Integration of spectral vegetation indices and thermal measurements from space is the prime methodology used in this study. The integration of thermal information with vegetation indices has the potential to result in an important contribution to ecological remote sensing. This study has investigated the triangular distribution pattern which has been repetitively observed in spectral domains defined by thermal measurements and vegetation indices. Results show that the triangular shape of an AVHRR data cluster can be consistently observed on different continents and at different times of the year. The triangular data pattern has also been observed using a seasonally averaged data set, representing the mean thermal and biomass conditions of a growing season. The triangular shape of the data spread in feature space clearly suggests an ecosystem triangle model for simulation of the global ecology. A closer analysis of 15 test sites representing the major biomes in the U.S. Southwest study area has shown that each biome has a stable territory in the two dimensional space of temperature and biomass. If the territory of each test site in the triangle can be viewed as a vegetation cell, the ecosystem as a whole may be modeled by using this cell structure. The ecosystem triangle model and the concept of the cell structure have been applied in a vegetation classification exercise. The significant improvement achieved in the vegetation classification supports the conclusion that the ecosystem triangle model is a reflection of surface biomes, and may be used as a tool to study the structure, organization, and function of the biosphere.

The formation of viable pollen relies upon a complex interaction of genes in time and space within the anther. One of the most important maternal tissues involved in the production of functional pollen is the tapetum, which is a highly active tissue that plays a major secretory role during pollen development. This project involved the molecular analysis of genes that are expressed in the anther tapetum and are critical for functional pollen development. A number of these are thought to be regulated by, or interact with MALESTERILITY1 (MS1), a transcriptional regulator of male gametogenesis (Yang et al., 2007) or ABORTED MICROSPORE (Xu et al., 2010). Work involved analysis of an ABC transporter (At3g13220), which has been shown to be critical for viable pollen formation and confirmed as directly regulated by AMS (Xu et al., 2010). Another protein, POB2, which appears to be involved in ubiquitin-based proteolytic breakdown, is thought to interact with the MS1 protein. POB2 was identified from a previous screen of a stamen specific yeast-2-hybrid library using the MS1 protein. This interaction has been subsequently confirmed in this work by further yeast two hybrid analyses and bifunctional fluorescent complementation. Further work involved verification of this interaction in vitro and in planta by pull-downs and transient expression of proteins in E. coli and Nicotiana benthamiana respectively. Other work focused on identifying factors that regulate MS1 expression; this identified novel male sterile mutants derived from screening fast neutron mutagenised seed carrying the MS1Prom:MS1-GFP functional fusion protein. Microscopic observation of the fluorescent reporter showed changes in the stage specific expression of MS1 in some of these mutants. Backcrossing of the male sterile mutants with the parental plants (carrying the MS1Prom:MS1-GFP fusion construct) and the ms1 mutant confirmed one as a new mutant and the other three as being allelic to the ms1 mutation. Gene mapping of this mutant was subsequently conducted and suggest that it may be located on chromosome 3. These results are providing insight into the regulatory network of MS1 and AMS during anther development.

This thesis contains a literature review of Holcus lanatus and records studies on both the growth and spread of the species and the response of it and of Lolium perenne to several management and edaphic factors. Holcus lanatus is an adaptable, competitive species with ecotypes growing in a wide range of environments. It is valuable on hill land, acid, low nutrient soils and to prevent erosion. Beef cattle grazing it have made greater liveweight gains than on L. perenne. Experiments used plants growing in pots and small field plots. A growth study of spaced H. lanatus plants showed they can produce up to 240,000 seeds, most of which germinated shortly after being shed onto moist soil. Seedlings established poorly in a closed sward. Spaced plants produced runners in autumn whose plantlets established better when plants were cut regularly in spring. Holcus lanatus plants needed vernalization in order to flower. This was enhanced by and to a small extent replaced by short days. When H. lanatus plants in bud were cut, useful summer vegetative regrowth resulted. The New Zealand cultivar Massey Basyn was more productive than Oxfordshire H. lanatus in a pot trial. Holcus lanatus dominated a mixture with L. perenne in a glasshouse experiment, especially under high or infrequent cutting, but it was not so dominant in a field experiment. Cattle treading damaged H. lanatus more than it did L. perenne. Holcus lanatus responded to a high water table by producing adventitious and surface roots. Propyzamide at 2.24 and linuron at 1.12 kg a.i./ha in early summer and asulam at 1.12 or 2.24 kg a.i./ha in early September gave good control of established H. lanatus in L. perenne in preliminary trials. The agricultural significance of these results is discussed.