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A dissertation submitted to the faculty of science university of the Witwatersrand, Johannesburg for the Degree of Master of Science Johannesburg 1992 / The gametophyte generation of the fern life cycle is initiated with the formation of spores. The spores of C. viridis (Fonsic) Swarts var. glaeca (Sim) schelp Anthony are trilete and have a cristate spore wall ornamentation. Under favourable conditions the spores of C. viridis var. glauca show polar germination [Abbreviated Abstract. Open document to view full version] / GR2017

Orientador: Marcelo Nogueira Rossi / Banca: Renata Cristina Batista Fonseca / Banca: Adriana Maria Zanforlin Martini / Resumo: Devido à reconhecida importância dos morcegos frugívoros para a dispersão e reprodução das plantas e, conseqüentemente, para a regeneração das florestas, o presente estudo teve como objetivo: (1) conhecer a riqueza e abundância das espécies de morcegos na área de estudo; (2) identificar as espécies vegetais cujos frutos servem de alimento para as principais espécies de morcegos frugívoros, as quais têm suas sementes dispersas por eles e (3) caracterizar a fenologia reprodutiva das espécies vegetais cujos frutos servem de alimento para os morcegos. Este estudo foi realizado na Fazenda Experimental Edgardia, município de Botucatu, Estado de São Paulo, em um fragmento de floresta secundária tardia alta, denominado "Mata da Bica". Os morcegos foram capturados mensalmente com redes neblina, durante um ano. As sementes encontradas nas fezes dos morcegos foram separadas, lavadas, secadas naturalmente e identificadas. Foi feito o acompanhamento mensal da fenologia reprodutiva de dez espécies vegetais, possíveis fontes de alimento para os morcegos. A maioria das espécies teve seu período de frutificação durante a estação chuvosa e apenas três frutificaram na estação seca. Foram capturados 309 morcegos, sendo que 78,9% eram espécies frugívoras, num total de 14 espécies dentro de três famílias. Carollia perspicillata e Sturnira lilium foram as espécies mais abundantes. Pelo menos 22 espécies diferentes de plantas foram utilizadas como recurso, e houve também o consumo de insetos e pólen. S. granuloso-leprosum foi o recurso mais importante, pois seus frutos foram consumidos por praticamente todas as espécies de morcegos frugívoros capturados. No geral, C. perspicillata e S. lilium demonstraram um padrão de consumo baseado em suas reais preferências (frutos de Piper e Solanum... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: As frugivorous bats are important organisms for plant dispersion and reproduction and also for forest regeneration, the objectives of this study were to: (1) know the abundance and bat species richness in the studied area; (2) identify plant species which fruits are consumed and seeds dispersed by the main frugivorous bats (3) characterize reproductive phenology of plants with fruits consumed by bats. This study was caried out at the Fazenda Experimental Edgardia, municipality of Botucatu, State of São Paulo, Brazil, in a semi-deciduous forest fragment, named as "Mata da Bica". Bats were monthly captured with mist nets for a year. Seeds found in bat feces were separated, washed, naturally dried and identified. Reproductive phenology was recorded monthly for ten plant species, which possibly were food source for bats. Most species presented fructification periods during the wet season and only three species presented fruits in the dry season. Three hundred and nine bats were captured and 78.9% were frugivorous species, totalizing 14 species distributed in three families. Carollia perspicillata and Sturnira lilium were the most abundant species. At least 22 plant species were used as food source; however, insects and pollen were also consumed. S. granuloso-leprosum was the most important food source because their fruits were consumed by most frugivorous bat species. In general, C. perspicillata and S. lilium consumed their preferred food items (Piper and Solanum fruits, respectively). However, A. lituratus was an opportunist species because individuals usually consumed the most abundant resource, probably as an alternative to the low availability of its preferred food items. / Mestre

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Diss. (sammanfattning) Stockholm : Univ., 2004. / Härtill 5 uppsatser.

The primary aim of this project was to examine factors which are likely to provide a mechanism by which the polymorphism for capitulum type and associated outcrossing rate in Senecio vulgaris may be maintained. The majority of studies conducted examined the demographic genetics (i.e. the changes in the number of individuals of the two morphs at different life history stages) in field experiments initiated either in Spring or Autumn, The first series examined the demography of each morph raised from seedlings to senescence in pure stand and mixture. The second series examined the demography of each morph from seed to senescence and thereby investigated the effect on fitness of any difference between morphs in germination behaviour. The importance of inbreeding depression on the maintenance of the polymorphism was examined by comparing the relative fitness of self and open pollinated offspring of each morph under glasshouse conditions. Germination behaviour of seeds of each morph was also investigated in a series of field trials conducted over an extended period. These field studies were complemented by a series of synchronous laboratory studies to examine the effect of temperature on morph germination behaviour. It was found that inbreeding depression is not an important factor in the maintenance of the polymorphism. No short term advantage of the radiate over the non-radiate morph was evident in the first series of demography experiments. The germination studies showed that differences between morphs in germination behaviour may occur frequently in autumn sown seed. The second series of demography experiments showed that under certain conditions this difference in germination can lead to the radiate morph attaining a greater relative fitness than the non-radiate morph. Temperature was found to be a major factor controlling the initial dormancy of seeds after sowing. It is concluded that the difference between morphs in germination behaviour is the most likely factor that could maintain the polymorphism for capitulum type in Edinburgh populations of 8. vulgaris.

The abundance of invasive alien plants, with their numerous associated negative effects, has resulted in challenging and costly management requirements in South Africa. Management of invasives is further complicated when species have rapid inherent growth rates, atmospheric nitrogen fixing capabilities and large, persistent seed banks. Management strategies other than the usual mechanical, chemical, and biological (and combinations thereof) methods may be more effective. An alternative strategy is ’habitat management’, whereby management may be aimed at favouring native species. If the native species could compete favourably with, and possibly exclude, the invasive species, which is more likely when the species are ecologically similar, management may be more effective. This study investigated the competitive performance of two invasive species, Acacia mearnsii De Wild. and Acacia melanoxylon R.Br., and an indigenous ecological analogue, Virgilia divaricata Adamson, on the southern Cape Coast of South Africa. Both acacias are included among the five worst invasive species in the native forest and fynbos shrubland ecosystems. Performance was compared among the three species in terms of germination success (responses to five stimuli, namely chipping, hot water exposure, dry heat pulse, smoke, and control, incubated at 12 or 20°C), soil-stored seed bank densities and viability at different soil depths, and individual growth performance in seedling and sapling stages (and the effect of inter-specific competition on the latter). Virgilia divaricata performed comparably to the acacias in most aspects. Responses to germination stimuli at both temperature regimes were comparable among species, with chipping and hot water exposure resulting in the highest germination success. Acacia melanoxylon displayed poorer germination response under the cool temperature regime than the warm regime. Of the three species, A. mearnsii (7 596 seeds m-2) had the highest seed bank density, followed by V. divaricata (938 seeds m-2) and A. melanoxylon (274 seeds m-2). Seed viability was high (87-91%) in all three species. Neither seed density nor seed viability differed significantly between soil depths, and there were no clear differences in this aspect between species. In terms of growth during the seedling stage, V. divaricata outperformed A. mearnsii. In the sapling stage, growth was comparable between the three species and was not affected by the extent of competition from neighbouring saplings. Overall, the findings of this study suggest that the success of A. mearnsii as an invader is primarily attributable to its large seed banks. However, the good performance of V. divaricata seedlings and no apparent negative effect of competition on sapling growth from A. mearnsii and A. melanoxylon suggest that it may be used in the management of the acacias along with other management strategies. Due to the similarity observed between the three species, any management operation (such as fire) that would benefit V. divaricata recruitment would benefit the acacias equally (except for potentially reduced germination of A. melanoxylon in cooler seasons). Management should thus attempt to prevent the germination of Acacia seeds. Alternatively, dense localised Acacia seed banks may be reduced by repeat burning. On a small scale, areas where V. divaricata would occur naturally (or which are completely compromised ecologically) can be seeded with pre-treated (chipped or hot water exposure) V. divaricata seeds. If V. divaricata is given enough time to establish dense stands, subsequent germination and growth of the acacias should be suppressed and simultaneously promote forest re-establishment. To further decrease Acacia success, biocontrol (seed-boring weevils, flower-galling midges, and rust fungus) should be widely disseminated.

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