Thesis--University of Wisconsin. / Includes bibliographical references (leaves 54-56).

This study examines fruit predation of species in the family Dipterocarpaceae. It was conducted in Pasoh Forest Reserve, a Lowland Dipterocarp Rain Forest in West Malaysia. The work concentrates upon the pre-dispersal weevil predators, whose larvae develop within dipterocarp fruit. After describing the pre-dispersal predators the host specificity of their larvae is examined. A comparison of host records determined in this study with records in the literature demonstrates statistically significant generic specialization by the larvae of some weevil species. The larvae of other species are also restricted to hosts within one genus, but sampling effort was insufficient to demonstrate generic specialization. The most abundant pre-dispersal weevil predator was <i>Nanophyes shoreae</i>. Aspects of the biology of this species are described. These include: the activity of the adult weevils during dipterocarp flowering events; the timing of oviposition; the length of the pre-imaginal development period; the survivorship of adult beetles kept under laboratory conditions. The period of pre-imaginal development varied between host species but was consistent between trees of one species. Quantitative analyses of <i>Nanophyes shoreae's</i> pre-imaginal mortality are also described. The primary mortality factors were abortion of fruit containing eggs and consumption of pupae and III instar larvae by vertebrates. Adaptations that may reduce losses to these primary mortality factors are considered. They include oviposition within those fruit that are least likely to abort and variability in the length of the pre-imaginal development period, causing synchronous development in larvae developing from eggs that were deposited on different dates. None of the dipterocarp fruit predators could be located during periods when dipterocarp fruit were not available. Analyses of their population recruitment during fruiting events and of the availability of fruiting trees (as determined by a phenological survey of Pasoh Forest Reserve) indicates that they are unlikely to have dispersed widely in search of fruiting dipterocarps. The existence of an alternative larval or adult host is discussed.

Thesis (Ph.D.)--Ohio University, November, 2006. / Title from PDF t.p. Includes bibliographical references.

This study examined patterns of growth shown by Rubus fruticosus L.agg. - the bramble - and looked at factors which controlled its growth. Literature on bramble ecology that was relevant to British conditions was reviewed. The study took place in Wytham Woods, a mixed, mainly deciduous wood. The soils varied from shallow limestone soils to heavy clays. Rubus vestitus Weihe and Nees was the most common bramble species. Three sites were chosen ranging from one where bramble growth was very poor to one of the most productive bramble areas in Wytham. The changing distribution of dry weight within a bramble stand over a year was followed by splitting the plant into its components; leaves, laterals, canes of different ages. The bramble stands were sampled on ten occasions during 1974 at four to six week intervals. All above ground material was removed from ten one metre-square plots from each area, at each sample time. The overall pattern of dry weight change was the same for the three areas. Total biomass showed a summer peak, the result of three processes: (i) The dry weight increase by first-year canes. (ii) The initial increase and subsequent decline in weight of the second-year cane system because of growth and die-back of the laterals. (iii) The final die-back of the cane system that had flowered the previous year. Standing dead, dead canes still attached to the rootstock and separate from the litter-layer - showed no seasonal change in dry-weight. The dry weight increase by the laterals was of the same magnitude as that by canes. The main cane growth however was 5-6 weeks later than that of the laterals. Thus lateral leaves formed the bulk of the early summer canopy while cane leaves became more important in autumn and over winter. Leaf area per plot was estimated from direct measurement of a sample of known dry weight. The winter bramble canopy was only half that in summer. Summer leaf-area-index were 0.8 in the poorest bramble site measured, 2.1 in the best. The main growth of canes and literals was by increase in length. Total stem length per plot showed a summer peak. Variations in both plant size and plant density (numbers/sq.m) caused the dry weight differences between the areas. Tree competition appeared to control these differences, the best growth occurring under an ash canopy, the worst under an oak/sycamore one. Bramble biomass in Wytham was up to seven times greater than that reported for other sites in Britain. Published values summer biomass of bramble in Britain range from 30-450 g/sq.m and annual turnover of dry weight from 50-300 g/sq.m/yr. This annual dry weight turnover is less than that for open-grown, herb communities, but similar to that for herb and shrub layers in British woodlands. Not all of this dry weight turnover represents currant photosynthesis because there are transfers between roots, canes and laterals. Over the year the bulk of the biomass was in the second-year cane system. The turnover time for the standing dead was 1-2 years. Cycling of material in a bramble stand was thus faster than for woody shrubs. A few rootstocks were excavated. The sizes of the root crowns matched the differences in shoot growth between areas. Crowns ranged from 5-60mm in diameter and may act as storage organs. The size and spread of the major roots, 4-6 per crown was also greatest in the areas of greatest shoot growth. Records of flowering and fruiting were kept both per unit area and per cane. Flowering was less in areas of low vigour of growth, which were usually the most shaded. A direct correlation between length of laterals and flowering success was found by comparing flowering on regrowth canes, or defoliated canes, with the control canes for that area. Length of lateral and flowering success depended on the overall vigour of the cane and the laterals' position on it. Laterals on side branches and the terminal portions of canes were shorter and flowered less. The process of tip-rooting was investigated. Root-boss formation increased when the tips of growing canes were covered by black fabric bags, but not when clear polythene bags were used. This confirmed the results of others that root-boss formation is increased if the stem apex is in the dark. Although defoliating canes reduced their growth it did not increase the number that tip-rooted. The growth of the daughter plants was followed. The parent cane was cut at different times after the original tip-rooting and leaving different lengths of cane attached to the daughter plant. Transfer of material to the daughter plant was shown to start in autumn and continue until the following July. The material was largely derived from the metre of cane nearest to the daughter plant. Reverse transfer, from daughter rootstock to parent cane can occur. Sections of parent cane separated from their parent root remained alive and bore laterals if attached to the daughter plant. Competition for cane reserves between laterals and daughter plants may occur, as in one experiment lateral growth was greater on canes separated from their daughter plants than where a daughter plant was present. Tip rooted canes were more abundant in areas of poor bramble growth than in vigorous areas. Such low vigour areas had a poorly developed stand structure such that cane tips were more likely to touch the ground. Vegetative and floral reproduction were complementary within the areas considered. Flowering increased and tip-rooting decreased as the canes became more vigorous. Non-destructive measurements WPTB investigated as a means of recording bramble growth. Some measurements were made on individual stems, but the main emphasis was on plot based measurements. These were calibrated against destructive sampling. Point-quadrats were used for leaf-assessment. Changes in leaf-hits per plot agreed well with variations in measured leaf weight and area. agreement was better for new leaves than for those which survived over winter, because the former were more horizontal. Mean canopy height, derived from the heights of leaf hits rose in the summer during lateral growth and declined in autumn, partly because of lateral die-back from the tips, partly because of settling of canes under their own weight. A dense bramble stand was found to have three layers; an upper leafy zone containing the bulk of the current canopy; a layer in which are the second year canes and the remains of the previous years' canopy; the leafless lower layer containing most of the standing dead. Each year's canes grow through the lower layers and come to lie horizontally as a result of their own weight and that of their laterals the subsequent year. In following years these canes are forced lower down the structure. Intersection values were used to estimate stem quantities. These were a variant of Buffon's Needles technique, adapted by Newman (1966) for root length determinations. The number of stem intersections with rods placed across a plot was related to total stem length per plot. Stems differed greatly in-angle which caused variation in the relationship particularly with the taller bramble stands. Intersection values multiplied by height were well correlated with plot dry-weight, r² = 0.8. Regressions of dry weight on adjusted intersection values showed little difference for different times of the year. These non-destructive methods were used to assess bramble stands which were too limited in area for repeated destructive sampling. Part of the growth of first-year canes is based on rootstock reserves part on photosynthesis built up by the cane leaves. To separate these two, leaves on first year canes were removed as they formed. This reduced cane growth by 20-50% relative to the controls.

Thesis (Ph. D.)--Ohio University, 2006. / Includes bibliographical references. Also available in PDF format via the Internet.

Thesis (Ph. D.)--University of Washington, 1990. / Vita. Includes bibliographical references (leaves [174]-190).

The objective of this study was to quantitatively describe the structure, composition and ecological relationships of old-growth forests of west-central Vancouver Island. Data were obtained by sampling 172 plots, at elevations up to 1000 m, located within thirteen drainage areas. Hypothesized relationships between vegetation and environmental variation were examined using gradient analysis and multivariate methods. Successive reciprocal averaging ordination of the vegetation data led to the recognition of six vegetation groups (floodplain, subalpine, Pinus contorta, Pseudotsuga, Thuja, Abies) and twenty-three community types. Data from the tree, sapling, seedling, shrub, herb and bryophyte-lichen strata were used. Vegetation groups are differentiated along macro-climatic and soil parent material gradients. The vegetation of the Pseudotsuga group, dominant inland, appears to respond to gradients of elevation and soil moisture. The Thuja group is found only near the coast, and its vegetation varies along gradients of soil nutrients and elevation; soil moisture having little effect. The vegetation patterns of the Abies group are correlated to elevation and soil moisture. Canonical variates analyses revealed a close relationship between vegetational and environmental patterns within most vegetation groups. A precipitation continentality gradient was identified as the major determinant of modal vegetation variation. Along this gradient, alpha and beta diversity increased towards the drier and more continental interior as predicted. Tree size-class distribution data indicate that Pseudotsuga menziesii is a seral species in most community types. The dominance of Thuja plicata near the coast may be maintained because of its longevity and, possibly, its wind damage resistance. Attention is drawn to the ecological mechanisms operating in coastal forests which have important implications for their successful management. / Science, Faculty of / Botany, Department of / Graduate

dissertation submitted in fulfilment of the academic requirements for the degree of Master of Science in the School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg. May 2015 / In this study I investigated the climate ecology and population biology of Brachystegia spiciformis (miombo) woodland at the distributional range edge in southern Africa. The main aim of the study was to exploit miombo relict populations, isolated well beyond contemporary distribution, to establish likely spatial and population dynamic response to future global climate change. Miombo woodlands have expanded and contracted across the central African plateau over geological time, with palynological evidence supporting an extensive latitudinal range during the Holocene altithermal. It is hypothesised that small shifts in climate may have major impacts on woodland dynamics and distribution. However, miombo relict populations in southern Africa, one in Mozambique and one in South Africa, suggest refugia; physiographic settings that support a once prevalent regional climate that has been lost (or is being lost) due to climatic shifts. Inclusion of relict populations has been shown to improve the performance of model-based projections elsewhere and have value as natural laboratories for investigating how populations react to on-going climatic change. This study aims to contribute to a better understanding of miombo woodland - an ecologically and economically significant savanna community - response to global climate change in southern Africa. A niche modelling approach was used to produce present-day and select future B. spiciformis woodland ecological niche models. Precipitation of the wettest quarter and temperature seasonality were identified as the two most important bioclimatic variables explaining B. spiciformis woodland distribution in southern Africa. Both variables displayed a relatively narrow range of optimal suitability for the species; 422 - 576 mm and 2.6 - 3.0 °C, respectively. In addition, significantly high temperature seasonality and maximum temperature of the warmest month were identified as limiting factors at the periphery of the contemporary miombo woodland distribution. Considering future regional climate change projections, it is suggested that the B. spiciformis climate niche could retract by between 30.6 - 47.3% in southern Africa by 2050. v In addition, a meta-population analysis of miombo woodland at the southern distributional range edge was carried out to elucidate patterns in population dynamics that could validate theorized climate response. Whilst the continuous miombo woodlands occurring to the north of the southern African range edge are internally relatively homogenous in community composition, relict populations reflected a loss of natural biota and a restructuring of the vegetation unit resulting in clear divergence from the core and range edge communities, and from each other. Although B. spiciformis reproduction, population density and structural dimensions were significantly low at the recently discovered relict population in South Africa relative to populations occurring to the north, we suggest that the medium-term persistence of this population is plausible based on the longevity of genets, their historic resilience, and a traditional management regime. The vicariant B. spiciformis relict population located in southern Mozambique is greater in extent than its South African counterpart and data suggest suitable reproduction dynamics for medium-term persistence. However, this population is currently heavily impacted by unsustainable habitat transformation under a lack of formal ecological or conservation protection. This study uniquely highlights B. spiciformis woodland as a climate (precipitation) sensitive component of savanna ecosystems in southern Africa and provides important baseline data for population dynamics at the distributional range edge.

Orientador: Edson Luiz Furtado / Banca: Waldir Cintra de Jesus Júnior / Banca: Leo Zimback / Banca: Cristiane De Pieri / Banca: Iraê Amaral Guerrini / Resumo: O Brasil possui uma infinidade de espécies arbóreas com elevado potencial para a produção de madeira, bem como componente de paisagem, de conservação, fixação de carbono e também recuperação de áreas degradadas. Portanto, há uma grande necessidade de estudos relacionados a árvores de espécies nativas. Isso se deve não só pela importância que as florestas nativas têm para o ecossistema, mas também pela necessidade de descrever aspectos relevantes quanto à sobrevivência, produção, fenologia, comportamento em determinados ambientes e às diversas doenças que incidem sobre as espécies, pouco relatadas na literatura. Todavia, a identificação de doenças em plantas nativas não é uma tarefa fácil, devido à falta de informações na literatura e também pelo comportamento dos fungos quando isolado. Novos patógenos podem originar-se da floresta, quando as essências nativas e/ou exóticas passam a ser cultivadas em escala comercial, sendo a identificação de elevada importância a fim de evitar danos. Este trabalho teve por objetivo avaliar a sobrevivência, crescimento, produção, fenologia e doenças em diferentes espécies de árvores nativas do Brasil, plantadas em área de declive. A área foi dividida em três blocos, sendo baixa encosta (BE), meia encosta (ME) e Topo (TP). Avaliaram-se parâmetros concernentes à taxa de mortalidade das espécies, alturas totais, diâmetro, volume e fenologia das espécies. Para identificação das doenças, o plantio foi acompanhado pelo período de um ano, a fim de de... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Brazil has a multitude of tree species with high potential for wood production, as well as landscape component, conservation, carbon fixation and also recovery of degraded areas. Therefore, there is a great need for studies related to trees of native species. This is due not only to the importance of native forests to the ecosystem, but also to the need to describe relevant aspects regarding survival, production, phenology, behavior in certain environments and the various diseases that affect species, which are not reported in the literature . However, the identification of diseases in native plants is not an easy task due to the lack of information in the literature and also the behavior of fungi when isolated. New pathogens can originate from the forest, when the native and / or exotic essences are grown on a commercial scale, with the identification of high importance in order to avoid damages. The objective of this work was to evaluate the survival, growth, production, phenology and diseases in different native tree species of Brazil, planted in a slope area. The area was divided into three blocks, being low slope (BE), half slope (ME) and Topo (TP). Parameters related to the mortality rate of the species, total heights, diameter, volume and phenology of the species were evaluated. To identify the diseases, the planting was followed for a period of one year, in order to determine their distribution in the species. The plants with symptoms were photographed with the object... (Complete abstract click electronic access below) / Doutor

Abstract not available