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1
Prescott, T. A. K. "Antimicrobial compounds from tropical rainforest plants." Thesis, University of Edinburgh, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.660747.
Testo completoAbstract (sommario):
Ethnobotanical fieldwork was carried out in New Guinea. An antibacterial field assay kit was developed using freeze-dried strains of <i>S. epidermidis </i>and <i>E. coli</i> which allowed plants used in traditional medicines to be screened in situ without having to take them back to a laboratory. This approach identified <i>Lunasia amara </i>(Blanco) as a candidate species; the use of its bark by tribes of the Whitman Range to treat tropical ulcers, supported by clear zones of inhibition with <i>S. aureus.</i> Samples of the bark were collected for analysis and through activity-guided fractionation, the anti- <i>S. aureus </i>activity of the bark extract was pinned down to a single well resolved HPLC peak (MIC <i>S. aureus </i>NCTC 6571 64μg/ml) which subsequent NMR analysis revealed to be the quinoline alkaloid lunacridine; 2’-<i>O</i>-trifluoroacetyl lunacridine was found to be a more stable derivative however. Lunacridine’s planar cationic structure suggested it might act as a DNA intercalator; 220μM giving 50% binding in an ethidium bromide displacement assay. This in turn suggested DNA topoisomerase II as a likely target for the compound which was confirmed with a kDNA decatenation assay revealing complete inhibition of the enzyme at 5μM. Cell viability assays with MRC-5, H226 and HELA cells showed the compound to be cytotoxic in a time dependent manner producing non-linear dose response curves indicative of a topoisomerase poison mode of action. Activation of the apoptosis pathway enzymes caspase 3/7 was also detected, reaching maximal activity between 24 and 48 hours for the H226 cell line. Thus, lunacridine does not represent a selective antibiotic but with the right structural modifications could be developed as an antineoplastic agent.
2
Healey, John Robert. "Regeneration in a Jamaican montane tropical rainforest." Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335160.
Testo completo
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Thomas, Raquel Simone. "Productivity and resource availability in lowland tropical rainforest in Guyana." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.404769.
Testo completo
4
Gilman, Alex Caroline. "Biodiversity patterns in tropical montane rainforest flora of Costa Rica." Diss., Restricted to subscribing institutions, 2007. http://proquest.umi.com/pqdweb?did=1472126481&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
Testo completo
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Nik, Abdul Rahim H. "The effects of selective logging methods on hydrological parameters in Peninsular Malaysia." Thesis, Bangor University, 1990. https://research.bangor.ac.uk/portal/en/theses/the-effects-of-selective-logging-methods-on-hydrological-parameters-in-peninsular-malaysia(9ed5e3d1-33ab-4cb1-91b0-7c043891921f).html.
Testo completoAbstract (sommario):
An experimental forest watershed, consisting of three small catchments at Berembun, Negeri Sembilan, in Peninsular Malaysia has been monitored from 1979 to 1987. Adequate instruments were installed for continuous collection of hydrologic and climatic data. The calibration and post-treatment phases lasted for three and four years respectively. Two types of treatments were imposed -namely commercial selective logging and supervised selective logging in catchment 1 and catchment 3 whilst catchment 2 remained as a control. Pertinent logging guidelines were prescribed and assessed in C3 in terms of hydrological responses. Significant water yield increases were observed after forest treatment in both catchments amounting to 165 mm (70%) and 87 mm (37%) respectively in the first year; increases persisted to the fourth year after treatment. Magnitude and rate of water yield increase primarily depended on the amount of forest removed and the prevailing rainfall regime and the increase was largely associated with baseflow augmentation. Interestingly, both types of selective loggings produced no significant effect on peak discharge while the commercial logging resulted in a significant increase in stormflow volume and initial discharge. Such responses can be explained by the extensive nature of selective logging which normally left a substantial area of forest intact and minimal disturbance to flow channels. Thus, conservation measures introduced in this study - the use of buffer strips, cross drains, an appropriate percentage for the forest road network,- were found to be effective and beneficial in ameliorating the hydrological impacts.
6
Paul, Miriam. "Restoring Rainforest – the Capacities of Three Different Reforestation Pathways to Re-establish Ecosystem Properties." Thesis, Griffith University, 2011. http://hdl.handle.net/10072/366066.
Testo completoAbstract (sommario):
The broad scale destruction of tropical and subtropical rainforests has been one of the largest land-cover conversions taking place on earth, with a wide range of deleterious consequences at local, landscape, and global scales. While the resulting loss of biodiversity and habitat for rainforest-dependent fauna and flora has been well-studied as a major effect, clearing of rainforests also significantly influences soil processes such as biochemical cycles and microbial functions. More recently, there has been a growing public interest in reforestation activities. There are a range of different pathways by which rainforest cover can be restored to cleared land, including autogenic, or „natural‟, regrowth, management of this autogenic regrowth, and tree planting for ecological restoration. However, little is known about the recovery processes of ecosystem properties under different reforestation pathways in the same landscape. The broad objective of this thesis was to assess both the effects of deforestation on a range of ecosystem processes and the potential of different reforestation pathways to restore these processes. The study was conducted in the Big Scrub area in subtropical eastern Australia, a basaltic plateau that once supported the continent‟s largest continuous stand of lowland subtropical rainforest, which was mostly cleared for pasture in the mid to late 19th century. In this landscape, the properties of five site-types were compared, with five replicate sites in each. The site-types consisted of two reference conditions, pasture and intact rainforest, and three different reforestation pathways. These pathways were: autogenic regrowth dominated by the non-native tree species camphor laurel (Cinnamomum camphora); similar regrowth managed in order to remove the camphor laurel and release the growth of recruited rainforest seedlings; and ecological restoration plantations. Camphor laurel is a dominant species in the Big Scrub region, where it readily colonises abandoned pastures and is known to facilitate the recruitment of later successional rainforest tree species. In ecological restoration plantings, a high diversity of native rainforest tree seedlings is planted to restore biodiversity. The main ecosystem properties studied within the sites were as follows: 1. size and composition of viable soil seed banks; and 2. soil physical properties and nutrient cycles. This study also assessed the consequences of altered soil properties and nutrient dynamics for the early growth of rainforest pioneer seedlings. To assess the effects of deforestation and reforestation on soil seed banks, germination experiments were conducted using soil from all five site-types (three reforestation pathways, pasture, and rainforest sites). Germination trays were positioned in a shade-house and seedling emergence was monitored over a period of six months. Germinated seedlings were classified into functional groups according to their life-form, origin, successional stage, and dispersal mode. Additionally, floristic data from a subset of the study sites was used to examine how the seed bank was related to the standing vegetation. Despite a much larger total abundance of seeds in seed banks from pasture sites, these sites contained very few native woody plants and were dominated by grasses and herbaceous species. Further, seed banks of reforested and rainforest sites were mainly composed of pioneer and early secondary species, whereas late secondary and mature phase species appeared almost solely in the standing vegetation. The abundance and diversity of most of the functional groups that were impacted by deforestation showed values similar to rainforest in at least one of the three reforestation pathways; whilst the three pathways differed only slightly in their capacities to restore soil seed banks. In the initial phases of reforestation, however, seed banks play no vital role after long-term pasture establishment. The effects of deforestation and reforestation on the physical and biochemical properties of soil were tested by measuring a range of properties in soil samples from all five site-types. The main emphasis was placed on carbon- and nitrogen-related soil properties, as they are major nutrients in terrestrial ecosystems. Before these data were collected, a study was performed in a subset of the sites to identify the variation of soil properties at different spatial scales (subplot, site, and site-type level) and to develop a spatial design for the collection of soil samples within sites. For each of the five site-types, two replicate sites were measured, with 16 subplots in each site. Subplots were seven cm in diameter and regularly aligned with a spacing of 10 m. The seven soil properties measured in this soil variability study were: gravimetric water content; soil organic matter; pH; total organic carbon; microbial biomass carbon; nitrate-nitrogen, and nitrification rate. Across all sites, water content, soil organic matter, and pH showed a consistently low variability at all three spatial scales. In contrast, soil properties related to microbial processes exhibited higher degrees of spatial variability at the site and the subplot level. However, even in soil properties with a high tendency for spatial variability, the physical mixing of subsamples from subplots within a site, in contrast to analysing subsamples individually, could be validated as a useful technique to reduce analytical effort and cost. In the main study of soil properties under deforestation and reforestation, 19 properties were measured at each of five sites in each of the five site-types (the same 25 sites used for the seedling germination experiment). These properties consisted of: eight nitrogen-related variables (total nitrogen (N), ammonium-N, nitrate-N, total inorganic N, plant-available ammonium-N, plant-available nitrate-N, nitrification rates, and denitrification rates); six carbon-related properties (total carbon (C), total organic carbon, soil organic matter, 13C value, microbial biomass carbon, and soil microbial activity); and five general soil properties (gravimetric water content, pH, bulk density, fine root biomass, and plant-available phosphate). Of the 19 soil properties, nine differed significantly between rainforest and pasture. Nitrate-N levels, plant-available nitrate-N levels, nitrification rates, and fine root biomass were significantly greater in rainforest than in pasture sites, while plant-available ammonium-N levels, 13C values, pH, bulk density, and plant-available phosphate concentrations showed greater levels in pasture sites. Apart from fine root biomass, all of these soil properties were re-established to a level similar to that in rainforest in at least one of the three reforestation pathways. However, the capacity to re-establish soil properties varied among the three reforestation pathways. For example, autogenic regrowth dominated by camphor laurel showed a good recovery of nitrification, ammonium, and phosphate levels, but did not significantly facilitate the re-establishment of nitrate-N and bulk density. The impacts of soil properties – and hence deforestation and reforestation – on early seedling development were tested by measuring the growth of rainforest pioneer seedlings in soils collected from the three different reforestation pathways, as well as from pasture and rainforest soils. Three species, Alphitonia excelsa, Guioa semiglauca, and Omalanthus nutans, all fast-growing pioneer species that are common in the Big Scrub region, were chosen for this study. The seedlings were kept in a shade-house over a period of about seven months, and height and diameter were measured at regular time intervals. Although the three species varied significantly in height and diameter growth, they responded similarly to the five site-types, with generally lower growth rates in untreated autogenic regrowth and higher rates in soils from all other site-types, including pasture. However, there was little evidence that seedling performance was directly influenced by soil properties. Across all three species and all 25 sites, seedling growth rates...<br>Thesis (PhD Doctorate)<br>Doctor of Philosophy (PhD)<br>Griffith School of Environment<br>Science, Environment, Engineering and Technology<br>Full Text
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Nitsch?Velasquez, Lucia. "Bioprospecting Three Plants from the Tropical Rainforest as Potential Antimicrobial Adjuvants." Thesis, State University of New York at Buffalo, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=13428243.
Testo completoAbstract (sommario):
<p> The ‘resistance bacteria era’ is intrinsically related to the hospital acquired infections (HAI). The most frequent HAI causal agent in USA is multidrug resistant <i>Staphylococcus aureus</i> (MRSA) a priority of the Center for Disease Control for development for development of new drug treatments. A HAI key treatment is the oto and nephrotoxic aminoglycosides. One strategy is to enhance the antibiotic activity of antibiotics by combination with NPs, <i>e.g.</i>, amoxicillin and the beta–lactamase inhibitor clavulanate. </p><p> Solutions for this urgent worldwide need can derive from bioprospecting species, specially from biodiversity rich countries <i>e.g.</i>, the Guatemalan rainforests. Bioprospecting studies are envisioned under a business framework that are economic, social and eco–sustainable in the long term. </p><p> The enhancement of the bactericidal activity of commercially available aminoglycosides (<i><sub>GEN</sub></i>, VAN) by polar extracts from three Guatemalan rain forest plants were evaluated: the cosmetic oil producer palm <i>Attalea cohune</i> (Ac and fraction Ac11k), the Catholic relic <i>Bourreria huanita</i> (Bh), and the food spice <i> Dysphania ambrosioides</i> (Da). The antibiotics’ minimal bactericidal concentration (MBC) against MRSA–USA–300: Ac11k was reduced to 1/16MBC<i><sub>GEN</sub></i> at 9.9 Ac11k mg/mL (synergistic effects), and to 1/2MBC<i><sub>VAN</sub></i> at 94 Ac11k mg/mL (additive effects), and to 1/4MBC<i><sub>GEN</sub></i> at 136 mg/mL ethanolic extract of Bh. The Da–ascaridol–less leaves’ extracts reduced <i> Erwinia carotovora</i> doubling time from 17 min to 12.5 min. hinting out that they may be potentially useful for the probiotics’ industry. </p><p> With an emphasis in natural products dereplication by chemoinformatics tools, the experimental data gathered (HR–MS, FTIR, <sup>1</sup>H–NMR spectroscopies) and the computational–assisted structure elucidation scheme were applied to derive the proposed structure of a new chemical entity probably present in Ac11k sample, Corozine A: a non–basic alkaloid with several putative ring types: (Z)-4-ethyl-1,2,6,7- tetrahydro-6,9-(methanoazenometheno)pyrrolo[2,1-d][1,5]oxazonine. Two additional potential targets related to sugars metabolism were found with ligand similarity search engines. </p><p> Corozine A and the other extracts studied are of interest for further research to improve its commercial exploitation. The vision of new commercial products derived from <i>A. cohune</i> would require a pilot project that re–engineers the extraction of fatty acids, essential oil, and alkaloids from the same raw material. </p><p>
8
Azim, Amir Affan Abdul. "Growth ring formation of selected tropical rainforest trees in Peninsular Malaysia." Master's thesis, Kyoto University, 2014. http://hdl.handle.net/2433/188776.
Testo completoAbstract (sommario):
Kyoto University (京都大学)<br>0048<br>新制・課程博士<br>博士(農学)<br>甲第18338号<br>農博第2063号<br>新制||農||1023(附属図書館)<br>学位論文||H26||N4845(農学部図書室)<br>31196<br>京都大学大学院農学研究科森林科学専攻<br>(主査)教授 大澤 晃, 教授 髙部 圭司, 教授 北山 兼弘<br>学位規則第4条第1項該当
9
Kroc, Jonathan Fleming. "Tucson's Rainforest: Data Processing for Tracing Carbon in Soil, Plants, and Atmosphere in the Tropical Rainforest of Biosphere 2." Thesis, The University of Arizona, 2014. http://hdl.handle.net/10150/323455.
Testo completo
10
Grainger, A. "The future role of the tropical rain forests in the world forest economy." Thesis, University of Oxford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377888.
Testo completo
11
Garraway, Shani. "Measurement and modelling of volatile organic compounds in a tropical rainforest environment." Thesis, University of York, 2018. http://etheses.whiterose.ac.uk/21337/.
Testo completoAbstract (sommario):
This thesis describes measurements of volatile organic compounds made at the Danum Valley Global Atmosphere Watch station in Sabah, Malaysia using gas chromatography with flame ionization detection. Measurements of 13 VOCs were made between August 2015 and March 2016. A non-negative matrix factorization analysis is performed on the observational data, which identified three main periods within the dataset. A period influenced by the Indonesian biomass burning season characterized by large increases in most VOCs concentrations; background periods where local conditions dominate; and a period influenced by local anthropogenic events where short lived increases in some species were seen. Biomass burning in the region caused a substantial increase in most VOCs at the measurement site between August and October 2015. Comparison of VOC emission ratios with previous studies indicates that the burning in the region is a combination of peat and forest burning. Combining fire maps with air mass trajectories shows that changes in meteorological conditions, not changes in fire activity, drives the variability in VOC concentrations at the measurement site during the biomass burning period. The background periods were dominated by biogenic emissions. The two VOCs identified as being mainly biogenic in origin were isoprene and propene, with isoprene being the dominant VOC during the background periods. Comparison of propene observations with the GEOS-Chem model shows that the model substantially overestimates propene concentrations. This shows that the current MEGAN propene emissions algorithm based on mid-latitude observations is not appropriate for the tropics. There was good agreement between measured isoprene concentrations and MEGAN derived GEOS-Chem model concentrations. Most previous studies have shown the MEGAN overestimates isoprene emissions. No clear seasonality was seen in isoprene concentrations at the Danum Valley measurement site. This is unlike previous studies in the Amazon, where strong seasonal cycles are observed.
12
Bito, Darren. "Structure and Dynamics of Herbivore Assemblages Along an Altitudinal Gradient: Indicators of Climate Change." Thesis, Griffith University, 2011. http://hdl.handle.net/10072/366400.
Testo completoAbstract (sommario):
Herbivory is one of the major ecosystem processes, as are pollination and seed dispersal, which drives ecological changes in both the phytophagous fauna and their host plant assemblages. The amount of herbivory damage on a host species represents not only the amount of herbivory pressure due to phytophagous insects but also the predatory pressure due to predators at higher trophic levels. Furthermore, additional interactions of climate and environmental factors determine the conditions of the host species and subsequently the assemblage of herbivorous insects that colonize them. All these direct and indirect, positive and negative influence of climate and environmental factors combined with the requirement to propagate themselves cascades to through the higher trophic levels down to assemblage of herbivorous insects and their host species at the lower trophic levels. This study considered the host specificity of caterpillars, herbivory pressure and herbivory damage on trees and shrubs along an altitudinal gradient within subtropical and temperate rainforest. The work has attempted to show how a selected ecological process (herbivory) is being influenced by various factors including altitude, ant predation pressure and host plant species, canopy strata and physical properties of leaves.<br>Thesis (PhD Doctorate)<br>Doctor of Philosophy (PhD)<br>Griffith School of Environment<br>Arts, Education and Law<br>Science, Environment, Engineering and Technology<br>Full Text
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Maunsell, Sarah. "Food Webs along Elevational Gradients: Interactions among Leaf Miners, Host Plants and Parasitoids in Australian Subtropical Rainforest." Thesis, Griffith University, 2014. http://hdl.handle.net/10072/368145.
Testo completoAbstract (sommario):
Gradients in elevation are used to understand how species respond to changes in local climatic conditions and are therefore a powerful tool for predicting how mountain ecosystems may respond to climate change. While many studies have shown elevational patterns in species richness and species turnover, little is known about how multi-species interactions respond to elevation. An understanding of how species interactions are affected by current clines in climate is imperative if we are to make predictions about how ecosystem function and stability will be affected by climate change.
This challenge has been addressed here by focussing on a set of intimately interacting species: leaf-mining insects, their host plants and their parasitoid predators. Herbivorous insects, including leaf miners, and their host plants and parasitoids interact in diverse and complex ways, but relatively little is known about how the nature and strengths of these interactions change along climatic gradients. In order to determine how elevational changes in climatic conditions affect interactions among leaf miners, their host plants and their parasitoids, I quantified these communities and their interactions along three elevational gradients in eastern Australian subtropical rainforest. In doing so, I aimed to 1) provide information on host plant use of leaf miners and the elevational associations of these relationships, 2) understand how the species richness and assemblage composition leaf miners and their parasitoids, and composition of interactions with their hosts (plants or leaf miners), is affected by elevation, 3) uncover any elevational changes in the structure of quantitative networks connecting leaf miners and their parasitoids, and 4) test if parasitism pressure increases at the lower edge of, and below the elevational range of a specific leaf miner species.<br>Thesis (PhD Doctorate)<br>Doctor of Philosophy (PhD)<br>Griffith School of Environment<br>Science, Environment, Engineering and Technology<br>Full Text
14
Bloor, J. "Effects of light on the performance of shade-tolerant tropical rainforest tree seedlings." Thesis, University of Cambridge, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.596725.
Testo completoAbstract (sommario):
This thesis set out to investigate the light responses of shade-tolerant tropical tree species, and to assess whether or not there was a trade-off between shade tolerance and responsiveness to high light. Shadehouse experiments indicated that low-light relative growth rate was positively correlated with that of high light across species, and all seedlings showed typical 'sun' and 'shade' characteristics when grown in high- and low-light survival amongst the species studied. These trends were mirrored in forest-growth plants. Seedling mortality rate in the forest varied across species and was driven by vertebrate herbivory rather than light availability. In the shadehouse studies, seedling light responses did not appear to be confounded by nutrient limitation. Some evidence was found for phylogenetic effects across species, particularly in root morphology. Ontogenetic effects were also found for a number of plant traits, although the significance of these effects was not consistent across species. Species showed changes in growth ranking both across light levels and over time, suggesting a role for shifting competitive hierarchy in promoting species coexistence. The shade-tolerant species studied also varied significantly in the flexibility of their plant traits in response to changes in light conditions. Nonetheless, all species showed significant acclimation to an increase in light in terms of growth, photosynthesis, morphology and architecture. Acclimation to a decrease in light involved a significant decrease in photosynthetic rate and growth across species, but changes in morphology were limited.
15
Odell, Erica. "Lianas, trees and insect herbivory." Thesis, Griffith University, 2018. http://hdl.handle.net/10072/380989.
Testo completoAbstract (sommario):
Insect herbivory is a key ecological process which mediates the structure, functioning and maintenance of forests. Studies of insect herbivory in tropical forests typically focus on trees whereas the contributions of other plant types, particularly climbing plants, remains undervalued and under studied. Lianas, or woody climbing plants, are important ecosystem contributors. Per unit basal area, lianas support substantially more leaves than trees and typically comprise 20-40% of the above ground leaf biomass in rainforests. This indicates a likely function in insect herbivory. Little data, however, exists which quantifies the importance of their contribution to overall ecosystem dynamics, particularly in contrast with trees. Information on the contributions of other plant types to herbivory are necessary if we are to fully appreciate the role of lianas in herbivory and understand the ways in which forests and associated processes may shift given anticipated environmental and vegetation changes.
This thesis aims to address this knowledge gap and demonstrate the value of lianas in supporting herbivory and associated insect assemblages. I aim to establish the need for a better understanding of liana-supported insect herbivory, quantify the trophic link among different plant types and insects in two contrasting rainforests, and determined the influence of structural and chemical leaf traits.
First, I determine the need for liana focussed herbivory research by providing a comprehensive review of the literature.
Second, I examine the temporal changes in liana and tree communities over two decades in a 1 ha plot of Australian subtropical rainforest. It is firmly established that lianas are increasing in Neotropical rainforest. In other bioregions, however, the pattern is less clear and derived from few sources. In Australia, where the factors influencing vegetation dynamics may differ, no such studies exist. I found liana abundance and biomass increased substantially from 2005 to 2015 while tree abundance remained stable from 1995 to 2015. Tree biomass also rose considerably, but at approximately half the rate of lianas. Based on the structure of liana and tree communities, I suggest increasing atmospheric CO2 to be the most probable explanatory hypothesis over changes in rainfall or tree mortality. Given the results presented here and other documented increases in liana abundances globally, it is concerning we do not know more about the ecosystem services they provide.
Third, theoretical and empirical evidence suggests lianas may be an important food source for phytophagous insects. I address this hypothesis by two methods. First, in a literature-based study I assess the relative use of lianas as host plants for Australian butterflies. Second I make quantitative assessments Insect herbivory is a key ecological process which mediates the structure, functioning and maintenance of forests. Studies of insect herbivory in tropical forests typically focus on trees whereas the contributions of other plant types, particularly climbing plants, remains undervalued and under studied. Lianas, or woody climbing plants, are important ecosystem contributors. Per unit basal area, lianas support substantially more leaves than trees and typically comprise 20-40% of the above ground leaf biomass in rainforests. This indicates a likely function in insect herbivory. Little data, however, exists which quantifies the importance of their contribution to overall ecosystem dynamics, particularly in contrast with trees. Information on the contributions of other plant types to herbivory are necessary if we are to fully appreciate the role of lianas in herbivory and understand the ways in which forests and associated processes may shift given anticipated environmental and vegetation changes.
This thesis aims to address this knowledge gap and demonstrate the value of lianas in supporting herbivory and associated insect assemblages. I aim to establish the need for a better understanding of liana-supported insect herbivory, quantify the trophic link among different plant types and insects in two contrasting rainforests, and determined the influence of structural and chemical leaf traits.
First, I determine the need for liana focussed herbivory research by providing a comprehensive review of the literature.
Second, I examine the temporal changes in liana and tree communities over two decades in a 1 ha plot of Australian subtropical rainforest. It is firmly established that lianas are increasing in Neotropical rainforest. In other bioregions, however, the pattern is less clear and derived from few sources. In Australia, where the factors influencing vegetation dynamics may differ, no such studies exist. I found liana abundance and biomass increased substantially from 2005 to 2015 while tree abundance remained stable from 1995 to 2015. Tree biomass also rose considerably, but at approximately half the rate of lianas. Based on the structure of liana and tree communities, I suggest increasing atmospheric CO2 to be the most probable explanatory hypothesis over changes in rainfall or tree mortality. Given the results presented here and other documented increases in liana abundances globally, it is concerning we do not know more about the ecosystem services they provide.
Third, theoretical and empirical evidence suggests lianas may be an important food source for phytophagous insects. I address this hypothesis by two methods. First, in a literature-based study I assess the relative use of lianas as host plants for Australian butterflies. Second I make quantitative assessments Insect herbivory is a key ecological process which mediates the structure, functioning and maintenance of forests. Studies of insect herbivory in tropical forests typically focus on trees whereas the contributions of other plant types, particularly climbing plants, remains undervalued and under studied. Lianas, or woody climbing plants, are important ecosystem contributors. Per unit basal area, lianas support substantially more leaves than trees and typically comprise 20-40% of the above ground leaf biomass in rainforests. This indicates a likely function in insect herbivory. Little data, however, exists which quantifies the importance of their contribution to overall ecosystem dynamics, particularly in contrast with trees. Information on the contributions of other plant types to herbivory are necessary if we are to fully appreciate the role of lianas in herbivory and understand the ways in which forests and associated processes may shift given anticipated environmental and vegetation changes.
This thesis aims to address this knowledge gap and demonstrate the value of lianas in supporting herbivory and associated insect assemblages. I aim to establish the need for a better understanding of liana-supported insect herbivory, quantify the trophic link among different plant types and insects in two contrasting rainforests, and determined the influence of structural and chemical leaf traits.
First, I determine the need for liana focussed herbivory research by providing a comprehensive review of the literature.
Second, I examine the temporal changes in liana and tree communities over two decades in a 1 ha plot of Australian subtropical rainforest. It is firmly established that lianas are increasing in Neotropical rainforest. In other bioregions, however, the pattern is less clear and derived from few sources. In Australia, where the factors influencing vegetation dynamics may differ, no such studies exist. I found liana abundance and biomass increased substantially from 2005 to 2015 while tree abundance remained stable from 1995 to 2015. Tree biomass also rose considerably, but at approximately half the rate of lianas. Based on the structure of liana and tree communities, I suggest increasing atmospheric CO2 to be the most probable explanatory hypothesis over changes in rainfall or tree mortality. Given the results presented here and other documented increases in liana abundances globally, it is concerning we do not know more about the ecosystem services they provide.
Third, theoretical and empirical evidence suggests lianas may be an important food source for phytophagous insects. I address this hypothesis by two methods. First, in a literature-based study I assess the relative use of lianas as host plants for Australian butterflies. Second I make quantitative assessments of herbivore damage in the canopy of a tropical Chinese rainforest and the understory of a subtropical Australian rainforest based on new, primary data.
Lianas, and vines alike, are hypothesised to be important food plants for butterflies. This speculation, however, has never been formally tested. Based on available food plant information of Australian butterflies, I found lianas to be an important food source for butterfly caterpillars in rainforests and their use as host plants to be greater than what simple plant diversity would predict. Interestingly, butterflies feeding on climbing plants had significantly greater incidences of monophagy than those feeding on trees. The patterns of host plant use and specialisation on trees and lianas are similar to those found in phytophagous rainforest beetles elsewhere.
If lianas support greater diversity and abundances of foliar feeding insects than trees, we would expect this to be reflected by asymmetrical incidences of herbivore damage across the two plant types. I found no overall significant difference across plant types in neither the canopy of a tropical Chinese rainforest or the understory of a subtropical Australian rainforest, providing further support for this hypothesis. I did however observe that; 1) lianas influence their host’s leaf traits, most likely through inputs of nitrogen rich leaf litter around the base of their hosts, 2) under drought conditions lianas may reduce the amount of herbivory occurring on their host trees, and 3) leaf traits important for predicting herbivory are not consistent across plant types.
Through the combination of studies, I have shown that lianas are an important food source for herbivorous insects at least as much so as trees. The results of this thesis have helped close the knowledge gap in our understanding of herbivory and demonstrate the importance of lianas in supporting insect assemblages. Without understanding the contributions of other plant types to herbivory (and the associated insect faunas they support) we are unable to make accurate models and predictions about their future. Given lianas are increasing in many tropical rainforests, including those studied here, it is concerning that not more is known about their contributions to herbivory and their relationships with the insect herbivores they support – this thesis goes part way to allay this concern.<br>Thesis (PhD Doctorate)<br>Doctor of Philosophy (PhD)<br>School of Environment and Sc<br>Science, Environment, Engineering and Technology<br>Full Text
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Nagamitsu, Teruyoshi. "Community ecology of floral resource partitioning by eusocial bees in an Asian tropical rainforest." 京都大学 (Kyoto University), 1998. http://hdl.handle.net/2433/157161.
Testo completoAbstract (sommario):
本文データは平成22年度国立国会図書館の学位論文(博士)のデジタル化実施により作成された画像ファイルを基にpdf変換したものである<br>Kyoto University (京都大学)<br>0048<br>新制・課程博士<br>博士(理学)<br>甲第7176号<br>理博第1950号<br>新制||理||1049(附属図書館)<br>UT51-98-G105<br>京都大学大学院理学研究科動物学専攻<br>(主査)教授 山村 則男, 教授 堀 道雄, 教授 湯本 貴和<br>学位規則第4条第1項該当
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Berglund, Hanna. "Biological Soil Invertebrate Activity in a Tropical Rainforest : A comparison of soil invertebrate activity in two tropical rain forests in Borneo." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-411109.
Testo completoAbstract (sommario):
Logging of tropical forests is increasing worldwide. Logging alters the forest conditions such as temperature, soil water content and litter input into the soil. This study explored how soil invertebrate activity in Borneo differs between pristine forests and two secondary forests, with 10 and 40 years of recovery time since the last logging. To measure the soil fauna feeding activity, the bait lamina stick method was applied. The study was conducted in Sabah, Malaysian Borneo, during April and May 2019. 33 forest plots were examined with ten lamina sticks placed in each of the three replicas per forest plot. The sticks were kept in the soil for four weeks before being removed. Upon removal, the soil invertebrate activity was determined by assessing how many holes of the bait lamina sticks were eaten and at what depth. The activity was related to the above-ground carbon density (ACD, a density measure for amount of above-ground carbon), as well as depth-specific activity in the different plots. Moreover, further relationships with the invertebrate activity and environmental conditions such as cumulative throughfall during the study time as well as the soil water content were studied. The results showed that the soil activity slightly decreased with increased ACD, but no statistical significance was found. This study also suggests that the activity was higher in the upper 0-5cm of the soil than in the lower 5-10 cm. Lastly, the results showed that the activity was highest in the forest with the shortest recovery time (10 years). This implies that it might be possible to regain the original soil activity since the activity of the 40-year-old forest was closer to the pristine forest than that of the 10- year-old forest.
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Binks, Oliver John. "The role of leaf hydraulic function and anatomy in the acclimation of tropical forest trees to drought." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/18752.
Testo completoAbstract (sommario):
Seasonality in the Amazon Rainforest is predicted to become more extreme, with dry seasons increasing in length and severity, while severe episodic droughts are expected to occur with greater frequency. Drought stress can reduce the capacity of the rainforest to sequester carbon, and severe drought events can switch the region from being a net sink to a temporary source of carbon to the atmosphere. A key component in the drought-induced carbon flux is tree mortality, and there is evidence of strong feedbacks globally and regionally in the Amazon with climate change. Although the exact cause of drought-induced mortality in trees is difficult to ascertain, recent data suggests that reduced functionality of the water transport pathway (hydraulic failure) is an important factor. Hydraulic vulnerability in trees is often assessed using measurements of the capacity of stems and branches to cope with the strongly negative internal water pressures associated with drought. However, leaves play a vital role in protecting the integrity of the ‘upstream’ hydraulic pathway by influencing the rate of transpiration and thus the tension in the water column. Therefore, the physiology of leaves can be informative of, and influence, tree species’ sensitivity to drought. This thesis uses a long-term large-scale rainfall exclusion experiment in the Eastern Amazon to examine the possible link between leaf physiology and drought sensitivity (or tolerance) by different taxa, and the capacity of mature, upper canopy Amazonian trees to respond to drought via plastic changes in leaf physiology. The plasticity in response to experimental drought and the differences between taxa classed as drought-sensitive and drought-resistant based on drought induced mortality records were tested by the study of leaf water relations (Chapter 2), leaf anatomy (Chapter 3) and foliar water uptake (Chapter 4). No consistent differences were found between drought-resistant and drought-sensitive species suggesting that the sensitivity of these species to drought may be due to other aspects of plant physiology. However, a limited response to the imposed drought conditions was detected across all taxa and included reductions of osmotic potential at full turgor and turgor loss point (Chapter 2), and increases in the thickness of the upper epidermis and the leaf internal cavity volume (Chapter 3). Interestingly, drought-sensitive taxa showed more seasonal osmotic adjustment than drought-resistant taxa, indicating that short-term responses to drought (e.g. season) are not representative of the capacity for adjustment in response to long-term water deficits. No significant changes occurred in leaf size, thickness, stomatal and vein density, the quantity of the inner leaf tissues (i.e. the palisade and spongy mesophyll) and mesophyll cell size, in response to the experimental drought. The experiments on foliar water uptake in Chapter 4 revealed that this rarely-considered process occurs in all taxa, but the response to the drought treatment differed among taxa. Using a simple model, foliar water uptake was scaled up to canopy level. Under normal conditions (i.e. no drought) canopy foliar uptake was calculated to be 29.9 ± 2.3 mm year-1 from rainfall alone, but this increased to a maximum of 51.9 ± 2.3 mm year-1 when including the input of dew in the dry season. However, lower water potential in the drought plot causing increased rates of foliar water uptake, led to estimates of 38.7 ± 3.0 mm year-1 (rainfall only) and 68.9 ± 2.9 mm year-1 (including dry season dew). Taken together, these results demonstrate that Amazonian trees show some limited capacity for acclimation to drought through the changes in leaf physiology measured in this thesis. Low turgor loss point is associated with dry climate-adapted plants, so the finding that this parameter reduced in response to the drought reveals some potential for Amazonian trees to acclimate with the predicted changes in moisture availability. However, the limited response of leaf anatomy to long-term drought might suggest that acclimation may only occur within a narrow range. The finding that six common Amazonian tree genera can take water up through their leaves has considerable implications for understanding the Amazon water budget, in terms of the contribution of dew and light rainfall to canopy water status, but also the implications it has for the hydraulic vulnerability of trees in rainforests right across the Amazon basin.
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Cozza, John. "Sex Expression in a Rainforest Understory Herb, Begonia urophylla." Scholarly Repository, 2008. http://scholarlyrepository.miami.edu/oa_dissertations/186.
Testo completoAbstract (sommario):
Monoecy, the production of distinct male and female flowers on the same plant, is an important, though little studied, sexual strategy in the rainforest understory. This study of a monoecious plant discovered a cue to induce flowering, explored the interplay of gender constraint vs. plasticity in a natural population, and tested possible causes of gender in two laboratory experiments. An experiment in the lab found that reduced photoperiod for three weeks is an unambiguous cue for flowering. The remarkably long inductive period is followed by a long and variable period of floral initiation. This results in only partial synchronization of flowering among plants in a patch, which enhances mating opportunities in this protandrous plant. Inflorescence architecture is highly constrained, and ideally produces a phenotypic gender (proportion female) of about 0.5. However, in the forest at Las Cruces, Costa Rica, most plants were less female than predicted, mostly through abortion of female buds. Plants showed gender plasticity between and within years. Large plants produced more flowers and were more female in gender, and less variable in gender, than small plants. Reproduction was poorly correlated with environmental resource availability, measured as canopy openness, soil moisture, pH, and soil phosphorus, ammonium and nitrate. Phenotypic selection analysis on seed production suggests an optimal gender of 50-60% female, yet plasticity to be less female than this optimum, and in particular to express only male function, has been maintained. In a factorial experiment in the lab, high light or high nitrogen caused plants to produce more flowers and to be proportionally more female, and larger in weight, than low light or nitrogen. The effects of light and nitrogen on reproduction, plant size, and leaf greenness suggest an energy based determination of gender. Gender may be mostly influenced by plant size, but sometimes also opportunistically by environment. Inoculation with mycorrhizas caused plants to be less female in gender, and smaller in weight, than plants that were not inoculated. This suggests a net cost of mycorrhizas under experimental conditions, and supports the emerging view of the mycorrhizal symbiosis as not necessarily mutualistic under all circumstances.
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Pugh, Thomas Alan Miller. "Development and application of a box model to boundary layer chemistry above a tropical rainforest." Thesis, Lancaster University, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.551635.
Testo completoAbstract (sommario):
Biogenic volatile organic compounds (BVOCs), in particular isoprene and monoter penes, dominate the oxidation capacity of the tropical boundary layer and play an important role in the formation of the radiatively and ecologically significant gas ozone. This work investigates the oxidation of isoprene and monoterpenes in the tropical boundary layer using a box model of atmospheric chemistry, which is adapted for this purpose. The model output is compared with measurements of atmospheric composition and fluxes made over the tropical rainforest during the Oxidant Particle and Photochemical Processes (OP3) campaign in Sabah, Malaysia. The model can replicate 03 and NOx concentrations well during the daytime, but at night, the simplified mixing assumptions of the model compromise the representation of deposition of these species. A simple parametrisation for an effective night-time deposition velocity for ozone can correct this poor representation. Conversely, the ability of the model to simulate the daytime oxidation chemistry of isoprene and the concentration of the oxidant OH is severely compromised. Possible reasons for the poor model performance in this regard are discussed and tested. The most satisfactory solution to improve model fit appears to be a reduction in the rate of reaction of lsoprene/rnonoterpenes with OH, based upon the hypothesis of segregation of these species in the boundary layer. However, a novel method of calculating the segregation intensity from isoprene concentration measurements rules out this hypothesis. The reason for the model-measurement discrepancies of isoprene and OH remains unsolved. Following this detailed assessment of the strengths and limitations of the model, it is used as a predictive tool to investigate the effect of a change in BVOC emission on atmospheric chemistry. Conversion of natural rainforest to oil palm plantation substantially increases isoprene emissions, and will lead to dangerously high boundary layer ozone concentrations if future NOx concentrations are allowed to approach those in Western Europe. Meanwhile, landscape-scale circadian control can modify the magnitude and timing of isoprene emission, significantly affecting boundary layer ozone and oxidant concentrations. Further measurement studies to confirm landscape-scale circadian control of isoprene emissions are required.
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Krause, Alena [Verfasser]. "Changes in trophic niches of oribatid mites with transformation of tropical rainforest systems - from rainforest into rubber and oil palm plantations in Sumatra, Indonesia / Alena Krause." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2021. http://d-nb.info/1224681703/34.
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Cunningham, Shaun Cameron 1971. "Comparative ecophysiology of temperate and tropical rainforest canopy trees of Australia in relation to climate variables." Monash University, Dept. of Biological Sciences, 2001. http://arrow.monash.edu.au/hdl/1959.1/9040.
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Werner, Christian. "Compilation of a global N2O emission inventory for tropical rainforest soils using a detailed biogeochemical model." Karlsruhe : Forschungszentrum Karlsruhe, 2007. http://d-nb.info/986508675/34.
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Saulei, Simon M. "The recovery of tropical lowland rainforest after clearfell logging in the Gogol Valley, Papua New Guinea." Thesis, University of Aberdeen, 1985. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU363256.
Testo completoAbstract (sommario):
Recovery of tropical rain forest in Gogol Valley, Papua New Guinea was monitored for 2 years following clear-fel1ing in the wet and dry seasons. Further redevelopment, reconstructed by measurements of regrowth of known ages from 1.5-10.8 years, were compared with forest heavily disturbed by fire 55 years ago and primary forest. The vegetation, survey was assessed principally by Counting and measuring trees. Because of the importance of soil seed bank in influencing vegetation recovery processes, special attention was given to the spatial and temporal changes in the soil seed bank and the seed rain which supplies it. The major findings were: (1) vegetation recovery was rapid and 97% of all colonizing trees regenerated from seeds while 3% were resprouts; (2) regrowth after felling in the dry-season differed from that following wet-season felling in having lower density, slower growth and mostly comprised resprouting tree species; (3) after 10 years, regrowth is composed principally of large pioneer trees (65% of basal area or 64% of stems); (4) the 55 year-old forest also had many (48%) pioneer trees: much of the forest in the area is of this kind and may be classified as advanced secondary forest; (5) forest soil seed bank following felling was rapidly depleted due to germination, but was rapidly replaced as early pioneer herbs matured and set seed. Trees in soil seed bank do not approach that of primary forest until after 10 years of regrowth; (6) the intensity of pioneer trees' seed rain was correlated with the fecundity of nearby parent trees and clearly controlled soil seed bank redevelopment. There was evidence of dispersal of pioneer seeds several hundred metres into an isolated area of closed forest; (7) trees left uncut following felling contribute significantly to seed rain and therefore to soil seed bank.
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SOBIERAJ, JOSEF ALLEN. "SPATIAL PATTERNS OF SATURATED HYDRAULIC CONDUCTIVITY AND ITS CONTROLLING FACTORS FOR FORESTED SOILSCAPES." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1060889831.
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Nightingale, Joanne M. "Modelling carbon dynamics within tropical rainforest environments using the 3-PG and 3-PGS ecosystem process models /." [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18498.pdf.
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Naito, Yoko. "Reproductive ecology and early demography of two dipterocarp species in a lowland tropical rainforest of Peninsular Malaysia." Kyoto University, 2008. http://hdl.handle.net/2433/136600.
Testo completoAbstract (sommario):
Kyoto University (京都大学)<br>0048<br>新制・課程博士<br>博士(農学)<br>甲第13873号<br>農博第1688号<br>新制||農||953(附属図書館)<br>学位論文||H20||N4340(農学部図書室)<br>UT51-2008-C789<br>京都大学大学院農学研究科森林科学専攻<br>(主査)教授 太田 誠一, 教授 井鷺 裕司, 教授 大澤 晃<br>学位規則第4条第1項該当
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Abe, Hitofumi. "Forest management impacts on growth, diversity and nutrient cycling of lowland tropical rainforest and plantations, Papua New Guinea." University of Western Australia. School of Plant Biology, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0098.
Testo completoAbstract (sommario):
[Truncated abstract] Globally, tropical rainforests are noted for their high biodiversity and key roles in carbon storage and influence on climate. Nevertheless, tropical deforestation in many parts of the world continues at an alarming rate. In Papua New Guinea (PNG), tropical rainforest is relatively well maintained, with about 70 % of the land area still covered by primary forest. However, PNG's native forests are coming under increasing pressure, particularly from selective logging for high quality timber. While the forests of PNG, and more broadly the entire New Guinea Island, are recognised as of high conservation and ecological significance, they remain grossly understudied with little knowledge of key ecosystem processes within lowland forests in particular. Such knowledge is urgently required if the impacts of logging and other land-use change are to be assessed and in order to develop sustainable management systems. This thesis investigated the impacts of logging on diversity and nutrient cycling in a lowland tropical rainforest growing on limestone soils in the area of the Mongi-Busiga Forest Management Agreement (FMA, which is a logging concession area), in northeastern PNG. These forests are on relatively young soils and provide a useful contrast to the majority of tropical forests. The research includes a four-year study of the recovery of diversity and structure after logging, and quantified forest structure, tree species diversity, forest biomass and productivity, and nutrient distribution and cycling. This thesis also examines the ecological sustainability of Eucalyptus deglupta plantations in Wasab, PNG as an alternative resource for timber and biomass energy. The thesis concludes with a discussion of long-term forest recovery and sustainable forest management in north-eastern PNG. Two adjacent one-hectare plots were established in lowland tropical rainforest at Mongi-Busiga FMA. One of these plots was subsequently selectively logged, one year after establishment. Before logging, the two one-hectare plots contained a total of 37 families, 70 genera and 110 tree species that were >5 cm in diameter at breast height. Mean basal area was 42.4 m2 ha-1. Two tree species, Madhuca leucodermis (Sapotaceae) and Pometia pinnata (Sapindaceae) accounted for ~60% of the total basal area. Gymnacranthera paniculata (Myristicaceae) was the most common species and accounted for 13% of individuals. ... This study concludes that the Mongi-Busiga forest has many unusual characteristics for a tropical forest, including relatively low diversity of tree species, high accumulation of P in the biomass, and N limitations, compared to other tropical rainforests. However, those extraordinary characteristics may be explained well by the underlying geology of young, marine-derived limestone. Sustainable management of the lowland tropical forests of PNG should consider the consequences of logging on nutrient cycling processes, with the possible significant removal of P from site with repeated logging, as well as the interactions between N and P in these systems. Establishment of Eucalyptus plantations on previously cleared land also has the potential to meet some of the timber and biomass energy requirements of northern PNG in ecologically sustainable manner.
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Werner, Christian [Verfasser]. "Compilation of a global N2O emission inventory for tropical rainforest soils using a detailed biogeochemical model / Christian Werner." Karlsruhe : Forschungszentrum Karlsruhe, 2007. http://d-nb.info/986508675/34.
Testo completo
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Thormann, Birthe [Verfasser]. "Biodiversity of leaf beetles (Coleoptera: Chrysomelidae) in a tropical montane rainforest ecosystem assessed with DNA barcoding / Birthe Thormann." Bonn : Universitäts- und Landesbibliothek Bonn, 2016. http://d-nb.info/1113688246/34.
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Dykes, Alan Philip. "Hydrological controls on shallow mass movements and characteristic slope forms in the tropical rainforest of Temburong District, Brunei." Thesis, King's College London (University of London), 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364787.
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Tsujii, Yuki. "Significance of the phosphorus-use strategies of trees for the cycling of phosphorus in Bornean tropical rainforest ecosystems." Kyoto University, 2018. http://hdl.handle.net/2433/232348.
Testo completoAbstract (sommario):
Kyoto University (京都大学)<br>0048<br>新制・課程博士<br>博士(農学)<br>甲第21147号<br>農博第2273号<br>新制||農||1058(附属図書館)<br>学位論文||H30||N5121(農学部図書室)<br>京都大学大学院農学研究科地域環境科学専攻<br>(主査)教授 北山 兼弘, 教授 小杉 緑子, 教授 北島 薫<br>学位規則第4条第1項該当
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Kefa, Christopher Amutabi. "Assessing the Impacts of Bioenergy Extraction and Human Land Use of the Biodiversity of Kakamega Tropical Rainforest, Kenya." Bowling Green State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1465254368.
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34
Werner, Christian. "Compilation of a global N 2 O emission inventory for tropical rainforest soils using a detailed biogeochemical model." [S.l. : s.n.], 2007.
Cerca il testo completo
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Howard, Joniqua A'ja. "Gold mining in a tropical rainforest : mercury sorption to soils in the mining region of Arakaka-Mathew's Ridge, Guyana." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001797.
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Nussbaum, Ruth Elizabeth. "The effects of selective logging of tropical rainforest on soil properties and implications for forest recovery in Sabah, Malaysia." Thesis, University of Exeter, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262290.
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Ribeiro, Maria Ruth Rodrigues. "Valoração econômica dos ativos ambientais provenientes de uma floresta tropical." Universidade Federal do Amazonas, 2012. http://tede.ufam.edu.br/handle/tede/2984.
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Previous issue date: 2012-10-25<br>Atualmente, é notória a importância das florestas tropicais para o equilíbrio ambiental do planeta. No entanto, também, pode ser observada uma degradação contínua dessas áreas como conseqüência da exploração madeireira desordenada e da ampliação das áreas de pecuária. Na tentativa de reduzir esse problema, os gestores públicos têm usado de vários métodos, um desses métodos são os subsídios verdes , que constam, basicamente, da concessão de remunerações em espécie para os habitantes dessas áreas com o objetivo de compensá-los pelo não uso direto da floresta, como exemplo pode ser citado o programa ambiental denominado Bolsa Floresta adotado no estado do Amazonas. Por outro lado, tem-se observado em alguns casos, que mesmo após a aceitação da compensação monetária, os habitantes dessas áreas continuam desmatando a floresta alegando que o valor pago não corresponde à receita obtida no passado com o uso direto da floresta. Por conta disso, a presente pesquisa tem como objetivo principal verificar se existe diferença significativa entre o valor percebido pelos habitantes da Reserva de Desenvolvimento Sustentável do Uatumã e o valor pago pelo programa Bolsa Floresta . A metodologia utilizada na pesquisa será o Método de Valoração Contingente (MVC) que se baseia na percepção das pessoas para valorar os ativos e passivos ambientais, para isso será utilizada uma amostra correspondente a 82 entrevistados, derivada de um tamanho populacional de 380 famílias existentes na RDS do Uatumã, considerando um nível de confiança de 95% e uma margem de erro máxima permitida de 8%. De acordo com os resultados obtidos pode-se concluir que existe diferença significativa entre o valor percebido pelos habitantes da Reserva de Desenvolvimento Sustentável do Uatumã e o valor pago pelo programa Bolsa Floresta, sendo o valor estimado de R$ 200,00/família/mês. Isso indica que ajustes deveriam ser feitos no programa para alcançar melhore resultados.
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Asano, Iku. "Patterns of dipterocarp seed utilization by insect seed predators in a Bornean tropical rain forest." Kyoto University, 2019. http://hdl.handle.net/2433/242725.
Testo completoAbstract (sommario):
Kyoto University (京都大学)<br>0048<br>新制・課程博士<br>博士(人間・環境学)<br>甲第21848号<br>人博第877号<br>新制||人||210(附属図書館)<br>2018||人博||877(吉田南総合図書館)<br>京都大学大学院人間・環境学研究科相関環境学専攻<br>(主査)教授 市岡 孝朗, 教授 加藤 眞, 教授 瀬戸口 浩彰, 准教授 西川 完途<br>学位規則第4条第1項該当
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Nakai, Wataru. "Examination of stable oxygen isotope as a tree ring proxy of tropical ring-less trees." Kyoto University, 2019. http://hdl.handle.net/2433/242922.
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Marryanna, Lion. "Effects of spatio-temporal distribution of soil moisture on a lowland dipterocarp forest at Pasoh Forest Reserve in Peninsular Malaysia." Kyoto University, 2018. http://hdl.handle.net/2433/232153.
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Stone, Philippa Mary Rose. "Response of rainforest trees to climate warming along an elevational gradient in the Peruvian Andes." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31560.
Testo completoAbstract (sommario):
The tropical rainforests of the Peruvian Andes are some of the most biodiverse and most vulnerable to climate warming in the world. The Andes are predicted to experience substantial increases in warming of between +2 °C to +5 °C by the end of the century, in addition to an increases in the frequency of high temperature extremes, drought and flood events. The response of these forests to climate change over the next century has global relevance, due to the high levels of endemic species present and the potential role these areas will play as refugia for lowland species. Despite this, the response of tropical montane forests (TMCFs) to climate change remains under-studied. Our current understanding of how Andean species will respond to climate change is based on studies of past compositional changes. Upslope shifts in plant communities of approximately 1.2 - 2.0 m·y-1 have been observed along elevational gradients within Central and South America over the last decade. Based on these migration rates, it has been estimated that the majority of communities will lag behind increases in temperature by 5.5 °C by the end of the century. The implications of this for populations at the trailing range edge is unclear, due to a lack of mechanistic data concerning the acclimatory limits of rainforest species. When faced with rapid warming plant species will need to rapidly adapt, acclimate or migrate in order to survive. In the case of Andean species, migration rates may not be sufficient for a species to remain within its optimal thermal niche and adaptive responses will likely be too slow to be effective, hence individuals will have to acclimate in situ to prevent a decline in performance. The acclimatory ability of species can be quantified by measuring changes in performance, leaf physiology and anatomy in response to experimental manipulations of climate, however such studies are rare within the tropics. Here we carried out a seedling transplant experiment, utilising an extensive 400-3500 m asl elevational gradient in the Peruvian Andes, to simulate climate warming and upslope migration of tree seedlings under real-world conditions. To provide context for the transplant study, natural variation in leaf anatomical traits and physiological stress were explored for twelve species belonging to lowland (LF), mid-elevation (LMF) and tropical montane cloud forest communities. Adults and seedlings from the centre and furthest-most extent of each species' elevational range were studied and compared. Seedlings of each elevational forest community were transplanted downslope and upslope of their local elevational range by the equivalent of ±2 °C and ±4 °C in mean annual temperature. The experiment followed the transplanted seedlings of eleven species over a one year period, monitoring survival, growth and physiological stress (Fv/Fm) of individuals. The acclimatory ability of a subset of these species was quantified by measuring changes in photosynthetic capacity (Vcmax and Jmax), respiratory capacity (Rd) and anatomical traits (Na, Pa, LMA, LDMC) in response to transplantation. The results showed that within the natural population there was little evidence of leaf trait acclimation to elevational shifts in climate, but also little evidence of physiological stress at the trailing range edge. There were however differences in the leaf trait strategies employed by each elevational community, increasing in abiotic stress-tolerance with elevation. Physiological stress was greatest in the seedling population and, unlike the adult population, increased slightly at the trailing edge. This indicated that seedlings were more vulnerable to warming than their adult counterparts and at mid-elevations TMCF seedlings were more vulnerable than LMF seedlings. Seedling survival and growth declined in response to transplantation away from the home elevation for the majority of species, with upslope declines as a result of abiotic limitations, and downslope declines due to biotic limitations. All seedlings were found to be able to acclimate their respiratory capacity in response to transplantation, however this was not the case for photosynthetic capacity. LMF species performed significantly better than TMCF seedlings with transplantation, demonstrating a greater acclimatory capacity for photosynthesis. LMF species were able to adjust Jmax in order to maintain rates at ambient temperatures, but were not able to upregulate Vcmax upslope, whereas TMCF species were not able to respond in either transplant direction. Overall, these findings suggest that under moderate warming scenarios LMF species will have a competitive advantage over TMCF species at mid-elevations, gradually expanding their range into TMCF species' habitat over the next century. As a result of this and due to the slow pace of upslope migration, we predict that TMCF species will undergo range retractions and possible extinctions. The speed of this response will be determined by the trajectory of future warming and the frequency of extreme climatic events.
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Almeida, Thomé Simpliciano. "Sensibilidade da refletância de uma floresta tropical em 460 nm, 650 nm e 850 nm aos parâmetros ópticos e arquitetônicos do dossel." Universidade Federal de Viçosa, 2009. http://locus.ufv.br/handle/123456789/5226.
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Previous issue date: 2009-02-16<br>Conselho Nacional de Desenvolvimento Científico e Tecnológico<br>Studying and monitoring the vegetation - forest, savannah or other types - is important to understand the current climatic standard. Dynamical vegetation models (DVM) are useful tools in biome studies as they are based on physical principles as well as on initial and boundary conditions, therefore can obtain evidence of the influence of factors on the modeled environment, predict future vegetation behavior and, in association with other models, make predictions about vegetation future influence on climate or about the effect of climate change on vegetation. In particular, reflectance models are part of DVMs. Some studies have attempted to identify, canopy elements on the response of the vegetation cover albedo, the effect of obtaining the best parameters configuration. However, the reflectance study for electromagnetic spectrum narrower bands shows further features of the studied objects. Important features are estimated from the response of specific bands vegetation reflectance. Therefore, the objective of this thesis was to add three bands - red, near infrared and blue, corresponding to the bands 1, 2 and 3 of the sensor MODIS, onboard the TERRA and AQUA satellites, into the IBIS model - Integrated Biosphere Simulator, observe the canopy reflectance sensitivity to architectural and optical parameters, and calibrate these parameters according to the surface reflectance products and vegetation index from MODIS for the Reserve Cuieiras (K34). The sensitivity analysis indicates a strong response to the upper canopy parameters. The parameters combination that minimizes the RMSE of EVI - Enhanced Vegetation Index (RMSE = 0.0245) are the slope of the upper canopy leaves up χ = 0.92, reflectance from the upper canopy leaves in the blue band blue−up ρ = 0.0162, red band red −up ρ = 0.0466 and near infrared band nir−up ρ = 0.4427.<br>Estudar e monitorar a vegetação - floresta, cerrado ou outro tipo de cobertura - é de suma importância para se entender o padrão climático atual. Os Modelos de Dinâmica de Vegetação (MDV) são ferramentas úteis nos estudos de determinado bioma, pois são baseados em princípios físicos e em condições iniciais e de contorno, podendo então obter indícios dos fatores que influenciam o ambiente modelado, fazer previsões futuras do comportamento da vegetação e, associados a outros modelos, fazer previsões futuras da influência da vegetação no clima, ou da mudança do clima na vegetação. Em particular, os modelos de refletância fazem parte dos MDV. Alguns estudos têm sido feitos para identificar a influência dos componentes do dossel sobre a resposta do albedo da cobertura vegetal, obtendo a melhor configuração dos parâmetros a serem usados. Porém, o estudo da refletância para menores faixas do espectro eletromagnético indica mais detalhadamente as feições dos alvos estudados. Para a vegetação, importantes características são estimadas a partir da resposta da refletância de faixas específicas. Nesse aspecto o objetivo desse trabalho foi adicionar três bandas vermelho, infravermelho próximo e azul, referentes às bandas 1, 2 e 3 do sensor MODIS, a bordo dos satélites TERRA e AQUA, no modelo IBIS - Integrated Biosphere Simulator - observando a sensibilidade aos parâmetros óticos e arquitetônicos do dossel e calibrando esses parâmetros de acordo com os produtos de refletância de superfície e índice de vegetação do MODIS para a Reserva do Cuieiras (K34). A análise de sensibilidade indicou forte resposta para os parâmetros referentes à parte superior do dossel. A combinação dos parâmetros que minimizou o RMSE do EVI - Enhanced Vegetation Index (RMSEmin = 0,0245) foi a inclinação das folhas do dossel superior up χ = 0,92, refletância das folhas da parte superior do dossel na faixa do azul blue−up ρ = 0,0162, vermelho red −up ρ =0,0466 e infravermelho próximo nir−up ρ = 0,4427.
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Woebbe, Eric. "Survey of a Neotropical anuran assemblage (Pacaya-Samiria Reserve, Peru)." Wright State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=wright1493154522047725.
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Brown, Calum. "Spatial patterns and species coexistence : using spatial statistics to identify underlying ecological processes in plant communities." Thesis, University of St Andrews, 2012. http://hdl.handle.net/10023/3084.
Testo completoAbstract (sommario):
The use of spatial statistics to investigate ecological processes in plant communities is becoming increasingly widespread. In diverse communities such as tropical rainforests, analysis of spatial structure may help to unravel the various processes that act and interact to maintain high levels of diversity. In particular, a number of contrasting mechanisms have been suggested to explain species coexistence, and these differ greatly in their practical implications for the ecology and conservation of tropical forests. Traditional first-order measures of community structure have proved unable to distinguish these mechanisms in practice, but statistics that describe spatial structure may be able to do so. This is of great interest and relevance as spatially explicit data become available for a range of ecological communities and analysis methods for these data become more accessible. This thesis investigates the potential for inference about underlying ecological processes in plant communities using spatial statistics. Current methodologies for spatial analysis are reviewed and extended, and are used to characterise the spatial signals of the principal theorised mechanisms of coexistence. The sensitivity of a range of spatial statistics to these signals is assessed, and the strength of such signals in natural communities is investigated. The spatial signals of the processes considered here are found to be strong and robust to modelled stochastic variation. Several new and existing spatial statistics are found to be sensitive to these signals, and offer great promise for inference about underlying processes from empirical data. The relative strengths of particular processes are found to vary between natural communities, with any one theory being insufficient to explain observed patterns. This thesis extends both understanding of species coexistence in diverse plant communities and the methodology for assessing underlying process in particular cases. It demonstrates that the potential of spatial statistics in ecology is great and largely unexplored.
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Rahman, Dede Aulia. "New insights into ecology and conservation status of Bawean deer (Axis kuhlii) and red muntjac (Muntiacus muntjak) in Indonesian tropical rainforest." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30136.
Testo completoAbstract (sommario):
Les objectifs de cette étude consistaient d'une part à étudier l'écologie de deux cerf tropical de taille moyenne, le cerf de Bawean Axis kuhlii et le Muntjac Muntiacus muntjac dans la réserve naturelle et sanctuaire de la vie sauvage de l'île de Bawean et le parc national d'Ujung Kulon respectivement, et d'autre part de mettre à jour leur statut de conservation. Nous avons utilisé pour la première fois une nouvelle technique de contrôle, les caméras-pièges, associées à aux méthodes écologiques classiques afin d'évaluer la taille des populations, d'examiner l'utilisation de l'habitat, d'estimer le domaine utilisé et d'identifier les patrons d'activité. Les résultats montrent que si les caméra-pièges sont couteuses au départ, elles ont facilité le recueil de données sur le terrain et ont fourni beaucoup d'informations pour les analyses ultérieures. De plus, la méthode des caméra-pièges a permis d'acquérir un plus grand nombre d'informations sur espèces étudiées mais aussi sur les autres espèces présentes sur les sites, que les autres méthodes employées. Pour l'estimation des tailles de population nous avons utilisé un modèle de rencontre aléatoire (REM), une technique efficace pour évaluer la densité d'espèce élusives, rares et dont les individus ne sont pas reconnaissables individuellement. Ce qui ne peut être obtenu par la technique de capture-recapture photographique qui requière que les individus soient identifiables et donc une grande qualité photographique. Les résultats ont été comparés avec ceux obtenus par la technique de comptage de tas de fèces. Les deux méthodes ont fourni des évaluations de densité de population semblables, plus élevées durant la saison sèche et une taille de population estimée entre 227 et 416 cerfs de Bawean. L'étendue de l'aire utilisée par le cerf de Bawean est apparue considérablement plus réduite que lors des précédentes estimations, le comptage de tas de fèces ayant fourni des données complémentaires aux images issues des caméra-pièges. Les deus espèces de cervidés ont essentiellement été relevées dans des habitats de forêt secondaire. L'analyse faite par la méthode de l'entropie maximale (Maxent) a montré que les variables anthropogéniques (pour les deux espèces) et climatiques (Muntjac seulement) sont les prédicteurs principaux pour l'utilisation de l'habitat. Enfin, en utilisant les indicateurs horaires fournis par les caméra-pièges, les patrons d'activité ont été examinés en relation avec le sexe et les conditions environnementales. Bien qu'il soit considéré comme espèce nocturne, l'essentiel des clichés de cerf de Bawean ont été pris durant le jour, et l'activité nocturne dépend de la luminosité. Le muntjac a également témoigné d'une certaine activité diurne avec les plus forts pics situés après le lever et avant le coucher de soleil, alors que l'activité nocturne n'est pas apparue liée à la luminosité. Il n'a pas été observé de différences entre mâles et femelles pour les deux espèces. Alors que le statut du muntjac est classé "peu préoccupant" par UICN, même si des mesures locales de conservation devraient être prises dans la zone d'étude, le cerf de Bawean devrait être maintenu dans la catégorie "en danger critique" car cette population qui apparaît toujours aussi réduite est toujours soumise à une perte d'habitat par déforestation illégale et à des perturbations par les chiens et les chasseurs<br>The aim of this study was to investigate the ecology of two medium-sized tropical deer, the Bawean deer Axis kuhlii and the red muntjac Muntiacus muntjac in Bawean Island Nature Reserve and Wildlife Sanctuary and Ujung Kulon National Park respectively, and to update their conservation status. We used for the first time a new monitoring technique, camera trapping, together with classical ecological field methods for estimating population size, investigating habitat use, predicting range, and identifying activity pattern. Results show that camera traps were initially expensive but they lightened the field work and provided much information for further analyses. Moreover, camera trapping provided a higher number of records and accurate species identification than other methods. For estimating population size we used a random encounter model (REM), a technique accurate for estimating density of elusive, rare and unmarked species contrary to photographic capture-recapture techniques which require both unique mark and good photographs for individual recognition, and compared the results with those obtained by faecal pellet group count. Both methods provided similar population density estimates, higher in the dry than in the wet season, and a population size of ca. 227-416 deer. The range of Bawean deer established dramatically narrower than previously reported, faecal pellet group count bringing additional data to camera trapping. Both deer species were mainly recorded in secondary forests; Analysis with Maximum entropy model (Maxent) showed that anthropogenic (for both species) and climatic (for red muntjac only) variables were the main predictors of habitat use. Finally, using time data recorded by camera traps, we investigated the activity pattern related to sex and environmental conditions. The believed nocturnal Bawean deer was predominantly photographed during the day, and its nocturnal activity was linked to luminosity. Red muntjac also showed some diurnal activity with higher peaks after sunrise and before sunset, and a nocturnal activity which was not influenced by luminosity. No difference was observed between males and females for both species. Whereas red muntjac is listed "Least concern" by IUCN even if local conservation measures should be undertaken in our study area, Bawean deer should remain "Critically endangered" as the population is still small and the main threats, habitat loss due to illegal logging and human disturbance by dogs and hunters, are ongoing
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Tanaka, Hiroshi. "Effects of an ant symbiont (Crematogaster difformis) of epiphytic ferns on herbivores and lianas on emergent trees in a tropical rainforest." Kyoto University, 2010. http://hdl.handle.net/2433/120432.
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Kyoto University (京都大学)<br>0048<br>新制・課程博士<br>博士(人間・環境学)<br>甲第15466号<br>人博第496号<br>新制||人||121(附属図書館)<br>21||人博||496(吉田南総合図書館)<br>27944<br>京都大学大学院人間・環境学研究科相関環境学専攻<br>(主査)准教授 市岡 孝朗, 教授 松井 正文, 教授 加藤 眞, 教授 市野 隆雄<br>学位規則第4条第1項該当
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Breidenbach, Natalie [Verfasser], Reiner [Akademischer Betreuer] [Gutachter] Finkeldey, and Holger [Gutachter] Kreft. "Plant genetic diversity in tropical lowland rainforest transformation systems in Sumatra (Indonesia) / Natalie Breidenbach. Betreuer: Reiner Finkeldey. Gutachter: Reiner Finkeldey ; Holger Kreft." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2016. http://d-nb.info/1110148526/34.
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Sjödin, Henrik. "Effects of commercial use of tropical rainforest on communities of riparian frogs on Borneo: an identification of relevant environmental and microclimatic factors." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-30917.
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Krause, Leonhard. "Floral biology, flowering phenology and floral visitors of five insect-pollinated tree species in a tropical lowland rainforest remnant of Pernambuco, Brazil." [S.l. : s.n.], 2008. http://nbn-resolving.de/urn:nbn:de:bsz:289-vts-65292.
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Godsey, Sarah. "Runoff Generation on Barro Colorado Island (BCI), Panamá." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1059398714.
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