Dissertations / Theses on the topic 'Forest plants'
To see the other types of publications on this topic, follow the link: Forest plants.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Forest plants.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Hewitt, Nina. "Plant dispersal and colonization in fragmented forest systems." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ43425.pdf.
Full text
2
Tyler, Marnie W. "Forests of the western Olympic Peninsula : understory plant species diversity, forest policy, and landscape pattern /." Thesis, Connect to this title online; UW restricted, 2002. http://hdl.handle.net/1773/5464.
Full text
3
McManus, Erin Michael. "Primary succession of lianas in an Amazonian floodplain forest /." Electronic thesis, 2003. http://etd.wfu.edu/theses/available/etd-11292003-151813/.
Full text
4
Naficy, Cameron Edwards. "Changes in forest structure and composition associated with unique land use histories:." [Missoula, Mont.] : The University of Montana, 2008. http://etd.lib.umt.edu/theses/available/etd-12012008-173306/unrestricted/Naficy_Cameron_Thesis.pdf.
Full text
5
Addessi, Andrew David. "Urban Impacts to Forest Productivity, Soil Quality, and Canopy Structure in Forest Park, Portland, Oregon." PDXScholar, 2017. https://pdxscholar.library.pdx.edu/open_access_etds/3881.
Full textAbstract:
Land use practices and exposure to low impact disturbances associated with an urban environment can alter forest structure and function. Past and ongoing research in Forest Park, a large urban forest in Portland, Oregon, suggests that mature mixed Douglas-fir (Psuedotsuga meziesii)-hardwood stands in the more urban end of the park lack a shade-tolerant conifer understory composed of the late successional conifer tree species, such western hemlock (Tsuga heterophylla) and western red-cedar (Thuja plicata). 5-year plot remeasurement data that characterizes productivity and mortality patterns did not show a strong relationship to urban proximity. Plot productivity was generally consistent with values taken from studies of other similarly aged (~100 years old) Douglas-fir /Western Hemlock stands. Mortality was highest in rural plots, and was driven by large windthrow events to canopy trees. Soil organic matter, soil pH, and depth of organic horizon indicated a legacy of soil impact in urban areas most impacted by past intensive logging. The urban mature plot had higher mean soil pH at site (5.87, se: ±0.06) compared to a rural mature, and old growth reference sites located within the park. Although surface organic and A layer soil horizon depth was thinnest at the urban mature site, soil organic matter was not found to be significantly different across sites. Light detection and ranging (LiDAR) data showed that old-growth plots and plots in the middle section of the park had the highest degree of canopy structure as measured by Rumple and standard deviation of point elevation. Measures of stand height showed OG plots and urban plots to have the tallest trees. Rural plots showed a high degree of variability in all LiDAR metrics, showing a wider range of stand height and complexity than urban and middle plots.
These results suggest that past land-use and urban proximity affect plot level productivity, soil quality, and above-ground canopy structure in Forest Park. These results clarify how the lack of late-successional tree species might be most linked to differing histories of intensive logging activity within the park. Reduced old-growth legacy features (remnant seed trees, coarse woody debris) in plots with a clear history of aggressive clear-cuts has led to a reduction in regeneration of western hemlock and western red-cedar in the understory.
6
Persson, Jörgen. "Organic nitrogen uptake by boreal forest plants /." Umeå : Dept. of Forest Genetics and Plant Physiology, Swedish Univ. of Agricultural Sciences, 2003. http://epsilon.slu.se/s265-ab.html.
Full text
7
Rezende, Andreia Alves. "Comunidade de lianas e sua associação com arvores em uma floresta estacional semidecidual." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/315445.
Full textAbstract:
Orientador: Neusa Taroda RangaTese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-08-04T02:57:19Z (GMT). No. of bitstreams: 1 Rezende_AndreiaAlves_D.pdf: 680315 bytes, checksum: 35c8e450ad258314b9f2c48dbcf0cd7a (MD5) Previous issue date: 2005
Resumo: Lianas são plantas que germinam no solo, mantêm-se enraizadas durante toda a vida e necessitam de suporte físico para alcançarem o dossel. Elas são membros característicos das florestas tropicais, onde contribuem com cerca de 25% da diversidade vegetal. Às vezes, dominam a vegetação, principalmente em áreas perturbadas. Lianas competem com árvores por nutrientes e luz, e influenciam a taxa de crescimento e a mortalidade de sua árvore hospedeira. Embora as lianas iniciem sua escalada a partir do chão, muitas colonizam árvores vizinhas pelo dossel da floresta, ¿amarrando-se¿ às outras, podendo ocasionar a queda de várias árvores quando uma delas cai. Devido a sua abundância e o seu impacto sobre as árvores, é de grande importância conhecer os fatores que governam a distribuição e dinâmica das lianas na floresta tropical e, assim, desenvolver estratégias de uso sustentável. Assim, os objetivos desta tese foram: (1) avaliar a riqueza e abundância das lianas e (2) a relação das lianas com as características do hospedeiro e com a estrutura da floresta. O trabalho foi realizado em um fragmento de floresta estacional semidecidual, com cerca de 435,73 ha, na Estação Ecológica de Paulo de Faria, SP. Foram amostradas 100 parcelas de 10 x 10 m (1 ha). As lianas com diâmetro ³ 1 cm e as árvores ³ 3 cm enraizadas nas parcelas foram medidas no DAP (diâmetro à altura do peito - 1,30m) e identificadas. Amostrou-se 1427 indivíduos de 45 espécies de lianas, pertencentes a 14 famílias, sendo as mais ricas: Bignoniaceae (14 espécies), Sapindaceae (nove) e Malpighiaceae (seis), e as mais abundantes Bignoniaceae, Sapindaceae e Apocynaceae. A riqueza de lianas foi aproximadamente igual à metade (razão 0,51) da riqueza de árvores (87 espécies). A densidade média de lianas e árvores foi semelhante, cerca de 1400 indivíduos/ha. Melloa quadrivalvis (Bignoniaceae) foi a espécie mais comum na área estudada. Do total de indivíduos de lianas amostrados, 57,6% apresentaram diâmetros entre 1 - 2,5 cm, correspondendo a 95% da riqueza total amostrada. Das 1419 árvores amostradas, 53% carregavam pelo menos uma liana. As espécies menos infestadas que a média geral foram Inga marginata, Piper amalago, Trichia catigua e T. claussenii, e somente uma, Machaerium paraguariense, foi mais infestada que a média, considerando todas as espécies. Os resultados, de modo geral, não apoiaram a hipótese de especificidade entre espécies de lianas e espécies de árvores, pois a riqueza e a diversidade de espécies de lianas aumentaram com a proporção de infestação. Se houvesse especificidade, esperar-se-ia que uma espécie de árvore fosse mais infestada por uma determinada espécie de liana. O mecanismo de escalada das lianas não influenciou o número de árvores que cada liana escalou, embora tenha ocorrido associação positiva entre árvores com casca rugosa e lianas com gavinhas. Considerando-se as características individuais do hospedeiro, as árvores com diâmetros maiores apresentaram maior densidade de lianas. Com relação às características da vizinhança, as diferenças encontradas provavelmente se devem as condições de luminosidade do ambiente. As parcelas com maior proporção de árvores com DAP > 30 cm apresentaram relação negativa significativa com a densidade de lianas. A relação foi positiva em parcelas com maior proporção de árvores com copas £ 3 m de altura. Assim, as evidências deste estudo sugerem que a distribuição das lianas foi mais influenciada por características da comunidade do que pelas características das espécies de árvores presentes
Abstract: Lianas are soil-germinating plants, perennially rooted and which need support to reach the canopy. They are characteristically from the rain forests, where they contribute with near 25% of vegetal diversity. Lianas compete with trees for nutrients and light, influencing growth and mortality rates of its host tree. Although lianas begin their life on the ground, many of them colonize vicinity trees through the forest canopy, ¿tying¿ themselves to the others, and may cause the fall of many trees. Due to their abundance and impact over other trees, it is important to know the factors governing distribution and dynamics of the lianas in order to better understand the rain forest and to develop sustainable strategies. Thus, the aims of this study were: (1) to assess the richness and abundance of lianas, and (2) to establish the relation of lianas with the characteristics of the hosts and the structure of the forest. The research was carried out in a fragment of a Semideciduous Stational Forest with 435.73 ha, at the Paulo de Faria Ecological Station. The sampling consisted of 100 plots of 10 x 10 m (1 ha), allotted in an area of 4 ha. Lianas with a diameter ³ 1 cm and trees ³ 3 cm rooted in the plots were measured in DBH (diameter at breast height ¿1.30m) e identified. In the study area, 1427 individuals were sampled from 45 species of lianas, belonging to 14 families, the richest ones being Bignoniaceae (14 species), Sapindaceae (nine) e Malpighiaceae (six), and the more abundant Bignoniaceae, Sapindaceae e Apocynaceae, adding up to 80% of the sampled individuals. The liana richness was approximately equal to half (ratio 0.51) the tree richness (87 species). Average density of lianas and trees was similar, around 1400 individuals/ha. Melloa quadrivalvis (Bignoniaceae) was the most common species in the study area. From the total number of the sampled liana individuals, 57.6% presented diameters between 1- 2.5 cm, corresponding to 95% of the total sampled richness. Only 26 individuals presented diameter higher than 10 cm. From the 1419 trees with diameter ³ 3 cm, 53% carried at least one liana, with the higher rate of infestation (79%) occurred in the individuals with diameters > 10 cm. Species less infested than the expectation were Inga marginata, Piper amalago, Trichia catigua e T. claussenii. One species, Machaerium paraguariense, was more infested than the expectation. In general, results did not support the hypothesis of species-specificity between lianas and trees, since the richness and diversity of liana species increased with the infestation rate. Climbing mechanism did not influence the number of trees climbed by each liana, although we have found positive association between wrinkled bark and tendrils. Considering the individual characteristics of the host, trees with larger diameters showed higher density of lianas. In relation to the vicinity characteristics, the plots with higher rate of big trees (DBH > 30 cm) showed significant negative relation with the density of lianas. The relation was positive in plots with higher rate of trees with small crown (£ 3 m). Thus, our study showed the association between tree and vicinity characteristics with infestation and density of lianas
Doutorado
Biologia Vegetal
Mestre em Biologia Vegetal
8
Mokonya, Ngomba Henry. "Diversity of vascular plants in Swedish forests. : Comparison among and within forest, partially cut down and clear cut forest communities." Thesis, Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-6063.
Full textAbstract:
Swedish forests are mostly used for timber harvesting and 96 % of this harvesting is made by clear cutting while only 4 % is effected through other methods such as single tree harvesting. All species are not affected by forestry to same magnitude. Some specifically generalists are not affected at all. Hence, this study, had its aim to find out vascular plant species that persist, disappear or colonize other species as a result of anthropogenic disturbances in different production forests, so as to determine not only if canopy openness affects the species distribution but also the magnitude of the effects. I examined 10 different forest localities during May and June 2008. Three of these localities were made up of clear cut forest plots, 3 with partially cut down forest plots and 4 with undisturbed production forest plots. Species composition and diversity were then compared between these plots. A total of 34 different species were found. Statistical Analysis was made on how well the species in the partially cut down forest plots fitted into the undisturbed forest group as well as comparing this results with results of how counterpart species in the clear cut forest plots fitted into the undisturbed forest groups. These results showed that there was no significant difference, ANOVA values of P = 0.839, 0.602 and 0.564 respectively among the species composition between the forest, partially cut down and clear cut forest groups between the forest, partially cut down and clear cut forest plots. However, among the 54 species found in all study plots, 11 were common between the forest and partially logged sites whereas only Carex sp in the clear cut forest was common to those in the forest plots implying that canopy openness did not affect the total species number but had an effect in species composition. Clear cutting seems to kill off everything but trees and generalists. Hence, resiliency of vegetation should be increased by management practices that ensure the maintenance of prior species.
9
Goodwin, Nicholas R. School of Biological Earth & Environmental Sciences UNSW. "Assessing understorey structural characteristics in eucalypt forests: an investigation of LiDAR techniques." Awarded by:University of New South Wales. School of Biological, Earth and Environmental Sciences, 2006. http://handle.unsw.edu.au/1959.4/28365.
Full textAbstract:
The potential of airborne LiDAR technology to quantify forest structure within eucalypt forests has been evaluated with a focus on the understorey stratum. To achieve this, three studies have been undertaken using multiple (4) LiDAR datasets acquired over three test areas located in Wedding Bells State Forest, Coffs Harbour, Australia. Initially, the effects of sensor configuration were evaluated using field measurements collected from three structurally and topographically differing field plots (40 x 90 m areas). Results indicated that canopy height profiles derived from LiDAR data at the plot scale were largely unaffected by a change in platform altitude from 1000 to 3000 m (p > 0.05). In addition, the derivation of individual tree attributes was found to be highly sensitive to the density of LiDAR observations whilst higher platform altitudes showed an increased proportion of single returns over forested areas. In the second study, an innovative field based approach was developed to sample the structure of the understorey (horizontally and vertically) for LiDAR validation purposes. Using two separate LiDAR datasets, this research confirmed that mean understorey height and understorey cover can be effectively mapped in areas of low to medium canopy cover whilst no significant relationship (p > 0.05) was identified between field and LiDAR estimates of maximum understorey height. In the third study, an optimised LiDAR beam interception model was developed and validated, and then applied to assess the interaction of extrinsic and intrinsic factors of the LiDAR survey. This demonstrated that the probability of beam interception through the forest canopy can be affected by factors both intrinsic (e.g. crown cover) and extrinsic (e.g. scan angle) to the structure of the canopy. Overall, the results of this research indicate that optimising the sensor configuration is important to the derivation of particular forest structural attributes and significantly, there is potential for LiDAR technology to provide quantitative and spatially detailed estimates of key understorey attributes such as mean height and cover.
10
Nordin, Annika. "Physiological ecology of nitrogen utilisation by forest plants /." Umeå : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1998. http://epsilon.slu.se/avh/1998/91-576-5610-X.gif.
Full text
11
Steele, Kyle Lindsay. "Restoring forest composition and structure of riparian corridors in the Missouri Ozarks." Diss., Columbia, Mo. : University of Missouri-Columbia, 2008. http://hdl.handle.net/10355/5690.
Full textAbstract:
Thesis (M.S.)--University of Missouri-Columbia, 2008.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 14, 2009) Includes bibliographical references.
12
Gedler, Mark S. "Secondary succession of spring flora associated with windthrow pits as influenced by microtopography and light in an old-growth beech-maple forest in east-central Indiana." Virtual Press, 1998. http://liblink.bsu.edu/uhtbin/catkey/1115740.
Full textAbstract:
This research focused on the secondary succession of spring flora occurring within pits of windthrows located in the area described as Ginn/ Nixon Woods, an old growth beech-maple forest community that transitions to a mixed mesophytic forest community, approximately 12 miles north of Muncie, IN. More specifically, this research sought to identify the vegetative production capacities of pits as well as determine the extent to which pit microtopography and light influx affect the production of spring flora.In all sixty plots were established--30 test plots within the confines of windthrow pits, and 30 control plots, each one just six feet away from a test plot on undisturbed forest soil. One sampling period occurred in 1993 (just prior to leafing); four sampling periods occurred in 1994 (two prior to leafing and two after leafing). Species presence, density and cover data were used to produce two-dimensional ordinations for examination. Species presence, plot depth, slope, and light data were subjected to the Spearman Rank Order Correlation Test to determine the extent of influence pit microtopography and light influx have on spring flora.Examination of the data clearly showed that disturbed areas known as windthrow pits experience a significant decline in vegetative production--at least for a few years but likely for many years, after the initial disturbance or windthrow occurs. The data also clearly showed that over time windthrow pits eventually recover vegetative production.The recovery of vegetative production in pits was shown to have a positive correlation with plot depth; that is to say, as pit depth decreases, vegetative diversity increases. Standing water in pits, though not recorded statistically, was observed in the field as having a strong negative impact on vegetative recovery. Consequently, the environmental factors that work together to affect the topographical recovery of the pit to an elevation equal to or greater than the surrounding forest floor were found to be critical in the vegetative recovery of pits. This researcher has appropriately termed this recovery process as "elevation equilibrium," since the end result is a pit whose topographical relief has given way to a relatively static elevation equal to adjacent undisturbed areas of the forest floor.Unlike plot depth, the amount of slope in pits did not seem to play a significant role in reducing or encouraging vegetative recovery. Likewise the amount of shade cast on pits prior to leafing, and the size and/or presence of gaps in the canopy after leafing, appeared to have little influence on the recovery of spring flora. When plant diversity data for each test plot was correlated with its slope, pre-leafing light influx and post-leafinglight influx data using the Spearman Rank Order Correlation test, it found no significant relationships between any of the sets of variables.Department of Natural Resources and Environmental Management
13
Uliczka, Helen. "Forest biodiversity maintenance : instruments and indicators in the policy implementation /." Uppsala : Dept. of Conservation Biology, Swedish Univ. of Agricultural Sciences, 2003. http://epsilon.slu.se/s291.pdf.
Full text
14
Mahmud, Khairil. "Distribution and functional significance of Al in tropical forest plants." Thesis, University of Aberdeen, 2017. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=235553.
Full textAbstract:
The general aim of this thesis was to investigate the mechanisms that determine variation in Al accumulation among tropical woody plants. The focus of the study variation among populations of the well-studied Al accumulator Melastoma malabathricum, but this was coupled with sampling 50 tree species growing on the 50 ha forest dynamics plot at Pasoh Forest Reserve in Peninsular Malaysia in order to gain a perspective on Al accumulation at a community scale. I sampled mature leaves and seeds of M. malabathricum from 20 populations growing in six habitats across Peninsular Malaysia. Concentrations of Al, N, P, K, Ca and Mg were determined in air-dried leaves and the soil from each site. The seeds were used to generate cohorts of seedlings that were grown in hydroponic solutions amended with Al in the form of 1.0 mM AlCl3. Foliar Al concentrations varied significantly among populations, but were not consistently different among plants growing in different habitats and showed no relationship to total or exchangeable Al concentrations in soils collected at the 20 sites. Similarly, foliar Al concentrations in seedlings grown in the presence of Al differed significantly among source populations, but values did not correlate with foliar Al concentrations in wild plants from parent populations. Mean foliar Al concentration in wild plants was positively correlated with foliar Ca concentration, and with total soil Ca and Mg concentrations, across the 20 populations. Furthermore, total dry mass and relative growth rates were significantly greater for seedlings that had received Al in the growth medium than for seedlings that had received no Al. The growth response to Al addition varied among populations of M. malabathricum, and relative growth rate in response to Al addition was greater for populations that accumulated higher foliar Al concentrations. In a further experiment, increasing Al concentrations from In a further experiment, increasing Al concentrations from 0 to 2.0 mM in the nutrient solution increased rates of growth, but growth declined at 5.0 mM Al. The responses to Al addition varied among populations for growth, photosynthesis, respiration, carbon allocation, and foliar P, Ca, and Mg concentrations. The rates of photosynthesis and respiration, and total nonstructural carbohydrate concentrations, were higher for seedlings grown in the presence of 2.0 mM Al in the nutrient solution than in the absence of Al, while lignin concentration in roots decreased. These results suggest that Al addition stimulate growth stimulation by increasing rates of photosynthesis and respiration, resulting in higher non-structural carbohydrate concentrations. Increased allocation of photosynthate to root systems coupled with their lower lignification results in enhanced nutrient uptake (particularly P, Ca and Mg), which contributes to enhanced whole-plant growth. To test the prevalence of Al accumulation at the community scale I sampled 50 tree species growing on the 50 ha Forest Dynamics Plot at Pasoh Forest Reserve in Peninsular Malaysia. Twenty two species possessed foliar Al concentrations that exceeded a value of 2.3 mg g-1 Al dry mass, which is a suitable threshold for detecting Al accumulators in Southeast Asian forests. A phylogenetic signal was detected for foliar concentrations of Al and other elements, suggesting that more closely related species have more similar values of these traits. A canonical correspondence analysis (CCA) revealed that soil Al concentrations have limited influence on the fine-scale distribution of the tree species sampled at Pasoh. I conclude that the distribution of differences in the expression of Al accumulation among populations of M. malabathricum and the distribution of Al accumulator species within a tree community growing at one site are uncoupled from soil Al concentrations, but may be linked to other soil properties such as Ca and Mg concentrations. When supplied in nutrient solutions, Al promotes the growth of the Al accumulator M. malabathricum through a physiological mechanism that includes up-regulation of photosynthetic and respiration rates. The functional significance of this growth response for plants growing under natural conditions in the field requires further investigation.
15
Chamberlain, James Luther. "The Management of National Forests of Eastern United States for Non-Timber Forest Products." Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/30053.
Full textAbstract:
Many products are harvested from the forests of the United States in addition to timber. These non-timber forest products (NTFPs) are plants, parts of plants, or fungi that are harvested from within and on the edges of natural, disturbed or managed forests. Often, NTFPs are harvested from public forests for the socio-economic benefit they provide to rural collectors.
Social science and market research methods were used to examine the extent that NTFPs are addressed in national forest management plans, identify and explore issues that affect their management, and determine the attitudes and perceptions of forest managers at various levels within the U.S. Forest Service.
Non-timber forest products have not been considered in national forest management plans to the extent that have other forest resources. Fewer that 25 percent of the current management plans for the national forests of eastern United States address NTFPs. However, the Forest Service Directive System provides sufficient policy and procedural direction at the national and regional level for the management for NTFPs and legislation enacted in 2000 directs the Forest Service to develop a pilot program to beginning managing for these products.
Managers with expertise and education in botany, wildlife, recreation, and wilderness had significantly more positive attitude toward managing for NTFPs than did managers with a more traditional (timber-based) educational background. A regression model of intention to include NTFPs in the forest management plans was developed using data from forest managers and based on the Theory of Reasoned Action. Both attitude and perception were found to be significant determinants of behavior intention.
A common perception among forest managers is that NTFP management is not an issue of public concern. Also, managers do not perceive that the lack of management is a problem. Without a visible and vocal constituency, the impetus for change must necessarily come from within the organization. Efforts by the U.S. Forest Service to manage for NTFPs will be hampered by a lack of information and expertise. But, the activities of more progressive national forests suggest that sufficient knowledge does exist for the agency to take a more proactive approach to management.Ph. D.
16
Faust, Thomas McCullough. "Woody species and forest structure in northern Missouri riparian forests with different ages and watershed sites." Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4441.
Full textAbstract:
Thesis (Ph.D.)--University of Missouri-Columbia, 2006.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on May 1, 2009) Vita. Includes bibliographical references.
17
Zinko, Ursula. "Plants go with the flow : predicting spatial distribution of plant species in the boreal forest." Doctoral thesis, Umeå : Ekologi och geovetenskap, Univ, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-315.
Full text
18
Nelson, Cara Ritchie. "Effects of timber harvest and forest edges on abundance, viability, and physiology of understory plants in Pseudotsuga forests of western Washington /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/5553.
Full text
19
Strengbom, Joachim. "Nitrogen, parasites and plants : key interactions in boreal forest ecosystems." Doctoral thesis, Umeå universitet, Ekologi och geovetenskap, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-111110.
Full textAbstract:
In the work described in this thesis I studied how increases in nitrogen (N) inputs may affect plant community structure in boreal forest understorey vegetation. These phenomena were investigated in N fertilization experiments and along a national N deposition gradient. After five years of N additions, large changes in understorey vegetation composition were observed in the fertilization study. In plots that received 50 kg N ha'1 year"1 (N2), the abundance of the dominant species, Vaccinium myrtillus, decreased on average by 32 %. No decrease was observed in control plots during the same period. In contrast, the grass Deschampsia flexuosa responded positively to increased N input, being on average more than five times as abundant in the N2 treatments as in controls. Also an increase was seen in the incidence of disease caused by the parasitic fungus Valdensia heterodoxa on leaves of V. myrtillus following N additions. The parasite was on average nearly twice as abundant in N2 plots than in control plots. This could be explained by increased N concentrations in host plant tissue. Disease incidence also increased following experimental additions of glutamine to leaf surfaces of V. myrtillus, suggesting a causal connection between plant N concentration and performance of the fungus. The parasite also played a key role in the observed changes in understorey species composition. D. flexuosa was more abundant in patches in which V. myrtillus was severely affected by V heterodoxa. This suggests that V heterodoxa mediates the increased abundance of D. flexuosa following increased N additions. The fungus mediates changes in the composition of understorey vegetation mainly by increasing light availability via premature leaf loss of V. myrtillus. The incidence of disease due to the parasite was on average higher in large than in smaller N-treated plots, indicating that the response to N fertilization is spatially scale dependent. This shows that using small plot sizes in experiments that simulate changed environmental conditions may be problematic, as important interactions may be underestimated. Comparison of the occurrence of understorey species between regions with different rates of N deposition revealed that the occurrence of the two dwarf shrubs V. myrtillus and V. vitis- idaea was lower in regions with high N deposition compared to regions with low deposition. The opposite pattern was found for V heterodoxa. This is consistent with expectations from N fertilization experiments. For D. flexuosa no differences in occurrence were found between the different regions investigated. The effects on vegetation and mycorrhizal fungi observed following N additions were also found to be long lasting. Nine years after termination of the fertilization, no signs of recovery were detected, and nearly 50 years after termination characteristic signs of N fertilization were found among bryophytes and mycorrhizal fungi. This suggests that the time needed for re-establishment of the original biota following N-induced changes may be substantial.Diss. (sammanfattning) Umeå : Umeå universitet, 2002, härtill 5 uppsatser
digitalisering@umu
20
Foy, Elizabeth Christina. "Riparian vegetation and forest structure of two unregulated tributaries, compared to the regulated Snake River, Grand Teton NP, WY." Thesis, Montana State University, 2008. http://etd.lib.montana.edu/etd/2008/foy/FoyE1208.pdf.
Full textAbstract:
The dynamic nature of rivers shapes riparian plant communities, and changes to the flow regime can have profound effects on these diverse ecosystems. To examine how riparian plant communities of the dam-regulated Snake River in Grand Teton National Park, WY respond to hydro-geomorphological factors, I studied the vegetation of two unregulated tributaries, Pacific Creek and Buffalo Fork, in relation to the main river. I considered three perspectives in this analysis. In chapter 2, I examined hydro-geomorphological processes shaping riparian vegetation in naturally flowing systems, by evaluating 15 environmental variables, and determining which were most related to vegetation. Using cluster analysis, I identified six distinct communities. I described environmental conditions associated with each community, using the unconstrained ordination technique NMDS, coupled with generalized additive models (GAMs). Community types occur on characteristic geomorphologic landforms. Depth to gravel, soil texture, pH, distance to bankfull channel, and elevation above water are all related to vegetation, and interact to determine where community types occur. In my third chapter, I compared the vegetation of the unregulated tributaries to the Snake River, as a means of assessing dam effects. Species richness per plot is higher on the tributaries, despite higher overall richness on the Snake River. Through the use of NMDS ordination and clustering techniques, I found the composition of the upper section of the Snake River, immediately below the dam, to be distinct. However, this section is naturally more incised, and the lower sections of the river do not seem to be influenced, suggesting dam impacts on vegetation are minimal. Environmental variables related to vegetation composition include elevation above water, depth to gravel, and geomorphological landform. In chapter 4, I compared age class distributions of spruce and cottonwoods across river sections, and found no evidence for a late-successional trend on the regulated river, versus unregulated tributaries. Age distribution is related to geomorphological landform, and browing also influences forest structure through root coppicing. Forest understory communities are structured by cottonwood age.
21
Sugita, Shinya. "Palynological records of forest disturbance and development in the Mountain Meadows watershed, Mt. Rainier, Washington /." Thesis, Connect to this title online; UW restricted, 1990. http://hdl.handle.net/1773/5130.
Full text
22
Franklin, Oskar. "Plant and forest dynamics in response to nitrogen availability /." Uppsala : Swedish University of Agricultural Sciences, 2003. http://diss-epsilon.slu.se/archive/00000345/.
Full textAbstract:
Thesis (doctoral)--Swedish University of Agricultural Sciences, 2003.Appendix consists of reprints of three papers and a manuscript, three of which are co-authored with others. Includes bibliographical references. Also partially issued electronically via World Wide Web in PDF format; online version lacks appendix.
23
Albrecht, Matthew A. "Reproductive Biology of Medicinal Woodland Herbs Indigenous to the Appalachians." Ohio : Ohio University, 2006. http://www.ohiolink.edu/etd/view.cgi?ohiou1163427974.
Full text
24
Jacobs, Karen Marie. "Fire and vegetation history of the last 2000 years in Jackson Hole, Grand Teton National Park, Wyoming." Thesis, Montana State University, 2007. http://etd.lib.montana.edu/etd/2007/jacobs/JacobsK0507.pdf.
Full text
25
Smith, Jason Richard. "Seral stage, site conditions, and the vulnerability of understory plant communities to forest harvesting /." Burnaby B.C. : Simon Fraser University, 2005. http://ir.lib.sfu.ca/handle/1892/2024.
Full textAbstract:
Research Project (M.R.M.) - Simon Fraser University, 2005.Theses (School of Resource and Environmental Management) / Simon Fraser University. Research Project (School of Resource and Environmental Management) / Simon Fraser University.
26
Santala, Kierann R. "THE INTRODUCTION OF NATIVE FOREST FLOOR PLANT SPECIES INTO THE INDUSTRIALLY DISTURBED FORESTS OF SUDBURY, ONTARIO, CANADA." Thesis, Laurentian University of Sudbury, 2014. https://zone.biblio.laurentian.ca/dspace/handle/10219/2147.
Full textAbstract:
This study investigated the transplantation of understory plants within the Cu-Ni smelterdamaged
urban forest of Sudbury, Ontario, Canada, to increase plant biodiversity in an area
where natural colonization of understory species is delayed. The goal of my study was to
evaluate establishment of 16 m2 vegetation mats along a gradient of smelter disturbance and to
relate successful establishment to abiotic and biotic site characteristics. Specific investigations
were conducted to determine whether soil quality influenced root growth and transplant
establishment. Variables associated with smelter emissions and soil temperature were the best
predictors of successful transplant establishment of understory plant species, but relationships
were species specific. Also, root growth was not limited to organic soils of the transplant mat
and roots were able to grow into receptor site soil. Knowledge of environmental factors
influencing establishment will help to determine site locations and to select species to introduce
when transplanting understory species in future reclamation projects.
27
Persson, Viveca. "Effects of climatic seasonality on reproductive phenology of tropical forest plants." Thesis, University of Aberdeen, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.715415.
Full text
28
Nordström, Högberg Mona. "Carbon and nitrogen relations among soils, microbes and plants in boreal forests /." Uppsala : Dept. of Forest Mycology and Pathology, Swedish Univ. of Agricultural Sciences, 2004. http://epsilon.slu.se/s314.pdf.
Full text
29
Nock, Erin Elizabeth. "A simple GIS approach to predicting rare plant habitat north central Rocky Mountains, United States Forest Service, Region One /." CONNECT TO THIS TITLE ONLINE, 2008. http://etd.lib.umt.edu/theses/available/etd-06102008-173011/.
Full text
30
Bessa, Nélita Gonçalves Faria de. "Brazilian savanna forest : conservation, medicinal reservoir and bioprospecting." Doctoral thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/13350.
Full textAbstract:
Doutoramento em Biologia e Ecologia das Alterações GlobaisThis study aimed to analyse the Brazilian savanna forest from a Legal Reserve (LR) area from a perspective of conservation, reservoir of organic carbon and medicinal biomass for a prospective use of native medicinal plants. An ethnobotanical and ethnopharmacological survey was carried out close to a community settled in the rural area in the south of Tocantins, being selected 9 of the most cited species (cajuí- Anacardium othonianum; inharé-Brosimum gaudichaudii; jatobá-Hymenaeae courbaril; jenipapo-Genipa americana, aroeira-Myracrodruon urundeuva; negramina-Siparuna guianensis; barbatimão- Stryphnodendron obovatum; assa peixe-Vernonia brasiliana, embaúba-Cecropia pachystachya). Crude foliar extracts were subjected to a preliminary phytochemical prospection and triage of secondary metabolites with antimicrobial activity of potential interest in health and familiar agriculture. Phenolic compounds, terpenes and flavonoids were detected in the extracts of most species, which suggests the presence of antimicrobial, antioxidant and anti-insect activities. It was evident the need to better know the LR as a reservoir of medicinal biomass in an area under ecological tension where 35% (610ha) of the property is LR and should be protected by law. Therefore, a forest inventory of live woody species was performed using the allometric or indirect method. This identified a rare remnant of Semidecidual Seasonal Forest amidst the largest world savannah, the Cerrado biome. An analysis of the forest average productivity per basal area (m².ha), aerial live biomass (ton.ha-1) and carbon stock was carried out. The forest fragment was considered relatively rich in species and diversity, although showing signs of disturbance and dominance by a few species. Its horizontal structure suggests biotic regeneration conditions. It is an important reservoir of medicinal plants. Of the families (57.5%) presenting medicinal species, 19 from a total of 33 are represented in the area and contain 44% (27) of the total species (61) and 63% (432) of the total individuals catalogued. Medicinal species have ecological importance for the equilibrium of the local flora and represent 80% of the 10 species with higher Importance Value Index (IVI): Tetragastris altissima, Chrysophyllum marginatum, Oenocarpus distichus, Sclerolobium paniculatum, Simarouba versicolor, Alibertia macrophylla, Siparuna guianensis, Maprounea guianensis, Licania parvifolia e Physocalymma scaberrimum. Medicinal productivity was high for this type of phytophysionomy: 183,2 ton. ha-1 of biomass and 91,51 ton. ha-1 of carbon representing 66% of the total biomass and carbon of this Cerrado forest. From this stage S. guianensis (Siparunaceae) was selected for performing bioassays in order to verify its biological activity against microorganisms of health and agricultural relevance. This is a native aromatic medicinal plant recommended as priority for conservation, with local popular medicinal validation and availability of medicinal feedstock (3300 Kg.ha-1), with the foliar fraction giving 38Kg/ha of crude extract and 5L/ha of essential oil. Foliar crude extracts and essential oil were obtained and tested in vitro using a disk diffusion bioassay. Different concentrations of these natural products were tested against gram-positive bacteria (Staphylococcus aureus ATCC 29213), gram-negative bacteria (Escherichia coli ATCC 25922 and ATCC 35218; Pseudomonas aeruginosa ATCC 10145) and fungi (Candida albicans ATCC 6258 e Fusarium oxysporum). The essential oil inhibited the growth of S. aureus in its crude concentration (380μg.mL-1), as well as diluted to half (190μg.mL-1) and a quarter strength (95μg.mL-1). It’s likely that such action is due to sesquiterpenes major components, such as bisabolol and bisabolene (10.35%), measured by gas chromatography (GC-MS, GC-FID). Extracts did not exhibit any antimicrobial activity against the microorganisms tested. The native medicinal plants prospective market is an alternative that favours the conservation of biodiversity while generating benefits for the development of sustainable family productive activities within local ecosystems instead of the current inappropriate uses. This strengthens conservation policies of Legal Reserve in rural settlements and is in agreement with public policy on global warming and climate changes.
O estudo objetivou analisar floresta de área de Reserva Legal (RL) de savana brasileira na perspectiva da conservação, reservatório de carbono orgânico e biomassa medicinal para uso prospectivo das plantas medicinais nativas. Foi realizado levantamento etnobotânico e etnofarmacológico junto à comunidade assentada em área rural do Estado do Tocantins, sendo eleitas 9 espécies mais citadas (cajuí-Anacardium othonianum; inharé-Brosimum gaudichaudii; jatobá-Hymenaeae courbaril; jenipapo-Genipa americana, aroeira-Myracrodruon urundeuva; negramina-Siparuna guianensis; barbatimão-Stryphnodendron obovatum; assa peixe-Vernonia brasiliana, embaúba-Cecropia pachystachya). Foi feita a prospecção fitoquímica preliminar dos extratos brutos foliares e triagem dos metabolitos secundários potenciais de atividades antimicrobianas. Os compostos fenólicos, terpenos e flavonoídicos apresentaram positividade nos extratos da maioria das espécies, sugerindo atividades antimicrobianas, antioxidantes e contra insetos. A RL é criada por lei e ocupa localmente 35% da propriedade rural, tornando-se importante reservatório de biomassa medicinal, mas está sob tensão ecológica. Nela foi realizado inventário florestal de espécies lenhosas arbórea-arbustivas vivas usando o método alométrico, identificando raro remanescente de Floresta Estacional Semidecídua em meio à maior savana mundial, o Bioma Cerrado. Foi feita a análise da produtividade média da floresta pela área basal (m².ha), biomassa (ton.ha-1) aérea viva e estoque de carbono (ton.ha-1). O fragmento de floresta foi considerado relativamente rico em espécies e diversidade ainda mantida, mas com sinais de distúrbios e dominada por poucas espécies. Sua estrutura horizontal é sugestiva de condições de regeneração biótica. É um importante reservatório de plantas medicinais: mais da metade (57,5%) das famílias são de espécies medicinais, 19 de um total de 33; guardam 44% (27) do total de espécies (61) e 63% (432) do total de indivíduos (686) inventariados. As espécies medicinais têm importância ecológica para o equilíbrio da flora local, onde 80% estiveram representadas dentre as 10 espécies de maior Índice de Valor de Importância (IVI): Tetragastris altissima, Chrysophyllum marginatum, Oenocarpus distichus, Sclerolobium paniculatum, Simarouba versicolor, Alibertia macrophylla, Siparuna guianensis, Maprounea guianensis, Licania parvifolia e Physocalymma scaberrimum. A produtividade medicinal foi alta para este tipo de fitofisionomia: biomassa de 183,2 ton. ha-1 e carbono de 91,51 ton. ha-1 representando 66% de toda biomassa e carbono desta floresta de Cerrado. Desta etapa foi eleita S. guianensis (Siparunaceae) para realização de bioensaio objetivando verificar atividade biológica frente aos microorganismos de interesse da agricultura familiar e da saude, sendo uma espécie medicinal aromática nativa e recomendada como prioritária de conservação, com validação medicinal popular local e disponibilidade de matéria prima medicinal (3300 Kg.ha-1), conferindo a fração foliar 38Kg/ha de extrato bruto e 5L/ha de óleo essencial. Extratos brutos e óleo essencial foliar foram obtidos e testados em bioensaio in vitro feito por difusão em disco, utilizando diferentes concentrações dos produtos naturais frente a bactérias gram-positivas (Staphylococcus aureus ATCC 29213), bactérias gram-negativas (Escherichia. coli ATCC 25922 e ATCC 35218; Pseudomonas aeruginosa ATCC 10145) e fungos (Candida albicans ATCC 6258 e Fusarium oxysporum). O óleo essencial inibiu o crescimento bacteriano de S. aureus nas concentrações brutas (380μg. mL-1), diluído a metade (190μg.mL-1) e a um quarto (95μg.mL-1). É provável que tal ação seja devido aos componentes majoritários sesquiterpenos, como bisabolol e bisaboleno (10,35%), avaliados por cromatografia gasosa (CG-SM; CG-FID). Para os extratos não houve positividade quanto à ação antimicrobiana. Estudos prospectivos envolvendo plantas medicinais nativas podem ajudar na conservação da biodiversidade, gerando subsídios para o desenvolvimento de atividades produtivas familiares sustentáveis no âmbito de ecossistemas locais em lugar dos usos inadequados atualmente praticados. Isto fortalece a politica de conservação de RL em assentamentos rurais e está em sintonia com a política pública de aquecimento global e mudanças climáticas.
31
Banaitis, Michael R. "Biogeochemical Response of a Northeastern Forest Ecosystem to Biosolids Amendments." Fogler Library, University of Maine, 2007. http://www.library.umaine.edu/theses/pdf/BanaitisMR2007.pdf.
Full text
32
Urban, Michael A. "Forest responses to late Holocene climate change in north-central Wisconsin a comparative plant macrofossil study of two adjacent lakes /." Laramie, Wyo. : University of Wyoming, 2008. http://proquest.umi.com/pqdweb?did=1798966561&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
Full textAbstract:
Thesis (M.S.)--University of Wyoming, 2008.Title from PDF title page (viewed on Mar. 26, 2010). Raw data available as a supplemental file in Microsoft Excel. Includes bibliographical references (p. 31-37).
33
Gagnon, Daniel. "Forest vegetation of west-central Vancouver Island, British Columbia." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/25796.
Full textAbstract:
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
34
Mohd, Salim @. Halim Jamilah. "Tree resistance and responsiveness to mechanical damage and fungal pathogens in dipterocarp forest of Sabah, Malaysia." Thesis, University of Aberdeen, 2009. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=130838.
Full textAbstract:
A survey of dipterocarp forest in four sites revealed that the incidence of stem canker was relatively low but high localized incidences were recorded. No consistent association was obtained between the presence of mechanical damage and cankers. Cankers occurred more frequently on dipterocarps and less frequently on euphorbs. Field studies and experimental manipulations were used to compare sapling resistance and responsiveness to wounding and stem breakage in relatively nutrient-rich, alluvial forest and relatively nutrient-poor, sandstone ridge forest. Species found on sandstone ridges showed greater resistance to damage (e.g., greater stem flexibility, narrower crowns) than those on alluvial soils. Species common on alluvial soils tended to be more responsive to damage (e.g., faster wound closure rates, more likely to re-sprout). Results from manipulation experiments conducted on pot-grown seedlings were consistent with results from the field studies, where conditions of greater nutrient availability, saplings closed wounds at faster rates, had less flexible stems, more narrow crowns, and lower levels of foliar total phenolics. Species showed differential rezones to resource availability which, in part, may relate to contrasting strategies for investment in passive defence (i.e., resins and phenolics) over investment in growth. Through their narrower crowns, greater whole stem flexibility, and lesser stem taper, tree species characteristic of sandstone ridges had greater resistance to mechanical damage from debris falling from above than congeneric species characteristic of alluvial soils. Tree species characteristic of alluvial soils were more responsive to damage than congeners on sandstone ridges, by producing earlier and longer sprouts following stem snapping and more rapid rates of wound closure following wounding.
35
Larson, Jill E. "A floristic inventory of vascular plants of the Carson National Forest and vicinity, north-central New Mexico." Laramie, Wyo. : University of Wyoming, 2008. http://proquest.umi.com/pqdweb?did=1594496631&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
Full text
36
Ladwig, Laura Marie. "Ecology and impacts of lianas in regenerating forests /." View online, 2009. http://repository.eiu.edu/theses/docs/32211131566659.pdf.
Full text
37
Romano, Anthony John. "Spatial distribution of non-native invasive plants following large-scale wind damage at LaRue Pine Hills - Otter Pond Research Natural Area, Union County, Illinois." OpenSIUC, 2012. https://opensiuc.lib.siu.edu/theses/819.
Full textAbstract:
The objective of this study was to determine if a large-scale wind disturbance facilitated the invasion of forest interiors by non-native invasive plant species. The northern portion of LaRue Pine Hills - Otter Pond Research Natural Area in the Shawnee National Forest, of southern Illinois, was severely damaged by high winds during a derecho event on May 8th 2009. In the summer of 2011, 53 permanent research plots, as well as 20 additional plots located along roads that form the boundaries of the study site, were surveyed for the presence of 20 non-native invasive plant species. Only three of 53 interior plots (5.6%) contained invasive plant species (Rosa multiflora, Lonicera japonica, and Lonicera maackii). Sixteen of 20 road plots contained a non-native invasive species (80%), and six species were identified (Dioscorea oppositifolia, Lactuca serriola, Lonicera maackii, Microstegium vimineum, Rosa multiflora, and Sorghum halepense). These findings indicate that wind damage does not appear to have facilitated invasion of forest interiors in the first two years following the storm. The spatial distribution of non-native invasive plants in the study area fits the pattern of other studies conducted in southern Illinois with non-native invasive plants associated primarily with forest edges and diminishing in the forest interior despite the opportunity for establishment following the wind disturbance.
38
Klinka, Karel. "Plant diversity in old-growth and second-growth stands in the coastal rainforests of British Columbia." Forest Sciences Department, University of British Columbia, 1997. http://hdl.handle.net/2429/652.
Full textAbstract:
One of the human activities impacting biodiversity is the cutting of old-growth forests. In response to the controversy surrounding the cutting of old-growth in the coastal rainforest of BC, the Ministries of the Environment and Forests have produced biodiversity guidelines that are to be applied when manipulating stands in the provincial forest.
This study augments these guidelines by investigating the diversity differences between second-growth and old-growth forests in relation to site quality. We demonstrate how standlevel plant diversity differs between 40-year-old and old-growth stands in the Very Wet Coastal Western Hemlock subzone (CWHvm) on Vancouver Island. This information is intended to provide foresters with an understanding of the effects of age, disturbance and site quality on stand-level plant diversity, thereby allowing for informed professional management decisions.
39
Furtenback, Örjan. "Fuel substitution in district heating plants : CGE modeling with a forest resource /." Umeå : Sveriges lantbruksuniv, 2009. http://epsilon.slu.se/11862745.pdf.
Full text
40
Dahlberg, C. Johan. "The role of microclimate for the performance and distribution of forest plants." Doctoral thesis, Stockholms universitet, Institutionen för ekologi, miljö och botanik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-129488.
Full textAbstract:
Microclimatic gradients may have large influence on individual vital rates and population growth rates of species, and limit their distributions. Therefore, I focused on the influence of microclimate on individual performance and distribution of species. Further, I examined differences in how microclimate affect species with contrasting distributions or different ecophysiological traits, and populations within species. More specifically, I investigated the performance of northern and southern distributed forest bryophytes that were transplanted across microclimatic gradients, and the timing of vegetative and reproductive development among northern, marginal and more southern populations of a forest herb in a common garden. Also, I compared the landscape and continental distributions across forest bryophytes and vascular plants and, thus, their distribution limiting factors at different spatial scales. Lastly, I examined the population dynamics across microclimatic gradients of transplants from northern and southern populations of a forest moss. The effects of microclimatic conditions on performance differed among bryophytes with contrasting distributions. There were no clear differences between northern and southern populations in the timing of development of a forest herb or in the population dynamics of a moss. However, within each region there was a differentiation of the forest herb populations, related to variation in local climatic conditions and in the south also to proportion of deciduous trees. The continental distributions of species were reflected in their landscape distributions and vice versa, in terms of their occurrence optima for climatic variables. The variation in landscape climatic optima was, however, larger than predicted, which limit the precision for predictions of microrefugia. Probably, the distributions of vascular plants were more affected by temperature than the distributions of bryophytes. Bryophytes are sensitive to moisture conditions, which was demonstrated by a correlation between evaporation and the population growth rate of a forest moss. We might be able to predict species’ landscape scale distributions by linking microclimatic conditions to their population growth rates, via their vital rates, and infer larger scale distribution patterns.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 3: Manuscript. Paper 4: Manuscript.
EkoKlim
41
Longbrake, A. Christina W. "Ecology and invasive potential of Paulownia tomentosa (Scrophulariaceae) in a hardwood forest landscape." Ohio : Ohio University, 2001. http://www.ohiolink.edu/etd/view.cgi?ohiou992358342.
Full text
42
Peeters, Paula J. (Paula Jane) 1969. "Relationships between leaf traits and herbivorous insect assemblages in a temperate Australian forest." Monash University, Dept. of Biological Sciences, 2001. http://arrow.monash.edu.au/hdl/1959.1/8792.
Full text
43
Gonçalves, Edilma Pereira [UNESP]. "Avaliação do potencial fisiológico de sementes de mutamba (Guazuma ulmifolia Lam.) por meio de diferentes testes de vigor." Universidade Estadual Paulista (UNESP), 2003. http://hdl.handle.net/11449/105118.
Full textAbstract:
Made available in DSpace on 2014-06-11T19:33:36Z (GMT). No. of bitstreams: 0
Previous issue date: 2003-02-17Bitstream added on 2014-06-13T19:04:46Z : No. of bitstreams: 1
goncalves_ep_dr_jabo.pdf: 289095 bytes, checksum: 7269bd2d477247a23b6cbac1169ace2c (MD5)O trabalho teve como objetivo verificar a eficiência de diferentes testes de vigor para identificação do potencial fisiológico de quatro lotes de sementes de mutamba (Guazuma ulmifolia Lam.). O estudo foi desenvolvido no Laboratório de Análise de Sementes e no Viveiro Experimental de Plantas Ornamentais e Florestais - UNESP, Jaboticabal, SP. Foram utilizados quatro lotes de sementes provenientes de três localidades paulistas: lotes I e 11, coletados no município de Jaboticabal em 2000 e 2001, respectivamente, lote 111, coletado em Santa Rita do Passo Quatro, e lote IV, coletado em Luiz Antonio, os dois últimos em 2001. As sementes utilizadas em todos os testes foram escarificadas com ácido sulfúrico durante 50 minutos e lavadas em água corrente durante 15 minutos. Foram avaliados: teor de água, teste de germinação, teste de primeira contagem, índice de velocidade de germinação, emergência em viveiro, índice de velocidade de emergência, envelhecimento acelerado conduzido nas temperaturas de 410e e 450e, durante nove períodos de avaliação, e condutividade elétrica com diferentes números de sementes (50, 75, 100), postas para embeber em copos de plástico contendo 50, 75 e 100 mL de água desionizada, à temperatura de 250e, fazendo leituras freqüentes durante 72 horas. Os teores de água das sementes nos diferentes lotes apresentaram pequenas variações (9,2 a 10,0 %). Não foram verificadas diferenças estatísticas para a porcentagem de germinação, emergência em viveiro e índice de velocidade de emergência. Diante dos resultados obtidos, concluiu-se que o envelhecimento acelerado pode ser realizado na temperatura de 41°C por um período mínimo de 120 horas ou a 45°C durante 96 horas para avaliação do potencial fisiológico, e o teste de condutividade elétrica não se mostrou adequado para avaliação do potencial fisiológico das sementes...
The work had as objective to compare the efficiency of different vigor tests for identification of the physiologic potential in four lots of Guazuma ulmífolia seeds. The experiments were carried out at Jaboticabal, State of São Paulo, Brazil. Four seed lots from three places of São Paulo State were used: lots I and 11, collected in the municipal district of Jaboticabal in 2000 and 2001, lot 111, collected in Santa Rita do Passa Quatro, and lot IV, collected in Luiz Antonio, the last two in 2001. The seeds used in ali the tests were escarified with sulfuric acid during 50 minutes, and washed in running water during 15 minutes. The results were evaluated with base on seed moisture content, germination test, first count test, germination speed index, emergency in nursery, emergency speed index, accelerated aging at the temperatures of 41°C and 45°C (nine evaluation periods of time) and electric conductivity with different numbers of seeds (50,75, 100), put to soak in plastic boxes containing 50, 75 and 100 mL of water, at 25°C, with frequent observations during 72 hours. The seed moisture content in the different lots presented small variations (9,2 to 10,0%). Statistical differences were not verified for the germination percentage, emergency in nursery and emergency speed index. It was concluded that the accelerated aging at 41°C during a minimum period of 120 hours or at 45°C during 96 hours can be used for evaluation of the physiologic potential of the seeds, and the test of electric conductivity was not appropriate for this purpose. The test of first count and index of germination speed showed to be adequate for evaluation of the physiologic potential of the lots. The germination tests, emergency in nursery and index of emergency speed did not detect differences in the physiologic potential of the studied lots. The seeds lot from Santa Rita do Passa Quatro presented physiologic potential superior to the other lots.
44
Fribley, Laura A. "Woody plant species composition in forest fragments at Muscatatuck National Wildlife Refuge." Virtual Press, 2006. http://liblink.bsu.edu/uhtbin/catkey/1339145.
Full textAbstract:
Several invasive woody plants grow in forest fragments at Muscatatuck National Wildlife Refuge in Seymour, Indiana. The objective of this study was to determine what woody species were growing in two upland forests and to assess the level of dominance that invasive species had in these areas. The variables of depth into the forest and directional aspect were also considered. Thirty-two belt transects were sampled and 54 woody species were found, including six invasive species: Ailanthus altissima (tree-ofheaven), Berberis thunbergii (Japanese barberry), Elaeagnus umbellata (autumn olive), Lonicera japonica (Japanese honeysuckle), Lonicera maackii (amur honeysuckle), and Rosa multiflora (multiflora rose). Importance values were calculated as an indicator of relative species dominance. Detrended Correspondence Analysis and Cluster analysis suggested that the invasive species were grouped on the forest edge transects; aspect was not found to be a determinant in where invasive species grew. Correlation coefficients demonstrated a significant difference between transect depth and the following variables at both forests: woody species density per transect, invasive species dominance, Elaeagnus umbellata density per hectare, and Lonicera japonica dominance. Rosa multiflora was one of the three most dominant understory species in both forests; on the edge transect, it was one of the top two. Soil temperatures were also measured at each transect, but no consistent trends were found within the data. In light of resources available, it is suggested that land managers focus on controlling Rosa multiflora and Ailanthus altissima.Department of Natural Resources and Environmental Management
45
Toy, Robin J. "The pre-dispersal insect fruit-predators of Dipterocarpaceae in Malaysian rain forest." Thesis, University of Aberdeen, 1988. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=128428.
Full textAbstract:
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 Nanophyes shoreae. 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 Nanophyes shoreae's 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.
46
Stein, Beth R. "Applications of Imaging Spectroscopy in Forest Ecosystems at Multiple Scales." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/77390.
Full textAbstract:
Forests provide a number of ecosystem services which sustain and enrich the wildlife, human societies, and the environment. However, many disturbances threaten forest ecosystems, making it necessary to monitor their health for optimal management and conservation. Although there are many indicators of forest health, changes in biogeochemical cycling, loss of species diversity, and invasive plants are particularly useful due to their vulnerability to the effects of climate change and intensive agricultural land use. Thus, this work evaluates the use of imaging spectroscopy to monitor forest nutrient status, species diversity, and plant invasions in the Mid-Atlantic region. The research is divided into four separate studies, each of which evaluated a unique application for imaging spectroscopy data at a different scale within the forest.
The first two studies examined loblolly pine nutrient status at the leaf and canopy scales, respectively. The first study determined that loblolly pine foliar macronutrient concentrations can be successfully modeled across the Southeastern US (R2=0.39-0.74). Following on these results, the second study focused on the relationship between physical characteristics, reflectance, and nutrients. Reflectance values and W scattering coefficients produced successful nitrogen models across loblolly pine plots at the canopy scale. Regression models showed similar explanatory power for nitrogen, although W scattering coefficients were significantly correlated with nitrogen at multiple wavelengths and reflectance variables were not. However, the direction of some of the correlations with W and the unusually high directional area scattering factor values indicate a need for further experimentation. The third study found that several imaging spectroscopy algorithms were moderately successful in identifying wavyleaf basketgrass invasions in mixed deciduous forests (overall accuracy=0.35-0.78; kappa=0.41-0.53). Lastly, the fourth study used a novel imaging spectroscopy/lidar fusion to identify canopy gaps and measure species diversity of understory vegetation. The lidar algorithm identified 29 of 34 canopy gaps, and regression models explained 49 percent of the variance in gap species diversity. In conclusion, imaging spectroscopy can be used to evaluate ecosystem health through forest nutrient status, nitrogen models, species diversity estimates, and identification of invasive plant species.Ph. D.
47
Bailey, Brent. "Social and economic impacts of wild harvested products." Morgantown, W. Va. : [West Virginia University Libraries], 1999. http://etd.wvu.edu/templates/showETD.cfm?recnum=968.
Full textAbstract:
Thesis (Ph. D.)--West Virginia University, 1999.Title from document title page. Document formatted into pages; contains viii, 103 p. : ill. (some col.), maps. Vita. Includes abstract. Includes bibliographical references (p. 81-83).
48
Klooster, Wendy S. "Forest Responses to Emerald Ash Borer-Induced Ash Mortality." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1338337754.
Full text
49
Liang, Yu. "EXOTIC INVASIVE PLANTS IN KENTUCKY." UKnowledge, 2010. http://uknowledge.uky.edu/gradschool_theses/23.
Full textAbstract:
Invasion of exotic species is a significant problem in natural ecosystems, reaching epidemic proportions and resulting in significant economic losses. However, insufficient knowledge of explicit spatial distribution of invasive species hinders our ability to prevent and/or mitigate future invasion. In this study, we demonstrate the use of existing voluntary data to survey invasive plant species in Kentucky. We also reconstructed the historical distribution of 16 exotic invasive plants typical to Kentucky using herbarium records. We found that Kentucky is facing a large threat from exotic invasive plants as they are reported throughout most counties. The distribution maps for four of the top 10 most reported invasive species revealed that Kentucky is presently or was previously a front of invasion. The majority of the 16 targeted invasive species were scattered throughout Kentucky with no concentrations within particular regions. Cumulative curves of occupied counties over time fit a “J” shape expansion curve, which indicates the potential for further future invasion. This study demonstrates the usefulness of voluntary data and herbarium data to reconstruct the historical and current distribution of invasive species. Further studies on other invasive species can take advantage of information associated with herbarium specimens to achieve more fruitful results.
50
Kull, Matthew Austin. "Abundance patterns for vascular epiphytes in a tropical secondary forest, Costa Rica." Diss., Online access via UMI:, 2007.
Find full text