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1
Harrelson, Sarah M. « A floristic survey of the terrestrial vascular plants of Strouds Run State Park, Athens County, Ohio ». Ohio : Ohio University, 2005. http://www.ohiolink.edu/etd/view.cgi?ohiou1113581854.
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Mallick, Debanshu. « Study on diversity and ecology of vascular plants at medicinal plant conservation areas (MPCAs) in Terai and Duars, West Bengal ». Thesis, University of North Bengal, 2022. http://ir.nbu.ac.in/handle/123456789/4799.
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Santos, Leonardo Biral [UNESP]. « Florística vascular da Mata da Pavuna, Botucatu, SP, Brasil ». Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/87842.
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A Mata da Pavuna é um fragmento de floresta estacional semidecídua em um cânion com afloramento rochoso e solo raso, localizado no município de Botucatu, Estado de São Paulo. Foram amostradas todas as espécies vasculares em estádio reprodutivo e identificadas até o menor nível possível. Foram encontradas 381 espécies em 83 famílias. Fabaceae foi a família com maior número de espécies (44), seguido de Asteraceae (33), Euphorbiaceae (18), Poaceae (17), Malvaceae (14), Bignoniaceae e Solanaceae (12). Em Pteridophyta sensu stricto as famílias mais diversas foram Pteridaceae (oito espécies) e Polypodiaceae (sete). Comparado a outros levantamentos florísticos extensos na Mata Atlântica os resultados ressaltam a elevada diversidade florística local, bem como a presença de espécies típicas de formações xerofíticas sugerindo, inclusive, a ocorrência de um encrave de vegetação seca. Noticiamos também o primeiro registro de Pellaea ovata (Desv.) Weath. (Pteridaceae) para o Brasil
The „Mata da Pavuna‟ is a semideciduous seasonal forest fragment located in a canyon characterized by rock outcrops and shallow soil, in municipality of Botucatu, State of São Paulo. We collected all vascular plants in reproductive stage, and identified them to the lowest taxonomic level possible. We found 381 species in 83 families. Fabaceae was the most diverse family with 44 species, followed by Asteraceae (33), Euphorbiaceae (18), Poaceae (17), Malvaceae (14), Bignoniaceae (12) and Solanaceae (12). In the Pteridophyta sensu lato the most diverse families was Pteridaceae (eight species) and Polypodiaceae (seven). Compared to other comprehensive floristic surveys carried out in the Atlantic Forest these results show the high floristic diversity and the presence of typical xerofitic vegetation species, suggesting the presence of an enclave of dry forest. We reported here the first mention of Pellaea ovata (Desv.) Weath. (Pteridaceae) for Brazil
4
Heathcote, Steven John. « The ecology of vascular epiphytes in the Peruvian Andes ». Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:d7bee986-6066-48a1-8849-4aed22a3d766.
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Little is known about the composition of tropical epiphytic communities and the influence of environmental variables on community composition. In this thesis I quantify the diversity and biomass of bromeliads, and other vascular epiphytes along an altitudinal transect on the eastern slope of the southeast Peruvian Andes and then look for species’ adaptations related to patterns of diversity and biomass. I compare patterns with those of woody species. Bromeliad species, like tree species, were found to form ecological zones related to climate. The lowest altitude ecological zone (below 1250 m) is the lowland rainforest (LRF), which has the warmest climate and highest evapotranspiration. In LRF vascular epiphytes are less prominent than other ecological zones, with the lowest bromeliad species richness and lowest vascular epiphyte biomass. However, low water-availability gives rise to most variable shoot morphology of bromeliads. The tropical montane forest (TMF), between 1250 m and 2250 m, is intermediate in climate between the LRF and the tropical montane cloud forest (TCF). The TMF has the highest α-diversity, but species richness is lower than the TCF. The shoot morphology of bromeliads is intermediate between TCF and LRF. The highest altitude ecological zone with forest is the TCF (above 2250 m). The TCF has the highest bromeliad species richness, and lowest diversity of shoot forms. The low diversity of shoot forms represents the need for a large phytotelm (water-impounding shoot) to intercept and store precipitation. The TCF has the highest vascular epiphyte biomass, although the biomass is variable as a consequence of the natural disturbance caused by landslides. Along the transect bromeliad species with CAM photosynthesis are only present in the LRF. Terrestrial bromeliad distribution records covering the Neotropics show CAM photosynthesis is more prevalent in drier environments showing that CAM photosynthesis is primarily an adaptation to drought. Epiphytic bromeliads, pre-adapted to a water-stressed environment show no differences in presence along rainfall gradients, but species with CAM photosynthesis occupy warmer environments.
5
Kull, Matthew Austin. « Abundance patterns for vascular epiphytes in a tropical secondary forest, Costa Rica ». Diss., Online access via UMI:, 2007.
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6
Santos, Leonardo Biral. « Florística vascular da Mata da Pavuna, Botucatu, SP, Brasil / ». Rio Claro : [s.n.], 2011. http://hdl.handle.net/11449/87842.
Texte intégralRésumé :
Orientador: Julio Antonio LombardiBanca: Marco Atonio de Assis
Banca: Milton Groppo Junior
Resumo: A Mata da Pavuna é um fragmento de floresta estacional semidecídua em um cânion com afloramento rochoso e solo raso, localizado no município de Botucatu, Estado de São Paulo. Foram amostradas todas as espécies vasculares em estádio reprodutivo e identificadas até o menor nível possível. Foram encontradas 381 espécies em 83 famílias. Fabaceae foi a família com maior número de espécies (44), seguido de Asteraceae (33), Euphorbiaceae (18), Poaceae (17), Malvaceae (14), Bignoniaceae e Solanaceae (12). Em Pteridophyta sensu stricto as famílias mais diversas foram Pteridaceae (oito espécies) e Polypodiaceae (sete). Comparado a outros levantamentos florísticos extensos na Mata Atlântica os resultados ressaltam a elevada diversidade florística local, bem como a presença de espécies típicas de formações xerofíticas sugerindo, inclusive, a ocorrência de um encrave de vegetação seca. Noticiamos também o primeiro registro de Pellaea ovata (Desv.) Weath. (Pteridaceae) para o Brasil
Abstract: The „Mata da Pavuna‟ is a semideciduous seasonal forest fragment located in a canyon characterized by rock outcrops and shallow soil, in municipality of Botucatu, State of São Paulo. We collected all vascular plants in reproductive stage, and identified them to the lowest taxonomic level possible. We found 381 species in 83 families. Fabaceae was the most diverse family with 44 species, followed by Asteraceae (33), Euphorbiaceae (18), Poaceae (17), Malvaceae (14), Bignoniaceae (12) and Solanaceae (12). In the Pteridophyta sensu lato the most diverse families was Pteridaceae (eight species) and Polypodiaceae (seven). Compared to other comprehensive floristic surveys carried out in the Atlantic Forest these results show the high floristic diversity and the presence of typical xerofitic vegetation species, suggesting the presence of an enclave of dry forest. We reported here the first mention of Pellaea ovata (Desv.) Weath. (Pteridaceae) for Brazil
Mestre
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Trentanovi, Giovanni. « Vascular plant species diversity in fragmented secondary plant communities : a landscape ecology approach ». Doctoral thesis, Università degli studi di Padova, 2012. http://hdl.handle.net/11577/3421745.
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Landscape ecology has been defined in a variety of different ways, but the common theme is the study of the ecological effects of ecosystem spatial patterning. Since the long history
of landscape alteration has created novel systems with unknown dynamics, new tools are necessary to understand, manage and restore human dominated landscapes, preventing the loss of biodiversity. Among all, habitat fragmentation is the main process which affects biodiversity
especially in human dominated landscapes.
This thesis is based on three research papers concerning the evaluation of plant species diversity in fragmented and secondary plant communities. Moreover, the effect of natural
reforestation process on biodiversity of secondary plant communities was investigated through a review paper. Focusing in each paper on different specific objectives due to the variability of landscape context and habitat type, the overall goal of this work was to detect spatial and
management components influencing vascular plant species diversity. Through the different tools and methodologies used in each case study, we want to demonstrate the great applicability and versatility of landscape ecology approach both in theory and practice.
The analyses were conducted on three fragmented secondary plant communities, i.e. meadow-pastures (Paper II), recent secondary woodlands (Paper III) and hedgerows (Paper IV),
scattered in a dominant matrix type. Paper III was done during the collaboration with the Technische Universität of Berlin (Department of Ecology) during my research period abroad.
The case studies were conducted both at patch and at landscape level, considering actual field data and management variables of the secondary plant communities surveyed (patch level) and the analysis of landscape asset around (landscape level). The latter was performed by GIS
analysis. Regression models were used to relate plant species diversity to spatial and management variables.
The survival of species depends on landscape dynamics and on spatial plant community configuration (Paper I). More specifically, where environmental site condition and management variables have not impact on secondary community variability and they did not differ between
the surveyed communities, plant species diversity can be deeply influenced by spatial variables (Paper II and III). On the contrary, where management variables have a strong effect on secondary community alteration, i.e. in agrarian hedgerows, this effect is independent from the
landscape assets of the different surveyed sites (Paper IV).
In general, the integrative methods used by the “landscape ecology approach” allowed us to quantify in a holistic way complex natural-cultural patterns and processes on different time-space scales that influenced vascular plant species diversity.L’ecologia del paesaggio studia l’influenza dei pattern spaziali sui flussi di specie. La continua frammentazione ed alterazione delle fitocenosi in paesaggi antropizzati rende necessario comprendere le dinamiche delle comunità vegetali che caratterizzano il paesaggio antropizzato, cercando di evitare il più possibile la perdita di diversità biologica che spesso è conseguenza di tali trasformazioni. La mia tesi è basata su tre articoli di ricerca riguardanti l’analisi della diversità della flora vascolare in fitocenosi secondarie e frammentate. In un lavoro di review invece, è stato analizzato l’effetto della riforestazione spontanea su fitocenosi secondarie a seguito dell’abbandono delle pratiche agricole. Ciascun lavoro è stato caratterizzato da specifici obiettivi, adattati in base alla variabilità del paesaggio e del tipo di fitocenosi secondaria indagata. Ciononostante, l’obiettivo comune di questa tesi è stato quello di esaminare l’influenza delle variabili di paesaggio e gestionali sulla variabilità della flora vascolare, tramite l’utilizzo di metodologie e strumenti propri dell’ecologia del paesaggio. Le analisi sono state effettuate in tre fitocenosi secondarie e frammentate, i.e. pascoli (Paper II), neoformazioni boschive (Paper III) e siepi rurali (Paper IV), inserite all’interno di differenti matrici paesaggistiche. Il terzo caso di studio (Paper III) è stato sviluppato in collaborazione con la Technische Universität di Berlino durante il mio periodo di dottorato all’estero. Le analisi sono state effettuate sia a livello di patch che di paesaggio, considerando quindi congiuntamente i rilievi floristici e le variabili gestionali (livello di patch) e l’analisi dell’assetto paesaggistico attorno alle fitocenosi indagate (livello di paesaggio). Le analisi di paesaggio sono state effettuate tramite strumenti GIS. Vari modelli di regressione sono stati utilizzati per mettere in relazione la diversità di specie vascolari con le variabili di paesaggio e gestionali. La sopravvivenza delle specie dipende profondamente dalle dinamiche del paesaggio e dalla sua configurazione spaziale (Paper I). Più nello specifico, nei casi di studio in cui le variabili stazionali e gestionali sono ininfluenti o omogenee in tutti i siti, la diversità di specie vascolari è profondamente influenzata dalle variabili spaziali (Paper II e III). Dove invece la gestione altera sostanzialmente l’equilibrio della fitocenosi, l’effetto è indipendente dalle variabili di paesaggio (Paper IV). In generale, i principi ed i metodi dell’ecologia del paesaggio che sono stati utilizzati nei casi di studio presentati, hanno permesso di quantificare precisamente i processi e le dinamiche che influenzano la diversità di specie vascolari a differnti scale spaziali e temporali.
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Forster, Paul I. « The pursuit of plants : studies on the systematics, ecology and chemistry of the vascular flora of Australia and related regions / ». [St. Lucia, Qld], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18317.pdf.
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Vanderplank, Sula E. « The Vascular Flora of Greater San Quintín, Baja California, Mexico ». Scholarship @ Claremont, 2010. http://scholarship.claremont.edu/cgu_etd/2.
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The plants of San Quintín (Baja California, Mexico) were documented through intensive fieldwork and the collection of herbarium specimens to create a checklist of species. This region is home to a diverse flora with high levels of local endemism and many rare plants. The flora documented in this study was compared to historical records from the region and shows the impact of agriculture and urbanization on the plants, including several extirpated species. A study of the perennial vegetation using a 1 km grid provides species distribution data for 140 native species, which were assessed to highlight areas of significant species richness for native, rare, and endemic taxa. Several non-native plants were also mapped to provide baseline data. Areas of conservation priority for the flora of Greater San Quintín are discussed in light of these combined findings.
10
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.
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Dinato, Daniela de Oliveira [UNESP]. « Florística vascular não arbórea de um fragmento de floresta estacional semidecidual no munícipio de Analândia - SP ». Universidade Estadual Paulista (UNESP), 2014. http://hdl.handle.net/11449/108707.
Texte intégralRésumé :
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000765240.pdf: 2148936 bytes, checksum: 2e4ee0eae4227c322f90609fd9a24f17 (MD5)(Florística vascular não arbórea de um fragmento de Floresta Estacional Semidecidual no município de Analândia - SP). O Parque Rawistcher localiza-se na Fazenda Pedra Vermelha, no município de Analândia, região centro-leste do Estado de São Paulo, entre as coordenadas 22°06’53’’- 05’35’’S e 47°46’06’’- 45’14’’W. Trata-se de um fragmento de cerca de 80 ha de Floresta Estacional Semidecidual que ocorre sobre cuestas basálticas. O presente trabalho teve como objetivo principal realizar inventário da flora vascular (incluindo pteridófitas s.l.) não arbórea (arbustos, ervas terrestres, epífitas, trepadeiras) da área. Foram realizadas coletas de abril de 2012 a dezembro de 2013, utilizando-se o método de caminhamento em trilhas. A flora não arbórea do Parque Rawistcher é constituída por 230 espécies, distribuídas em 74 famílias, sendo 89% angiospermas e 11% pteridófitas s.l. Asteraceae foi a família fanerogâmica com maior número de espécies (17), seguida de Piperaceae (13), Malvaceae (12), Rubiaceae (11), Cyperaceae (10) Solanaceae, Fabaceae e Poaceae (9), Bignoniaceae (8) e Orchidaceae (7). Polypodiaceae foi a família de pteridófita s.l. mais representativa (5). A flora não arbórea constitui cerca de 53% da flora amostrada total do Parque Rawistcher. Em relação à forma de vida, a maioria são ervas terrestres (48%), seguidas de arbustos (23%), trepadeiras (22%) e epífitas (7%). Do total de espécies, 19 são endêmicas da Mata Atlântica e nove não são nativas da flora brasileira. Seis espécies do presente levantamento são consideradas ameaçadas ou quase ameaçadas de extinção, segundo o Livro Vermelho das espécies vegetais ameaçadas do Estado de São Paulo. Em comparação com outros levantamentos florísticos, os resultados mostram uma elevada riqueza florística local e ressaltam a heterogeneidade e particularidade de cada fragmento florestal do Estado, confirmando a importância..
(Nontrees Vascular Floristic of a fragment of Semideciduous Seasonal Forest in the municipality of Analândia - SP). The Rawistcher Park is located in Pedra Vermelha farm, in the city of Analândia, central-eastern region of São Paulo state, between the coordinates 22°06’53’’- 05’35’’S and 47°46’06’’- 45’14’’W. It is a Semideciduous Seasonal Forest fragment of about 80 ha that occurs on basaltic cuestas. This study aimed to conduct inventory of the nontrees (shrubs, ground herbs, epiphytes, climbers) vascular flora (including pteridophytes s.l.) of the area. Samplings were conducted from April 2012 to December 2013 using the method of traversal on trails. The nontrees flora of Rawistcher Park consists of 230 species belonging to 74 families, 89% angiosperms and 11% pteridophytes s.l. Asteraceae was the fanerogamic family with the highest number of species (17), followed by Piperaceae (13), Malvaceae (12), Rubiaceae (11), Cyperaceae (10) Solanaceae, Poaceae and Fabaceae (9), Bignoniaceae (8) and Orchidaceae (7). Polypodiaceae was the more representative family of Pteridophytes s.l. (5). Nontree flora represents above 53% of total know flora of Rawistcher Park. Regarding the life form, most are herbs (48%), followed by shrubs (23%), climbers (22%) and epiphytes (7%). Among all species, 19 are endemic to the Atlantic Forest and nine are non-native from brazilian flora. Six species of this survey are considered threatened or near threatened with extinction, according to the Red List of endangered species in the state of São Paulo. Compared with other floristic surveys, the results show a high local floristic richness and emphasize the heterogeneity and particularity of each forest fragment of São Paulo state, confirming the importance of its preservation
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Dinato, Daniela de Oliveira. « Florística vascular não arbórea de um fragmento de floresta estacional semidecidual no munícipio de Analândia - SP / ». Rio Claro, 2014. http://hdl.handle.net/11449/108707.
Texte intégralRésumé :
Orientador: Julio Antonio LombardiBanca: Natália Macedo Ivanauskas
Banca: Reinaldo Monteiro
Resumo: (Florística vascular não arbórea de um fragmento de Floresta Estacional Semidecidual no município de Analândia - SP). O Parque Rawistcher localiza-se na Fazenda Pedra Vermelha, no município de Analândia, região centro-leste do Estado de São Paulo, entre as coordenadas 22°06'53''- 05'35''S e 47°46'06''- 45'14''W. Trata-se de um fragmento de cerca de 80 ha de Floresta Estacional Semidecidual que ocorre sobre cuestas basálticas. O presente trabalho teve como objetivo principal realizar inventário da flora vascular (incluindo pteridófitas s.l.) não arbórea (arbustos, ervas terrestres, epífitas, trepadeiras) da área. Foram realizadas coletas de abril de 2012 a dezembro de 2013, utilizando-se o método de caminhamento em trilhas. A flora não arbórea do Parque Rawistcher é constituída por 230 espécies, distribuídas em 74 famílias, sendo 89% angiospermas e 11% pteridófitas s.l. Asteraceae foi a família fanerogâmica com maior número de espécies (17), seguida de Piperaceae (13), Malvaceae (12), Rubiaceae (11), Cyperaceae (10) Solanaceae, Fabaceae e Poaceae (9), Bignoniaceae (8) e Orchidaceae (7). Polypodiaceae foi a família de pteridófita s.l. mais representativa (5). A flora não arbórea constitui cerca de 53% da flora amostrada total do Parque Rawistcher. Em relação à forma de vida, a maioria são ervas terrestres (48%), seguidas de arbustos (23%), trepadeiras (22%) e epífitas (7%). Do total de espécies, 19 são endêmicas da Mata Atlântica e nove não são nativas da flora brasileira. Seis espécies do presente levantamento são consideradas ameaçadas ou quase ameaçadas de extinção, segundo o Livro Vermelho das espécies vegetais ameaçadas do Estado de São Paulo. Em comparação com outros levantamentos florísticos, os resultados mostram uma elevada riqueza florística local e ressaltam a heterogeneidade e particularidade de cada fragmento florestal do Estado, confirmando a importância..
Abstract: (Nontrees Vascular Floristic of a fragment of Semideciduous Seasonal Forest in the municipality of Analândia - SP). The Rawistcher Park is located in Pedra Vermelha farm, in the city of Analândia, central-eastern region of São Paulo state, between the coordinates 22°06'53''- 05'35''S and 47°46'06''- 45'14''W. It is a Semideciduous Seasonal Forest fragment of about 80 ha that occurs on basaltic cuestas. This study aimed to conduct inventory of the nontrees (shrubs, ground herbs, epiphytes, climbers) vascular flora (including pteridophytes s.l.) of the area. Samplings were conducted from April 2012 to December 2013 using the method of traversal on trails. The nontrees flora of Rawistcher Park consists of 230 species belonging to 74 families, 89% angiosperms and 11% pteridophytes s.l. Asteraceae was the fanerogamic family with the highest number of species (17), followed by Piperaceae (13), Malvaceae (12), Rubiaceae (11), Cyperaceae (10) Solanaceae, Poaceae and Fabaceae (9), Bignoniaceae (8) and Orchidaceae (7). Polypodiaceae was the more representative family of Pteridophytes s.l. (5). Nontree flora represents above 53% of total know flora of Rawistcher Park. Regarding the life form, most are herbs (48%), followed by shrubs (23%), climbers (22%) and epiphytes (7%). Among all species, 19 are endemic to the Atlantic Forest and nine are non-native from brazilian flora. Six species of this survey are considered threatened or near threatened with extinction, according to the Red List of endangered species in the state of São Paulo. Compared with other floristic surveys, the results show a high local floristic richness and emphasize the heterogeneity and particularity of each forest fragment of São Paulo state, confirming the importance of its preservation
Mestre
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Searles, Peter S. « Responses of Sphagnum and Carex Peatlands to Ultraviolet-B Radiation, and a Meta-Analysis of UV-B Effects on Vascular Plants ». DigitalCommons@USU, 2000. https://digitalcommons.usu.edu/etd/6578.
Texte intégralRésumé :
The severity of stratospheric ozone depletion in the temperate and polar latitudes has raised concerns about the sensitivity of terrestrial vegetation and ecosystems to solar ultraviolet (UV-B) radiation. This dissertation examined the responses of plants and microbes to solar UV-B for 3 years in Tierra de! Fuego, Argentina (55° S). This region is under the influence of the Antarctic "ozone hole" during the austral spring. Additionally, a quantitative review of the UV-B literature was conducted using a set of statistical techniques known as meta-analysis.
For the field studies in Tierra de! Fuego, plots were established in a Sphagnum moss peatland and a Carexsedge fen during the spring of 1996. These plots received either near-ambient solar UV-B (90% of ambient) or reduced UV-B (20% of ambient) using specially designed plastic films. At the end of the first field season, no effects of the solar UV-B treatments were apparent on the growth and pigmentation of the plant species in either community The height growth of the moss Sphagnum mageffanicum was less under near-ambient solar UV-B than reduced UV-B during the second and third growing seasons. In contrast, volumetric density of the moss was greater under nearambient UV-B. The growth of the vascular plants did not respond to the solar UV-B treatments even after 3 years although UV-B-absorbing compounds were greater under near-ambient UV-B in some species. Populations of testate amoebae (i.e., shelled amoebae) inhabiting S. magellanicum had greater numbers under near-ambient UV-B than reduced UV-B throughout the 3 years. This response may be an indirect effect of solar UV-B mediated by the direct effect of UV-Bon S. mageffanicum height growth. Fungi on the leaf surfaces of the tree Nothojagus antarctica appeared to be directly inhibited by solar UV-B.
The quantitative literature review of plant field studies simulating stratospheric ozone depletion assessed the effects of elevated UV-B on 10 plant response variables from papers published between 1976 and mid-1999. Modest significant inhibitions of leaf area, aboveground biomass, and plant height were apparent due to increased UV-B using meta-analysis. An increase in UV-B-absorbing compounds appears to be the most robust general response to increased UV-B radiation.
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Campeau, Suzanne. « The relative importance of algae and vascular plant detritus to freshwater wetland food chains / ». Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60458.
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This study examines the relative contribution of algae and vascular plant litter to the food chains of freshwater marshes. Twelve enclosures (5 m diam.) were deployed in a nutrient-poor marsh of the Interlake region of Manitoba. Algae levels in six of the enclosures were increased by fertilizing the water column. In addition, the hardstem bulrush (Scirpus lacustris glaucus (Sm.) Hartm) litter present was replaced with a non-nutritive artificial substrate in half of the fertilized and unfertilized enclosures. Fertilization did not affect the dry weight loss of bulrush litter, but N and P concentrations were higher in the decomposing litter of the fertilized treatments. Dominant taxa of nektonic herbivores-detritivores responded to fertilization but were not affected by the replacement of plant litter by a non-nutritive substrate. Epiphytic herbivores-detritivores responded to changes in both detritus and algal food sources. Fertilization resulted in early peaks of emergence for the Chironominae, Tanypodinae and Orthocladiinae. Emergence data late in the study period suggest that the importance of litter as a food source may increase as decomposition progresses.
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Marcusso, Gabriel Mendes [UNESP]. « Epifitismo vascular em duas fisionomias vegetais, floresta paludosa e floresta estacional semidecidual no município de Botucatu, estado de São Paulo, Brasil ». Universidade Estadual Paulista (UNESP), 2015. http://hdl.handle.net/11449/123930.
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O epifitismo vascular é responsável por considerável parcela da biodiversidade dos trópicos. Neste trabalho foi avaliada a composição florística das epífitas vasculares, a distribuição vertical e as relações da comunidade epifítica vascular com seus respectivos forófitos (tipo de ritidoma, altura e diâmetro) em uma floresta paludosa (FP) e uma floresta estacional semidecidual (FES) no município de Botucatu, SP. Para o levantamento florístico foram realizadas coletas mensais durante o período de um ano (junho de 2013 a junho de 2014). As epífitas foram classificadas de acordo com as categorias ecológicas e síndromes de dispersão em que se enquadram. Comparações de similaridades entre a área estudada com outros trabalhos disponíveis na literatura foram realizadas, através do índice de similaridade de Jaccard (modificado). Para a identificação foram utilizados trabalhos taxonômicos, consulta a herbários e a especialistas. O material coletado foi preparado e depositado no Herbário Rioclarense (HRCB). A amostragem para avaliar as relações entre epífitas e forófitos foi realizada em transectos lineares ao longo da área de estudo, utilizando método de quadrantes centrados (PAP ≥ 15 cm). Foram identificadas 87 espécies de epífitas vasculares pertencentes a 51 gêneros e 13 famílias, sendo a FP a fisionomia com maior riqueza. Orchidaceae, Polypodiaceae, Bromeliaceae e Piperaceae foram as famílias mais representativas. 72,4% são anemocóricas e 87,4% holoepífitas obrigatórias. 19,5% das espécies são endêmicas do Domínio Atlântico e 33,3% do Brasil. Sete espécies encontram-se ameaçadas ou quase ameaçadas de extinção. A área estudada foi mais similar a áreas no Paraná, Rio Grande do Sul e Argentina. Das árvores amostradas, 28,2% e 56,3%, respectivamente na FES e na FP, apresentaram-se como suporte para as epífitas. As espécies de árvores que apresentaram os maiores números de indivíduos foram...
Vascular epiphytes are responsible for considerable part of tropical biodiversity. In this work was evaluated the floristic composition of vascular epiphytes, the vertical distribution and the relationship among the epiphyte community with the host tree (type of bark, height and diameter) in a swamp forest (FP) and in a seasonal semideciduous forest (FES) in the Botucatu municipality, SP. To the floristic survey were performed monthly collections during the period of one year (june 2013 to june 2014). The epiphytes were classified according with the ecological categories and the dispersion syndrome. Comparisons of the similarity among the study area with others surveys published were carried, using the Jaccard similarity index (modified). For identification were used taxonomic literature, consult to herbarium specimens and experts. The collected specimens were deposited at the Herbário Rioclarense (HRCB). To evaluate the relationship among the epiphytes and the host trees were performed linear transect along the study area, using the quadrant centered method (PAP ≥ 15 cm). Were registered 87 species of vascular epiphytes belonging to 51 genera and 13 families. The FP was the richest phytophysiognomy. Orchidaceae, Polypodiaceae, Bromeliaceae and Piperaceae were the more representative families. 72,4% were anemocoric and 87,4% obligatory holoepiphytes. 19,5 % of the species are endemic for Atlantic Domain and 33,3% from Brazil. Seven species were threatened or near threatened, two of them presumably extinct. The studied area was most similar to sites in Paraná, Rio Grande do Sul and Argentina. Of the trees, 28,2% and 56,3%, respectively in the FES and FP, showed as host tree. The tree species which had the highest number of individuals were too that which showed the highest host tree number. The host tree species Protium heptaphyllum was related to the higher scores of abundance. The holoepiphytes occured in the majority host trees in...
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Marcusso, Gabriel Mendes. « Epifitismo vascular em duas fisionomias vegetais, floresta paludosa e floresta estacional semidecidual no município de Botucatu, estado de São Paulo, Brasil / ». Rio Claro, 2015. http://hdl.handle.net/11449/123930.
Texte intégralRésumé :
Orientador: Reinaldo MonteiroBanca: Rodrigo de Andrade Kersten
Banca: Alessandra Tomaselli Fidelis
Resumo: O epifitismo vascular é responsável por considerável parcela da biodiversidade dos trópicos. Neste trabalho foi avaliada a composição florística das epífitas vasculares, a distribuição vertical e as relações da comunidade epifítica vascular com seus respectivos forófitos (tipo de ritidoma, altura e diâmetro) em uma floresta paludosa (FP) e uma floresta estacional semidecidual (FES) no município de Botucatu, SP. Para o levantamento florístico foram realizadas coletas mensais durante o período de um ano (junho de 2013 a junho de 2014). As epífitas foram classificadas de acordo com as categorias ecológicas e síndromes de dispersão em que se enquadram. Comparações de similaridades entre a área estudada com outros trabalhos disponíveis na literatura foram realizadas, através do índice de similaridade de Jaccard (modificado). Para a identificação foram utilizados trabalhos taxonômicos, consulta a herbários e a especialistas. O material coletado foi preparado e depositado no Herbário Rioclarense (HRCB). A amostragem para avaliar as relações entre epífitas e forófitos foi realizada em transectos lineares ao longo da área de estudo, utilizando método de quadrantes centrados (PAP ≥ 15 cm). Foram identificadas 87 espécies de epífitas vasculares pertencentes a 51 gêneros e 13 famílias, sendo a FP a fisionomia com maior riqueza. Orchidaceae, Polypodiaceae, Bromeliaceae e Piperaceae foram as famílias mais representativas. 72,4% são anemocóricas e 87,4% holoepífitas obrigatórias. 19,5% das espécies são endêmicas do Domínio Atlântico e 33,3% do Brasil. Sete espécies encontram-se ameaçadas ou quase ameaçadas de extinção. A área estudada foi mais similar a áreas no Paraná, Rio Grande do Sul e Argentina. Das árvores amostradas, 28,2% e 56,3%, respectivamente na FES e na FP, apresentaram-se como suporte para as epífitas. As espécies de árvores que apresentaram os maiores números de indivíduos foram...
Abstract: Vascular epiphytes are responsible for considerable part of tropical biodiversity. In this work was evaluated the floristic composition of vascular epiphytes, the vertical distribution and the relationship among the epiphyte community with the host tree (type of bark, height and diameter) in a swamp forest (FP) and in a seasonal semideciduous forest (FES) in the Botucatu municipality, SP. To the floristic survey were performed monthly collections during the period of one year (june 2013 to june 2014). The epiphytes were classified according with the ecological categories and the dispersion syndrome. Comparisons of the similarity among the study area with others surveys published were carried, using the Jaccard similarity index (modified). For identification were used taxonomic literature, consult to herbarium specimens and experts. The collected specimens were deposited at the Herbário Rioclarense (HRCB). To evaluate the relationship among the epiphytes and the host trees were performed linear transect along the study area, using the quadrant centered method (PAP ≥ 15 cm). Were registered 87 species of vascular epiphytes belonging to 51 genera and 13 families. The FP was the richest phytophysiognomy. Orchidaceae, Polypodiaceae, Bromeliaceae and Piperaceae were the more representative families. 72,4% were anemocoric and 87,4% obligatory holoepiphytes. 19,5 % of the species are endemic for Atlantic Domain and 33,3% from Brazil. Seven species were threatened or near threatened, two of them presumably extinct. The studied area was most similar to sites in Paraná, Rio Grande do Sul and Argentina. Of the trees, 28,2% and 56,3%, respectively in the FES and FP, showed as host tree. The tree species which had the highest number of individuals were too that which showed the highest host tree number. The host tree species Protium heptaphyllum was related to the higher scores of abundance. The holoepiphytes occured in the majority host trees in...
Mestre
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Sousa, Naiara Lopes de [UNESP]. « Composição florística de uma área de campo úmido no município de Analândia, São Paulo ». Universidade Estadual Paulista (UNESP), 2014. http://hdl.handle.net/11449/108712.
Texte intégralRésumé :
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000765472.pdf: 1650159 bytes, checksum: 6ee3284b0e0b7c322b892cbd453f2485 (MD5)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
(Composição florística de uma área de campo úmido da Fazenda Pedra Vermelha, Analândia, São Paulo). A fitofisionomia do campo úmido integra-se ao bioma Cerrado próximo a nascentes e cursos d'água, e em áreas com lençol freático superficial. Devido às condições edáficas particulares que restringem e selecionam as espécies, esse ambiente apresenta uma flora bastante típica. Dentre os elementos que compõem o Cerrado, o estrato herbáceosubarbustivo é o menos contemplado em termos de avaliação florística, com isso a presença de muitas espécies em áreas úmidas ainda pode estar desconhecida. O presente estudo objetivou listar as espécies de plantas vasculares registradas no campo úmido da Fazenda Pedra Vermelha, Analândia e compará-lo com outras áreas campestres alagadas localizadas no estado de São Paulo. A área amostrada possui 5ha e está situada nas coordenadas 22º07'50”-08'01”S e 47º46'40’-53”O, e a 760-770 m de altitude. Foram realizados 18 meses de coletas e a similaridade florística foi calculada através do Índice de Jaccard. Registraramse 178 espécies distribuídas em 121 gêneros e 62 famílias de plantas vasculares. Famílias como Asteraceae (19 espécies), Cyperaceae (15), Poaceae (14), Melastomataceae (13), Xyridaceae e Eriocaulaceae (8) mostraram-se mais diversas. Uma espécie nova para Cyperaceae foi diagnosticada e 7 espécies encontram-se em risco de extinção. A similaridade florística entre o campo úmido amostrado e as quatro áreas comparadas apresentou-se baixa. Os resultados obtidos comprovam uma riqueza florística significativa para o campo úmido da Fazenda Pedra Vermelha
(Floristic composition of an area of moist grassland in Fazenda Pedra Vermelha, Analândia, São Paulo). The moist grassland phyto-physiognomy integrates the Cerrado biome near springs and streams, and in areas with shallow groundwater. This vegetation presents a very typical flora, due the particular soil conditions that restrict and select the species. Among the layers that compose the Cerrado, the herbaceous-subshrub is the least contemplated in terms of floristic evaluation, because the presence of many species in wetlands may still be unknown. The main objective of this study was to record the species of vascular plants in moist grassland in Fazenda Pedra Vermelha, at Analândia municipality, São Paulo state, and to compare the floristic composition with others wetlands areas in this state. The area has 5ha and is located at coordinates 22º07'50”-08'01”S and 47º46'40’-53”O, and at altitudes ranging from 760 to 770 meters. The floristic survey was carried along 18 months. The floristic similarity was calculated using the Jaccard Index. A total of 178 species, 121 genera and 62 families of vascular plants were registered in the area. Asteraceae (19 species), Cyperaceae (15), Poaceae (14) Melastomaceae (13) Xyridaceae and Eriocaulaceae (8) were the most rich families. A new species for Cyperaceae was diagnosed and 7 species endangered were found. The floristic similarity between the wet grassland sampled and the four areas compared was low. The results show a significant floristic richness of the wet grassland at the Fazenda Pedra Vermelha
FAPESP: 12/12772-5
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Sousa, Naiara Lopes de. « Composição florística de uma área de campo úmido no município de Analândia, São Paulo / ». Rio Claro, 2014. http://hdl.handle.net/11449/108712.
Texte intégralRésumé :
Orientador: Julio Antonio LombardiBanca: Leonardo Dias Meireles
Banca: Fátima Regina Gonçalves Salimena
Resumo: (Composição florística de uma área de campo úmido da Fazenda Pedra Vermelha, Analândia, São Paulo). A fitofisionomia do campo úmido integra-se ao bioma Cerrado próximo a nascentes e cursos d'água, e em áreas com lençol freático superficial. Devido às condições edáficas particulares que restringem e selecionam as espécies, esse ambiente apresenta uma flora bastante típica. Dentre os elementos que compõem o Cerrado, o estrato herbáceosubarbustivo é o menos contemplado em termos de avaliação florística, com isso a presença de muitas espécies em áreas úmidas ainda pode estar desconhecida. O presente estudo objetivou listar as espécies de plantas vasculares registradas no campo úmido da Fazenda Pedra Vermelha, Analândia e compará-lo com outras áreas campestres alagadas localizadas no estado de São Paulo. A área amostrada possui 5ha e está situada nas coordenadas 22º07'50"-08'01"S e 47º46'40'-53"O, e a 760-770 m de altitude. Foram realizados 18 meses de coletas e a similaridade florística foi calculada através do Índice de Jaccard. Registraramse 178 espécies distribuídas em 121 gêneros e 62 famílias de plantas vasculares. Famílias como Asteraceae (19 espécies), Cyperaceae (15), Poaceae (14), Melastomataceae (13), Xyridaceae e Eriocaulaceae (8) mostraram-se mais diversas. Uma espécie nova para Cyperaceae foi diagnosticada e 7 espécies encontram-se em risco de extinção. A similaridade florística entre o campo úmido amostrado e as quatro áreas comparadas apresentou-se baixa. Os resultados obtidos comprovam uma riqueza florística significativa para o campo úmido da Fazenda Pedra Vermelha
Abstract: (Floristic composition of an area of moist grassland in Fazenda Pedra Vermelha, Analândia, São Paulo). The moist grassland phyto-physiognomy integrates the Cerrado biome near springs and streams, and in areas with shallow groundwater. This vegetation presents a very typical flora, due the particular soil conditions that restrict and select the species. Among the layers that compose the Cerrado, the herbaceous-subshrub is the least contemplated in terms of floristic evaluation, because the presence of many species in wetlands may still be unknown. The main objective of this study was to record the species of vascular plants in moist grassland in Fazenda Pedra Vermelha, at Analândia municipality, São Paulo state, and to compare the floristic composition with others wetlands areas in this state. The area has 5ha and is located at coordinates 22º07'50"-08'01"S and 47º46'40'-53"O, and at altitudes ranging from 760 to 770 meters. The floristic survey was carried along 18 months. The floristic similarity was calculated using the Jaccard Index. A total of 178 species, 121 genera and 62 families of vascular plants were registered in the area. Asteraceae (19 species), Cyperaceae (15), Poaceae (14) Melastomaceae (13) Xyridaceae and Eriocaulaceae (8) were the most rich families. A new species for Cyperaceae was diagnosed and 7 species endangered were found. The floristic similarity between the wet grassland sampled and the four areas compared was low. The results show a significant floristic richness of the wet grassland at the Fazenda Pedra Vermelha
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Le, Roux Peter Christiaan. « Climate change and vascular plant species interactions on sub-Antarctic Marion island ». Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/3186.
Texte intégralRésumé :
Thesis (PhD (Conservation Ecology and Entomology))--Stellenbosch University, 2008.ENGLISH ABSTRACT: Shifts in species ranges are an important consequence of climate change, and can affect the composition, structure and functioning of ecosystems. Generally, in response to rising temperatures, species have increased their altitudinal and latitudinal distributions along their cooler boundaries, although there has been large variation between species. However, in addition to climatic factors, species range limits are also sensitive to biotic interactions. Therefore, interspecific interactions may be able to influence the impact of climate change on species distributions. In this thesis climate change, range shifts and spatial variation in plant-plant interactions are documented to examine the potential for biotic interactions to mediate climate-driven altitudinal range shifts on sub-Antarctic Marion Island. The climate on Marion Island changed considerably between 1949 and 2003, with significant trends in biologically-relevant parameters encompassing average climatic conditions, variability in climate parameters and extreme weather events. Combining these trends showed that while environmental conditions have ameliorated for some species, they have become more abiotically stressful for others (e.g. hygrophilous species). Concurrent with changes in the island’s climate, there have been rapid changes in the elevational distribution of Marion Island’s native vascular flora. On average species ranges expanded upslope (as predicted in response to the warming experienced on the island), although individual range expansion rates varied greatly. As a result of the idiosyncratic expansion rates, altitudinal patterns of species richness and community composition changed considerably. Therefore, both speciesand community-level changes occurred in the flora of Marion Island, demonstrating the community’s sensitivity to climate change. To determine the potential for interspecific interactions to have mediated these changes in species elevational ranges, spatial variation in the balance of positive and negative plant-plant interactions were examined. Increasing spatial association between four dominant species along an altitudinal severity gradient suggested that the intensity of facilitation, relative to the intensity of competition, is greater under more severe conditions. While, interaction strength varied between species pairs, the nature of relationship was consistent across the species. At a broader spatial scale, the performance of the grass Agrostis magellanica was compared in the presence and in the absence of the cushion plant Azorella selago along the entire altitudinal range of both species. The influence of the cushion plant on A. magellanica switched from negative to positive with increasing environmental severity, reaching a positive asymptote under extreme environmental conditions. Therefore, on Marion Island the spatial variation in the nature of biotic interactions is related to environmental severity, and facilitative interactions can be strong under extreme environmental conditions. These results show that positive biotic interactions are important at higher elevations on Marion Island, and could thus accelerate upslope range expansions in response to climate change. Nonetheless, competitive inhibition of upslope species movement, especially in areas of dense vegetation (i.e. mid or low altitudes), could have the opposite result, acting antagonistically with the effect of rising temperatures. This research highlights the importance of considering interspecific interactions when examining the biotic implications of climate change, both for affecting the rate at which species ranges change and the extent of species distributions.
AFRIKAANSE OPSOMMING: Die verskuiwing van spesies se verspreidingspatrone is ‘n belangrike gevolg van klimaatsverandering en kan die samestelling, struktuur en funksionering van ekosisteme affekteer. Oor die algemeen, in reaksie op verwarming, kom spesies op hoër hoogtes bo seespieël en hoër breedtegrade voor, alhoewel daar groot verskille tussen spesies in hierdie aspek is. Behalwe vir klimatologiese faktore, is spesies se verspreidingslimiete ook sensitief vir biotiese interaksies met ander spesies. Daarom kan interaksies tussen spesies die effek van klimaatsverandering op spesiesverspreiding verder beïnvloed. In hierdie verhandeling word klimaatsverandering, verandering in verspreiding van spesies en geografiese variasie in plant-plant interaksies ondersoek. Dit word gedoen ten einde die moontlikheid te toets dat biotiese interaksies die verandering in verspreidingspatrone van klimaat gedrewe spesies op sub-Antarktiese Marion Eiland beïnvloed. Marion Eiland se klimaat het aansienlik tussen 1949 en 2003 verander, met betekenisvolle neigings in biologies-relevante parameters, insluitend gemiddelde klimaatstoestande, variasie in klimaat en uiterste weerstoestande. As die veranderinge saam beskou word, wys dit dat, terwyl omgewingstoestande vir sommige spesies verbeter het, toestande vir ander spesies abioties meer ongunstig geword het (bv. akwatiese plantsoorte). Tesame met die veranderinge in die eiland se klimaat, het die hoogte bo seespieël verspreiding van Marion Eiland se inheemse vaatplante vinnig verander. Gemiddeld het spesies-verspreiding se hoogte bo seespieël na hoër hoogtes verskuif (soos voorspel in reaksie op verwarming), alhoewel die tempo van verskuiwing na hoër hoogtes tussen spesies verskil het. As gevolg van hierdie idiosinkratiese reaksies, het die aantal en samestelling van plant spesies op verskillende hoogtes op die eiland aansienlik verander. Die sensitiwiteit van Marion Eiland se flora ten opsigte van klimaatsverandering word deur hierdie verandering gedemonstreer. Om te bepaal of die interaksies tussen spesies verspreidingspatrone kan beïnvloed, is die geografiese variasie in die balans van positiewe en negatiewe interaksies ondersoek. Vier dominante vaatplante het meer geassosieerd geraak hoe hoër hulle bo seespieël voorgekom het. Dit is ‘n aanduiding dat die sterkte van die positiewe interaksies (fasilitering), relatief tot die sterkte van die negatiewe reaksie (kompetisie), groter onder uiterste omgewingstoestande is. Die sterkte van die interaksie het verskil tussen spesies pare, maar die verhouding tussen omgewingstoestande en die sterkte van die interaksie was dieselfde vir alle spesies. Op ‘n breër geografiese vlak is die opbrengs van die gras Agrostis magellanica in die teenwoordigheid en afwesigheid van die polsterplant Azorella selago op alle hoogtes waar die plante saam voorkom vergelyk. Die invloed van A. selago op A. magellanica was negatief op lae hoogtes bo seespieël, maar het meer positief geraak met ‘n toename in hoogte bo seespieël, tesame met omgewingshardheid. Die invloed van die polsterplant op die gras het ‘n positiewe asimptoot onder uiterste omgewingstoestande bereik. Dus, op Marion Eiland is die geografiese variasie in biotiese interaksies verwant aan omgewingstoestande, en positiewe interaksies kan selfs onder die uiterste omgewingstoestande sterk wees. Hierdie resultate wys dat positiewe biotiese interaksies tussen plante belangrik is by hoër hoogtes bo seespieël op Marion Eiland. Die interaksies kan dus die opwaartse verspreiding van spesies in reaksie op klimaatsverandering versnel. Nogtans kan negatiewe interaksies die teenoorgestelde effek hê aangesien kompetisie tussen plante, veral in plekke met digte plantegroei (d.w.s. lae of middel hoogtes bo seespieël) opwaartse verskuiwing van spesies kan verhinder. Hierdie navorsing dui aan hoe belangrik dit is om interaksies tussen spesies in ag te neem, aangesien die interaksies die tempo en omvang van veranderinge in verspreiding kan beïnvloed.
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Wood, Troy E. « Plant speciation (I) Species delimitation and pollinator driven floral evolution in the Giliopsis group of Ipomopsis (Polemoniaceae). (II) Polyploidy and vascular plant diversity / ». [Bloomington, Ind.] : Indiana University, 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3354925.
Texte intégralRésumé :
Thesis (Ph.D.)--Indiana University, Dept. of Biology, 2009.Title from PDF t.p. (viewed on Feb. 5, 2010). Source: Dissertation Abstracts International, Volume: 70-04, Section: B, page: 2009. Adviser: Loren H. Rieseberg.
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Joanitti, Sabrina Anselmo [UNESP]. « Epifitismo vascular em três formações vegetais distintas : mata do brejo, floresta estacional semidecidual e cerradão, pertencentes ao município de Bauru, estado de São Paulo ». Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/108508.
Texte intégralRésumé :
Made available in DSpace on 2014-08-13T14:50:41Z (GMT). No. of bitstreams: 0
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000749216.pdf: 1944094 bytes, checksum: 6a91ff9dd9361601439833f0bb687018 (MD5)Epífitas são plantas autotróficas, vasculares, que germinam, enraízam e crescem utilizando-se de outras como suporte. Na interação conhecida como epifitismo vascular, a epífita utiliza-se apenas do substrato fornecido pela planta portadora, sendo independente do forófito na obtenção de nutrientes e água. As epífitas contribuem para a diversidade biológica nas comunidades vegetais, desempenham um papel importante na produtividade primária e na ciclagem de nutrientes, podem ser indicadoras ecológicas do estádio sucessional da floresta e são essenciais nos processos de recuperação de áreas degradadas e enriquecimento florestal. O recente reconhecimento do dossel das florestas tropicais como um dos celeiros da biodiversidade do planeta tem incentivado estudos que procuram entender os processos ligados à comunidade epifítica, destacando o seu papel na funcionalidade dos ecossistemas. Além disso, poucos estudos sobre epífitas no Brasil foram realizados no cerradão, na floresta estacional semidecidual sem influência fluvial e na floresta estacional semidecidual com influência fluvial permanente (mata de brejo), ocorrentes em uma mesma região, onde não há constância de umidade relativa do ar ao longo do ano. Estas formações vegetais ocorrem no município de Bauru e foram selecionadas como áreas de estudo para o desenvolvimento desta pesquisa. O intuito desta dissertação é contribuir para o conhecimento da composição florística e estrutura do componente epifítico nas três formações vegetais, analisando a similaridade florística, a diversidade e a distribuição vertical
Epiphytes are autotrophic vascular plants that germinate, take root and grow on other plants for support. In the interaction known as vascular epiphytism, the epiphyte uses only the substrate provided by the host plant, being independent of the phorophyte for water and nutrition. Epiphytes contribute to biological diversity in plant communities, play an important role in primary productivity and nutrient cycling, may be ecological indicators of successional stage of the forest and are essential in the process of degraded areas recovery and forest enrichment. The recent recognition of the tropical forest canopy as storehouses of biodiversity on the planet has encouraged studies that seek to understand the processes involved in epiphytic community, highlighting their role in ecosystem function. In addition, few studies about epiphytes in Brazil were carried out in the cerradão (woodland savanna), in the seasonal semideciduous forest without fluvial influence and, in the seasonal semideciduous forest with permanent fluvial influence (swamp forest) occurring in the same region, where there is no air relative humidity constancy throughout the year. These plant formations occur in the municipality of Bauru and were selected as study areas for the development of this research. The purpose of this dissertation is to contribute to the knowledge of the floristic composition and structure of the epiphytic component in the three plant formations, analyzing the floristic similarity, diversity and vertical distribution
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Joanitti, Sabrina Anselmo. « Epifitismo vascular em três formações vegetais distintas : mata do brejo, floresta estacional semidecidual e cerradão, pertencentes ao município de Bauru, estado de São Paulo / ». Botucatu, 2013. http://hdl.handle.net/11449/108508.
Texte intégralRésumé :
Orientador: Silvia Machado RodriguesCoorientador: Veridiana de Lara Weiser Bramante
Banca: Reinaldo Monteiro
Banca: Ana Odete Santos Silveira
Banca: Suzana Bissacot Barbosa
Banca: Anne Ligia Dokkedal Bosqueiro
Resumo: Epífitas são plantas autotróficas, vasculares, que germinam, enraízam e crescem utilizando-se de outras como suporte. Na interação conhecida como epifitismo vascular, a epífita utiliza-se apenas do substrato fornecido pela planta portadora, sendo independente do forófito na obtenção de nutrientes e água. As epífitas contribuem para a diversidade biológica nas comunidades vegetais, desempenham um papel importante na produtividade primária e na ciclagem de nutrientes, podem ser indicadoras ecológicas do estádio sucessional da floresta e são essenciais nos processos de recuperação de áreas degradadas e enriquecimento florestal. O recente reconhecimento do dossel das florestas tropicais como um dos celeiros da biodiversidade do planeta tem incentivado estudos que procuram entender os processos ligados à comunidade epifítica, destacando o seu papel na funcionalidade dos ecossistemas. Além disso, poucos estudos sobre epífitas no Brasil foram realizados no cerradão, na floresta estacional semidecidual sem influência fluvial e na floresta estacional semidecidual com influência fluvial permanente (mata de brejo), ocorrentes em uma mesma região, onde não há constância de umidade relativa do ar ao longo do ano. Estas formações vegetais ocorrem no município de Bauru e foram selecionadas como áreas de estudo para o desenvolvimento desta pesquisa. O intuito desta dissertação é contribuir para o conhecimento da composição florística e estrutura do componente epifítico nas três formações vegetais, analisando a similaridade florística, a diversidade e a distribuição vertical
Abstract: Epiphytes are autotrophic vascular plants that germinate, take root and grow on other plants for support. In the interaction known as vascular epiphytism, the epiphyte uses only the substrate provided by the host plant, being independent of the phorophyte for water and nutrition. Epiphytes contribute to biological diversity in plant communities, play an important role in primary productivity and nutrient cycling, may be ecological indicators of successional stage of the forest and are essential in the process of degraded areas recovery and forest enrichment. The recent recognition of the tropical forest canopy as storehouses of biodiversity on the planet has encouraged studies that seek to understand the processes involved in epiphytic community, highlighting their role in ecosystem function. In addition, few studies about epiphytes in Brazil were carried out in the cerradão (woodland savanna), in the seasonal semideciduous forest without fluvial influence and, in the seasonal semideciduous forest with permanent fluvial influence (swamp forest) occurring in the same region, where there is no air relative humidity constancy throughout the year. These plant formations occur in the municipality of Bauru and were selected as study areas for the development of this research. The purpose of this dissertation is to contribute to the knowledge of the floristic composition and structure of the epiphytic component in the three plant formations, analyzing the floristic similarity, diversity and vertical distribution
Mestre
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Sennblad, Adina. « Effects of past fragmentation and habitat loss and current management methods on the changes in vascular plant communities. : An evaluation of extinction debt in semi-natural grasslands in Sweden ». Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-447366.
Texte intégralRésumé :
Habitat loss and fragmentation are believed to be two of the main reasons for high extinction rates of species, resulting in decreased biodiversity. According to the island biogeography theory, the species richness in a patch, here a semi-natural grassland, is dependent on the landscape composition, and therefore changes in the landscape composition will result in changes in the species richness of the grassland. However, this change in species richness may be delayed for several years, causing an extinction debt. The aim of this study was to examine the change of species richness of vascular plants in Swedish semi-natural grasslands between 2007 and 2020 and investigate if there is evidence of an extinction debt and evaluate what factors causes changes in the plant community. Data of species richness and occurrence for 40 semi-natural grasslands, as well as data of landscape changes in area and connectivity between the 1950:s and the 2000:s for these grasslands, were analysed. This study found that changes in species richness in semi-natural grasslands were affected by the changes in connectivity of the landscape. However, the effect depended on the degree of specialisation of the species to semi-natural grassland. Between 2007 and 2020, the species richness of semi- natural grasslands specialist decreased, while the species richness of non-specialist species increased. This resulted in a mean increase of overall species richness between 2007 and 2020. Observed immigration of new non-specialist species appears to suggest that, not only the connectivity, but also the habitat types in the matrix surrounding the semi-natural grasslands may substantially influence the species composition in the grassland; this is in contrast to what is predicted by the original theory of island biogeography. Species that were classified as specialist were more vulnerable to ceased management, such as grazing, than to area and connectivity decrease. This was likely because the ceased management increased the competition for light. The results also indicated that re-established management of abandoned grasslands may increase specialist species richness, highlighting the need for management actions taken in order to reverse extinction debt.
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Schuettpelz, Eric. « Evolution and diversification of epiphytic ferns ». Diss., View online, 2007. http://hdl.handle.net/10161/181.
Texte intégral
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Affeld, Kathrin. « Spatial complexity and microclimatic responses of epiphyte communities and their invertebrate fauna in the canopy of northern rata (Metrosideros robusta A. Cunn. : Myrtaceae) on the West Coast of the South Island, New Zealand ». Diss., Lincoln University, 2008. http://hdl.handle.net/10182/771.
Texte intégralRésumé :
Rain forest canopies are renowned for their very high biodiversity and the critical role they play in key ecological processes and their influence on global climate. Despite that New Zealand supports one of the most diverse and extensive epiphyte flora of any temperate forest system, few studies have investigated epiphyte communities and their invertebrate fauna along with factors that influence their distribution and composition. This thesis represents the first comprehensive study of entire epiphyte communities and their resident invertebrate fauna in the canopy of New Zealand’s indigenous forests. The aim of this study was to determine spatial patterns of epiphyte and invertebrate species richness, abundance and community composition in relation to abiotic variables, and in particular, the responses of these communities to elevated temperature and rainfall. This study was carried out in coastal lowland podocarp-broadleaved forests at two sites on the West Coast of the South Island of New Zealand. Samples from 120 mat-forming epiphyte assemblages located on inner canopy branches of 40 northern rata (Metrosideros robusta) trees were studied to characterise the component flora and fauna. Additionally, biomass, branch and tree characteristics and community responses to treatments designed to elevate temperature and rainfall to simulate predicted climate change were measured. This investigation revealed astonishing diversity and functional complexity of epiphyte and invertebrate life in this ecosystem. The 30.6 kg (dry weight) of epiphyte material collected contained a total of 567 species, 170 epiphyte and 397 invertebrate (excluding immature specimens and mites) species, including at least 10 species new to science and many undescribed species Epiphyte communities were found to be dominated by non-vascular plants (80 % of the total species richness), particularly liverworts and invertebrate communities were dominated with respect to abundance (~ 80 % of the total individuals) by Acari, Collembola and Hymenoptera (primarily ants) and functionally by scavengers and ants. Epiphyte and invertebrate communities were highly variable with respect to spatial patterning of species richness, abundance and composition across sites, among trees within sites and among branches within trees. Overall, a highly significant proportion, > 75 %, of the variance could be attributed to differences at the branch level, but these differences could not be explained by the environmental factors measured. There were no consistent relationships between the spatial pattern of epiphytes and invertebrates, or between vascular and non-vascular plants. However, there were significant positive correlations between epiphyte biomass and invertebrate species richness (r = 0.472; p < 0.0001) and abundance (r = -0.395; p < 0.0001), as well as non-living epiphyte biomass and scavenger species richness (r = 0.4; p < 0.0001). Microclimatic measurements taken on epiphyte mats were also highly variable with respect to temperature and relative humidity at similar physical locations within the same tree as well as across trees within sites. There was also considerable variation in the intensity and frequency of climatic extremes, although potentially harmful climatic conditions were experienced by all the epiphyte mats for which weather variables were measured. Negative correlations existed between both epiphyte and invertebrate community composition and increased temperatures expressed as cumulative degree days above 5˚C. However, variability was such that there was no direct evidence that increased temperature and rainfall treatments had an effect on invertebrate species richness, abundance or diversity. Northern rata host trees harbour an astonishingly diverse and complex canopy flora and fauna that is characterised by high spatial variability. Such variability highlights that to determine species distribution and community dynamics in canopy habitats in response to disturbance caused either by climate change or invasive species the structure of entire communities at different taxonomic and spatial scales, along with their responses to microclimatic factors, need to be studied. If such complexities are not taken into account, inappropriate interpretation may result in poor decisions concerning the conservation status, vulnerability and subsequent management of such unique ecosystems.
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Clifford, Philip A. (Philip Alan). « Aquatic Vegetation Nutrient Budgets and Sedimentation in a Southwestern Reservoir ». Thesis, North Texas State University, 1986. https://digital.library.unt.edu/ark:/67531/metadc504467/.
Texte intégralRésumé :
During four growing seasons, aquatic vascular plant production and distribution were studied in Pat Mayse Lake, Texas, a 2425 hectare oligo-mesotrophic reservoir. The dominant macrophyte population was Myriophyllum spicatum L. Growth rates and regrowth rates of mechanically harvested Myriophyllum beds were found to be dissimilar. Based on estimates of watermilfoil nutrient content, there were insufficient nutrients in the entire population to alter the trophic status of this reservoir should all of the nutrients be instantaneously released. Sediments were the primary nutrient (nitrogen and phosphorus) sink. Bank erosion and solids transport from the watershed appear to contribute most of the sediments and a lake-wide mean sedimentation rate of 2.5 cm/year was estimated from sediment trap and core sample data.
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LOPES, Amanda Sibele da Silva. « Florística, influência altitudinal e aspectos ecológicos das samambaias ocorrentes na RPPN Pedra D’Antas (Lagoa dos Gatos, Pernambuco, Brasil) ». Universidade Federal de Pernambuco, 2013. https://repositorio.ufpe.br/handle/123456789/20185.
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Este estudo teve como objetivo apresentar dados relacionados à florística, à influência altitudinal e aos aspectos ecológicos das samambaias na RPPN Pedra D´antas, localizada no município de Lagoa dos Gatos, Pernambuco, Brasil. Para a execução deste estudo, foram realizadas três excursões semanais (oito horas diárias), nas quais o fragmento foi explorado através de caminhadas, priorizando os habitats onde as samambaias ocorrem com maior frequência. Os processos de coleta, identificação e herborização do material seguiram a literatura especializada. Na RPPN Pedra D’Antas foram registradas 82 espécies de samambaias, distribuídas em 37 gêneros e 17 famílias, Pteridaceae (20 spp.), Polypodiaceae (15 spp.) e Dryopteridaceae (10 spp.), as mais representativas. Os gêneros com maior número de espécies foram Adiantum e Thelypteris, com 10 e sete espécies, respectivamente. A riqueza específica variou entre as faixas altitudinais, sendo maior na faixa entre 600-700 m com 63 espécies, e a menor representatividade foi registrada na faixa entre 400-500 m com 15 espécies. A variação altitudinal também ocasionou modificação na composição florística, principalmente entre a faixa 400-500 com as demais. Estes dados indicam uma riqueza de samambaias importante no contexto da Floresta Atlântica Nordestina, além de demonstrar a influência da altitude nos aspectos ecológicos destas plantas.
This paper aimed present data related to floristc survey, the altitudinal influence and ecological aspects of ferns in the RPPN Pedra D´Antas, located in the municipality of Lagoa dos Gatos, Pernambuco, Brazil. For the execution of this study, there were three excursions per week (eight hours) to field works, in which the fragment was explored prioritizing habitats where ferns occur with greater frequency. The processes of collecting, identifying and herborization material followed the literature. In RPPN Pedra D'Antas were recorded 82 species of ferns, belonging to 37 genera and 17 families, Pteridaceae (20 spp.), Polypodiaceae (15 spp.) and Dryopteridaceae (10 spp.) were the most representative. The richest genera were Adiantum and Thelypteris, with 10 and seven species, respectively. The richness varied between altitudinal zones, being higher in the range between 600-700 m with 63 species, and the lowest representation was recorded in the range of 400-500 m with 15 species. The altitudinal variation also resulted in changes in the floristic composition, especially between the 400-500 range with the other. These data indicate a richeness of ferns important in the context of the Northeastern Atlantic Forest, as well as demonstrating the influence of altitude on the ecological aspects of these plants.
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Mania, Luiz Felipe [UNESP]. « Composição florística de comunidades epifíticas vasculares em unidades de conservação no Estado de São Paulo ». Universidade Estadual Paulista (UNESP), 2012. http://hdl.handle.net/11449/100671.
Texte intégralRésumé :
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mania_lf_dr_rcla.pdf: 1318863 bytes, checksum: b36c6e75fcc3ef4a1eb86560a9e0d29e (MD5)O epifitismo é uma relação ecológica interespecífica harmônica do tipo inquilinismo que ocorre entre espécies vegetais, onde umas beneficiam-se do substrato e suporte proporcionados por outras espécies sem que haja prejuízo para esta última. Tal interação biológica é responsável por grande parte da riqueza específica das florestas tropicais úmidas. Além disso, as plantas epífitas desempenham importantes funções como proporcionar recursos alimentares e abrigo para uma grande variedade de organismos componentes da fauna de dossel. Em algumas espécies, o acúmulo de água parada entre suas folhas proporciona o ambiente ideal para que um grande número de invertebrados completem seus ciclos de vida. No entanto, a coleta predatória de espécies com potencial econômico e a redução do hábitat das epífitas devido a atividades extrativistas nas florestas tem causado uma redução na população dessas plantas. Este estudo abordou as formações vegetacionais do bioma Mata Atlântica (Florestas Ombrófilas Densa e Mista, Floresta Estacional Semidecidual, Restinga e Manguezal) e áreas de Cerrado paulistas, em virtude da grande diversidade desses ambientes e do grau de perturbação a que estão sujeitos. Através de estudos florísticos, tem-se uma base para o conhecimento da flora de uma determinada área e subsídios para o planejamento e a implementação de áreas para conservação. Dessa forma, este estudo realizou um levantamento florístico da comunidade epifítica vascular em sete Unidades de Conservação do estado de São Paulo, totalizando 250 espécies, 90 gêneros e 21 famílias de epífitas vasculares. Informações acerca das categorias ecológicas, síndromes de polinização e de dispersão foram analisadas para cada espécie...
The epiphytism is an ecological harmonic interspecific relationship inquilinism type that occurs between plants species, where some benefit from the substrate and support provided by other species without prejudice to the latter. Such biological interaction is responsible for much of the richness of rainforests. Moreover, the epiphytic plants have important roles as providing food resources and shelter for a wide variety of fauna organisms components canopy. In some species, the accumulation of stagnant water between their leaves provides the ideal environment for a large number of invertebrates complete their life cycles. However, the predation of species with economic potential and reducing the habitat of epiphytes due to extractive activities in forests has caused a reduction in the population of these plants. This study approached the vegetation formations of the Atlantic Forest biomes (Ombrophilous Dense Forest, Mixed Ombrophilous Forest, Semideciduous Forest, Restinga and Mangrove) and Cerrado areas of São Paulo, because of the great diversity of these environments and the degree of disturbance to which they are subject. Through floristic studies, there is a basis for the knowledge of the flora of a particular area, and subsidies for planning and implementation of conservation areas. Thus, this study conducted a floristic survey of vascular epiphyte community in seven Conservation Units of São Paulo State, totaling 250 species, 90 genera and 21 families of vascular epiphytes. Information about the ecological categories, pollination and dispersion syndromes were analyzed for each species. In addition, listings of species produced by other studies for the same analyzed regions were complemented and... (Complete abstract click electronic access below)
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Mania, Luiz Felipe. « Composição florística de comunidades epifíticas vasculares em unidades de conservação no Estado de São Paulo / ». Rio Claro, 2013. http://hdl.handle.net/11449/100671.
Texte intégralRésumé :
Orientador: Julio Antonio LombardiBanca: Rodrigo de Andrade Kersten
Banca: Paulo Gunter Windisch
Banca: Rafaela Campostrini Forzza
Banca: Marco Antônio de Assis
Resumo: O epifitismo é uma relação ecológica interespecífica harmônica do tipo inquilinismo que ocorre entre espécies vegetais, onde umas beneficiam-se do substrato e suporte proporcionados por outras espécies sem que haja prejuízo para esta última. Tal interação biológica é responsável por grande parte da riqueza específica das florestas tropicais úmidas. Além disso, as plantas epífitas desempenham importantes funções como proporcionar recursos alimentares e abrigo para uma grande variedade de organismos componentes da fauna de dossel. Em algumas espécies, o acúmulo de água parada entre suas folhas proporciona o ambiente ideal para que um grande número de invertebrados completem seus ciclos de vida. No entanto, a coleta predatória de espécies com potencial econômico e a redução do hábitat das epífitas devido a atividades extrativistas nas florestas tem causado uma redução na população dessas plantas. Este estudo abordou as formações vegetacionais do bioma Mata Atlântica (Florestas Ombrófilas Densa e Mista, Floresta Estacional Semidecidual, Restinga e Manguezal) e áreas de Cerrado paulistas, em virtude da grande diversidade desses ambientes e do grau de perturbação a que estão sujeitos. Através de estudos florísticos, tem-se uma base para o conhecimento da flora de uma determinada área e subsídios para o planejamento e a implementação de áreas para conservação. Dessa forma, este estudo realizou um levantamento florístico da comunidade epifítica vascular em sete Unidades de Conservação do estado de São Paulo, totalizando 250 espécies, 90 gêneros e 21 famílias de epífitas vasculares. Informações acerca das categorias ecológicas, síndromes de polinização e de dispersão foram analisadas para cada espécie... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The epiphytism is an ecological harmonic interspecific relationship inquilinism type that occurs between plants species, where some benefit from the substrate and support provided by other species without prejudice to the latter. Such biological interaction is responsible for much of the richness of rainforests. Moreover, the epiphytic plants have important roles as providing food resources and shelter for a wide variety of fauna organisms components canopy. In some species, the accumulation of stagnant water between their leaves provides the ideal environment for a large number of invertebrates complete their life cycles. However, the predation of species with economic potential and reducing the habitat of epiphytes due to extractive activities in forests has caused a reduction in the population of these plants. This study approached the vegetation formations of the Atlantic Forest biomes (Ombrophilous Dense Forest, Mixed Ombrophilous Forest, Semideciduous Forest, Restinga and Mangrove) and Cerrado areas of São Paulo, because of the great diversity of these environments and the degree of disturbance to which they are subject. Through floristic studies, there is a basis for the knowledge of the flora of a particular area, and subsidies for planning and implementation of conservation areas. Thus, this study conducted a floristic survey of vascular epiphyte community in seven Conservation Units of São Paulo State, totaling 250 species, 90 genera and 21 families of vascular epiphytes. Information about the ecological categories, pollination and dispersion syndromes were analyzed for each species. In addition, listings of species produced by other studies for the same analyzed regions were complemented and... (Complete abstract click electronic access below)
Doutor
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Maliniemi, T. (Tuija). « Decadal time-scale vegetation changes at high latitudes:responses to climatic and non-climatic drivers ». Doctoral thesis, Oulun yliopisto, 2018. http://urn.fi/urn:isbn:9789526220123.
Texte intégralRésumé :
Abstract Boreal and arctic plant communities are responding to anthropogenic climate change that has been exceptionally rapid during the recent decades. General responses include increased productivity, range expansions and biodiversity changes, all of which affect ecosystem functions. Vegetation dynamics are however controlled by multiple drivers, and the outcomes under the changing climate are not yet fully clear. As high latitude areas often lack long-term monitoring of vegetation, alternative methods are required to observe and understand vegetation changes and dynamics. Recently, resurveying historical vegetation data has become a valuable method of studying vegetation changes over the past few decades. In this thesis, I studied multidecadal (23–60 years) vegetation changes in forest and treeless heath and tundra plant communities along a latitudinal gradient in northern Fennoscandia using both vegetation resurveys and long-term experimental data. In addition to examining climate-driven vegetation changes, I related changes in plant communities to key local drivers of each context including mesotopography, grazing, soil moisture and soil fertility. General trends among the resurveyed treeless heath sites were the pronounced increase of the dwarf shrub Empetrum nigrum ssp. hermaphroditum in snow-protected habitats and the decrease of lichens throughout. Southernmost heath communities showed strong responses to multidriver effects and had shifted towards new community states. The long-term experiment in the tundra confirmed that depending on driver combinations, tundra communities evolve towards divergent alternative states, highlighting the importance of local drivers in modifying tundra vegetation over time. Communities in fertile forest sites experienced greater temporal turnover compared to infertile forest sites, suggesting that the soil fertility level is a key predictor of vegetation changes under climate change. This particularly important finding previously relied mainly on experimental evidence. Despite these generalities, changes in diversity, plant groups and species varied under a rather uniform climatic warming trend and were often habitat- or region-specific. Thus, the results of my thesis highly motivate continued monitoring and resurveying of vegetation under rapid environmental change and also form baseline time-series data for future studiesTiivistelmä Poikkeuksellisen nopea ilmastonmuutos on johtanut viime vuosikymmenten aikana muutoksiin boreaalisissa ja arktisissa kasviyhteisöissä. Muutoksiin lukeutuvat tuottavuuden lisääntyminen, levinneisyysrajojen siirtyminen sekä muutokset biodiversiteetissä, mitkä kaikki muuttavat ekosysteemien toimintaa. Kasvillisuuden dynamiikkaa säätelevät kuitenkin useat paikallistason tekijät, minkä seurauksena ei ole täysin selvää, miten kasvillisuus on eri alueilla ja habitaateissa muuttunut. Koska kasvillisuuden jatkuva monitorointi on harvinaista pohjoisilla alueilla, vanhojen kasvillisuusaineistojen uudelleenkartoituksista on tullut tärkeä menetelmä muutosten havaitsemiseksi. Tutkin väitöskirjassani vuosikymmenten kuluessa tapahtuneita (23–60 vuotta) kasvillisuusmuutoksia Pohjois-Fennoskandian metsissä, puuttomilla kankailla ja tundralla uudelleenkartoitusten ja kokeellisen tutkimuksen avulla, ja kytkin ne ilmastonmuutokseen sekä tärkeimpiin paikallisiin tekijöihin. Yleisiä trendejä uudelleenkartoitetuilla puuttomilla kankailla olivat variksenmarjan (Empetrum nigrum ssp. hermaphroditum) voimakas lisääntyminen lumensuojaisissa habitaateissa sekä jäkälien väheneminen kaikkialla. Yhteisöjen kokonaismuutos oli voimakkainta eteläisillä puuttomilla kankailla, jossa se korreloi yhtä aikaa lisääntyneiden lämpötilojen ja laidunpaineen kanssa. Kokeellinen tutkimus tundralla osoitti, että kasviyhteisöt kehittyvät hyvin erilaisiksi paikallisten tekijöiden voimakkuussuhteista riippuen, jotka voivat joko hidastaa tai nopeuttaa ympäristömuutoksista johtuvia kasvillisuusmuutoksia. Metsien uudelleenkartoitus osoitti yhteisöjen kokonaismuutoksen olevan pitkällä aikavälillä suurempaa tuottavilla maaperillä lehtometsissä verrattuna karumpiin kangasmetsiin. Tutkimuksen mukaan maaperän tuottavuus on avaintekijä, joka ennustaa kasvillisuusmuutosten voimakkuutta ilmastonmuutoksen aikana. Tästä tärkeästä löydöstä oli aiemmin pääasiassa vain kokeellista tutkimustietoa. Yleisistä trendeistä huolimatta, muutokset diversiteetissä, kasviryhmissä ja yksittäisissä lajeissa olivat kuitenkin vaihtelevia ja usein habitaatti- tai aluesidonnaisia. Väitöskirjani tulokset, jotka muodostavat myös aikasarjan tuleville tutkimuksille, osoittavat kasvillisuuden monitoroinnin ja uudelleenkartoitusten olevan ensisijaisen tärkeitä, jotta kasvillisuuden dynamiikkaa voidaan ymmärtää paremmin nopeasti muuttuvissa olosuhteissa
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Rai, Hardeep Singh. « Molecular phylogenetic studies of the vascular plants ». Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/3889.
Texte intégralRésumé :
To investigate vascular-plant phylogeny at deep levels of relationship, I collected and analyzed a large set of plastid-DNA data comprising multiple protein-coding genes and associated noncoding regions. I addressed questions relating to overall tracheophyte phylogeny, including relationships among the five living lineages of seed plants, and within two of the largest living gymnosperm clades (conifers and cycads). I also examined relationships within and among the major lineages of monilophytes (ferns and relatives), including their relationship to the remaining vascular plants. Overall, I recovered three well-supported lineages of vascular plants: lycophytes, monilophytes, and seed plants. I inferred strong support for most of the phylogenetic backbones of cycads and conifers. My results suggest that the cycad family Stangeriaceae (Stangeria and Bowenia) is not monophyletic, and that Stangeria is instead more closely related to Zamia and Ceratozamia. Within the conifers, I found Pinaceae to be the sister-group of all other conifers, and I argue that two conifer genera, Cephalotaxus and Phyllocladus (often treated as monogeneric families) should be recognized under Taxaceae and Podocarpaceae, respectively. Systematic error likely affects inference of the placement of Gnetales within seed-plant phylogeny. As a result, the question of the relationships among the five living seed-plant groups still remains largely unresolved, even though removal of the most rapidly evolving characters appears to reduce systematic error. Phylogenetic analyses that included these rapidly evolving characters often led to the misinference of the “Gnetales-sister” hypothesis (Gnetales as the sister-group of all other seed plants), especially when maximum parsimony was the inference method. Filtering of rapidly evolving characters had little effect on inference of higher-order relationships within conifers and monilophytes, and generally resulted in reduced support for backbone relationships. Within the monilophytes, I found strong support for the majority of relationships along the backbone. These were generally congruent with other recent studies. Equisetaceae and Marattiaceae may be, respectively, the sister-groups of the remaining monilophytes and of the leptosporangiate ferns, but relationships among the major monilophyte lineages are sensitive to the outgroups used, and to long branches in lycophytes.
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Sutherland, Margery Louise. « Recognition of host plants by vascular pathogens ». Thesis, University of Reading, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303155.
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Kücükoglu, Melis. « CLE/RLK regulated vascular signalling pathways in plants ». Thesis, Umeå University, Plant Physiology, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-26276.
Texte intégralRésumé :
Entire postembryonic production of plant tissues are maintained by meristems. These specialized structures provide a pool of undifferentiated stem cells and a limited population of proliferating cells which are destined for differentiation in order to generate a variety of tissues in the plant body. For the forest trees, a large part of the biomass is produced by a secondary meristem called vascular cambium. Vascular cambium forms a continuous cylinder of meristematic cells in the stem, producing both secondary phloem and secondary xylem or wood. Maintenance and differentiation of meristems are much conserved and strictly regulated for the production of correct tissues and organs. Receptor-like kinases (RLKs) are characterized by the presence of a signal sequence, a putative amino-terminal extracellular domain connected to a carboxyl-terminal intracellular kinase domain with a trans-membrane domain. They control a wide-range of physiological processes, including development, disease resistance, hormone perception, and self-incompatibility. Leucine-rich repeat receptor-like kinases (LRR-RLKs) represent the largest group of RLKs in the Arabidopsis thaliana genome, with more than 200 members.Several LRR-RLKs and their putative ligands CLAVATA3 (CLV3)/ Endosperm Surrounding Region (ESR)-related (CLE) peptides have been found to be involved in the regulation of vascular development. In the current study, the main aim was to study the tissue-specific expression patterns of LRR-RLK genes in A. thaliana by generating promoter::GUS transcriptional fusions. The results confirmed that these genes are expressed in the vasculature of the plants. Moreover, Populus orthologs of the CLE genes were detected by bioinformatic tools as putative ligands of LRR-RLKs and an extensive quantitative Real-Time Reverse Transcriptase PCR (qRT-PCR) analysis was performed to test for significant changes in transcript levels across different tissue types. As a result, a collection of potential candidate genes for vascular development were identified.
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Gersbach, Paul Vincent, University of Western Sydney et of Science Technology and Environment College. « Aspects of essential oil secretion in vascular plants ». THESIS_CSTE_XXX_Gersbach_P.xml, 2001. http://handle.uws.edu.au:8081/1959.7/775.
Texte intégralRésumé :
A study of some aspects of essential oil secretion in plants was conducted. The first part of the study involved analysis of the volatile terpenoid content and composition of leaf extracts from a range of Australian native plants by gas chromatography and mass spectrometry. Secretory structures were studied by several microscopic imaging techniques including conventional bright and dark field optical microscopy, confocal microscopy, and scanning (SEM) and transmission (TEM) electron microscopy. Three methods were employed for scanning electron microscopy. Sample material was prepared for conventional SEM by chemical fixation and rapid freeze fixation, and fresh material was imaged by environmental SEM. These methods were compared, and the images acquired by environmental SEM were invariably of a superior standard as the biological integrity of the samples was retained throughout, and the samples were free of process-induced artefacts. Several other tests were conducted and results discussed in some detail. In the final part of the study, aspects of essential oil secretion were examined by histochemical methods. The first of these was a new method based on traditional approaches to histochemistry. The monoterpene phenols thymol and carvacrol were located in glandular trichomes of Lamiaceae species by means of a colour-change reaction of the phenols with a nitrosophenol/acid reagent. The second used magnetic resonance imaging by a chemical shift selective method to locate, non invasively, the aromatic monoterpenes thymol and anethole in secretory structures in the fruit of Carum copticum (Apiaceae) and the leaves of Backhousia anisata (Myrtaceae) respectively.Doctor of Philosophy (PhD) (Science)
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Gersbach, Paul V. « Aspects of essential oil secretion in vascular plants / ». View thesis, 2001. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20031223.143208/index.html.
Texte intégralRésumé :
Thesis (Ph.D.) -- University of Western Sydney, 2001."This thesis is presented in fulfilment of the degree of Doctor of Philosophy in Science at the University of Western Sydney, Richmond, New South Wales, Australia" Bibliography : p. 145-163.
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Duflot, Rémi. « Hétérogénéité fonctionnelle et biodiversité : quel est le rôle des interfaces ou lisières dans les paysages agricoles ? » Phd thesis, Université Rennes 1, 2013. http://tel.archives-ouvertes.fr/tel-01019974.
Texte intégralRésumé :
L'hétérogénéité du paysage, définie par la composition en habitats et leur configuration spatiale, est considérée comme un facteur majeur affectant la biodiversité. Cependant, les effets de la composition et de la configuration sont souvent confondus du fait de corrélations entre les descripteurs de ces deux composantes. Il est crucial de déterminer leurs effets indépendants pour comprendre les processus qui contrôlent la biodiversité, et allouer les ressources dédiées à la conservation des espèces aux actions de gestion les plus pertinentes. L'objectif de cette thèse est, grâce à la mise en place de protocoles pseudo-expérimentaux dans l'ouest de la France, d'étudier les effets indépendant de la composition et de la configuration paysagère sur la richesse spécifique, la composition spécifique et la composition en traits fonctionnels des coléoptères carabiques et plantes vasculaires. Ces indices de diversité ont été mesurés au niveau du paysage (diversité gamma), et différentes représentations paysagères ont été testées pour comprendre le rôle de l'hétérogénéité de l'espace cultivé, au-delà de la seule prise en compte des habitats semi-naturels. Les résultats indiquent que l'hétérogénéité paysagère joue un rôle de filtre écologique sur les espèces de carabes et de plantes en fonction de leurs traits fonctionnels. La composition paysagère affecte la composition spécifique de ces groupes, les divers habitats hébergeant des communautés différentes. La configuration affecte la diversité des carabes en lien avec des processus possibles de complémentation entre habitats, tandis qu'elle n'a pas d'effet sur la diversité des plantes, qui ne semble donc pas déterminée par les processus de dispersion. Enfin, nos résultats soulignent que l'hétérogénéité liée aux habitats agricoles contribue à la diversité gamma.
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Wilson, Ann Margaret. « Reproductive allocation in flowering plants ». Thesis, University of Plymouth, 1986. http://hdl.handle.net/10026.1/2206.
Texte intégralRésumé :
The proportion of resources which an organism devotes to reproduction has been assumed to be of great evolutionary and ecological significance. However, in previous studies of reproductive allocation (RA) in plants, there has been no consensus of precisely what is being measured nor how it should be measured. An attempt was made to determine the 'best' method of measuring RA and then apply this to a range of species with differing ecological strategies. Under nutrient stress caused by a low N treatment Taraxacum officinale and Poa annua were found to maintain their RA despite up to 4 fold reductions in biomass. Under K and P deficient conditions there was a preferential allocation of these elements to reproductive structures in Taraxacum. Ruderal plants therefore, seem to maintain biomass RA and seed quality despite nutrient stress. Although the nutrient RA in Taraxacum was found to be significantly different from biomass RA (KRA = 71% PRA = 66% BRA= 51.7%) the extent of the difference varied between treatments. There was therefore no obvious alternative currency to biomass. The evolutionary consequences of reproduction may also be measured through a reproductive cost which may take the form of reduced future reproduction, survival or growth. Prevention of flowering in Digitalis purpurea resulted in an increase in the number of axillary buds produced, Similarly in Plantago lanceolata removal of flowers resulted in a 3 fold increase in production of buds. In both species realisation of a reproductive cost was prevented. The importance of individual variability was noted. The importance of plant morphology was evident and was used to explain some of the anomalous RA values in the comparative experiment. RA values were collected for 40 species of Gramineae. RA was a useful ecological index which emphasised the ruderal element of a plant's strategy. When used in conjunction with other parameters particularly Rmax, RA produced a meaningful classification of species in terms of their ecological strategy.
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Arana, Bustamante Augusto. « Ecología y biogeografía de las plantas vasculares de las lomas del Perú Central ». Master's thesis, Universidad Nacional Mayor de San Marcos, 2019. https://hdl.handle.net/20.500.12672/10859.
Texte intégralRésumé :
Analiza los factores geográficos y climáticos que influyen sobre la diversidad florísticas en las lomas de la costa del Perú Central (entre 9 y 15°S) abarcando las regiones de Ancash, Lima e Ica. Con este fin se realizaron viajes de colectas, visitas a herbarios y se recopiló toda la información accesible de publicaciones y bases de datos. Se reportan 51 lomas de las cuales 39 fueron evaluadas en cuanto a su flora (21 por colecta propia y 18 desde publicaciones y registro de herbarios). Las Lomas fueron clasificadas respecto a su geografía en tres categorías: oceánicas, montañas aisladas o asociadas a laderas de valles. La evaluación florística registró 542 especies de plantas vasculares incluidas en 81 familias botánicas. Esta riqueza de especies representa el 64% del total de la flora reportada para las Lomas del Perú y el 63% de lo reportado para todos los ambientes silvestres de la costa del Perú central. Las familias con mayor número de especies fueron las Asteráceas, Solanáceas y Poáceas. Sin embargo, con excepción de Nolana y Solanum (Solanaceae), los géneros con mayor número de especies fueron de otras familias Heliotropium (Boraginaceae), Oxalis (Oxalidaceae), Euphorbia (Euphorbiaceae) y Palaua (Malvaceae). El 23% del total de la flora es endémica y el 14% es introducida. La flora es predominantemente herbácea, terófita, pero también incluye un grupo interesante de plantas geofitas e incluso epifitas que son escasas en los desiertos y que muestra la naturaleza de la fuente principal de humedad en este ecosistema, la neblina. El aislamiento de esta comunidad podría favorecer la polinización cruzada principalmente por entomofilia (71%), mientras que la dispersión por semillas es en primer lugar por anemocoria (43%) y por barocoria (26%), dos estrategias favorecidas por el tamaño pequeño de las semillas que evita la depredación y propicia el ingreso al banco de semillas del suelo. La clasificación de las Lomas por su flora muestra una gran diferencia entre las de la región Ica al sur, con el resto y de manera secundaria entre las floras de islas y de Lomas intermedias entre Lima e Ica y entre Lima y Ancash al norte. 40 especies están incluidas en alguna categoría de amenaza, sobresaliendo los cactus y orquídeas. El tamaño de las Lomas mostró ser el factor geográfico más importante en determinar la riqueza de especies, además de otros factores ligados a la facilidad de llegada de las neblinas, mientras que la precipitación regional no mostró importancia significativa. Se incluye una clave dicotómica para las familias registradas en las Lomas y la descripción de éstas. Adicionalmente, se propone un modelo de metacomunidades que explicaría como se mantiene el equilibrio de la diversidad vegetal en estos ecosistemas bajo la influencia de los cambios climáticos estacionales y los inducidos por la ocurrencia de los eventos El Niño y La Niña.Tesis
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Saka, Mariana Naomi. « Florística vascular não arbórea da reserva particular do patrimônio natural Paiol Maria, São Lourenço da Serra, SP / ». Rio Claro : [s.n.], 2012. http://hdl.handle.net/11449/87838.
Texte intégralRésumé :
Orientador: Julio Antonio LombardiBanca: Lívia Godinho Temponi
Banca: Marco Antonio de Assis
Resumo: A Reserva Particular do Patrimônio Natural Paiol Maria, São Lourenço da Serra, SP, possui 76 ha e localiza-se no Corredor de Biodiversidade da Serra do Mar, considerado uma área prioritária para conservação e um importante centro de endemismo. Foram coletadas 332 espécies de plantas vasculares não arbóreas distribuídas em 85 famílias, sendo aproximadamente 80% de Angiospermas e 20% de Monilophyta s.l. Em relação ao hábito, a maioria é herbácea (47%), seguido de epífitas, arbustivas e trepadeiras (20%, 18% e 15%, respectivamente). Do total de espécies, 87 são endêmicas da Mata Atlântica, 205 são nativas do Brasil, mas não endêmicas deste bioma, 29 ainda não estão identificadas a nível de espécie e 11 não são nativas da flora brasileira. As espécies endêmicas estão representadas principalmente pelas epífitas e arbustivas, sendo Orchidaceae e Melastomataceae duas das famílias mais diversas e com grande número de espécies endêmicas. Dentre as espécies não nativas, a maioria foi considerada naturalizada ou invasora. Youngia japonica (L.)DC., Curculigo capitulata Kunze, Nephrolepis brownii (Desv.) Hovenkamp & Miyam., Cordyline fruticosa (L.)A.Chev. e Cobaea scandens Cav. não estão incluídas em listagens recentes como exóticas para o Brasil, sendo pontualmente classificadas para a área de estudo como naturalizadas, colonizantes ou casuais
Abstract: The Reserva Particular do Patrimônio Natural Paiol Maria, São Lourenço da Serra, SP, has 76 ha and is located in the Biodiversity Corridor of the Serra do Mar, considered a priority area for conservation and an important center of endemism. Were collected 332 species of nontrees vascular plants distributed in 85 families, approximately 80% and 20% of Angiosperms and Monilophyta s.l. Regarding the habit the most are herbs (47%), followed by epiphytes, shrubs and vines (20%, 18% and 15% respectively). Among all species, 87 are endemic to the Atlantic Forest, 205 are native to Brazil, but not endemic to this biome, 29 are not identified to the species level and 11 are not native to the flora of Brazil. The endemic species are represented mainly by epiphytes and shrubs, being Orchidaceae and Melastomataceae two of the most diverse families with several endemic species. Among the non-native species, most were considered naturalized or invasive. Youngia japonica (L.) DC., Curculigo capitulata Kunze, Nephrolepis brownii (Desv.) & Hovenkamp Miyam., Cordyline fruticosa (L.) A.Chev. and Cobaea scandens Cav. are not included in recent lists as exotic to Brazil and were occasionally qualified for the study area as naturalized, colonizing or casual
Mestre
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Jennings, David. « The Conservation and Ecology of Carnivorous Plants ». Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3169.
Texte intégralRésumé :
As discussed in Chapter 1, although our understanding of the ecology and evolution of carnivorous plants has greatly improved in recent years, many fundamental questions remain unanswered. Unfortunately, at the present time, many carnivorous plants are increasingly threatened by anthropogenic activities. Indeed, over half of the carnivorous plant species assessed by the International Union for the Conservation of Nature (IUCN) are listed as `threatened', but the threats to carnivorous plants have not previously been quantified. In Chapter 2, I quantified the conservation threats to carnivorous plant taxa worldwide by searching peer-reviewed literature, and found data on the threats to 48 species of carnivorous plants from nine genera. The most common threat was habitat loss from agriculture, followed by the collection of wild plants, pollution, and natural systems modifications. As I found in Chapter 2, while agrochemical pollution is thought to be an important conservation threat to carnivorous plants, the effects of insecticides in particular on these taxa have not previously been quantified. Therefore in Chapter 3 I tested the effects of commercial and technical grades of three widely used insecticides (carbaryl, lambda-cyhalothrin, and malathion) on survival and the expression of traits associated with carnivory of pink sundews (Drosera capillaris) and Venus flytraps (Dionaea muscipula) using a combination of lab- and field-based experiments. Commercial grades were generally more harmful than technical grades under lab and field conditions, but all three insecticides were capable of causing negative effects on the plants within recommended application rates. Pink sundews appeared to be more susceptible to insecticides than Venus flytraps, perhaps because of larger numbers of digestive glands on the leaf surfaces. Given the effects observed, I suggest that the use of insecticides should be carefully managed in areas containing vulnerable carnivorous plant species. For Chapters 4 and 5, I explored the ecological role of carnivorous plants, specifically if they could compete with animals for shared prey resources. In Chapter 4 I characterized the ground-surface spider and arthropod assemblages of two mesic flatwood habitats in Florida, to resolve what the most likely animal competitor was for pink sundews. I identified 31 spider species from 27 genera in 12 families, with wolf spiders (Lycosidae) being the dominant spider family at both sites. Based on their abundance and the behavioral traits they exhibited, I determined that the funnel-web-building wolf spider Sosippus floridanus was the most likely potential competitor with pink sundews. Collembola and Formicidae were the most abundant arthropod taxa present, but ground-surface spiders were not strongly associated with any typical prey groups, suggesting that environmental factors might also be important in structuring this community. Subsequently, in Chapter 5 I examined the potential for competition between carnivorous plants and animals by studying dietary and microhabitat overlap between pink sundews and wolf spiders in the field, and by conducting a lab experiment examining the effects of wolf spiders on sundew fitness. In the field, I found that sundews and spiders had high dietary overlap with each other and with the available arthropod prey. Associations between sundews and spiders depended on spatial-scale: sundews and spiders were both found more frequently in quadrats with more abundant prey, but within quadrats spiders constructed larger webs and located them further away from sundews as the total sundew trapping area increased. Spiders also constructed larger webs when fewer prey were available. In the lab, my experiment revealed that spiders can significantly reduce sundew fitness. All of these results suggest that members of the plant and animal kingdoms can and do compete. These findings provided inspiration for Chapter 6, where I explored if phylogenetic distance was a good predictor of the strength of competition between taxa, using a meta-analytical approach. I collected data from studies published from 1998-2008 in eight ecology journals using the keyword `interspecific competition', gathering a total of 191 effect sizes. I found no significant relationship between phylogenetic distance and the strength of competition, contrary to the long-standing assumption that it should be greatest in strength between closely related species. However, these findings could presently be limited by publication bias, and I suggest several directions for future research.
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Chowdhury, Anurag. « Studies on the diversity and ethnic uses of wetland vascular plants in Terai and Duars of West Bengal, India ». Thesis, University of North Bengal, 2015. http://ir.nbu.ac.in/hdl.handle.net/123456789/1871.
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Steynen, Quintin John, et University of Lethbridge Faculty of Arts and Science. « Genetic analysis of leaf vascular patterning in Arabidopsis thaliana ». Thesis, Lethbridge : University of Lethbridge, University of Lethbridge. Faculty of Arts and Science, 2001, 2001. http://hdl.handle.net/10133/143.
Texte intégralRésumé :
I have isolated and characterized a recessive mutation in the Forked (FKD) gene that results in the abnormal initiation of vascular bundles in the foliar organs, such that the apices of the vascular bundles initiate freely. Once initiated, the development of Fkd vascular bundles is like wild type, generating an open vascular pattern of similar complexity to the closed venation pattern of wild type. Despite the significant alteration in the vascular pattern, Fkd plants are morphologically indistinct from wild type. fkd mutants do not show altered sensitivity to the effects of auxin and show additive phenotypes with auxin response mutants, suggesting the FKD is part of a pathway acting independently of auxin. The similarity of the open vascular pattern of Fkd plants to that of ancestral vascular plants suggests that acquisition of this pathway may have been critical in the evolution of the closed vascular pattern.x, 55 leaves : ill. ; 28 cm.
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Haig, David. « Applications of allocation and kinship models to the interpretation of vascular plant life cycles ». Phd thesis, Australia : Macquarie University, 1990. http://hdl.handle.net/1959.14/23227.
Texte intégralRésumé :
Thesis by publication.Thesis (PhD) -- Macquarie University, School of Biological Sciences, 1990.
Bibliography: leaves 269-324.
Introduction -- Models of parental allocation -- Sex expression in homosporous pteridophytes -- The origin of heterospory -- Pollination and the origin of the seed habit -- Brood reduction in gymnosperms -- Pollination: costs and consequences -- Adaptive explanations for the rise of the angiosperms -- Parent-specific gene expression and the triploid endosperm -- New perspectives on the angiosperm female gametophyte -- Overview -- Glossary -- Kinship terms in plants -- Literature Cited.
Among vascular plants/ different life cycles are associated with characteristic ranges of propagule size. In the modern flora, isospores of homosporous pteridophytes are almost all smaller than 150 urn diameter, megaspores of heterosporous pteridophytes fall in the range 100-1000 urn diameter, gymnosperm seeds are possibly all larger than the largest megaspores, but the smallest angiosperm seeds are of comparable size to large isospores. -- Propagule size is one of the most important features of a sporophyte's reproductive strategy. Roughly speaking, larger propagules have larger food reserves, and a greater probability of successful establishment, than smaller propagules, but a sporophyte can produce more smaller propagules from the same quantity of resources. Different species have adopted very different size-versus-number compromises. The characteristic ranges of propagule size, in each of the major groups of vascular plants, suggest that some life cycles are incompatible with particular size-versus-number compromises. -- Sex expression in homosporous plants is a property of gametophytes (homosporous sporophytes are essentially asexual). Gametophytes should produce either eggs or sperm depending on which course of action gives the greatest chance of reproductive success. A maternal gametophyte must contribute much greater resources to a young sporophyte than the paternal gametophyte. Therefore, smaller gametophytes should tend to reproduce as males, and gametophytes with abundant resources should tend to reproduce as females. Consistent with these predictions, large female gametophytes release substances (antheridiogens) which induce smaller neighbouring ametophytes to produce sperm. -- The mechanism of sex determination in heterosporous species appears to be fundamentally different. Large megaspores develop into female gametophytes, and small icrospores develop into male gametophytes. Sex expression appears to be determined by the sporophyte generation. This is misleading. As argued above, the optimal sex expression of a homosporous gametophyte is influenced by its access to resources. This is determined by (1) the quantity of food reserves in its spore and (2) the quantity of resources accumulated by the gametophyte's own activities. If a sporophyte produced spores of two sizes, gametophytes developing from the larger spores' would be more likely to reproduce as females than gametophytes developing from the smaller spores, because the pre-existing mechanisms of sex determination would favor production of archegonia by larger gametophytes. Thus, the predicted mechanisms of sex determination in homosporous species could also explain the differences in sex expression of gametophytes developing from large and small spores in heterosporous species.
Megaspores of living heterosporous pteridophytes contain sufficient resources for female reproduction without photosynthesis by the gametophyte (Platyzoma excepted), whereas microspores only contain sufficient resources for male reproduction. Furthermore, many more microspores are produced than megaspores. A gametophyte's optimal sex expression is overwhelmingly determined by the amount of resources supplied in its spore by the sporophyte, and is little influenced by the particular environmental conditions where the spore lands. Gametophytes determine sex expression in heterosporous species, as well as homosporous species. A satisfactory model for the evolution of heterospory needs to explain under what circumstances sporophytes will benefit from producing spores of two distinct sizes. -- In Chapter 4, I present a model for the origin of heterospory that predicts the existence of a "heterospory threshold". For propagule sizes below the threshold, homosporous reproduction is evolutionarily stable because gametophytes must rely on their own activities to accumulate sufficient resources for successful female reproduction. Whether a gametophyte can accumulate sufficient resources before its competitors is strongly influenced by environmental conditions. Gametophytes benefit from being able to adjust their sex expression in response to these conditions. For propagule sizes above the threshold, homosporous reproduction is evolutionarily unstable, because the propagule's food reserves are more than sufficient for a "male" gametophyte to fertilize all eggs within its neighbourhood. A population of homosporous sporophytes can be invaded by sporophytes that produce a greater number of smaller spores which could land in additional locations and fertilize additional eggs. Such'spores would be male-specialists on account of their size. Therefore, both spore types would be maintained in the population because of frequency-dependent selection. -- The earliest vascular plants were homosporous. Several homosporous groups gave rise to heterosporous lineages, at least one of which was the progeniture of the seed plants. The first heterosporous species appear in the Devonian. During the Devonian, there was a gradual increase in maximum spore size, possibly associated with the evolution of trees and the appearance of the first forests. As the heterospory threshold was approached, the optimal spore size for female reproduction diverged from the optimal spore size for male reproduction. Below the threshold, a compromise spore size gave the highest fitness returns to sporophytes, but above the threshold, sporophytes could attain higher fitness by producing two types of spores. -- The evolution of heterospory had profound consequences. Once a sporophyte produced two types of spores, microspores and megaspores could become specialized for male and female function respectively. The most successful heterosporous lineage (or lineages) is that of the seed plants. The feature that distinguishes seed plants from other heterosporous lineages is pollination, the capture of microspores before, rather than after, propagule dispersal. Traditionally, pollination has been considered to be a major adaptive advance because it frees sexual reproduction from dependence on external fertilization by freeswimming sperm, but pollination has a more important advantage. In heterosporous pteridophytes, a megaspore is provisioned whether or not it will be fertilized whereas seeds are only provisioned if they are pollinated.
The total cost per seed cannot be assessed solely from the seed's energy and nutrient content. Rather, each seed also has an associated supplementary cost of adaptations for pollen capture and of resources committed to ovules that remain unpollinated. The supplementary cost per seed has important consequences for understanding reproductive strategies. First, supplementary costs are expected to be proportionally greater for smaller seeds. Thus, the benefits of decreasing seed size (in order to produce more seeds) are reduced for species with small seeds. This effect may explain minimum seed sizes. Second, supplementary costs are greater for populations at lower density. Thus, there is a minimum density below which a species cannot maintain its numbers. -- By far the most successful group of seed plants in the modern flora are the angiosperms. Two types of evidence suggest that early angiosperms had a lower supplementary cost per seed than contemporary gymnosperms. First, the minimum size of angiosperm seeds was much smaller than the minimum size of gymnosperm seeds. This suggests that angiosperms could produce small seeds more cheaply than could gymnosperms. Second, angiosperm-dominated floras were more speciose than the gymnosperm-dominated floras they replaced. This suggests that the supplementary cost per seed of angiosperms does not increase as rapidly as that of gymnosperms, as population density decreases. In consequence, angiosperms were able to displace gymnosperms from many habitats, because the angiosperms had a lower cost of rarity. -- Angiosperm embryology has a number of distinctive features that may be related to the group's success. In gymnosperms, the nutrient storage tissue of the seed is the female gametophyte. In most angiosperms, this role is taken by the endosperm. Endosperm is initiated by the fertilization of two female gametophyte nuclei by a second sperm that is genetically identical to the sperm which fertilizes the egg. Endosperm has identical genes to its associated embryo, except that there are two copies of maternal genes for every copy of a paternal gene. -- Chapter 9 presents a hypothesis to explain the unusual genetic constitution of endosperm. Paternal genes benefit from their endosperm receiving more resources than the amount which maximizes the fitness of maternal genes, and this conflict is expressed as parent-specific gene expression in endosperm. The effect of the second maternal genome is to increase maternal control of nutrient acquisition. -- Female gametophytes of angiosperms are traditionally classified as monosporic, bisporic or tetrasporic. Bisporic and tetrasporic embryo sacs contain the derivatives of more than one megaspore nucleus. Therefore, there is potential for conflict between the different nuclear types within an embryo sac, but this possibility has not been recognized by plant embryologists. In Chapter 10, I show that many previously inexplicable observations can be understood in terms of genetic conflicts within the embryo sac.
Mode of access: World Wide Web.
324 leaves ill
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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.
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Stillman, R. A. « Models of growth patterns of clonal plants ». Thesis, University of East Anglia, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.278738.
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Flaig, Jeanette H. « A vascular plant inventory of the eastern San Juan Mountains and vicinity in southern Colorado ». Laramie, Wyo. : University of Wyoming, 2007. http://proquest.umi.com/pqdweb?did=1495959121&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
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Kowal, Jill. « Fungal interactions with vascular and non-vascular plants : an investigation of mutualisms and their roles in heathland regeneration ». Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/42788.
Texte intégralRésumé :
Mycorrhizal mutualisms between aboveground vascular plant communities, which reward their belowground fungal associates with photosynthates in return for growth-limiting nutrients such as phosphate, are widely recognized as stable long-term interactions which helped plants colonize land. Pezoloma ericae (D.J. Read) Baral, an ascomycete mycorrhiza-forming fungus present amongst plants in the Ericales, such as heathers, also forms associations in several families of non-vascular leafy liverworts. Whether there is a mutually beneficial functional relationship between these leafy liverworts and the fungus growing in their rhizoids was previously unconfirmed. Furthermore, an ecological role of this 'shared' mycobiont and its link between vascular (Ericaceae) and non-vascular (liverworts) plants was also unknown. Thus the main questions asked in this dissertation are: 1) Is there a measurable mutually beneficial relationship between a liverwort and its fungal partner?; and, 2) Can liverworts harbouring the ericoid mycorrhiza P. ericae act as inoculum that facilitates the re-establishment of Ericaceae - and henceforth be proposed as a practical tool in a restoration ecology context. This is the first time British species of leafy liverworts are conclusively identified to harbour the ericoid mycorrhizal fungus Pezoloma ericae using molecular identification. I have demonstrated a mutualism occurring between the leafy liverworts and their fungal symbiont in two independent microcosm growth experiments and confirmatory reciprocal trophic exchanges between phosphorus and carbon and the two organisms. Glasshouse experiments demonstrated P. ericae originating from leafy liverwort rhizoids, can repeatedly colonize Ericaceae plant roots. Under realistic ecological circumstances (further tested at two field sites), liverworts delivered mycorrhizal inoculum and improved the resilience and growth of vascular plants. By providing this novel source of mycorrhizal inoculum, symbiotic non-vascular plants can contribute to the restoration of plant communities dominated by Ericaceous plants. This research leads to broader knowledge about the function of ericoid mycorrhizas in ecosystems with multi-trophic non-vascular-fungi-vascular community interactions, both above and below ground.
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Cawley, Leigh Eric. « Pollutant nitrogen and drought tolerance in heathland plants ». Thesis, Manchester Metropolitan University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341054.
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It has been suggested that pollutant nitrogen inputs adversely influence the response of heathland plants to certain climatic and biotic stresses. One specific hypothesis being that elevated nitrogen deposition may reduce drought tolerance in heathland vegetation. However, there is little evidence from field studies that this is the case. The aims of this research project have been firstly to establish the effects of increased nitrogen inputs upon plant water relations in certain dwarf heathland shrubs under winter and summer drought conditions. Secondly, to contribute to the understanding of how changes in plant water relations caused by increased inputs of nitrogen affects the growth, physiological perfonnance and consequent long tenn survival of heath land plant communities. Experimental field work was carried out at an existing upland site in Clwyd, North Wales near Ruabon from July 1995 to April 1999. Experimental work with potted plants was carried out in the glasshouse at Crewe, Octoberl995 to June 1997. A lowland field site at Budworth Common in Cheshire, consisting of twenty, 2 x 1 metre plots in a replicated random block layout was established by the author during March 1996, remaining a site of investigation until December 1998. At both the upland and lowland field sites the vegetation was dominated by Calluna vulgaris (L.) Hull. At Ruabon a twelve month study of shoot relative water contents in relation to soil moisture deficits was carried out on a monthly basis. Visible frost injury was surveyed and recorded each spring (April 1996 to April 1999). At Budworth Common (summer 1997), following 12 months of nitrogen applications (0, 20, 60 and 120 kg N ha-1yr-1 (NH4N03» a protracted period of drought was imposed on field plots by the use of drought shelters, these covered the whole of each plot.Comparisons were drawn between watered and droughted plants in the field. This was carried out by applying the equivalent summer rainfall for Budworth Common to one half (1m2) of every treatment plot and droughting the other half (1m2). Nitrogen treatments were continued at fortnightly intervals throughout. Budworth Common was used to study the impacts of elevated nitrogen and drought for a five month period from May to September 1997. Intensive experimental field work over the drought period recorded: weekly measurements of soil moisture deficits, shoot water potentials and shoot extension growth. Measurements of shoot relative water contents and infra red gas analysis were taken, the flowering period was recorded. During the post drought year (summer 1998) a spontaneous outbreak of Lochmaea suturalis (heather beetle) in the field plots showed the beetles to have a preference for high N treated Calluna. An increase in the competitive grass species Deschampsia jlexuosa was seen in droughted plots during summer 1998, particularly the high N treatments. As a result of experimental work carried out both in the field and laboratory this study has shown that elevated nitrogen does have detrimental impacts on the drought tolerance of certain heathland plants. Field work results compared positively with those obtained from the pot experiment. A higher incidence of visible frost and drought damage was recorded in high nitrogen plots. Lower soil moistures were recorded in high nitrogen plots. Measurements of shoot water potentials revealed that high nitrogen treatments under drought conditions exhibited more negative values than did low nitrogen plants. High nitrogen increased the number of early opening flowers under conditions of full water but in plants receiving high nitrogen and drought flowering was delayed. This study increases the understanding of the impacts of elevated nitrogen inputs on the water relations of heathland plants.
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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.
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Backéus, Ingvar. « Aboveground production and growth dynamics of vascular bog plants in central Sweden ». Uppsala : Stockholm : Svenska växtgeografiska sällskapet ; Almqvist & ; Wiksell International [distributor], 1985. http://catalog.hathitrust.org/api/volumes/oclc/12807002.html.
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