Thèses sur le sujet « Tree Population dynamic »
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Villari, Caterina. « Fungi associated with the pine engraver beetle Ips acuminatus and their interactions with the host tree ». Doctoral thesis, Università degli studi di Padova, 2012. http://hdl.handle.net/11577/3422532.
Texte intégralGli scolitidi delle conifere sono insetti spesso associati ad un complesso di funghi con i quali possono instaurare differenti interazioni ecologiche. Alcuni di questi funghi, generalmente non fitopatogeni, sono coinvolti in un’interazione mutualistica diretta e vengono utilizzati come nutrimento per le larve del vettore. Altri funghi associati, invece, sono ritenuti coinvolti nel processo di esaurimento delle difese della pianta, che per l’insetto è uno dei passaggi necessari per superare la resistenza dell’ospite e poterlo quindi colonizzare. In quest’ultimo caso, i funghi associati sono di norma specie patogene appartenenti al gruppo morfologico dei funghi ophiostomatoidi, noti anche come ‘funghi di azzurramento’. Nonostante l’interesse che la simbiosi tra scolitidi e funghi ha riscosso nel tempo, molti degli aspetti fondamentali di questa interazione sono ancora discussi, come ad esempio il grado di dipendenza degli insetti vettori dai loro simbionti nelle fasi di colonizzazione della pianta ospite. In questa tesi è stata presa in considerazione la comunità fungina associata a Ips acuminatus (Gyll.), un piccolo scolitide che attacca di preferenza le parti del tronco del pino silvestre (Pinus sylvestris L.) con corteccia sottile, e che di recente ha causato numerose infestazioni in varie zone distribuite sull’arco alpino. Una delle specie che fanno parte della comunità fungina associata ad I. acuminatus è il simbionte alimentare Hyalorhinocladiella macrospora (Franke-Grosm.) Harr. Fa inoltre parte del complesso anche uno specifico fungo di azzurramento costantemente associato al vettore, ma la cui identità non è ancora ben definita. Le prime segnalazioni lo descrivono come Ophiostoma clavatum Math.-Käärik, mentre ricerche successive riportano O. brunneo-ciliatum Math. Gli obiettivi che questa tesi si è prefissa sono stati determinare l’effettiva identità del fungo di azzurramento associato ad I. acuminatus, ed indagare le interazioni del complesso fungino con la pianta ospite, al fine di definire meglio le relazioni che intercorrono tra scolitidi e fungi associati, e poter quindi contribuire ai tentativi di chiarire l’ecologia e la dinamica di popolazione di questo insetto dannoso. Nel primo lavoro sono stati descritti l’isolamento e l’identificazione di una specie fungina isolata da individui di I. acuminatus raccolti in Italia e in Svezia. L’identificazione della specie è avvenuta sia grazie all’osservazione delle caratteristiche morfologiche sia mediante un approccio di tipo molecolare. La specie è risultata essere O. clavatum, come era stato indicato nelle prime segnalazioni riguardanti i funghi associati ad I. acuminatus. Nel secondo lavoro sono stati descritti la messa punto e l’utilizzo di tre sonde molecolari per loop-mediated isothermal amplification (LAMP), con l’obiettivo di determinare quale delle due specie del genere Ophiostoma sopracitate fosse effettivamente il fungo maggiormente associato a I. acuminatus nell’arco alpino. I risultati, riguardanti sei popolazioni italiane dell’insetto, hanno confermato che la specie maggiormente presente è O. clavatum, mentre O. brunneo-ciliatum non è mai stata rilevata. I risultati di questo studio hanno mostrato anche che la frequenza di associazione di I. acuminatus con O. clavatum varia a seconda della fase epidemica, ed è minore nei nuclei di infestazione rispetto alle popolazioni endemiche. Nel terzo lavoro sono state caratterizzate le risposte sia locali sia sistemiche del pino silvestre alla colonizzazione da parte del simbionte alimentare e del fungo di azzurramento, identificando e quantificando alcuni metaboliti secondari, come terpeni, fenoli e lignina. I risultati hanno mostrato che il pino silvestre risponde in maniera generica anziché specifica all’induzione. Il fatto inoltre che il simbionte alimentare e il fungo di azzurramento abbiano stimolato una risposta simile di loro suggerisce che anche un fungo non patogeno possa partecipare al processo di esaurimento delle difese della pianta, assistendo quindi l’insetto nelle fasi di colonizzazione dell’ospite. Questo risultato contribuisce quindi allo sviluppo delle attuali teorie sul ruolo dei funghi associati nell’ecologia degli scolitidi. Nell’ultimo lavoro sono state studiate le correlazioni tra i metaboliti secondari delle difese costitutive del pino silvestre, e le correlazioni tra la concentrazione costitutiva e la variazione indotta dei singoli composti. I risultati hanno messo in evidenza una differenziazione di comportamento tra composti e l’assenza in generale di una correlazione inversa tra i tipi diversi di difese, al contrario di quanto previsto da alcune teorie. Nel complesso, i quattro contributi di questa tesi suggeriscono la rivalutazione di una delle attuali teorie sul ruolo dei funghi associati nella colonizzazione dell’ospite da parte degli scolitidi, e forniscono degli spunti per la comprensione del ruolo dei funghi associati nella dinamica di popolazione del vettore. Chiariscono inoltre alcuni degli aspetti dei meccanismi di difesa del pino silvestre, mettendo in evidenza la sua competitività.
Manokaran, N. « Population dynamics of tropical forest trees ». Thesis, Available from the University of Aberdeen Library and Historic Collections Digital Resources, 1988. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=59678.
Texte intégralStan, Amanda B., Thomas B. Maertens, Lori D. Daniels et Stefan Zeglen. « Reconstructing Population Dynamics Of Yellow-Cedar In Declining Stands : Baseline Information From Tree Rings ». Tree-Ring Society, 2011. http://hdl.handle.net/10150/622635.
Texte intégralLind, Brandon M. « NATURAL AND ANTHROPOGENIC DRIVERS OF TREE EVOLUTIONARY DYNAMICS ». VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5359.
Texte intégralKolodin, Dmitriy Pavlovich. « Dynamics of Tissue-Resident Regulatory T Cell Populations ». Thesis, Harvard University, 2014. http://dissertations.umi.com/gsas.harvard:11555.
Texte intégralAlalouni, Urwa [Verfasser], et Roland [Akademischer Betreuer] Brandl. « Insects in forests. Assemblages, effects of tree diversity and population dynamics / Urwa Alalouni. Betreuer : Roland Brandl ». Marburg : Philipps-Universität Marburg, 2014. http://d-nb.info/1059856425/34.
Texte intégralBoom, Arthur. « Diversification, evolution and population dynamics of the genus Brachystegia, a keystone tree of African miombo woodlands ». Doctoral thesis, Universite Libre de Bruxelles, 2021. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/331717.
Texte intégralDoctorat en Sciences
info:eu-repo/semantics/nonPublished
Houlgreave, John A. « Water tree dynamics and their scaling with field and frequency by analysis of time-series population data ». Thesis, University of Leicester, 1996. http://hdl.handle.net/2381/34781.
Texte intégralGiesecke, Thomas. « The Holocene Spread of Spruce in Scandinavia ». Doctoral thesis, Uppsala University, Department of Earth Sciences, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4623.
Texte intégralThe Holocene spread of Picea abies in Scandinavia provides an excellent opportunity for detailed study of the dynamics of tree spread and population expansion. Early- and mid-Holocene macrofossil evidence for the presence of Picea abies in Scandinavia has questioned traditional interpretations of the timing and direction of its spread. This study aims to determine the pattern of the spread of Picea abies in Scandinavia from pollen and other data, to evaluate the significance of possible early outpost populations and to deduce possible factors that influenced the spread and population expansion of Picea abies in Scandinavia.
Palaeoecological investigations were carried out on the sediments of four small lakes in central Sweden to gain detailed insight into the dynamics of the spread. Holocene pollen diagrams with independent dating control were collected from Fennoscandia and adjacent areas to compare the timing of selected features of the Picea abies pollen curve. Computer models were used to test possible scenarios for the spread and Picea abies population expansion.
Picea abies entered the Scandinavian peninsula from the east at different times and by different pathways. Early-Holocene outposts can be discerned in pollen records from northwest Russia, eastern and northeastern Finland for the time before 9000 cal. BP. Pollen records from Sweden and Norway indicate small Picea abies populations after 8000 cal. BP. The mid to late-Holocene spread, which superficially resembles a front-like pattern, may in fact represent a wave of expanding populations. Disturbance through fire and human activity did not significantly influence the pattern of the spread. Changing climate parameters, slow adaptation and gene flow through seeds and pollen have to be considered as possible explanations for the late spread of the tree. Population dynamics and propagule pressure are likely to be important factors that shaped the spread of Picea abies.
Valeriano, Diana Damasceno Barreto. « Dinâmica da floresta ombrófila mista altomontana, Campos do Jordão, São Paulo ». Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/41/41134/tde-25082010-114434/.
Texte intégralThe dynamics of the tree component of a Mixed Ombrophylous Forest in the Southeast Brazil was evaluated to verify its successional stage and its agreement with dynamic models proposed for this formation. The first one, Lozenge model, or temporal plot replacement, proposes that the dynamics of long-lived pioneers, often gymnosperms, which structurally dominates the forest, is influenced by intermittent recruitment pattern, dependent of severe disturbances. The second proposes that the presence of Araucaria angustifolia is indicative of ongoing succession and that the A. angustifolia fate is to be substituted by broadleaf species. A third one proposes gap dependent recruitment for the long-lived pioneers. The evaluation was conducted in three phases: through the analysis of the dynamics of the phytosociological structure it was observed if changes occurred in the order of importance of the species, with a demographic analysis to characterize the size structure of the tree populations and through the analysis of the spatial dynamics of the forest it was investigated if gap formation fostered the recruitment of long-lived pioneers. The results showed a phytosociological structure with no change in the order of importance of the species, although it was observed an increase in the representation of umbrophyllous species in the understory and the reduction of sun tolerant species. The demographic analysis showed that the gymnosperms present a cohort structure in accordance with what is expected for long-lived pioneers and that during the observed time span they did not recruit, indicating a decline in their population. The canopy species presented populations in development and, in the uderstorey, a more intense dynamic was observed with population increases for the umbrophyllous species. The spatial analysis showed that many species are independent of gaps for recruitment and development but the forest recruitment, mortality and species enrichment are correlated with this process. It was not observed the recruitment of long-lived pioneers in the gaps presented in the study area. These results indicate that the forest is under development and that its dynamics is influenced by the dynamics of the long-lived pioneers. There was indication of adherence to the first two models and that, in the absence of major disturbances, it can be expected that the long-lived pioneers will be replaced.
Bizotto, Lucas de Almeida. « Avaliação populacional, sanitária e recursos armazenados em colmeias de Apis mellifera Linnaeus, 1758 (Hymenoptera : Apidae) utilizadas em serviços de polinização em pomares de macieiras (Malus domestica Borkh.) ». Universidade do Estado de Santa Catarina, 2016. http://tede.udesc.br/handle/handle/2385.
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Capes
This study aimed to evaluate the behavior and health of hives of honeybees (Apis mellifera) used in pollination services in apple orchards in the municipality of Vacaria, RS. Conducted under the conventional production system. For that were evaluated during two consecutive seasons (2014/15 and 2015/16), the behavior of bees in the collection of flowers resources during the pollination period (09/23/14 to 10/20/14 – crop season 2014 / 15, 09.02.15 and 15.10.15 and between 2015/16 crop season), the occurrence of parasitism by Varroa destructor mites and infections caused by Nosema sp. areas of stored features, and areas of immature hives and A. mellifera used in the pollination of apple orchards. In the course of experiments, the hives had activities during evaluations with an average of 27.5 to 40.8’ bees observed in five minutes. Regardless of the place of origin of the hives or evaluation harvest, the nectar was the preferred feature by bees. It was found that 95% of the bees have sought nectar while only 5% of the search effected pollen. In both crops, beehives used had average ranging from 3.0 to 6.7% of parasitism by V. destructor. There was an increase in parasitism levels in the period of pollination, in high population hives, since hives with smaller populations have not followed the same behavior. The presence of spores Nosema sp. It was noted only in hives used in the harvest of 2014/15, and did not occur in the harvest of 2015/16. There are significant variations in the internal areas of stored resources and areas of immature of hives used for pollination of apple trees services, these related to places of origin, before the entry of the swarms in the orchards. It is that coming from places with large supply of resources are the most affected by the stay in the orchard. which they suffered decreases in the internal space of the hives by the withdrawal of nests in preparation for the stay in the orchards. This fact led to numerous swarming bees reflecting in food reserves and population status.
O presente estudo objetivou avaliar o comportamento e a sanidade de colmeias da abelha melífera (Apis mellifera) utilizadas em serviços de polinização em pomares de macieiras no município de Vacaria, RS. Conduzidos sob o sistema convencional de produção. Foram avaliados, no decorrer de duas safras consecutivas (2014/15 e 2015/16), o comportamento das abelhas na coleta de recursos florais no decorrer do período de polinização (23/09/14 a 20/10/14 - safra 2014/15, e entre 02/09/15 e 15/10/15 - safra 2015/16), a ocorrência de parasitismo pelo ácaro Varoa destructor e infecções causadas por Nosema sp., áreas de recursos armazenados, e áreas de imaturos em colmeias e de A. mellifera utilizadas na polinização de pomares macieiras. No decorrer do presente experimento as colmeias apresentavam atividades durante as avaliações com média de 27.5 a 40.8 abelhas observadas em cinco minutos. Independentemente do local de origem das colmeias ou safra de avaliação, o néctar foi o recurso preferido pelas abelhas. Foi verificado que 95% das abelhas buscaram o néctar enquanto apenas 5% efetuaram a busca de pólen. Em ambas as safras, as colmeias utilizadas apresentaram médias que variam de 8 3,0 a 6,7 % de parasitismo por V. destructor. Houve aumento nos níveis de parasitismo no período da polinização, em colmeias com alta população, já colmeias com populações menores não seguiram o mesmo comportamento. A presença de esporos de Nosema sp. foi constata apenas em colmeias utilizadas na safra de 2014/15, e não ocorreu na safra de 2015/16. Há variações significativas nas áreas internas de recursos armazenados e áreas de imaturos das colmeias utilizadas em serviços de polinização de macieiras, estas ligadas aos locais de origem, antes da entrada dos enxames nos pomares. Sendo que os vindos de locais com grande oferta de recursos são os mais prejudicados pela estada no pomar, os quais sofreram pelas diminuições no espaço internos das colmeias pela retirada de sobre ninhos em preparação para a estadia nos pomares. Fato que levou a inúmeras enxameações, refletindo nas reservas de alimentos e estado populacional
Portela, Rita de Cassia Quitete. « Ecologia populacional de tres especies de palmeiras em uma paisagem fragmentada no dominio da Mata Atlantica, RJ ». [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/316359.
Texte intégralTese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: O objetivo dessa tese foi comparar a densidade, estrutura e dinâmica de populações de três espécies de palmeiras (Astrocaryum aculeatissimum (Schott) Burret, Euterpe edulis Mart. e Geonoma schottiana Mart.) em uma paisagem fragmentada de Mata Atlântica. As populações foram marcadas em 2005, reamostradas em 2006 e 2007 em cinco fragmentos florestais (19, 21, 57, 2.400 e 3.500 ha). Todos os indivíduos das três espécies dentro das parcelas foram marcados e medidos: diâmetro à altura do solo, altura até a inserção da última folha, número de folhas e tipo de folha. Esses dados serviram para classificar os indivíduos em cinco classes: plântula, infante, jovem, imaturo e reprodutivo (Capítulo 1). Para testar a existência de relação entre densidade de cada espécie e o tamanho do fragmento, nós fizemos uma correlação para dados ranqueados, usando coeficiente de Spearman. A comparação das estruturas demográficas de cada espécie foi feita pela soma das diferenças entre o número de indivíduos em cada classe, em cada ano, para cada dois fragmentos (Capítulo 2). Para cada espécie, matrizes agregadas foram construídas para cada transição de ano, onde foram juntadas todas as parcelas de todos os fragmentos, depois estimadas as probabilidades de transição e fecundidade e calculado o ? e a sensibilidade (Capítulo 3). Matrizes agregadas foram construídas para E. edulis com os dados dos três fragmentos pequenos para comparar com a população do maior fragmento para cada transição de ano. Comparamos a dinâmica (? e elasticidade) entre os fragmentos, e quantificamos a contribuição de cada taxa vital básica para a diferença observada entre os ? das áreas através do LTRE (Capítulo 4). As densidades de A. aculeatissimum, E. edulis e G. schottiana não foram influenciadas pelo tamanho do fragmento, mas apresentaram grande variação entre as áreas. A estrutura da população de A.aculeatissimum foi alterada nos menores fragmentos, principalmente as plântulas e os reprodutivos. A estrutura populacional de E. edulis nos menores fragmentos foi fortemente impactada pela exploração do palmito; a maior parte da população estava representada por imaturos. A estrutura populacional de G. schottiana não foi afetada pelo tamanho do fragmento ou pela exploração de suas folhas. Baseado nas matrizes agregadas, os ?s de A. aculeatissimum e G. schottiana não foram diferentes de um, sugerindo que essas populações não estão crescendo e nem diminuindo de tamanho. As populações de E. edulis foram projetadas para diminuir de tamanho no segundo intervalo de amostragem. As sobrevivências das três espécies foram altas para todos os estádios e a taxa vital mais importante é a sobrevivência dos maiores indivíduos. Baseado na matriz do maior fragmento, a população de E. edulis está projetada para decrescer e baseado nas matrizes agregadas dos fragmentos pequenos, a população do E. edulis está projetada para crescer. O padrão da elasticidade para as populações foi muito similar para as duas transições de ano, com os maiores valores de elasticidade sendo para a sobrevivência das classes mais desenvolvidas. A análise do LTRE revelou que o maior ? encontrado para os menores fragmentos foi principalmente influenciado pela maior sobrevivência dos imaturos e reprodutivos. De maneira geral, sobrevivência e fecundidade contribuíram de maneira positiva para ? ?, e o crescimento teve uma contribuição negativa para o ? ?. Portanto, foram encontrados resultados bastante contrastantes para as três espécies de palmeiras estudadas. Apesar de pertencerem à mesma família botânica, as três espécies possuem características e sofrem pressões ambientais bem distintas, resultando em um comportamento diferente frente à redução do habitat e a exploração de seus recursos
Abstract: The aim of this thesis was to compare the density, the structure and the dynamic of populations of three tropical palm species, Astrocaryum aculeatissimum (Schott) Burret, Euterpe edulis Mart. and Geonoma schottiana Mart., in different size fragments of Atlantic Rain Forest. For these analysis palms were censused five forest fragments (19, 21, 57, 2.400 e 3.500 ha). We tracked the survival of the palms from year 2005 through the year 2007, and recorded all new individuals encountered. Each individual had its diameter and height measured; also the number and the kind of leaf recorded. With these measures we assigned each individual to one of the five pre-established class: seedling, infant, juvenile, immature and reproductive (Chapter 1). To test if there was a relationship between density of each species and the size of the fragment we did a correlation for rank-order data, using Spearman coefficients. The comparison of the demographic structure of each palm was analyzed with the sums of the differences between the numbers of individuals in each class in each year between two fragments (Chapter 2). Summary matrices were constructed for each transition years by pooling data from all plots of all fragments together for each species, and then estimating the transition probabilities and fecundity using pooled data. With these matrices we calculated the population growth rate (?) and its elasticities for each species (Chapter 3). We found difference between ? of E. edulis in a big and the smaller fragment. Therefore, to quantify the contribution of each lower level vital rate to the observed differences in ? between the fragments, we used a fixed-design LTRE (Chapter 4). A. aculeatissimum, E. edulis and G. schottiana densities were not influenced by the size of the fragment, but showed a high variation between areas. A. aculeatissimum population structure was altered, especially by the proportion of seedlings and reproductive individuals. E. edulis population structure in the smaller fragments seemed to be highly impacted by palm heart harvest where a large proportion of the populations were represented by immature individuals. On the other hand, fragment structure and leaf harvest did not have a strong effect on the population structure of G. schottiana. In a landscape level, A. aculeatissimum and G. schottiana asymptotic population growth rates were not significantly different from one, suggesting that populations of these palms were stable. E. edulis populations are projected to decrease in size in the second transition year. A. aculeatissimum, E. edulis and G. Schottiana survivorship was high for all stage classes. We found that the more important vital rates were the survival rates in larger stages for all three species. Based on the matrix of the bigger fragment, E. Edulis populations are projected to decrease in size. On the other hand, based on summary matrices made by pooling the three smaller fragments together, E. edulis populations are projected to growth. Our LTRE analysis revealed that the generally upper ? in the smaller fragments was due primarily to great survival of immatures and reproductives in both transitions years. On average, survival and fecundity made the largest positive total contribution to ? ?, and growth made a negative contribution to ? ?. Therefore, we found very different results or the three palms studied. In spite of being the same botany family, the species are very different in its characteristics and environmental pressure, resulting in a very different behavior in face of habitat reduction and harvesting
Doutorado
Doutor em Ecologia
Doublet, Violette. « Interactions biotiques et dynamiques des populations : approches empiriques et théoriques de la prédation pré-dispersion des graines par les insectes ». Thesis, Montpellier, 2020. http://www.theses.fr/2020MONTG007.
Texte intégralBiotic interactions are among key processes in population dynamics and critical issues for the renewal and persistence of species within ecosystems. In particular, herbivory by pre-dispersal seed insect predators is a major ecological process in forest dynamics due to its impact on tree reproductive success and on natural regeneration. However, its consequence on tree population dynamics and evolution remain poorly documented. This thesis contributed to fill this gap as an integrative combination of empirical and theoretical approaches. The empirical approach aimed to characterize the drivers of the spatio-temporal dynamics of seed predation rates in natural forest. We used a system of tree-insect interactions involving seed predators (Megastigmus spp., Hymenoptera: Torymidae) and their obligate host, the Atlas Cedar (Cedrus atlantica, Pinaceae), located in south-eastern France. At the host population scale, our results revealed that the transient pattern of the spatial distribution of insects was primarily explained by spatiotemporal variations in seed density. Thus, Cedar masting appeared to be a major driving force of the insects’ spatial and temporal dynamics. We have also highlighted the existence of an inter-individual variation in the sensitivity of trees to seed predation. A preliminary analysis has suggested that such variation is partly under genetic control and we propose further analyses to be carried out in such perspective. The theoretical approach aimed to analyse the joint effects of masting and the spatial distribution of pre-dispersal seed predation by insects on demographic processes and genetic diversity in an expanding tree population. The analytical modelling of these interactions revealed on the one hand that pre-dispersal seed predation induce Allee effects that may affect the spatial structure of genetic diversity in the expanding tree population, and on the other hand, that masting was likely to buffer such demogenetic impact of seed predation. This work has shed new light on the possible implications of pre-dispersal predation by insects in the dynamics and evolution of forests
Sirakov, Nikolay. « Modélisation de la dynamique de population d une plante native (palmier babaçu) dans le cadre d'un projet de gestion durable au Brésil ». Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTT302/document.
Texte intégralThe babassu palm tree (Attalea speciosa Mart. ex Spreng.) is an endemic species of the amazonian forests. The deforestation highlights henceforth this palm tree in the anthropogenic open areas (pastures and cultivated fields). The babassu is one of the "extractive" resources in Brazil: gathering activity followed by marketing of non-timber products. This activity involves people among the most disadvantaged in the country thus the importance to better manage its sustainability in a context of conflict. It is clear that knowledge of sustainable functioning of the species within these manmade environments is sorely lacking: its life cycle is not well known and its population dynamics unstudied.This PhD work is pioneer and is a part of an Open Science interdisciplinary project of the Agropolis foundation. The objective is twofold it is to generate a model of population dynamics of the babassu palm tree validated by in situ analysis and capitalizing knowledge from various scientific communities (biologists, ecologists, mathematicians, computer scientists and economists from France and Brazil). In the long-term the model should support the recommendations for the sustainable management of the species.Our approach explicit within different models the shared knowledge about the species and the potential mathematical models as well as the societal context. This has allowed us to provide an observation model compliant with the recommendations ofOBOE (Ontology on a semantic scientific observations) for the development of data acquisition protocol. The acquisition was made in situ by the French-Brazilian partnership between 2013 and 2016 in the community of Benfica (Pará, Brazil). The perpetuation of the data was made after conception, within a spatial database taking into account the socio-economic aspect.Finally, we proposed a random matrix model having as input aggregated variables based on the biological stages of the species. The probabilities of the between stages transition matrix are modeled using a hierarchical Dirichlet-Multinomial model. The integration of prior information was formulated through a Bayesian approach. The estimation and model validation were performed with Bayesian criteria.Simulations based on the estimated parameters represent a first outline of the study of the species behavior
Desplanque, Carole. « Dendroécologie comparée du sapin et de l'épicéa dans les Alpes internes et franco-italiennes : rôle des facteurs climatiques et anthropique sur leur répartition ». Université Joseph Fourier (Grenoble ; 1971-2015), 1997. http://www.theses.fr/1997GRE10011.
Texte intégralArquilliere, Sylvie. « Morphologie, croissance, reproduction végétative de l'épicéa (Picea abies(L. )Karsten. ) dans une zone de combat subalpine : massif du Taillefer, Alpes dauphinoises ». Grenoble 1, 1986. http://www.theses.fr/1986GRE10080.
Texte intégralSALBITANO, FABIO. « Meccanismi di occupazione dello spazio da parte di semenzali e polloni dopo la ceduazione nella macchia mediterranea ». Doctoral thesis, 1992. http://hdl.handle.net/2158/606202.
Texte intégralKneeshaw, Daniel D. « Tree population dynamics of some old sub-boreal spruce stands ». Thesis, 1992. http://hdl.handle.net/2429/2992.
Texte intégralLi, Pei-Hua, et 李佩樺. « Tree Growth and Population Dynamics of Abies kawakamii in Mt. Xue, North Taiwan ». Thesis, 2019. http://ndltd.ncl.edu.tw/cgi-bin/gs32/gsweb.cgi/login?o=dnclcdr&s=id=%22107NCHU5360006%22.&searchmode=basic.
Texte intégral國立中興大學
森林學系所
107
Abies kawakamii (Kawakami fir) is a critical ecological indicator in subalpine ecosystems and is composed mostly of pure forest distributed 3100–3600 m above sea level, most typically on Mt. Xue of North Taiwan. Thus, the estimation of growth and stock may be worth including in discussions on the regeneration, biomass, and carbon storage of Kawakami fir forest. The content is separated into two parts: one is small scale for the single-tree level, and the other is large scale for the stand-stock level. By reconstructing and verifying the volume equation of Abies kawakamii, the dynamic stock from Mt. Xue was evaluated. Seven permanent plots (50 m × 40 m) were established at the preserved area in 2008 and were resurveyed in 2017. The study sample consisted of 18 trees that were uprooted by Typhoon Soudelor in 2015; among them, nine provided the parameter estimates for reconstructing the tree volume equation. To evaluate the volume equation, six models were selected to test the fitted model for the tree volume equation of the Kawakami fir. After comparing the structure and composition of the stand stock of trees in permanent plots between 2008 and 2017, the model with the best fit was used to calculate the variation within 10 years. The results revealed that the best model was the logarithmic equation of the Schumacher function, V = aDbHc (V = 0.000073087 D1.71399 H1.14667). At the single-tree level, the growth pattern of Abies kawakamii was diverse from a microhabitat perspective. The real tree age of a Kawakami fir was difficult to estimate on the basis of the diameter at breast height (dbh) because of the effect of strong competition among neighboring trees on the growth rate. At the stand level, the main differences among trees at different plots were attributable to different stages of succession, stand-stock densities, and characteristics of neighboring trees as well as the interference of typhoons and the inhibition of regeneration by dominant understory species. The short-term dynamics of plots over a period of 10 years revealed that the stand stock of Kawakami fir belonged to a cyclic succession. Overall, the class structure of the Kawakami fir forest was similar between 2008 and 2017 on Mt. Xue; although, most of the reduction in the Kawakami fir forest was caused by typhoons. Moreover, the growth of stock exceeded the death of stock within the 10-year period, which indicated that the stand stock of the Kawakami fir forest was still stable. According to the results of evaluating the stand stock and estimating the biomass on Mt. Xue, the permanent plots of the Kawakami fir forest can offer carbon sequestration of 2.4 ton per hectare per year.
Kellner, James Robert. « Population and community dynamics of tropical rain forest canopy trees ». 2008. http://purl.galileo.usg.edu/uga%5Fetd/kellner%5Fjames%5Fr%5F200805%5Fphd.
Texte intégralStretch, Anne-Marie. « A modelling approach to elephant and tree population dynamics for a small game farm ». Thesis, 2005. http://hdl.handle.net/10321/110.
Texte intégralThroughout Africa, growing human populations and resulting loss of wildlife habitat is a critical issue for most animal species. It is more and more common for privately owned small or medium sized farms to reintroduce wildlife on their land and such protected areas are fast becoming the only refuges available to wild animals. However a comprehensive understanding of the complex ecological processes taking place is vital for the effective management of restricted areas and the conservation of biodiversity. Due to the enormous complexity of an ecological system and the long periods of the related dynamics, it is very difficult to analyse the interaction between animals and plant populations without suitable computer models. In this thesis, the dynamics between elephant and trees (a major food source) are considered using computer simulations.
Xu, Ru Jun, et 許如君. « Population dynamics, spatial distribution, and sampling procedures of aulacaspis yabunikkei kuwana on camphor trees ». Thesis, 1995. http://ndltd.ncl.edu.tw/handle/21677187731623921675.
Texte intégralRibbons, Relena R. « Evaluating the Influence of Disturbance and Climate on Red Spruce (Picea rubens Sarg.) Community Dynamics at its Southern Range Margin ». 2011. https://scholarworks.umass.edu/theses/710.
Texte intégralPalisetty, Raghunadh. « Effects of sheep, kangaroos and rabbits on the regeneration of trees and shrubs in the chenopod shrublands, South Australia ». 2007. http://arrow.unisa.edu.au:8081/1959.8/28390.
Texte intégralHöhn, Patrick. « Funktionelle Vielfalt von Hymenopteren entlang eines Gradienten agroforstlicher Nutzung in Indonesien ». Doctoral thesis, 2007. http://hdl.handle.net/11858/00-1735-0000-000D-F136-9.
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