Dissertations / Theses on the topic 'Biocenoses'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 17 dissertations / theses for your research on the topic 'Biocenoses.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
Klein, Jean-Paul, and ZILLIOX LOTHAIRE. "Mecanismes d'echange nappe-riviere dans l'hydrosysteme rhenan : relations entre les biocenoses alluviales, qualite de l'eau et connectivite." Université Louis Pasteur (Strasbourg) (1971-2008), 1997. http://www.theses.fr/1997STR13033.
Full textBatriu, Vila Efrem. "La construcció de les comunitats vegetals de maresma al delta del Llobregat. Gradients ambientals, trets funcionals i interaccions biòtiques." Doctoral thesis, Universitat de Barcelona, 2014. http://hdl.handle.net/10803/286272.
Full textThe objective of this thesis is to improve the knowledge of plant community assembly rules in Mediterranean coastal marshes, taking as a case study of the Llobregat delta marshes. Specifically, over four chapters, we try to determine the environmental gradients that determine the distribution of species and plant communities, and how these affect the distribution of plant functional traits and the interspecific relationships. To do this we have installed 45 sampling points on the three dominant salt marsh communities in the Llobregat delta (reeds, rushes and shrubby chenopods formations). These sampling points were distributed in four different locations, which aim to collect the full range of situations in which these communities live. At each sampling point, we done a phytosociological relevé, we periodically measured groundwater parameters (conductivity and height) and soil (salt concentration). For each plant found in all the inventories we have obtained a series of functional traits (specific leaf area, seed production, etc...). In addition, 20 of these points we have performed a sampling of interspecific competition between Phragmites australis and Juncus acutus. Marsh communities studied show species paucity and are highly monospecific. These communities dominated by five species; J. acutus, J. maritimus, Spartina versicolor and P. australis Arthrocnemum fruticosum. The presence of these species either mainly determined by the ability to effectively tolerate the stresses imposed three biological environmental gradients; height of the water table, groundwater conductivity and soil ionic balance. These gradients determine the presence and abundance of certain plant functional traits of marsh plants, more exactly specific leaf area and seed weight. If more than one species can tolerate a set of abiotic conditions, these species coexist and they experience interspecific interactions. In most of these cases, these relationships are competitive, and the species that is able to grow faster excludes competitively the others. In some situations, the interspecific interactions are facilitative or lead to a mutual exclusion, therefore species can coexist together for long periods of time. Although we have not directly studied, the results obtained in this thesis suggest that in most cases the coexistence of species is not stable over time. Factors such as founder effect, herbivorous or stochasticity determine which one species excludes the other end.
El objetivo general de esta tesis es profundizar en el conocimiento de las reglas de construcción de comunidades vegetales de las marismas costeras mediterráneas, tomando como caso de estudio las marismas del delta del Llobregat. Concretamente, a lo largo cuatro capítulos, intentamos determinar cuáles son los gradientes ambientales que condicionan la distribución de las especies y las comunidades vegetales, y cómo estos afectan a la distribución de los rasgos funcionales de las plantas y las relaciones interespecíficas. Para ello hemos instalado 45 puntos de muestreo sobre las tres comunidades de marisma dominantes en el delta del Llobregat (carrizales, juncales y salicorniares). Estos puntos de muestreo se han repartido en cuatro localidades diferentes, que pretenden recoger todo el abanico de situaciones donde viven estas comunidades. En cada punto de muestreo hemos realizado un inventario fitosociológico, hemos muestreado periódicamente parámetros del agua freática (conductividad y profundidad) y del suelo (concentración de sales). Por cada planta encontrada en el conjunto de los inventarios hemos obtenido una serie de rasgos funcionales (área foliar específica, producción de semillas, etc...). Además, en 20 de estos puntos de muestreo hemos realizado un experimento de competencia interespecífica entre Juncus acutus y Phragmites australis. Las comunidades de marisma estudiadas son paucifloras y altamente monoespecíficas. Se trata de comunidades dominadas por cinco especies; J. acutus, J. maritimus, Spartina versicolor, P. australis y Arthrocnemum fruticosum. La presencia de estas especies bien determinada principalmente por la capacidad de tolerar de forma eficaz los estreses biológicos impuestos por tres gradientes ambientales; produndidad del agua freática, conductividad del agua freática y balance iónico del suelo. Estas gradientes determinan también la presencia y abundancia de ciertos rasgos funcionales de las plantas de marisma, concretamente el área foliar específica y el peso de las semillas. Si más de una especie puede tolera unas condiciones abióticas concretas, estas especies coexisten temporalmente y encontramos interacciones interespecíficas. En la mayoría de estos casos, se imponen las relaciones de tipo competitivo y aquella especie que es capaz de crecer más y más rápido termina excluyendo combativament a las otras. En algunas situaciones concretas, las especies encontramos fenómenos de facilitación o exclusión mutua y las especies pueden coexistir juntas largos períodos de tiempo. Aunque no lo hemos estudiado directamente, los resultados obtenidos en esta tesis nos hacen pensar que en la mayoría de casos la coexistencia de especies es poco estable a lo largo del tiempo. Factores como el azar, el efecto fundador o la herbívora determinan, que una de las especies termine excluyendo al resto.
Capdevila, Lanzaco Pol. "Life history, population dynamics and conservation of underwater Mediterranean forests: insights from the long-lived alga Cystoseira zosteroides = Història de vida, ecologia de poblacions i conservació dels boscos submergits del Mediterrani: el cas de l'alga longeva Cystoseira zosteroides." Doctoral thesis, Universitat de Barcelona, 2017. http://hdl.handle.net/10803/456298.
Full textLa teoria sobre les històries de vida i l’ecologia de poblacions desenvolupen principis ecològics basats principalment en estudis realitzats en espècies terrestres, sovint sense tenir en compte les espècies marines. A través d’aquesta tesi preteníem descriure alguns dels processos i mecanismes que configuren la dinàmica poblacional de Cystoseira zosteroides, una macroalga longeva i formadora d’hàbitat, que habita en aigües profundes del Mediterrani Nord- Occidental. En un context més ampli, també es pretén augmentar la nostra comprensió actual sobre la dinàmica poblacional i la història de vida de les macroalgues. Els resultats obtinguts mostren que C. zosteroides presenta una dinàmica poblacional molt lenta. Mentre que altres poblacions de Fucals i de Kelps d’hàbitats de poca profunditat depenen principalment de processos reproductius i del creixement dels organismes, les poblacions naturals i no pertorbades de C. zosteroides es mantenen gràcies a l’elevada supervivència i la llarga esperança de vida dels individus adults. També demostrem que la capacitat de dispersió de les macroalgues brunes és molt limitada en comparació amb altres taxons, tot i que els Kelps presenten un major potencial de dispersió que les Fucals. Els nostres resultats també demostren que la denso-dependència juga un paper clau regulant la dinàmica poblacional de C. zosteroides, ja que pot impulsar la seva recuperació després de grans pertorbacions. A diferència de les poblacions no alterades, després de grans esdeveniments de mortalitat, la recuperació i dinàmica de les poblacions de C. zosteroides depèn molt dels processos reproductius. Això és especialment preocupant donada la limitada dispersió efectiva d’aquesta espècie. No obstant, tot i que els esdeveniments de mortalitat aïllats es poden compensar amb polsos de reclutament, les nostres simulacions demogràfiques demostren que l’efecte combinat dels pertorbacions físiques, com les tempestes i les xarxes de pesca abandonades, comprometen la viabilitat de les poblacions de C. zosteroides. A més, hem demostrat que l’escalfament té un gran impacte en les primeres etapes de vida d’aquesta espècie, fet que retarda la capacitat de recuperació de C. zosteroides i augmenta la seva vulnerabilitat a altres pertorbacions. En general, els nostres resultats no només contribueixen a comprendre millor la dinàmica poblacional de les macroalgues, sinó que també proporcionen noves idees per a la seva gestió eficaç. Amb aquesta tesi, es demostra el paper clau de l’ecologia de poblacions i la història de la vida en la comprensió de la dinàmica de les espècies i destaca com aquestes disciplines poden ajudar-nos a entendre millor el futur dels ecosistemes marins costaners.
Zvyagina, N. Yu. "Characteristic of urogenital tract biocenosis pecular for women with pelvic inflammatory diseases." Thesis, Sumy State University, 2014. http://essuir.sumdu.edu.ua/handle/123456789/36583.
Full textRollard, Christine. "La biocenose associee aux araneides, en landes armoricaines : etude des relations insectes-araignees." Rennes 1, 1987. http://www.theses.fr/1987REN10041.
Full textKRESPI, LILIANE. "Etude de la biocenose parasitaire des pucerons des cereales dans le bassin de rennes : cas particulier d'aphidius uzbekistanicus luz." Rennes 1, 1990. http://www.theses.fr/1990REN10111.
Full textLa, Greca Pierluigi. "Diversità ed Ecologia degli Imenotteri Apoidei in ambienti frammentati pedomontani dell'Etna a differente pressione antropica." Thesis, Universita' degli Studi di Catania, 2011. http://hdl.handle.net/10761/300.
Full textThe bee fauna is extremely sensitive to environmental fragmentation processes, so that its composition and density are direct expression of the ecosystem structure and state of conservation. The main purpose of the present research has been the investigation of the biodiversity of the Hymenoptera Apoidea (Apis mellifera L. excluded) in fragmented areas within the territory of the Etna, in order to obtain a better knowledge of the specific composition, and to evaluate in detail the seasonal variations of the populations and the specificity linked to different types of environments. The investigated sites lie in the oriental pedemontane sector of Etna volcano and have a differentiated degree of anthropization, but all of them can be considered as territories with mean-high environmental fragmentation. The sites are: two urban parks in the town of Catania (Parco Gioeni and Parco degli Ulivi), a high degree of naturality of pedemontane Etna (Riserva Naturale Integrale and SIC Complesso Immacolatelle-Micio Conti, San Gregorio di Catania), and an organic agroecosystem (citrus orchard) (Acicatena). Besides, a control site in the northern periphery of Catania (Leucatia locality), the bee community of which is well known, has been taken into consideration. The surveys were carried out for three years (2008-2010) with protocol of collection and census, similar to that used within the Progetto Finalizzato A.M.A. (Ape, Miele, Ambiente), and consisted of monthly collections in every site, by using the linear transect method. In total, 1139 specimens were collected, belonging to 105 species comprised in the following families: Andrenidae, Halictidae, Anthophoridae, Megachilidae and Apidae. Various comparative zoocenotic analyses have been carried out, by the calculation of the main diversity indexes and different methods of multivariate analysis. Besides, through cartographic instruments, a mapping of the level of bio-permeability of the pedemontane territory, within which the investigated sites lie, has been produced, putting in evidence the areas more subjected to anthropic disturbance and those, instead, characterized by a higher level of naturality, in order to define territorial systems which may function as ecologic corridors thus guarantying adequate ecological connection necessary to maintain of a good level of bee biodiversity. The degree of environmental fragmentation has been evaluated by the biogeographic model of islands, particularly using the linear regression specie-area, considering the examined sites as islands at least under the ecological-functional point of view. The data obtained allowed the author to individualize suitable managing strategies in order to maintain adequate levels of biodiversity, especially the bee one, for those areas with high environmental fragmentation.
Nimmergut, Anja. "Radiolarienfauna im Ochotskischen Meer - eine aktuopaläontologische Charakterisierung der Biozönose und Taphozönose = Radiolarians in the Sea of Okhotsk - actuopaleontological characterisation of the biocenosis and taphocenosis /." Bremerhaven : Alfred-Wegener-Inst. für Polar- und Meeresforschung, 2002. http://www.gbv.de/dms/bs/toc/345568362.pdf.
Full textВасилега, В. Д. "Характерстика теріофауни м. Суми." Thesis, Сумський державний університет, 2017. http://essuir.sumdu.edu.ua/handle/123456789/63505.
Full textBoemi, Rosa. "Analisi della biodiversità della pedofauna in frutteti a conduzione tradizionale e biologica in zona B del Parco Regionale dell'Etna." Thesis, Università degli Studi di Catania, 2011. http://hdl.handle.net/10761/278.
Full textCurrently, italian agro-ecosistyems is featured by high level of production obtained by some external input that, in relation to increasing productivity, cause a noticeable reduction of heterogeneity in agronomics and natural ecosystems Today various authors claim that, at a reduction of biodiversity correspond a low level of ecosystem stability; for this reason they purpose agronomics management systems based on crops diversification and increase of natural marginal areas neighboring the agro-ecosystems;this practice improve biodiversity, specially for generalist and specific predators, pollinating insects etc, with a decrease of human interventions like use of pesticides. Most part of researches in this field aimed to establish the relationship between a certain type of agronomical practice and a specific group of insects with results that it differs in relation to: insect species, selected agronomical practice and location. Seldom the target aimed to a wider scale of biodiversity in reference to landscape mosaic, its effect on agroecosystem biocenotics composition, dynamic and homeostatic. Recent studies show that to high level of biodiversity in agroecosystems correspond more to neighboring landscape mosaic than a reduction of conventional agronomical practices. The area this research has been carried out in is called "Palmintelli", which can be found in B zone of the southern side of the Etna Park. The territory that we are analysing shows a situation characterised by wide woods, interposed by lava streams going back to different periods and which sometimes surround some "dagala" (real isle of natural vegetation) and by some orchards and vineyards. All this determines a mosaic of natural enviroments, half-natural and agrarian, fragmented and isolated, inserted in a context characterised however by a high level of natural landscape. This research has involved the study of communities of coleoptera (beetles) found in the soil of an orchard in biological cultivation (Bio)and another one adjacent planted in a traditional way(Con), underlining the structure, the differences and similarities from a qualitative and quantitative point of view.In the same period a similar study was held in two other survey posts next to the two above named orchards: a "dagala" (Dag) and an allotment (Mis) where the presence of fruittrees is associated with pieces of wild vegetation represented by oaktrees and chestnut trees. Inside each surved post some pit-fall traps have been installed filled with a solution of water, vinegar and table salt in saturation; the gatherings of the pit-fall traps took a six month period beginning from the second half of April till the firsthalf of October 2008. Altogether 17.296 samples have collected which were sorted out and determined in a taxa superior level; as to coleopterons, they were divided into different Families, species and morphospecies with a particular attention to the ones belonging to Carabidae, Stafilinidae, Tenebrionidae Families.The entrapments were standardized according to the effort. Altogether 35 Families and 193 species or morphospecies were recorded.The rate of frequencies and entrapments expressed as value of CS, of Coleopterons both as Families and species, was analysed during the entire period of sampling and in the different survey post and even in the single traps of every survey post. The following data of biodiversity have been processed: à à à ¢ à à à ¢ Inex of Margalef to evaluate the richness in taxa among the survey posts, indexes of Simpson (D) and of Shannon-Weaver (H) to evaluate the biodiversity of the survey post. à à à ¢ à à à ¢ The equal distribution was evaluated with the use of Pielouà à à ¢ s indexes (E) and of dominance. à à à ¢ à à à ¢ Other similar indexes have been elaborated especially of Sà à à à ¸rensen (QS) and of Jaccard (Cj), and their importance has been tested with the T-student and with SIMPROF. As to the comparison between the communities researchers applied a multi-layered analysis of the communities using two methods: the Non Metric Multidimensional Scaling based on the index of similarity of Bray Curtis , tested with ANOSIM and SIMPROF, and the analysis of the corrispondences. All the indexes, and the multi layered analysis of the communities were elaborated in relation with both the Families and the species and morphospecies of coleoptera with a particular regard to Carabidae, Stafilinidae,Tenebrionidae. The study has underline that: 1) Biodiversity of soil fauna results quite high for all selected Taxa (referred at both the families and species or morpho-species group). The à à à à ±-biodiversity values for each Station results significantly higher than expected in relation to patch extension, level of fragmentation and isolation. In general, coherence is observed between index of Margalef, Simpson and Shannon and the evenness index of Pielou. 2) The soil fauna biodiversity shows diversity in relation to different Stations and Taxa analyzed. In some cases, biodiversity appears directly correlated to intrinsic feature of each Station while, in other cases, it is correlated to the analyzed groups. Data show that biodiversity level assessment referred to a site has to take into account the animal component investigated that represents a whole community diversity, being influenced by biological and ecological characters of component itself. So it is not possible to take conclusion only form considering one or a few animal groups, although some areas have intrinsic features that make a strong and homogeneous connotation to the structure and characteristic of the soil fauna. 3) The biodiversity shows different features in relation to different period of analysis. August and September are, for all Taxa, the critical months because of their humidity and temperature rates. However the most abundant species recorded show their number peak in different periods. In other months analyzed Taxa show structure and distribution that allow them to cover all habitats with species that succeed to each other during the different months; that sustains recent studies which consider landscape mosaic a really important source of biodiversity. 4) The similarity indexes and the Non-metric Multidimensional Scaling based on the index of similarity of Bray-Curtis and Correspondence Analysis show, with statistical significant values, an homogeneity among traps of each Station regarding the biocenosis of soil fauna at all level probed. So it is observed a low similarity between the stations, highlighted from the quality indexes of Sà à à à ¸rensen, Jaccard and especially from the Non-metric Multidimensional Scaling, based on the index of similarity of Bray-Curtis and from the Correspondence Analysis. Dissimilarities between species are statistically significant. Rank/abundance analysis highlights a different structure for each station for Coleoptera species, as well for Carabidae, Staphylinidae and Tenebrionidae. The homogeneity of the Stations and their differences, considering their proximity and similarity about exposition, steepness and altitude, may be ascribed at diverse management modality of agro-ecosystems investigated, modality determining differences in the soil features of each Station. This research shows that each Station has a well defined and different fraction of soil fauna, so each selected environment retains a relevant and important biodiversity portion. The presence of strips of natural vegetation within the agro-ecosystems increases the environmental heterogeneity determining more richness and dynamicity in soil fauna communities. 5) This study has underscored the specific zoocenosis in each Station and their role for the preservation of biodiversity. However it remains to define the role of biodiversity as ecology-stabilizer of agro-ecosystems. 6) In relation to a careful territory management, with particular attention to protected areas, all natural patches must be preserved for their high biodiversity value. The present study shows the strategic role of the landscape mosaic in the preservation of biodiversity of the studied environments. Final, for a correct strategy of biodiversity preservation especially within a natural reserve, based on aesthetic and scientific criteria, it is very important maintaining an high level of landscape heterogeneity.
Hereu, Fina Bernat. "Role of trophic interactions between fishes, sea urchins and algae in the northwestern Mediterranean rocky infralittoral, The." Doctoral thesis, Universitat de Barcelona, 2007. http://hdl.handle.net/10803/1443.
Full textOwing to the existence of previous investigations, my work, strictly speaking, does not break any new ground, since the subject matter has already been well studied in other oceans (see Castilla 2000 for a revision). Paradoxically, the Mediterranean, them cradle of the natural sciences (Aristotle, 350 BC) and home to the invention of scuba diving by Gagnan and Cousteau in 1944, has generally not been witness to any of the most important advances in experimental benthic science. Whilst not wanting to question the universality of discoveries regarding benthic communities made in other waters, it can surely not be an excessive precaution to attempt to understand the way regional peculiarities - the Mediterranean is a very singular sea in many ways (Margalef 1985) - affect general principals.
One highly significant way in which benthic experiments in the Mediterranean are playing a part in current debate is the role that marine reserves or protected marine areas (PMAs) can be expected to play as management tools in ecosystems adversely affected by human action. In this sense, my work shares a characteristic with many others: the use of marine reserves as experimental sites that can be compared with nearby unprotected zones in order to try and judge their worth.
As a final reflection on the main object of study in my thesis it is worth remarking that the system under study relates on a trophic level macroscopic algae - the main primary producers in the phyto-benthos - to their herbivores, which in the coastal Mediterranean benthos are essentially a sea urchin (Paracentrotus lividus), a fish, the salema (Sarpa salpa), and a guild of omnivorous fish that include optional grazers of algae and predators on sea urchins. My study investigated the interactions taking place between all the actors in this complex community and not just the interactions occurring between a certain group of species, although inevitably, given its central position, the sea urchin Paracentrotus lividus has been the focal point of our efforts. As a means of simplifying, throughout this paper I often refer to the "triangle" 'algae-sea urchins-fish', which is described in more detail in Annex 1.
I feel that my work has two main applications. Aside from any knowledge gained from the experimental study of the interactions within a complex community under natural conditions, our results have, firstly, a clear role to play in the management of coastal areas and biological conservation in general. It is known that high densities of sea urchins can cause a regression and a loss of diversity in algal communities (that can be compared to the effects of desertification on the biodiversity of forest ecosystems).
Studying experimentally the mechanisms that regulate these interactions is a way of searching for valid management criteria. Secondly, we looked at the relevance of the role played by changes of anthropic origin such as eutrophication or overfishing in the proliferation of sea urchins and the regression of algal communities.
Dins el ventall d'especialitats en que s'acostuma a dividir l'ecologia, aquesta tesi s'enquadra en l'anomenada "ecologia de comunitats" (Diamond i Case 1986). Amb més precisió, el meu treball ha estat dedicat a investigar el grau en que les relacions tròfiques entre els organismes que formen una xarxa tròfica arriben a governar l'estructura i dinàmica de la comunitat que formen. L'aproximació es experimental i tot el treball s'ha realitzat al camp, basat en el que hom anomena "experiments naturals" amb les seves virtuts i inconvenients. L'ecosistema triat ha estat el bentos marí litoral, i en concret les comunitats de l'infralitoral rocós. Es tracta d'un marc de treball favorable, ja que aquest escenari ha produït algunes de les contribucions més importants a l'ecologia de comunitats, sobretot en el que fa al desenvolupament de la seva vessant experimental (revisat per Castilla 2000).
A causa d'aquests treballs precedents, una part dels objectius del meu treball no és estrictament novedosa, ja que han estat molt estudiats en altres mars (veure Castilla 2000 per a una revisió). Paradoxalment tractant-se del mar que ha estat el bressol de les ciències naturals (Aristòtil, cap el 350 a.C.) i de la invenció de l'escafandre autònom per Gagnan i Cousteau el 1944, la Mediterrània ha quedat en gran mesura fora de l'àrea on han tingut lloc els avenços de l'ecologia bentònica experimental. Tot i que confíem en l'universalitat de les descobertes més sòlides de l'ecologia de comunitats bentòniques, mai serà una precaució excessiva per als ecòlegs copsar la forma en que les particularitats regionals (la Mediterrània es un mar en molts sentits singular; Margalef 1985) modelen aquests principis generals.
A més, almenys en una part sí que les experiències d'ecologia bentònica mediterrànies participen de la més disputada actualitat, i és en el paper que hom pot esperar que realitzin les Reserves Marines o Àrees Marines Protegides (MPA's) com eines de gestió racional d'uns ecosistemes massa castigats per l'acció humana. En aquest sentit el meu treball comparteix amb molts altres que es realitzen actualment el tret d'utilitzar les Reserves Marines com un dels tractaments experimentals estudiats i, per comparació amb el que succeeix a les zones properes no protegides, tracta d'esbrinar els seus efectes.
Per acabar de focalitzar el tema objecte de la meva tesi només cal afegir que el sistema estudiat és el que relaciona tròficament les algues macroscòpiques, com principals productors primaris del fito-bentos, amb els seus herbívors, que al bentos litoral mediterràni es poden simbolitzar en una espècie de garota de mar ("Paracentrotus lividus") i un peix ("Sarpa salpa"), i amb el gremi de peixos omnívors entre els que es compten opcionals pasturadors d'algues i depredadors de les garotes herbívores. L'estudi aborda les interaccions entre tots els elements d'una comunitat complexa, i no només d'algunes espècies selectes, encara que, pel seu paper central, la garota "Paracentrotus lividus" ha concentrat més esforços que la resta. Al llarg de la memòria i per simplificar, parlarem sovint d'aquest "triangle" algues-garotes-peixos, que es descriu amb més detalls en l'Annex 1.
Crec que l'interès d'aquest treball pot ser doble. Més enllà del coneixement que pot aportar a l'Ecologia de comunitats l'estudi experimental de les interaccions d'una comunitat complexa en condicions naturals, els resultats tenen un clar interès aplicat per a la gestió dels litorals i per a la biologia de la conservació. És sabut que altes densitats de garotes poden provocar la regressió de les comunitats algals i una forta pèrdua de diversitat (que pot ser comparada als efectes de la desertització sobre la biodiversitat dels ecosistemes forestals). Estudiant experimentalment els mecanismes que regulen aquestes interaccions busquem aportar criteris vàlids per a la gestió. Un tema d'especial interès ha estat esbrinar quin paper han pogut jugar canvis d'origen antròpic, com els derivats de l'eutrofització o de la sobre-pesca, en la proliferació de les garotes i la regressió de les comunitats algals.
Hennezel, Claire d'. "Analyse communicationnelle des stratégies d'intelligence économique et des pratiques de veille dans le cadre de l'innovation : le cas des petites entreprises de l’industrie aéronautique, en Nouvelle Aquitaine." Thesis, Bordeaux 3, 2017. http://www.theses.fr/2017BOR30005.
Full textCompetitive intelligence (CI) and business intelligence are strategies that are well established in large companies and large SMEs. Since the Carayon report in 2003, competitive intelligence has become a public policy. These concepts have been of interest to several scientific disciplines since then, which gives them an interdisciplinary character. They are empirical and hybrid objects because they are derived from the practices of companies. The main disciplines to be studied here are the CIS and the management sciences, for the main ones, but also for the economics. The subject has been much observed, especially in large companies, notably by the management sciences because the competitive intelligence is mainly strategy of decision support. Today, in SIC, these objects are studied in particular from an information point of view, because information is at the heart of the processes examined. There are recurring problems in the analysis of these rather young concepts, which revolve around the difficulties of implementing these strategies in companies on the one hand, and the obstacles to the establishment of French public policy on the matter on the other hand. There are paradoxes about them. Small businesses and especially very small businesses have been little studied by the various scientific disciplines concerned, which is surprising given the importance of this type of companies in the national economy. On the other hand, public policies, which are fairly well perceived by large companies and large SMEs, fail to penetrate small businesses. This leads us to question the reasons for the barriers to these small business strategies and policies. The postulates of this research are based on the central idea that there are characteristics specific to small enterprises because of their structural constraints. These small companies are implementing their own disruptive CI strategies, which are based on processes that are inverse to those modeled for large enterprises. These processes are communicational in nature. Competitive and business intelligence in small businesses are based on a collaborative information-sharing culture. These strategies are implemented within the framework of an innovative organizational structure, reticular, quasi-organization, based on an organizational communication and built on a network strategy. Finally, competitive intelligence in small enterprises is based on a sphere of mediation, economic biocenosis, constituted by an entanglement of relations between several economic actors including state institutions which play a leading role
Negroni, Mirko. "Studio degli ecosistemi bentonici nei sedimenti superficiali del Mare di Ross." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/18008/.
Full textValencia, Cruz José María. "Paràsits de mol·luscs bivalves a les Illes Balears: Detecció de Marteilia refringens i Perkinsus mediterraneus mitjançant tècniques moleculars." Doctoral thesis, Universitat de les Illes Balears, 2016. http://hdl.handle.net/10803/396224.
Full textUna de las principales limitaciones a la que se enfrenta la producción de moluscos bivalvos es la prevención y control de enfermedades, dispersadas, principalmente, por movimiento de partidas. En las Baleares, hemos encontrado parásitos de bivalvos poco patogénicos como Bucephalus haimeanus, Mytilicola intestinalis y metacercarias de tremátodos. También otros que suponen un riesgo para la producción, como Marteilia refringens, Perkinsus mediterraneus y P. olseni. La presencia de M. refringens es una grave amenaza, pues produce desórdenes fisiológicos que pueden matar al huésped. Probablemente, en los años 80, la desaparición de los bancos ostrícolas fue causada por esta enfermedad. Los mejillones también són susceptibles a la infección por M. refringens, pero són resistentes a la enfermedad. En 2004, se detectó una mortalidad en el banco de la chirla (Chamelea gallina) de s‘Arenal de Palma de Mallorca. Para detectar la especie causante de la enfermedad se recurrió a técnicas histológicas, hibridación in situ, PCR y PCR anidada. La secuencia obtenida a partir de un bloque de parafina mostró un 99,1% de similitud con M. refringens tipo O. De esta manera se concluyó que el agente etiológico era M. refringens y posteriormente, que la prevalencia era del 55,1%. La ubicación específica de las células de Marteilia refringens en los tejidos de la chirla se determinó por hibridación in situ, encontrando todas las fases conocidas, incluida la de esporulación, lo que demuestra que el parásito completa la infección en la chirla. Perkinsus mediterraneus infecta a una gran variedad de moluscos bivalvos en el archipiélago balear: Ostrea edulis, Mimachlamys varia, Arca noae, Chamelea gallina, Pinna nobilis y Venus verrucosa, sin mortalidades asociadas a este parásito. Perkinsus olseni sólo se ha detectado en V. verrucosa, pero en el presente estudio no lo hemos encontrado. La búsqueda de Perkinsus spp. se ha realizado mediante RFTM y la determinación de la especie por PCR-RFLP y secuenciación. La prevalencia de P. mediterraneus ha sido similar a la de otras especies de Perkinsus y la dinámica de su infección es similar a la de P. marinus en la bahía de Chesapeake, con valores máximos de detección del parásito en septiembre y octubre, después del máximo estival de temperatura, y regresión de la infección en invierno. Hemos encontrado 12 haplotipos de P. mediterraneus con una elevada similitud genética. Las diferencias se hacen mayores al incluir secuencias procedentes de la bases de datos del GenBank, aumentando el número de haplotipos a 24. Los análisis filogenéticos han detectado, en conjunto, tres grupos diferentes de O. edulis de Menorca, que se diferencian de otros linajes coespecíficos. Los análisis apoyan esta diferenciación entre las poblaciones de Menorca y Mallorca, la cual parece, en buena parte debida al aislamiento geográfico del puerto de Mahón. Sin embargo, otros factores, como la variabilidad ambiental, diferentes localidades y fechas de detección, la translocación de animales, la actividad humana, etc, pueden tener cierta influencia. En el Mediterráneo occidental se encuentran tres especies de Perkinsus. Aunque se conoce que se producen coinfecciones en la escupiña grabada del puerto de Mahón con P. olseni y P. mediterraneus, no hemos encontrado ningún caso, ni tampoco bivalvos afectados por P. chesapeaki, especie que se ha detectado en el delta del Ebro. En diferentes muestreos de C. gallina hemos detectado la presencia de M. refringens y P. mediterraneus. Aunque no hemos encontrado coinfección, ésta no se puede descartar, porque los individuos són muy jóvenes y posiblemente ambos patógenos estén en las fases iniciales de infección. Teniendo en cuenta que la esporulación de M. refringens se inicia cuando la temperatura del agua es de 17ºC (mes de mayo), que las zoosporas de P. mediterraneus aparecen más tarde (septiembre-octubre) y que la mortalidad se detecta en junio-julio, lo más probable es que la causa sea la marteiliosis
One of the main issues in bivalve mollusc production is the prevention and control of diseases, scattered mainly by stock movements. In the Balearic Islands, we found low pathogenic bivalve parasites as Bucephalus haimeanus, Mytilicola intestinalis and trematode metacercariae. Furthermore, we found others that are a threat for their welfare, like Marteilia refringens, Perkinsus mediterraneus and P. olseni. M. refringens is a serious threat, because it causes physiological disorders that could kill the host. Presumably, in the 80s, this disease was the agent of oyster banks die out. Mussels are susceptible to the infection, but they are resistant to the disease. Mass mortality was detected in 2004 at the striped Venus shell (Chamelea gallina) bed in S‘Arenal beach. We use histological techniques, in situ hybridization, PCR and nested PCR to detect the disease agent. From a paraffin block we retrieved a sequence which showed 99.1% similarity with M. refringens type O. Thus, it was concluded that the aetiological agent was M. refringens. Subsequently, we found a prevalence of 55.1%. Marteilia refringens specific location in striped Venus shell tissues was determined by in situ hybridization. We observed all known stages, including sporulation, thus this parasite could complete its vital cycle in C. gallina, and so striped Venus shell should be considered as a new host of M. refringens. A wide bivalve mollusc variety is infected by Perkinsus mediterraneus in Balearic Islands: Ostrea edulis, Mimachlamys varia, Arca noae, Chamelea gallina, Pinna nobilis and Venus verrucosa, but they are not killed by this parasite. Perkinsus olseni has only been detected in V. verrucosa from Mahon harbour, although we have not detected it in another bivalve species. Perkinsus spp. search was performed using RFTM and species was established by PCR-RFLP and sequencing. P. mediterraneus prevalence was similar to other Perkinsus species and their infection dynamics is like P. marinus’ in Chesapeake Bay, with maximum detection values in September and October, after summer peak temperature with infection regression in winter. We have found 12 P. mediterraneus haplotypes, all of them sharing a high similarity. Differences grow up when we added GenBank sequences. Then, the haplotype number raised 24. Three groups of O. edulis from Minorca were revealed by phylogenetic analyses which are different from other co-specifics lineages. Analysis supported this differentiation among populations from Minorca and Majorca. This differentiation could be due to Mahon harbour geographic isolation. Nevertheless, another factors, such environmental variability, different detection locations and dates, animal translocations, human activity, etc., might also have some influence. There are three Perkinsus species at the western Mediterranean. Although it is known that co-infections between P. olseni and P. mediterraneus can happen in warty Venus shell from Mahon harbour, we have not found any occurrence. Furthermore, we have not detected infection by P. chesapeaki, although it has been found in the Ebro delta. We have found out M. refringens and P. mediterraneus presence in different C. gallina samples. Although coinfection has not been found, we cannot discard it, because individuals are very young and perhaps both pathogens are in early infection stages. Given that M. refringens sporulation starts when water temperature is 17ºC (May), P. mediterraneus zoospores appear later (September-October) and mortality is detected in June-July, in this way, marteiliosis might be the candidate.
Carvalho, Joana Fernandez de. "Aplicação de técnicas de vídeo subaquático na caracterização de biocenoses marinhas." Master's thesis, 2008. http://hdl.handle.net/10400.1/489.
Full textDesenvolveu-se um trenó de vídeo subaquático para a caracterização das biocenoses marinhas da costa algarvia. Esta técnica foi usada pela primeira vez na região, pretendendo-se assim avaliar a sua aplicabilidade como técnica de amostragem. Filmaram-se um total de 19612m2, entre Junho e Novembro de 2005, no intervalo de profundidade dos 0 aos 30m. Dos vídeos, retirou-se tanto informação qualitativa e quantitativa relativa aos taxa, assim como referente ao habitat. Observou-se um total de 19401 especimens correspondentes a 64 taxa (23 de peixes e 41 de invertebrados). Verificou-se que a abundância foi significativamente diferente entre os três patamares de profundidade estudados ([0-10], [10-20] e [20-30]), tendo sido o intervalo mais profundo o que apresentou a maior abundância. Relativamente ao tipo de substrato arenoso, a abundância foi significativamente diferente entre a areia grosseira e fina, sendo esta a que apresentou uma maior abundância. Dados relativos à profundidade e características do substrato foram analisados e comparados com análise multivariada de forma a classificar e identificar os biótopos da zona de estudo. Desta análise distinguiram-se seis biótopos: Areias Grosseiras com povoamentos de Callionymus, Areias Grosseiras com povoamentos de Serpulidae e Sphaerechinus granularis, Areias finas com povoamentos de Infauna, Areias Finas e Vasa com bancos de ofiurídeos negros Ophiocomina nigra, Areias cascalhosas circalitorais com povoamentos de Phallusia mammillata e Serranus hepatus e Areias circalitorais com Bancos de Turritella. Os resultados do vídeo foram ainda comparados com os de outras duas técnicas de amostragem mais tradicionais, arrasto científico e censos visuais por mergulho. O mergulho apresentou a abundância total da zona de estudo e a diversidade mais elevada, enquanto que o vídeo apresentou os valores mais baixos em ambas categorias. O vídeo foi mais semelhante com o mergulho a nível qualitativo enquanto que quantitativamente esteve mais próximo do arrasto. Este trabalho avalia a aplicação do vídeo subaquático como técnica de amostragem, e demonstra a sua eficácia para a caracterização, classificação e mapeamento de habitats bentónicos marinhos e as suas comunidades.
Pinto, Cláudio André da Silva. "Coberturas verdes como biossistemas tecnológicos para espaços urbanos: estudo de caso e estudos à escala laboratorial." Master's thesis, 2018. http://hdl.handle.net/1822/55556.
Full textAs coberturas verdes são uma tendência cada vez maior em áreas urbanas pois oferecem serviços inquestionáveis. Os benefícios oferecidos estão relacionados com o funcionamento destes ecossistemas que depende principalmente, das espécies de plantas selecionadas, dos substratos que as suportam e das biocenoses da rizosfera. O desenvolvimento e capacidade de cobertura de Sedum album (Sa), Armeria maritima (Am) e Rosmarinus officinalis var. prostratus (Rp) foi avaliado em ensaios realizados em microcosmo e em mesocosmo, que seguiram a estrutura de uma cobertura verde extensiva. Em microcosmos com um substrato técnico (T), as plantas não apresentaram diferenças no crescimento se regadas ou não durante um mês. O efeito no desempenho de Sa em diferentes substratos: escórias da indústria metalúrgica (R), argila expandida e solo vegetal (P), P suplementado com 2% de hidróxido de alumínio (PLAA) e P com 10% de escórias de ferro (PFe), não foi muito relevante. As espécies acima referidas foram plantadas conjuntamente em mesocosmos, nos substratos T, R e P. Sem rega artificial durante 8 meses (fev - out), todas as plantas evidenciaram resistir ao stress hídrico em qualquer dos substratos. Contudo, Sa no substrato T evidenciou melhor performance. Apesar disso a utilização de resíduos metalúrgicos neste tipo de substratos, mostra potencialidade que precisa de confirmação. As biocenoses de eucariotas analisadas por microscopia ótica em suspensões de amostras de substrato de todas as condições experimentais evidenciaram sempre uma grande abundância de protistas (>80-90%), sobretudo ciliados e amebas com teca. No estudo de caso realizado numa cobertura verde extensiva, amostras recolhidas na rizosfera de 4 espécies de plantas, incluindo Sa e Am, apresentaram similar abundância relativa (%) de protistas e metazoários, mas maior diversidade do que nos ensaios em microcosmo e mesocosmo. Estudos mais aprofundados sobre o papel das biocenoses de eucariotas poderão confirmar a sua utilidade como bioindicadores da performance de coberturas verdes.
Green roofs are a growing trend in urban areas as they offer unquestionable benefits. The benefits offered are related to the functioning of these ecosystems, which depends mainly on the species of plants selected, the substrates that will support them and the rhizosphere’ biocenosis. The development and coverage of Sedum album (Sa), Armeria maritima (Am) and Rosmarinus officinalis var. Prostratus (Rp) was evaluated in microcosm and mesocosm, following the structure of an extensive green roof. In microcosms with a technical substrate (T), the plants showed no differences in growth whether irrigated or not for one month. The effect on the performance of Sa in different substrates: slag from the metallurgical industry (R), expanded clay and vegetal soil (P), P supplemented with 2% aluminum hydroxide (PLAA) and P with 10% iron slag (PFe), was not very relevant. The above species were planted together in mesocosms, on substrates T, R and P. Without artificial irrigation for 8 months (Feb - Oct), all plants resisted to water stress in any of the substrates, however Sa in substrate T showed better performance. Nevertheless, the use of metallurgical residues in this type of substrates shows potentiality that needs confirmation. The eukaryotic biocenosis analyzed by optical microscopy in suspended substrate samples from all experimental conditions, always showed a great abundance of protists (> 80-90%), mainly ciliates and testate amoebas. In the case study in an extensive green cover, where samples collected in the rhizosphere of 4 plant species, including Sa and Am, presented similar relative abundance (%) of protists and metazoa but greater diversity. Further studies on the role of these biocenosis’ organisms may confirm their utility as green roofs performance’ bioindicators.
Ferreira, Ana Bernardete Norberto. "Contribuição dos substratos de leitos de plantas para as biocenoses rizosféricas e eficiência do tratamento de águas residuais." Master's thesis, 2014. http://hdl.handle.net/1822/34567.
Full textOs leitos de plantas apresentam-se cada vez mais como uma solução tecnologicamente económica, eficiente e sustentável para o tratamento de águas residuais especialmente adequados a pequenos aglomerados populacionais. O substrato é um dos principais componentes destes sistemas, influenciando a eficiência do tratamento de águas residuais. Este é essencial para a fixação das plantas e também para o desenvolvimento das comunidades microbiológicas. Servindo de matriz ao percurso das águas residuais, pode eventualmente determinar as biocenoses da rizosfera. O trabalho desenvolvido incluiu a monitorização das biocenoses do substrato do leito de plantas a tratar águas residuais da unidade turística do Paço de Calheiros (Ponte de Lima), e a inventariação da biodiversidade do charco que recebe as águas tratadas no referido leito. Incluiu também a avaliação em mesocosmo e microcosmo da carga orgânica de diferentes tipos de materiais a utilizar como substrato, estudando a influência do uso destes no desenvolvimento de biocenoses. Foi ainda analisada a potencialidade do uso da espetrotofometria na monitorização da qualidade de águas e avaliada a informação fornecida pela determinação da tensão superficial de diferentes tipos de águas. Uma grande variabilidade foi observada entre as biocenoses dos sistemas do Paço de Calheiros, provavelmente associada às diferentes características de cada um dos sistemas. Dos materiais avaliados para substrato de leitos plantados, o Bagaço de Azeitona Extractado apresentou uma carga orgânica muito elevada, os colmos de Phragmites australis uma carga orgânica inicial da ordem dos 400mgL-1 de CBO5 e a casca de Eucalyptus globulus nunca ultrapassou os 60mgL-1 de CBO5. A espetofotometria apresentou fortes relações com a carga orgânica presente nas amostras de água residual, indiciando-se como uma alternativa viável, rápida e económica para estimar este parâmetro. A determinação da tensão superficial apesar de fornecer indicações sobre as características de uma amostra de água, não indica que tipo de substâncias poderão estar presentes na mesma, podendo ser complementada por análise espetrofotométrica UV-Vis.
The constructed wetlands are presented as an efficient, sustainable and economic technological solution for the treatment of wastewater especially suitable for small villages. The substrate is a key component of these systems influencing the efficiency of the wastewater treatment. It is essential for the establishment of plants and also for the development of microbial communities. Serving as a matrix to the route of wastewater may even eventually enhance rhizosphere biocenoses. This work included the monitoring of the substrate biocenoses from a constructed wetland treating wastewater of a tourism unit, Paço de Calheiros (Ponte de Lima), and the inventory of the pond’s biodiversity that receives treated water from that system. It also included the evaluation of the organic load from different types of materials as substrate using mesocosm and microcosm, studying their influence in rhizosphere biocenoses. The spectrophotometry potential to monitor water quality was also analysed, and the information supplied by surface tension determination from different types of water was evaluated. A great variability was observed among the Paço de Calheiros’s systems biocenoses probably related to the different characteristics of each system. Form the materials being evaluated it was the pomace extract the one with the highest organic load, followed by Phragmites australis stalks with inicial BOD5 about 400mgL-1 and Eucalyptus globulus barks with BOD5 never above 60mgL-1. The spectrophotometry showed strong relationships with organic matter present in the wastewater samples, indicating it could be a viable, fast and economical alternative to estimate this parameter. The determination of surface tension while providing information on the characteristics of a sample of water does not indicate what substances may be present in it, but tensiometry may be complemented by UV-Vis spectrophotometry.