Dissertations / Theses on the topic 'Ecosystem engineer'
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Wodika, Ben. "EFFECTS OF TIME, SEED SOURCE, AND PLANT COMPOSITION ON MACROINVERTEBRATES IN RESTORED PRAIRIE." OpenSIUC, 2015. https://opensiuc.lib.siu.edu/dissertations/1088.
Full textMcCaffery, Magnus. "The influence of an ecosystem engineer on nutrient subsidies and fish invasions in Southwestern Montana." Diss., [Missoula, Mont.] : University of Montana, 2009. http://etd.lib.umt.edu/theses/available/etd-03102010-102211.
Full textBush, Laura Elizabeth. "Stability and variability of the ecosystem engineer Sabellaria alveolata on differing temporal and spatial scales." Thesis, Bangor University, 2016. https://research.bangor.ac.uk/portal/en/theses/stability-and-variability-of-the-ecosystem-engineer-sabellaria-alveolata-on-differing-temporal-and-spatial-scales(1deae07d-a12b-4f61-9838-77e1a8bc9cca).html.
Full textHochhalter, Samuel J. "Patch-Scale Effects of an Invasive Ecosystem Engineer on the Structure and Function of a Eutrophic Stream." DigitalCommons@USU, 2009. https://digitalcommons.usu.edu/etd/307.
Full textVitelli, Frederico. "Herbivory by Parma mccullochi (Pomacentridae) : its role as an ecosystem engineer in temperate algal-dominated reefs." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2013. https://ro.ecu.edu.au/theses/583.
Full textJames, Alexandra Iona Biological Earth & Environmental Sciences Faculty of Science UNSW. "Development of resource-rich patches by soil-disturbing animals in arid environments." Awarded by:University of New South Wales. Biological, Earth & Environmental Sciences, 2009. http://handle.unsw.edu.au/1959.4/44353.
Full textMartin, Stephanie Ann, and Marietjie Landman. "The Aardvark as an ecological engineer in the Eastern Karoo: dig patterns and emergent processes." Thesis, Nelson Mandela Metropolitan University, 2017. http://hdl.handle.net/10948/11952.
Full textNjozela, Cuma. "The role of the sandprawn, Callichirus kraussi, as an ecosystem engineer in a temporarily open/closed Eastern Cape estuary, South Africa." Thesis, Rhodes University, 2013. http://hdl.handle.net/10962/d1001539.
Full textPosthumus, Erin Elizabeth. "Do Red Squirrel Middens Promote Vertebrate Species Diversity?" Thesis, The University of Arizona, 2013. http://hdl.handle.net/10150/294022.
Full textBancroft, Wesley J. "Environmental response to burrowing seabird colonies : a study in ecosystem engineering." University of Western Australia. School of Animal Biology, 2004. http://theses.library.uwa.edu.au/adt-WU2005.0064.
Full textSancomb, Elizabeth J. "Direct and indirect effects of white-tailed deer (Odocoileus virginianus) herbivory on beetle and spider assemblages in Northern Wisconsin." Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1408363956.
Full textJones, Kevin Christopher. "Ecological effects of the feeding and construction activities of the Eurasian beaver (Castor fiber) in Scotland : implications for reintroduction." Thesis, University of Stirling, 2006. http://hdl.handle.net/1893/211.
Full textVeras, Priscila de Cerqueira. "Papel do peixe Malacanthus Plumieri (Actinopterygii) na estrutura dos bancos de rodolitos do Arquipélago de Fernando de Noronha - Brasil." reponame:Repositório Institucional da UFABC, 2016.
Find full textDissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Evolução e Diversidade, 2016.
Engenheiros Ecossistemicos (EE) modulam a disponibilidade de recursos no ambiente. Este e o caso dos rodolitos (i.e. gnodulos de vida livreh compostos por mais de 50% de algas calcarias incrustantes que formam bancos em fundos inconsolidados) que promovem habitats para diversos organismos. Por outro lado, muitos desses organismos modulam condicoes para o crescimento de rodolitos. Esta interacao resulta na criacao de redes altamente dependentes de EEs. O peixe Malacanthus plumieri move rodolitos para a construcao de montes. Esta movimentacao altera o estado fisico de nodulos e, possivelmente, contribua para a diferenciacao das comunidades associadas. Portanto, avaliamos se as comunidades de macrofauna vagil (> 500¿Êm) presentes nos montes sao afetadas de forma positiva, negativa ou neutra em relacao a area controle (i.e. sem interferencia do M. plumieri). Alem disso, procuramos identificar as principais variaveis fisicas, que sao alteradas pelo peixe, que predizem a estrutura da macrofauna associada aos rodolitos. Para tanto, amostramos no Arquipelago de Fernando de Noronha 30 rodolitos na area controle e 30 nos montes. Cada nodulo foi individualmente inserido em sacolas de nylon com malha de 500¿Êm. Os epibiontes foram removidos e identificados. Mensuramos volume e diametros de cada rodolito e quantificamos o peso seco das macroalgas e do sedimento. Observamos que rodolitos da area controle apresentaram maior quantidade de macroalgas epifitas e sedimentos aprisionados quando comparados com rodolitos presentes nos montes (t=-0,04, p<0,001 e t=-0,54, p <0,001; respectivamente). A bioturbacao causada por M. plumieri altera as condicoes para o estabelecimento da macroalgas, reduzindo as taxas de sedimentos aprisionados. Como resultado, ha uma reducao na abundancia, riqueza e densidade de macroinvertebrados (t=-7,42, p<0,001; t=-7,92, p<0,001; t=-2,84, p<0,01; respectivamente). Portanto, M. plumieri afeta indiretamente a comunidade de macroinvertebrados vageis. Em contraste com outros estudos, o efeito da coexistencia destes EEs parece ser antagonico (i.e. positivo para a abundancia e riqueza de ictiofauna e negativo para macroalgas e macroinvertebrados). Assim, mudancas estruturais no sistema, embora promovidas pelo mesmo EE, influenciam comunidades de diferentes maneiras e sao dependentes da escala dos organismos em questao.
Ecosystem engineers (EE), such as rhodoliths, control the availability of resources in the environment, providing habitats for other organisms, as other algae and many animals. Some of these organisms are able to modulate the environmental conditions where rhodoliths grow, thus forming a highly dependent network. The sand tilefish Malacanthus plumieri, for example, moves rhodoliths to build mounds over their burrows. This behavior changes the physical medium in which the nodules are, and therefore, their associated communities¿ structure and composition. We assessed the effect of communities associated with mounds in comparison to non-mounded areas (i.e. rhodolith areas without the interference of the tilefish). Additionally, we seek to identify the main physical variables changed by the action of M. plumieri in predicting the structure of the macrofauna associated with rhodoliths. Rhodoliths from non-mounded areas showed higher amounts of epiphytic macroalgae and sediment trapped on rhodoliths than mounds (t=-0.04, p<0.001 and t=-0.54, p<0.001, respectively). Bioturbation caused by M. plumieri alters the conditions for macroalgae establishment, reducing the trapped sediment. As a result, there is also a reduction in the abundance, richness and density of macroinvertebrates (t=-7.42, p<0.001, t=-7.92, p<0.001, t=-2.84, p<0.01 respectively). The ecosystem role of M. plumieri indirectly affects the vagile macrofauna community. In contrast to other studies, the coexistence of these EEs (i.e. rhodoliths and tilefishes) seems to be antagonistic (i.e. positive for the abundance and richness of ichthyofauna and negative for macroalgae and macroinvertebrates). Thus, structural changes in the system, although promoted by the same EE, influence communities in different ways depending on the scale of the organisms in question.
Jones, Auriane. "Effect of an engineer species on the diversity and functioning of benthic communities : the Sabellaria Alveolata reef habitat." Thesis, Brest, 2017. http://www.theses.fr/2017BRES0142/document.
Full textCoastal zones worldwide are home to a large diversity of ecosystem engineers that perform key functions such as the recycling of organic matter and nutrients. The habitats resulting from the biological activity of these species are exposed to numerous disturbances such as over harvesting and trampling or via coastal modification. In this context, it is becoming key to understand the functioning of these engineered habitats and how they are affected by increasing disturbances. During my PhD, I used the reef habitat built by the gregarious tubiculous polychaete Sabellaria alveolata as a study case. First, the environmental and biotic changes associated with the establishment of a S. alveolata reef and its increasing disturbance were assessed, focusing on sediment characteristics (e.g. grain-size distribution, organic matter content) along with taxonomic diversity and species assemblage. In the same vain, the third article looks into the trophic functioning of the reef community and a control community to understand the effects of the establishment of the engineer species on carbon transfers, successively looking at the whole consumer community, the primary consumers and the importance of autochthonous (microphytobenthos and Ulva sp.) vs allochthone (phytoplankton) food sources. In this part, I used carbon and nitrogen stable isotopes and different analytical approaches such as isotopic niche metrics and mixing models. Article 2 aims towards understanding the interactions between reef habitat complexity, autochthonous food source heterogeneity and spatial scales in explaining the carbon isotopic ratio variations of S. alveolata and an associated suspension-feeder. In the last two chapters, I address the functioning of the engineered habitat either directly, using benthic core incubations to measure biogeochemical fluxes (e.g. oxygen demand) or indirectly, through the use of integrative functional and isotopic diversity indices. This last part reveals the existence of an optimum value of S. alveolata density, used as a disturbance proxy, where the trophic niche and the biogeochemical functioning of the reef are both maximal
Guerin, Natalia. "Impacto da invasão e mecanismos de regeneração natural do cerradão em áreas ocupadas por Pteridium arachnoideum (kaulf.) Maxon (Dennstaedtiaceae) no sudoeste do Estado de São Paulo." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/18/18139/tde-06052010-084435/.
Full textThe genus Pteridium comprises bracken species recognized by large fronds and a rhizome system that allows their fast expansion. Bracken presents an elevated biomass production throughout the year, that increases fire occurrence and release chemical compounds that are considered allelopathic. Nowadays, species of the genus Pteridium are well known as problem-species, due to their expansion and occupation of large areas around the world, causing great economic and ecological impacts. Aiming at the comprehension of bracken invasion over cerrado vegetation, we studied its impact over the plant community and, also, the slow natural regeneration process of cerrado recovery after invasion. We analyzed savanna woodland areas that have been invaded for over four decades, at Assis Ecological Station (EEcA), in southwestern São Paulo State. We analyzed the floristic composition and the plant community structure in an invaded area, compared to a non invaded patch of savanna vegetation. Components of the arboreal and regeneration strata were analyzed, in order to verify which species managed to pass by the physical and chemical barrier imposed by bracken. We assessed 100 points to assemble the floristic composition, using the quarter method, and for the community structure we used 15 plots of 10 m x 30 m to assemble the superior strata. The intermediate layer was assessed by sub-plots of 2 m x 30 m and the inferior strata using 2 m x 2 m sub-plots. We measured the canopy cover and also bracken cover inside the plots. The arboreal species first occupying the invaded area are shadow tolerant and fast growing, attributes which allowed them to overtake the bracken layer and establish. Nowadays, the invasive species has been replaced by a high number of arboreal species, the inferior strata being floristically similar to the area not invaded. The low density of adult trees in the invaded area reduce the competition among individuals that end up investing in growth, with greater size compared to those trees in the non invaded area. These large trees function as nurse trees, facilitating other species to establish under their canopies. We tested which variables related to the ecological functions and tree structure are favouring the understory, in order to comprehend the ecological processes and interactions that regulate the assembly rules of the invaded community being recovered. We assembled all individuals from arboreal species over 50 cm high growing under the projection of nurse trees canopy. These nurse trees were systematically selected, for the basis of functional and structural attributes. Understory density and richness were higher under trees with dense and permanent shadow, and that was the attribute better explaining the recovery process. The high resilience of savanna have helped the recovery of invaded areas. This process, however, has been very slow. Interventions whiling to restore those areas should be focused on bracken eradication and/or introduction of those species that can facilitate the natural regeneration.
DeVanna, Kristen M. "Spatial Correlation and Facilitation Between Dreissena and Hexagenia: Possible Food-Web Disruption?" University of Toledo / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1320935549.
Full textQueiros, Ana Filipa de Moura. "Ecosystem engineers in diversity and process relationships." Thesis, Bangor University, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.528333.
Full textBlanc, Lori A. "Experimental study of an avian cavity-nesting community: nest webs, nesting ecology, and interspecific interactions." Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/28420.
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Ward, Jessica MacKay. "Community-level effects of nonindigenous aquatic ecosystem engineers." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:8881/R/?func=dbin-jump-full&object_id=92244.
Full textHamani, Vincent. "Vers une meilleure compréhension des écosystèmes portuaires : interactions entre les organismes filtreurs et leur environnement." Thesis, La Rochelle, 2022. http://www.theses.fr/2022LAROS013.
Full textThe hyper-anthropization, particularly along our coasts, has profoundly modified the environment. New structures, such as harbors, emerging, forming “true” ecosystems. Among the multitude of species inhabiting the port, one group seems particularly interesting to study: the filter feeders (bivalves and tunicat). These organisms have a strong interaction with the port environment due to their behaviour. Indeed, by remaining anchored to the structures, they are constantly subjected to the environmental factors that characterize the port and their feeding behavior, the filtration, leads them to be in contact with a large quantity of water and therefore with the elements that are in it. The objective of this thesis is to study this particular socio-ecosystem that is the port environment through this key group: the filter feeders. Through a multidisciplinary approach, this work, has allowed :-to study and map the communities of filter feeders present in the marina of La Rochelle; showing the complexity of their community and the fact that they are impacted by anthropogenic and hydrosedimentary factors.-to analyze the effect of two common contaminants in the port environment, copper and zinc, on the metabolism of a model filter-feeder organism : the scallop (Mimachlamys varia); and to show that they impacted several metabolic pathways involved in numerous biological functions, such as osmoregulation, oxidative stress, energetic metabolism, reproduction and apoptosis.- to highlight the fact that filter feeders are involved in the composition of the mud by remobilizing the sediments present in the water column and by modifying their physico-chemical properties; and that is species dependent and is strongly modulated by environmental conditions such as the level of organic matter.- to develop several innovative sampling and analysis methods needed to understand this particular environment
Catano, Christopher. "Species and habitat interactions of the gopher tortoise: A keystone species?" Master's thesis, University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5153.
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De, almeida Tania. "Impact d’une espèce ingénieure de l’écosystème et son utilisation en restauration écologique : Le cas de Messor barbarus (L.) dans les pelouses méditerranéennes Above- and below-ground effects of an ecosystem engineer ant in Mediterranean dry grasslands Harvester ants as ecological engineers for Mediterranean grassland restoration: impacts on soil and vegetation A trait-based approach to promote ants in restoration ecology." Thesis, Avignon, 2020. http://www.theses.fr/2020AVIG0358.
Full textThe main objective of this thesis was double: (i) to assess the impact of an ant species on its ecosystem, in order to (ii) deduce potential applications in the field of ecological restoration.Ants are among the most abundant organisms in terrestrial ecosystems and occupy a wide range of geographical areas. They play key ecological roles in many ecosystems as soil engineers, predators or regulators of plant growth and reproduction. However, the information collected locally is often fragmented and does not provide a complete overview of the impact of a species on its environment.Messor barbarus (L.), known to redistribute seeds and to modify the soil physico-chemical properties, is widespread in South-Western Europe, particularly in Mediterranean grasslands. Therefore, it may play a major role in the composition and structuring of these ecosystems, which are characterised by high biodiversity but whose abundance and surface area have decreased drastically in recent decades.Through a multi-compartment study, we confirmed the hypothesis that M. barbarus is an ecological engineer in Mediterranean grasslands. This species changes this habitat by modifying, as expected, soil physico-chemical properties. These modifications are associated with an increase in both biomass and heterogeneity of plant communities, as well as changes in above- and belowground fauna (abundance, occurrence and structure of communities). Messor barbarus profoundly changes trophic and non-trophic relationships within and between species and their habitat. The heterogeneity created locally by the activity of M. barbarus leads to a diversification of ecological niches within these grasslands.Despite their major role in the functioning of ecosystems, ants are rarely considered in restoration ecology. In our study site, corresponding to a dry grassland rehabilited after an oil leak and a soil transfer, M. barbarus contributed to accelerate the restoration of the soil physico-chemical properties but also of the seed bank in the medium term - seven years after the rehabilitation. These results make this species a good candidate for ecological engineering.In order to generalise the use of ants in restoration ecology, we propose a trait-based methodology for stakeholders. We evaluated the potential of ants in restoration ecology, then listed all the traits known to affect abiotic and biotic compartments and/or relevant to monitor the success of the restoration phase. The proposed methodology provides a first selection of potentially relevant species according to the restoration objectives
Hortobágyi, Borbála. "Multi-scale interactions between riparian vegetation and hydrogeomorphic processes (the lower Allier River)." Thesis, Université Clermont Auvergne (2017-2020), 2018. http://www.theses.fr/2018CLFAL001/document.
Full textN ecosystems, such as rivers, salt marshes, mangroves, coastal dunes which are exposed to frequent and regular hydrogeomorphic fluxes (i.e. physical disturbances), feedbacks between geomorphology (water, sediment and landforms) and plants (e.g. Populus nigra L., Salix alba L., Salix purpurea L. in rivers) can occur. Vegetation esta¬blishment is controlled by hydrogeomorphic processes which in turn are modulated by vegetation. Such feedbacks control riparian ecosystem dynamics. In this thesis, we addressed two main questions in an effort to better understand feedbacks between riparian vegetation and hydrogeomorphic processes: (i) How does riparian vegetation respond to hydrogeomorphic constraints? (ii) How, and to what extent, do established engineer plants affect fluvial geomorphology? We studied these questions through a nested multi-scale approach from landscape pattern to plant trait scales on the dynamic wandering Allier River (France). We tested the applicability of the method of photogrammetry to quantify the response and the effect of riparian vegetation and biogeomorphic feedbacks at different spatio-temporal scales (i.e. corridor, alluvial bar and individual). At the corridor scale, we searched for the topographic signature of riparian vegetation in the landscape, using photogrammetric and LiDAR data. At the intermediate alluvial bar scale, we investigated the aptitude of three dominant pioneer riparian Salicaceae species (P. nigra, S. purpurea and S. alba) to establish and to act as ecosystem engineers by trap¬ping fine sediment. At the finest, plant trait scale, we quantified the relation between response trait attributes of young P. nigra plants and their exposure to three different levels of mechanical stress (a highly exposed bar-head, a less exposed bar-tail, a chute channel). We identified some difficulties or failures to properly apply photogrammetry in biogeomorphic feedback studies. However, photogrammetry appeared as a useful tool to quantify a set of relevant parameters to respond to fundamental research questions concerning biogeomorphic feedbacks at the three nested spatial scales. At the broadest, the topographic signature of vegetation was not easy to capture because of the complex shifting mosaic of landforms of the Allier River. However, by focusing on more connec¬ted, restricted areas (i.e. alluvial bars), the signature of vegetation could be captured. It seems to increase with increasing vegetation height corresponding to the evolutionary phases of the fluvial biogeomorphic succession (FBS) model. At the intermediate, alluvial bar scale, biogeomorphic feedbacks could be well identified. The capacity of riparian plants to establish and act as ecosystem engineers depended both on species and their physiognomy, their age and their location on alluvial bars. At the finest, individual plant scale, we captured the contrasting morphological and biomechanical response of P. nigra to variable mechanical stress exposure from a trait perspective. In all hierarchical levels, scale-related biogeomorphic feedbacks were detected and described in a conceptual model. The three scales were considered as cycles composed of four different phases, which can have a variable temporality. The broadest spatio-temporal scale represents the evolution over several decades of the landscape mosaic resulting from the balance between constructive (vegetation establishment, growth and succession) and destruc¬tive (floods) forces. [...]
Brown, Joseph K. "Emergent interactions influence functional traits and success of dune building ecosystem engineers." VCU Scholars Compass, 2016. http://scholarscompass.vcu.edu/etd/4111.
Full textChoosai, Chutinan. "Biological activity in paddy fields : the role of soil engineers in ecosystem functioning." Paris 6, 2010. http://www.theses.fr/2010PA066156.
Full textMitchell, Mark E. "Nutrient Cycling Dynamics and Succession in Green Roof Ecosystems." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin150487303109878.
Full textParrott, Lael. "Learning to engineer life, development of a generally configurable model for the simulation of artificial ecosystems." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq64489.pdf.
Full textSpeed, James D. M. "Ecosystem engineers of the tundra the impacts and extent of goose herbivory in the high Arctic /." Thesis, Available from the University of Aberdeen Library and Historic Collections Digital Resources, 2009. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=26470.
Full textDeVanna, Kristen M. "Role of Dreissena as ecosystem engineers : effects to native bioturbators and benthic community structure and function /." Connect to Online Resource-OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1165420236.
Full textTypescript. "Submitted as partial fulfillment of the requirements for The Master of Science Degree in Biology (Ecology-track)." Bibliography: leaves 26-34.
Sanabria-Blandon, Maria Catalina. "Effects of agricultural Landscape of the Colombian Llanos on Ecosystem Services and assemblages of soil engineers." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066025/document.
Full textTropical savannas are highly important for agricultural production and many other ecosystems services. In Colombia, these savannas have been traditionally managed through extensive livestock production and low-input agriculture. The current conversion of these natural systems to intensified agriculture can have devastating impacts on belowground and aboveground biodiversity. Soil macrofauna represents an important part of agroecosystem biodiversity and some groups have received considerable attention as ecosystem engineers. The general goal of the thesis is to evaluate and analyze the impacts of agricultural landscapes on soil engineer communities and soil ecosystem services in the Colombian Llanos. Three main questions were addressed: (1) What is the impact of agricultural management on ant communities and is it possible to identify ant species that could be used as indicators of soil-based ecosystem services? (2) What is the impact of land uses on ant and termite communities and is this impact associated with modifications of soil physical and chemical properties? (3) Do the ecological and morphological traits of ants respond to land uses and soil properties?The results of this thesis confirm that ant communities are highly sensitive to land use changes and constitute good early indicators of soil-based ecosystem services. More accurately, annual crops have shown to be detrimental to ant and termites communities and this is probably due to the application of chemical inputs, as well as to tillage and pesticides. All land uses (Savannas, rubber or oil palm plantations, improved pastures and annual crops) have a particular soil fauna, but some species have particular habitat requirements for nest sites, food, refugees, etc. Some species are more generalist and are particularly adapted to disturbed environment. The presence of all land uses within a landscape contributes to a certain extent to the total diversity. It was found that sites with a tree cover protect rare, sometimes inconspicuous and perhaps fragile species
Beltrand, Maeva Mereana Marion. "The effects of the macroalga Gracilaria gracilis and increasing temperatures on the performance of the endemic Cape eelgrass Zostera capensis." Master's thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/27537.
Full textWhittington-Jones, Gareth Morgan. "The role of aardvarks (Orycteropus afer) as ecosystem engineers in arid and semi-arid landscapes of South Africa." Thesis, Rhodes University, 2007. http://hdl.handle.net/10962/d1005445.
Full textHolland, Michael. "An Assessment of the U.S. Army Corps of Engineers' Environmental Plan Evaluation Methods." ScholarWorks@UNO, 2011. http://scholarworks.uno.edu/td/124.
Full textKavanagh, Lydia Jane. "An engineered ecosystem for environmentally sustainable wastewater treatment for remote tourist resorts in tropical/sub-tropical regions /." [St. Lucia, Qld.], 2003. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16958.pdf.
Full textPerfect, Charles. "From engineered channel to functioning stream ecosystem : rates, patterns and mechanisms of development in a realigned river channel." Thesis, University of Stirling, 2010. http://hdl.handle.net/1893/2431.
Full textTrue, Aaron Conway. "Ecological engines: Finescale hydrodynamic and chemical cues, zooplankton behavior, and implications for nearshore marine ecosystems." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/54019.
Full textSandom, Christopher. "Wild boar, wolves and fences : managing ecosystem engineers and keystone species to restore ecological processes, a case study in the Scottish Highlands." Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.542969.
Full textEriksson, Bert. "The zoo-geomorphological impact of fossorial rodents in sub-polar alpine environments." Licentiate thesis, Uppsala universitet, Kulturgeografiska institutionen, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-150807.
Full textOliveira, Marina Vasconcelos de. "Efeitos dos ninhos de Atta sexdens (Linnaeus, 1758) (Hymenoptera: Formicidae) sobre a estrutura da comunidade de artr?podes do solo na Mata Atl?ntica." Universidade Federal Rural do Rio de Janeiro, 2017. https://tede.ufrrj.br/jspui/handle/jspui/1925.
Full textMade available in DSpace on 2017-07-27T13:09:11Z (GMT). No. of bitstreams: 1 2017 - Marina Vasconcelos de Oliveira.pdf: 1221503 bytes, checksum: 9381f92942c7388888364c8566c8a781 (MD5) Previous issue date: 2017-02-13
Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES
Tropical forests support a great vegetal diversity, in part, through an nutrient cycling initiated by the soil arthropod?s fauna, which facilitated the litter decomposers action, propitiating the release of stock nutrients to the soil. Therefore, studies about these fauna and what factors alter it are extremely important to understand the nutrient cycling process in tropical forests. Among epigeic fauna represents, the leaf-cutting ants are considered the Neotropical region dominant herbivores and studies relate their multiple effects on vegetable community and the soil . Nonetheless, there aren?t studies about leaf-cutting ants effects on other arthropods communities, including mirmecofauna. This study aim to investigate the nests effects of the leaf-cutting ant Atta sexdens (Linnaeus, 1758) (Formicidae: Myrmicinae) on a soil arthropod community. The study site was Reserva Ecol?gica de Guapia?u, Cachoeiras de Macacu, Rio de Janeiro, Brazil, where we collected samples at ten A. sexdens nests in period of 2 February to 9 February 2016. Along a linear transect of 32 meters, we collected litter samples from 0,25 m? size at intervals of 8 meters from each nests? edge of A. sexdens, whereby we also measured the air and soil temperature, the light and the air relative humidity. We aim to verify if litter structure and microclimatic conditions alter arthropod community structure and if these effects can be mediated by A. sexdens nests. The hypothesis in question are: 1) Litter Hypothesis, whereby arthropod community structure would be influenced by litter and litter would be altered by A. sexdens; 2) Abiotic Factors Hypothesis, whereby arthropod community structure would be influenced by abiotic factors and these factors would be altered by A. sexdens and 3) Nest Hypothesis, whereby community alterations would happen through intrinsic factors to active nests presence and not explained by alterations in a litter and/or in abiotic factors measured. For the test of the first and the second hypothesis, we did simple regressions and next variance analysis, assessing the litter and abiotic factors effects on arthropod community parameters and if this effects can be mediated by A. sexdens. To test Nest Hypothesis, we did variance analysis and analysis of similarities, assessing direct effects of A. sexdens on other arthropods community. We collected 3074 arthropods, among them Acari and Collembola were the most abundant groups. In relation of the ants, we obtained 63 specimens, in 26 genera and 32 identified species. The Strumigenys genus was one of the most frequent genera and it detained the biggest richness among mirmecofauna predators.We didn?t detect A. sexdens effects on soil arthropod community around its nests. Studies that include sazonality and behavior comparison between different species of leaf-cutting ants can result in new knowledge about the interaction between these organisms and other arthropods
As florestas tropicais sustentam uma grande diversidade vegetal, em parte, devido ? ciclagem de nutrientes iniciada pela fauna de artr?podes do solo, que facilita a a??o dos decompositores da serrapilheira, propiciando a libera??o dos nutrientes estocados para o solo. Logo, estudos sobre essa fauna e que fatores a afetam s?o importantes para a compreens?o dos processos de ciclagem de nutrientes em florestas tropicais. Dentre os representantes da fauna epigeica, as formigas-cortadeiras s?o consideradas os herb?voros dominantes da regi?o Neotropical e estudos relatam seus m?ltiplos efeitos sobre a comunidade vegetal e o solo. Entretanto, n?o h? estudos sobre os efeitos das formigas-cortadeiras sobre a comunidade dos demais artr?podes. Este estudo visa investigar os efeitos dos ninhos de formigas-cortadeiras Atta sexdens (Linnaeus, 1758) (Formicidae: Myrmicinae) sobre a comunidade de artr?podes do solo. A ?rea de estudo foi a Reserva Ecol?gica de Guapia?u, munic?pio de Cachoeiras de Macacu, Rio de Janeiro, Brasil, na qual coletamos amostras em 10 ninhos de A. sexdens no per?odo de 2 a 9 de fevereiro de 2016. Ao longo de um transecto linear de 32 metros, coletamos amostras de serrapilheira de tamanho 0,25m? a intervalos de 8 metros a partir da borda de cada ninho de A. sexdens, nos quais tamb?m medimos as temperaturas do ar e do solo, a luz e a umidade relativa do ar. Objetivamos averiguar se a estrutura da serrapilheira e as condi??es microclim?ticas alteram a estrutura da comunidade de artr?podes e se esses efeitos podem ser mediados pelos ninhos de A. sexdens. As hip?teses em estudo s?o: 1) Hip?tese da Serrapilheira, na qual a estrutura da comunidade de artr?podes seria influenciada pela serrapilheira e a serrapilheira seria alterada por A. sexdens; 2) Hip?tese dos Fatores Abi?ticos, na qual a estrutura da comunidade de artr?podes seria influenciada pelos fatores abi?ticos locais e estes fatores seriam alterados por A. sexdens e 3) Hip?tese do Ninho, em que as altera??es na comunidade se dariam por fatores intr?nsecos ? presen?a dos ninhos ativos e n?o explicados por altera??es na serrapilheira e/ou nos fatores abi?ticos medidos. As duas primeiras hip?teses foram testadas atrav?s de regress?es lineares simples, seguidas de an?lises de vari?ncia, avaliando os efeitos da serrapilheira e dos fatores abi?ticos sobre os par?metros da comunidade de artr?podes e se esses efeitos podem ser mediados por A. sexdens. No teste da hip?tese do Ninho, fizemos an?lises de vari?ncia e an?lises de similaridade, avaliando os efeitos diretos de A. sexdens sobre a comunidade dos demais artr?podes. Coletamos 3074 artr?podes, dentre os quais Acari e Collembola foram os grupos mais abundantes. Em rela??o ?s formigas, obtivemos 63 morfoesp?cies, em 26 g?neros e 32 esp?cies identificadas. O g?nero Strumigenys foi um dos g?neros mais frequentes e deteve a maior riqueza dentre os predadores da mirmecofauna. N?o detectamos efeitos de A. sexdens sobre a comunidade de artr?podes do solo do seu entorno. Estudos que incluam a sazonalidade e que comparem o comportamento entre diferentes esp?cies de formigas-cortadeiras podem resultar em novos conhecimentos a respeito da intera??o desses organismos com os demais artr?podes
Heuner, Maike [Verfasser], Birgit [Akademischer Betreuer] Kleinschmit, Boris [Akademischer Betreuer] Schröder-Esselbach, Stijn [Akademischer Betreuer] Temmerman, and Reinhard [Gutachter] Hinkelmann. "Key ecosystem engineers in estuarine vegetation : their niches, traits, and services for coping with hydrodynamic stress / Maike Heuner ; Gutachter: Reinhard Hinkelmann ; Birgit Kleinschmit, Boris Schröder-Esselbach, Stijn Temmerman." Berlin : Technische Universität Berlin, 2016. http://d-nb.info/1156270472/34.
Full textVieira, Camila. "Engenheiros dos ecossistemas em plantas : modificações arquiteturais de folhas por largatas de Lepidoptera influenciam a estrutura de comunidades de artrópodes /." São José do Rio Preto : [s.n.], 2010. http://hdl.handle.net/11449/87623.
Full textBanca: Martin Francisco Pareja
Banca: Thiago Junqueira Izzo
Resumo: Engenharia dos ecossistemas é um processo em que organismos modificam a distribuição de recursos (i.e, disponibilizando novos habitats) para outras espécies via interação não trófica. Lagartas de Lepidoptera enroladoras de folhas podem atuar como engenheiros dos ecossistemas florestais, uma vez que são capazes de modular interações entre comunidade artrópode - planta fornecendo aos colonizadores secundários diversos tipos de benefícios. Essas lagartas quando engenheiras influenciam o padrão de distribuição e abundância de outras espécies facilitando indiretamente a ocorrência de novas espécies, bem como aumentam a diversidade de artrópodes sobre planta. Apesar de estudos terem demonstrado que lagartas engenheiras ampliam a diversidade de artrópodes sobre folhas (efeito local), apenas um estudo avaliou o efeito na planta por inteiro (efeito regional), mas apenas para guildas específicas (i.e., herbívoros); nenhum estudo até agora avaliou como comunidades diversificadas, de regiões tropicais, respondem aos impactos de lagartas engenheiras. Nesse estudo reportamos a influência das lagartas enroladoras sobre comunidades de artrópodes em grande escala espacial (i.e., efeito local e regional) e temporal (i.e., diferentes períodos sazonais). Especificamente, avaliamos se (i) abrigos foliares favorecem a ocorrência de artrópodes e amplificam diversidade sobre plantas, (ii) se o tipo de abrigo (funil, cilindro com diferentes diâmetros) interfere na colonização por diferentes guildas de artrópodes, (iii) se os efeitos dos abrigos é local (folha) ou estende-se por toda a planta hospedeira (efeito regional), (iv) se plantas com abrigos foliares atraem maior número de artrópodes nos períodos secos, e se (v) plantas com abrigos foliares, por atraírem mais predadores, têm menor taxa de herbivoria foliar. Nossos resultados demonstram que abundância, riqueza... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Ecosystem engineering is a process by which some organisms change the distribution of resources (i.e., creating new habitats) for other species via non-trophic interactions. Shelter-building caterpillars can act as forest ecosystem engineers, because they may modulate interactions, between arthropods-plant communities, by providing the secondary settlers with several kinds of benefits. These caterpillars as ecosystem engineers influence the distribution pattern and abundances of other species facilitating the occurrence of new species indirectly, as well as increasing the diversity of arthropods on the plant. Although some studies have demonstrated that caterpillar leaf shelters amplify the diversity of arthropods on leaves (local effect), only one study evaluated the effect in the whole plant (regional effect), but this study only took into account specific guilds (i.e., herbivores); To date, no evaluated how speciose communities of tropical regions respond to the impacts of engineer caterpillars. In this study we reported, for the first time the influence of the lepidopteran shelter leafs on communities of arthropods in the tropics along both large spatial (i.e., local and regional effects) and temporal scales (i.e., different seasonal periods). Specifically, we evaluated if (i) leaf shelters benefit the occurrence of arthropods and amplify the diversity on plants, (ii) if the shelter architecture (funnel, cylinders with different diameters) interferes with the colonization of differents arthropods guilds, (iii) if the effects of shelters are local (within leafs) or extends to the whole host plant (regional effect), (iv) if plants with leaf shelters attract more arthropods in the dry periods, and if (v) plants with leaf shelters, which likely attract more predators, have lower levels of leaf herbivory. Our results show that the abundance, richness and total biomass of arthropods within... (Complete abstract click electronic access below)
Mestre
Vieira, Camila [UNESP]. "Engenheiros dos ecossistemas em plantas: modificações arquiteturais de folhas por largatas de Lepidoptera influenciam a estrutura de comunidades de artrópodes." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/87623.
Full textFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Engenharia dos ecossistemas é um processo em que organismos modificam a distribuição de recursos (i.e, disponibilizando novos habitats) para outras espécies via interação não trófica. Lagartas de Lepidoptera enroladoras de folhas podem atuar como engenheiros dos ecossistemas florestais, uma vez que são capazes de modular interações entre comunidade artrópode – planta fornecendo aos colonizadores secundários diversos tipos de benefícios. Essas lagartas quando engenheiras influenciam o padrão de distribuição e abundância de outras espécies facilitando indiretamente a ocorrência de novas espécies, bem como aumentam a diversidade de artrópodes sobre planta. Apesar de estudos terem demonstrado que lagartas engenheiras ampliam a diversidade de artrópodes sobre folhas (efeito local), apenas um estudo avaliou o efeito na planta por inteiro (efeito regional), mas apenas para guildas específicas (i.e., herbívoros); nenhum estudo até agora avaliou como comunidades diversificadas, de regiões tropicais, respondem aos impactos de lagartas engenheiras. Nesse estudo reportamos a influência das lagartas enroladoras sobre comunidades de artrópodes em grande escala espacial (i.e., efeito local e regional) e temporal (i.e., diferentes períodos sazonais). Especificamente, avaliamos se (i) abrigos foliares favorecem a ocorrência de artrópodes e amplificam diversidade sobre plantas, (ii) se o tipo de abrigo (funil, cilindro com diferentes diâmetros) interfere na colonização por diferentes guildas de artrópodes, (iii) se os efeitos dos abrigos é local (folha) ou estende-se por toda a planta hospedeira (efeito regional), (iv) se plantas com abrigos foliares atraem maior número de artrópodes nos períodos secos, e se (v) plantas com abrigos foliares, por atraírem mais predadores, têm menor taxa de herbivoria foliar. Nossos resultados demonstram que abundância, riqueza...
Ecosystem engineering is a process by which some organisms change the distribution of resources (i.e., creating new habitats) for other species via non-trophic interactions. Shelter-building caterpillars can act as forest ecosystem engineers, because they may modulate interactions, between arthropods-plant communities, by providing the secondary settlers with several kinds of benefits. These caterpillars as ecosystem engineers influence the distribution pattern and abundances of other species facilitating the occurrence of new species indirectly, as well as increasing the diversity of arthropods on the plant. Although some studies have demonstrated that caterpillar leaf shelters amplify the diversity of arthropods on leaves (local effect), only one study evaluated the effect in the whole plant (regional effect), but this study only took into account specific guilds (i.e., herbivores); To date, no evaluated how speciose communities of tropical regions respond to the impacts of engineer caterpillars. In this study we reported, for the first time the influence of the lepidopteran shelter leafs on communities of arthropods in the tropics along both large spatial (i.e., local and regional effects) and temporal scales (i.e., different seasonal periods). Specifically, we evaluated if (i) leaf shelters benefit the occurrence of arthropods and amplify the diversity on plants, (ii) if the shelter architecture (funnel, cylinders with different diameters) interferes with the colonization of differents arthropods guilds, (iii) if the effects of shelters are local (within leafs) or extends to the whole host plant (regional effect), (iv) if plants with leaf shelters attract more arthropods in the dry periods, and if (v) plants with leaf shelters, which likely attract more predators, have lower levels of leaf herbivory. Our results show that the abundance, richness and total biomass of arthropods within... (Complete abstract click electronic access below)
Holbrook, David Lee. "Corbicula fluminea Invasion as a Secondary Effect of Hydrilla verticillata Management via Triploid Grass Carp (Ctenopharyngodon idella)." Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc1062823/.
Full textEngvall, Cecilia. "A first classification of zoogeomorphological activity and impacts by large mammals in national parks, South Africa." Thesis, Uppsala universitet, Kulturgeografiska institutionen, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-194811.
Full textPfeiffer, Birgit Verfasser], Rolf [Akademischer Betreuer] [Daniel, Michael [Akademischer Betreuer] Hoppert, Hermann [Akademischer Betreuer] Jungkunst, Stefanie [Akademischer Betreuer] Pöggeler, Stefan Pd [Akademischer Betreuer] Irniger, and Kai Jun [Akademischer Betreuer] Heimel. "Impact of plant species, N fertilization and ecosystem engineers on the structure and function of soil microbial communities / Birgit Pfeiffer. Gutachter: Michael Hoppert ; Hermann Jungkunst ; Stefanie Pöggeler ; Stefan Pd. Irniger ; Kai Jun.- Heimel. Betreuer: Rolf Daniel." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2014. http://d-nb.info/1047932199/34.
Full textDahlsjö, Cecilia A. L. "Termite assemblage structure and function : a study of the importance of termites in lowland equatorial forests." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:28a37283-4013-4c5a-be2e-aac26d97f838.
Full textRoman, Alexander Cesar Ferreira. "Rela??es ecologicas entre caranguejos e composi??o arb?rea em bosques de mangue naturais e restaurados no nordeste brasileiro." Universidade Federal do Rio Grande do Norte, 2014. http://repositorio.ufrn.br:8080/jspui/handle/123456789/14045.
Full textCoordena??o de Aperfei?oamento de Pessoal de N?vel Superior
This study aimed to compare the development of crab and tree communities of two restored mangrove areas, one planted with Rhizophora mangle and the other naturally recovered, and also to compare the predation of Grapsid crab Goniopsis cruentata and the Ocypodid Ucides cordatus over the propagules of three mangrove trees: Rhizophora mangle, Avicennia schaueriana e Laguncularia racemosa. Specifically, we tested the hypothesis that Goniopsis predation is more important that Ucides predation, and that these consumers have antagonist effects over propagule consumption. In each area, 10 quadrates were selected at random to analyze tree richness, diameter, height, tree biomass and crab richness and density five years after restoration experiment start. Results show that tree height, biomass and crab density were significantly higher in artificially restored area. No significant differences were observed in crab species richness between areas, but higher tree richness was observed in self-recovered area. Results suggest that planting propagules of Rhizophora can significantly increase tree recovering if the aim was increase tree biomass and crab density, which can accelerate return of ecological functionality. Goniopsis is a more important propagule predator than Ucides both in natural and restored areas. The effects of Goniopis were higher in absence of Ucides, due to negative interactions among these two predator species. The preference of Goniopsis by Avicennia and Laguncularia can favor the dominance of Rhizophora observed in Neotropical mangroves. This study suggests that propagule predation by Goniopsis should be controlled in restoration programs, if dominance of Rhizophora is undesirable respect to more rich tree communities
O presente estudo teve como objetivo comparar o desenvolvimento das comunidades de ?rvores e caranguejos de duas ?reas de mangue restauradas, uma plantada com Rhizophora mangle e outra naturalmente recuperada, al?m de comparar a magnitude da preda??o do Graps?deo Goniopsis cruentata e do Ocypod?deo Ucides cordatus sobre os prop?gulos de tr?s esp?cies de mangue: Rhizophora mangle, Avicennia schaueriana e Laguncularia racemosa. Em particular, foi testada a hip?tese de que a preda??o de Goniopsis ? mais importante que a preda??o por Ucides e que esses consumidores possuem efeitos antag?nicos sobre a preda??o de prop?gulos. Em cada ?rea, 10 quadrantes foram aleatoriamente selecionados para analisar a riqueza arb?rea, di?metro, altura, biomassa arb?rea e riqueza e densidade de caranguejos cinco anos ap?s o in?cio do experimento de restaura??o. Os resultados mostraram que tanto a altura e biomassa arb?reas quanto a densidade de caranguejos foram significativamente maiores na ?rea artificialmente restaurada. N?o foram observadas diferen?as significativas na riqueza de esp?cies de caranguejos entre as ?reas, mas houve uma maior riqueza de esp?cies de ?rvores na ?rea auto-recuperada. Estes resultados sugerem que o plantio de prop?gulos de Rhizophora pode aumentar significativamente a recupera??o da cobertura vegetal, se o objetivo for elevar a biomassa arb?rea e a densidade de caranguejos, o qual pode acelerar o retorno da funcionalidade ecossist?mica. Goniopsis foi um predador de prop?gulos mais importante que Ucides tanto em ?reas naturais quanto restauradas. Os efeitos de Goniopsis foram maiores na aus?ncia de Ucides devido a intera??es negativas entre estas esp?cies de predador. A prefer?ncia de Goniopsis por Avicennia e Laguncularia pode favorecer a domin?ncia de Rhizophora observada nos mangues Neotropicais. Este estudo sugere que a preda??o de prop?gulos por Goniopsis em programas de restaura??o de mangue deveria ser controlada se a domin?ncia de Rhizophora ? indesej?vel em rela??o a comunidades com mais esp?cies de ?rvore
Silva, Rodrigo Pires da. "The The sun coral as an ecosystem engineer." Master's thesis, 2018. http://hdl.handle.net/10451/36493.
Full textAs invasões biológicas são uma das maiores ameaças à biodiversidade e aos ecossistemas marinhos nos dias de hoje. A introdução de espécies não-indígenas começou a ser comum no início do século XX devido ao grande aumento do tráfego marítimo decorrente da globalização. Regra-geral, a introdução de novas espécies não é propositada. Grande parte dos indivíduos pioneiros são transportados em águas de lastro ou viajam encrustados em navios transoceânicos. Os indivíduos transportados para fora da sua zona original de distribuição podem assumir um estatuto de espécie invasora se detiverem determinadas características: elevada resiliência a mudanças ambientais, grandes taxas de recrutamento e crescimento, grande variabilidade genética, curto período de gestação, maturidade sexual precoce, grande capacidade reprodutiva e/ou uma dieta muito diversificada. A costa sudeste do Brasil, onde este estudo foi desenvolvido, não apresenta formações recifais de coral, contudo existem algumas espécies de coral na região, como é o caso do coral cérebro endémico Mussismilia hispida e do coral invasor Tubastraea spp. Este trabalho tem como principal objetivo perceber de que forma o coral invasor, Tubastraea spp., influencia a estrutura da comunidade local e o seu impacto na teia trófica. Para tal, foram desenvolvidos dois estudos em paralelo, no verão de 2017. O primeiro visa compreender como a presença de coral-sol influencia a macrofauna associada ao substrato rochoso, tendo em conta três coberturas de coral diferentes (0%, 50%, 100%), em dois locais distintos na Ilha de Búzios, SP, Brasil (capítulo 2). Enquanto que o segundo trabalho pretende caracterizar a teia trófica facilitada pelo coral-sol e elucidar se o bivalve invasor Leiosolenus aristatus recebe alimento do seu anfitrião, Tubastraea spp (capítulo 3). Ambos os estudos focam questões em aberto sobre o efeito do coral-sol como engenheiro ecossistémico na região. O género Tubastraea refere-se a um coral ahermatípico e azooxantelado, pertencente à ordem Scleractinia. É o único género de escleractíneos a invadir o Brasil atualmente, tendo uma alta taxa de invasão que o torna numa das maiores ameaças à biodiversidade marinha local. Coral-sol é a designação em português, devido à disposição dos seus pólipos e coloração amarela/alaranjada. As principais espécies a ocorrerem em águas brasileiras são Tubastraea coccínea e Tubastraea tagusensis. O coral-sol é nativo do Indo-Pacífico tendo uma vasta distribuição geográfica. O seu sucesso como espécie invasora advém da posse de algumas características, tais como o hermafroditismo, uma estratégia reprodutiva diversificada, uma elevada capacidade de fixação em substrato natural e artificial, altas taxas de recrutamento e crescimento, e uma preferência de assentamento em estruturas verticais. No oceano Atlântico, o início da sua invasão ocorreu no mar das Caraíbas (anos 1940) e o primeiro registo no Brasil foi nos anos 1980, numa plataforma petrolífera, na baía de Campos, a norte do estado do Rio de Janeiro. O Capítulo 1 introduz o tema em estudo, apresentando os principais objetivos de trabalho da tese, o Capítulo 2, foca o impacto do coral-sol na fauna bentónica, o Capítulo 3 descreve a teia trófica em que se insere o coral-sol, com recurso a análise de isótopos estáveis, e o Capítulo 4 apresenta as conclusões gerais e perspetivas futuras sobre este tema. O trabalho apresentado no Capítulo 2 contou com a recolha de amostras em dois locais distintos, separados por 3km, ao longo da Ilha de Búzios, São Paulo, Brasil, e duas áreas de amostragem em cada local, distanciadas por algumas dezenas de metros. O trabalho de campo consistiu na raspagem de três réplicas em cada área, em regiões saturadas pelo coral, parcialmente cobertas (aproximadamente 50% de cobertura) e sem presença do invasor. Todo o material recolhido foi lavado e peneirado em 9 crivos de malha com diâmetros decrescentes, onde ficou retida a macrofauna. Após separação, identificação e armazenamento da fauna encontrada, procedeu-se à análise de variáveis univariadas (abundância, biomassa e tamanho médio), à utilização do índice de diversidade e riqueza Shanon-Wiener e à análise multivariada da estrutura da comunidade. Todas as análises referidas seguiram o mesmo modelo, tendo “coral cover” como o principal fator (“no coral, half-coral e full coral”), examinados à escala espacial de dois locais e duas áreas. O coral-sol provou ser um elemento de exclusão de alguns macro-invertebrados (ex. tanaídeos, ostracodes e copépodes) e o responsável pelo declínio da abundância e riqueza na estrutura da comunidade local. É sugerida a existência de um cenário satisfatório, em termos de abundância, biomassa e riqueza, em regiões onde a presença do coral-sol é parcial ou inexistente. Perante os resultados obtidos, pode-se sugerir, também, que o limiar da resiliência do ecossistema estudado está iminente. Este estudo confirma o coral-sol como um importante engenheiro ecossistémico – organismo cuja presença ou atividade altera as características físicas circundantes, criando e modificando habitats e influenciando todas as espécies aí presentes. Medidas terão de ser tomadas rapidamente para evitar perdas permanentes de biodiversidade local. Por outro lado, a análise isotópica do δ13C e δ15N apresentada no Capítulo 3 revelou que a teia trófica associada ao coral é maioritariamente composta por organismos filtradores e que as novas comunidades, após a invasão, são dominadas por seres heterotróficos, em vez de autotróficos (organismos dominantes antes da invasão). Para além da importante expansão do coral-sol, o mitilídeo Leiosolenus aristatus, nativo do mar das Caraíbas, mas com uma distribuição geográfica muito alargada, foi frequentemente encontrado no interior das bases rígidas do coral invasor. Tubastraea spp. e Leiosolenus aristatus são originários de localizações geográficas distintas, portanto a sua associação apenas ocorre em locais onde ambos são alóctones. Os resultados obtidos sugerem que tanto o coral-sol, como o bivalve, são organismos filtradores. Uma das hipóteses para a ocorrência desta associação, seria a de que o bivalve beneficiaria de alimento providenciado pelo coral, mas tal não se verificou. A invasão do mitilídeo é facilitada pelo coral, por este encontrar refúgio nas suas bases calcárias. É expectável que a continuação da invasão pelo coral-sol seja acompanhada pela expansão da distribuição deste bivalve invasor. Conclui-se que a rápida invasão do coral-sol no litoral norte de São Paulo, é uma grave ameaça à biodiversidade local por estar iminente uma importante alteração do ecossistema, juntamente com a facilitação da introdução de um bivalve invasor, competidor com outras espécies nativas. A alteração de habitats, pode vir a ter consequências profundas nas comunidades locais. Ambos os estudos, são pontos de partida para o conhecimento do impacto negativo que o coral-sol pode ter na estrutura da comunidade associada aos fundos rochosos, como engenheiro ecossistémico. Sugere-se a continuação de estudos dentro desta temática, com o intuito de aumentar o conhecimento, contribuindo para a eventual gestão, minimização dos impactos ou erradicação desta espécie invasora.
Invasive species are a serious threat to biodiversity because they displace native species, change community structure and food webs and alter fundamental processes (such as nutrient cycling and sedimentation). Any organism that is outside of its native geographic range that may or has become injurious to animal or human health, the economy and/or natural environment is considered as invasive species. Globalization (i.e. increase of the international ship traffic) is the main driver of invasive species introduction. Tubastraea spp., commonly designated sun coral, is an ahermatypic and azooxanthellate scleractinian coral, the only scleractinian which has been introduced in Brazilian waters and one of the most widespread invaders in the world. The present work aimed to investigate the impact of Tubastraea spp. in the local biological community, examining the rocky shore associated macrofauna, in an area under rapid invasion, at Búzios Island, São Paulo, Brazil, under three different coral coverages (0%, 50% and 100%) (chapter 2) and characterizing the food web associated with Tubastraea spp., using stable isotopes (chapter 3), during the summer of 2017. Chapter 1 introduces the basis for this work and describes the main aims of this thesis. Chapter 2 investigates the impact of the sun coral on the benthic macrofauna, chapter 3 describes the food web where this coral is included, and chapter 4 presents the main conclusions and future perspectives. The alteration of mobile invertebrate assemblages according to the degree of sun-coral space occupation was examined on vertical walls (with 3 different coral cover levels) and the differences found among two study sites and areas, within each study site were examined. It was observed that the sun coral may exclude major invertebrate groups (i.e. tanaids, ostracods and copepods). Abundance, biomass and richness of associated macrofaunal species declined in areas saturated by the sun coral, confirming that this coral is an ecosystem engineer. The structure of the food web associated to the colonies of Tubastraea spp was previously unknwon. At the basis of this coral another invasive species is very often found, the bivalve Leiosolenus aristatus, a borer species that perforates the base of hard corals. Stable isotopic analysis was applied to all organisms occurring at the microhabitat built by Tubastraea spp. to 1) provide the first trophic characterization of the food web facilitated by Tubastraea spp., while also 2) elucidating if L. aristatus receives nutrition from its coral host Tubastraea spp. Stable isotopic analyses showed that the food web that accompanies this invasive coral seems to be mostly composed of suspension feeders, confirming that the new community established after Tubastraea spp. invasion is dominated by heterotrophs. It was also concluded that both Tubastraea spp. and L. aristatus are suspension feeders consuming similar resources. This way, L. aristatus seems to profit from the expansion of Tubastraea spp. because the coral provides it with a structure to live, but not a source of nutrition. As Tubastraea spp. progresses in its invasion of new areas, this borer bivalve should follow. This work describes for the first-time the impact of Tubastraea spp. on the southeast Brazilian rocky bottoms’ associated macrofauna and food webs. The rapid expansion of this ecosystem engineer is leading to the alteration of the native macrofaunal community. This work indicates that this invasion will result in a decline in local biodiversity and in profound alterations to the food web of subtidal rocky shores.
"Ecosystem Consequences Of Genetic Variation In The Salt Marsh Engineer Spartina Alterniflora." Tulane University, 2015.
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Brittany Marie Bernik
Verstege, Jacqueline. "Fox and lemming responses to climate and snow conditions at the Arctic’s edge." 2017. http://hdl.handle.net/1993/31976.
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