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Lopes, Thais Sasso. "Padrões espaciais e temporais de ocorrência de anuros em riachos de Mata Atlântica e sua detecção por meio de DNA ambiental". Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/41/41134/tde-20102016-142913/.
Pełny tekst źródłaBrazil ranks as the country with one of the highest amphibian species diversity. Streams in the Atlantic forest of southeastern Brazil have an important availability of microenvironments and harbors a particular richness in amphibian species. Monitoring herpetofauna and knowledge on their spatial and temporal dynamics provide primary information for ecological studies, and are essential to the development of other areas such as conservation biology. In this work we gather information on the occurrence and abundance of three torrent frogs, Cycloramphus boraceiensis, Hylodes asper and Hylodes phyllodes and examine the reliability of eDNA analysis to detect anuran communities. Samplings occurred within a 95 to 115 m transect in four streams in Núcleo Picinguaba, at the Parque Estadual da Serra do Mar, São Paulo, Brazil. Individual encounter number and their habitat were monthly recorded from January 2007 to December 2010 and every two months in 2011. We searched for post-metamorphic individuals while walking upstream for 30-60 min, checking all visually accessible spots in the streambed. The location of each active and inactive individual was mapped and its habitat use was characterized in relation to five ecological parameters. We collected eDNA samples at 16 sites on April, 2015. We used eDNA metabarcoding approach with a universal amphibian primer of a mitochondrial marker (12S) to detect amphibian communities. We recorded a total of 6335 visual observations. The three species abundance varied along and between streams and only Hylodes phyllodes were found in the stream 2. Abundance of C. boraceiensis and H. asper was significantly higher in the wet seasons. The three species were found active mainly in wet rocks, without moss and without cover. Inactive individuals of Hylodes asper and H. phyllodes were found mainly in dry leaves, without moss or cover. Through eDNA metabarcoding, we detected nine species, which were consistent with traditional survey results. DNA of riparian species and species with higher constancy in traditional surveys were detected in higher proportions. Our study showed that traditional survey and DNA metabarcoding results can be complementary and both methodologies can be combined in future ecology studies
Garland, Lincoln. "Microhabitat ecology of small mammals on grassy road verges". Thesis, University of Bristol, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251021.
Pełny tekst źródłaTurvey, Shannon Lee. "The role of microhabitat associations in producing cross-taxa congruence". Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/32496.
Pełny tekst źródłaForestry, Faculty of
Graduate
Zimmerman, Brian J. "Microhabitat Use by the Redside Dace (Clinostomus Elongatus) in Ohio". Bowling Green State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1250772332.
Pełny tekst źródłaHoman, Cassandra M. "Bottlenecks and Microhabitat Preference in Invasive Wall Lizard, Podarcis muralis". University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1377868885.
Pełny tekst źródłaMabray, Scott T. "Microhabitat Selection by Greater Sage-Grouse Hens in Southern Wyoming". DigitalCommons@USU, 2015. https://digitalcommons.usu.edu/etd/4160.
Pełny tekst źródłaAnderson, Jason J. "Microhabitat Use by the Meadow Vole, Microtus Pennsylvanicus (Ord), on a Reclaimed Grassland". Youngstown State University / OhioLINK, 1999. http://rave.ohiolink.edu/etdc/view?acc_num=ysu999188325.
Pełny tekst źródłaHubert, Jay Bradley. "INTERSPECIFIC COMPETITION AND MICROHABITAT SELECTION IN THE GOLDEN MOUSE (OCHROTOMYS NUTTALLI)". OpenSIUC, 2011. https://opensiuc.lib.siu.edu/theses/668.
Pełny tekst źródłaSailer, Gabriele. "The roles of local disturbance history and microhabitat parameters for stream biota". Diss., [S.l.] : [s.n.], 2005. http://edoc.ub.uni-muenchen.de/archive/00004500.
Pełny tekst źródłaDennis, Paul Gareth. "How do rhizosphere bacteria interact with their environment at the microhabitat scale?" Thesis, University College London (University of London), 2006. http://discovery.ucl.ac.uk/1444697/.
Pełny tekst źródłaFarallo, Vincent R. "Notes from the Underground: Linking Microhabitat and Species Distributions of Plethodontid Salamanders". Ohio University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou148156741016879.
Pełny tekst źródłaMoen, Daniel S., i John J. Wiens. "Microhabitat and Climatic Niche Change Explain Patterns of Diversification among Frog Families". UNIV CHICAGO PRESS, 2017. http://hdl.handle.net/10150/624675.
Pełny tekst źródłaLawson, Callum Robert. "From microhabitat to metapopulations : a model system for conservation under climate change". Thesis, University of Exeter, 2013. http://hdl.handle.net/10871/9557.
Pełny tekst źródłaGomez, Patricia A. "Microhabitat preference of the introduced gecko Hemidactylus turcicus in an urban environment". [Gainesville, Fla.] : University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0001213.
Pełny tekst źródłaSchwenke, Andrew C. "Riparian vegetation condition influences movement and microhabitat use by Mixophyes fasciolatus in South East Queensland". Thesis, Queensland University of Technology, 2016. https://eprints.qut.edu.au/102339/4/Andrew_Schwenke_Thesis.pdf.
Pełny tekst źródłaJeske, Jan Torsten. "Microbial adaptations and controlling mechanisms of surface-associated microhabitat heterogeneity in aquatic systems". Doctoral thesis, Uppsala universitet, Limnologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-263206.
Pełny tekst źródłaJarvis, Laurence Edward. "Microhabitat requirements of the great crested newt (Triturus cristatus) in a woodland area". Thesis, Open University, 2012. http://oro.open.ac.uk/54828/.
Pełny tekst źródłaWiley, Mark Joseph. "Usable Space and Microhabitat Characteristics for Bobwhites on Private Lands in Southwestern Ohio". The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1345548162.
Pełny tekst źródłaDe, Angelo Jacquelyn Alexis. "Mangrove Shoreline Fish Assemblages of Oleta River State Park: Baseline Conditions in an Urban System". Scholarly Repository, 2010. http://scholarlyrepository.miami.edu/oa_theses/75.
Pełny tekst źródłaFirmino, da Silva Clebson. "Mixobiota de floresta atlântica: espécies ocorrentes em Elaeis Guineensis Jacq. (Arecaceae)". Universidade Federal de Pernambuco, 2006. https://repositorio.ufpe.br/handle/123456789/1995.
Pełny tekst źródłaRealizou-se um estudo sobre as espécies de Myxomycetes que ocorrem em Elaeis guineensis Jacq. (dendezeiro), visando contribuir para o conhecimento sobre os representantes deste grupo que estão associados com palmeiras no Brasil. A incidência, abundância, diversidade taxonômica (espécie/gênero) dos esporocarpos em estipes, folhas, brácteas, inflorescências e frutos (vivos ou mortos) de dendezeiros foi analisada em 20 indivíduos presentes em três fragmentos de Floresta Atlântica da Reserva Ecológica do Gurjaú, Cabo de Santo Agostinho, Pernambuco (08º10 00 e 08º15 00 S; 35º02 30 e 35º05 00 WGr.). Calculou-se a abundância relacionando-se o número de espécimes do táxon e o total de espécimes obtidos, e enquadrou-se cada espécie como rara (0,5-1%), ocasional (2-4%), comum (5-7%) ou abundante (superior a 7%). Exsicatas foram depositadas no Herbário UFP. As espécies foram listadas em ordem alfabética por subclasse. Apresenta-se a distribuição conhecida para o Brasil para cada espécie e os registros para palmeiras neste país. O dendezeiro mostrou ser um excelente substrato para o desenvolvimento de mixomicetos. Todas as subclasses, cinco das seis ordens e 50% das famílias reconhecidas para este grupo foram registradas. Com este estudo, 22 espécies foram acrescentadas à lista de mixomicetos associados com dendezeiro no Brasil; destas, Ceratiomyxa sphaerosperma, Didymium anellus e Physarum gyrosum não haviam sido referidas como ocorrendo em palmeiras neste país. Nos ambientes estudados, as Physaraceae são as mais freqüentes, seguidas pelas Trichiaceae. Hemitrichia serpula, Arcyria cinerea e Physarum compressum são espécies comumente encontradas em E. guineensis, confirmando sua preferência em se associar com palmeiras. Conclui-se que a mixobiota do dendezeiro é diversificada, ocorrendo à esporulação preferencialmente em órgãos mortos
Machado, Renata Figueira. "USO DO HABITAT POR PEQUENOS MAMÍFEROS EM UM MOSAICO DE FLORESTA - CAMPO NO EXTREMO SUL DA FLORESTA ATLÂNTICA". Universidade Federal de Santa Maria, 2013. http://repositorio.ufsm.br/handle/1/5319.
Pełny tekst źródłaThe macro and microhabitat use by small-mammal was investigated in an Atlantic Forest- Pampa mosaic. A grid with 88 traps was used, being 27 installed in the understory every two traps placed on the ground, which were 70 m apart of each other. The fieldwork was carried out in 17 monthly phases, during five days, from June 2011 to October 2012, totalizing a sampling effort of 7480 trap-nights. An analysis of variance was used to verify differences in richness, total abundance and abundance of each species among grassland, edges and forest. The same analysis was performed to test if the body mass of each species differs between the vegetation types. Eleven environmental variables measured were summarized through a principal component analysis (PCA). Subsequently, a multiple linear regression analysis was performed between richness and total abundance of each species and the first two axes of PCA. The environmental variables were also correlated to the abundance of small mammal through an analysis of redundancy (RDA). Analysis of variance showed no difference in total abundance and richness for any vegetation types. However, abundance of Oligoryzomys nigripes differed significantly (Q = 1.88, P = 0.0009), being higher in grassland. Considering body mass, there was a significant difference for Akodon montensis (Q = 1824, P = 0.046) and O. nigripes (Q = 1262.1, P = 0.001). The first axis of the PCA, were associated Didelphis albiventris and O. nigripes (r = 0.06, P = 0.022, r = 006, P = 0.018, respectively), and related to variables that characterize forest environments (higher density of woody vegetation). Analysis of variance showed that environmental complexity is not the main factor influencing the richness and abundance of species in the studied area, but there were differences in the pattern of individual distribution according to age, since adults selected best environments than young. The PCA and RDA showed significant effect of microhabitat variables on species occurrence. The presence of A. montesis was influenced by zoochorous dispersion and number of epiphytes, while D. albiventris and O. nigripes were related to forested environments, with greater trees abundance, DAP and litter. The last ones were also correlated with open environments, being D. albiventris related to ferns and distance of water and O. nigripes related to grasses.
A distribuição macro e micro-espacial de pequenos mamíferos não-voadores em uma área de mosaico entre Floresta Atlântica e Pampa foi investigada. Foi utilizada uma grade com 88 armadilhas, 27 foram instaladas no sub-bosque a cada duas armadilhas instaladas no solo, as quais distavam 70 m uma da outra. Foram realizadas 17 fases mensais de campo, durante cinco dias, de junho de 2011 a outubro de 2012, totalizando um esforço amostral de 7480 armadilhas-noite. Uma análise de variância (ANOVA) foi utilizada para verificar se existem diferenças na riqueza, abundância total e abundância de cada espécie entre as fitofisionomias de campo, borda e interior de floresta. Também foi testada a existência de diferenças na massa corporal dos indivíduos para cada espécie, entre essas fitofisionomias. Onze variáveis ambientais mensuradas foram resumidas através de uma análise de componentes principais (PCA). Posteriormente, foi realizada uma análise de regressão linear múltipla entre a riqueza e a abundância total e de cada espécie e os dois primeiros eixos do PCA. As variáveis ambientais brutas foram relacionadas com a abundância de mamíferos por meio de uma análise de redundância (RDA). A análise de variância não mostrou diferença na riqueza e abundância total das espécies para nenhuma das fitofisionomias. Oligoryzomys nigripes foi mais abundante na fitofisionomia de campo (Q = 1,88, P = 0,0009). Quanto à massa corporal, houve diferença significativa para Akodon montensis (Q = 1824, P = 0,046) e O. nigripes (Q = 1262,1, P = 0,001). O primeiro eixo da PCA, associado com Didelphis albiventris e O. nigripes estiveram associadas (r = 0,06; P = 0,022; r = 006; P = 0,018, respectivamente), foi relacionado às variáveis que caracterizam ambientes florestais. A análise de variância mostrou que a complexidade ambiental não é o principal fator que influencia a riqueza e a abundância das espécies na área estuda, porém houve diferenças no padrão de distribuição dos indivíduos conforme a idade, com indivíduos adultos selecionando ambientes distintos dos jovens. A RDA mostrou que a abundância de A. montesis foi influenciada pela dispersão zoocórica e número de epífitas, já D. albiventris e O. nigripes foram relacionados a ambientes florestados, com maior número de árvores, DAP e folhiço. Esses últimos foram correlacionados também a ambientes campestres, com D. albiventris se relacionando a locais com presença de samambaias e distantes da água e O. nigripes a ambientes com alta abundância de gramíneas.
Mikaelyan, Aram [Verfasser], i Andreas [Akademischer Betreuer] Brune. "Microhabitat-specificity of the hindgut microbiota in higher termites / Aram Mikaelyan. Betreuer: Andreas Brune". Marburg : Philipps-Universität Marburg, 2014. http://d-nb.info/1052995004/34.
Pełny tekst źródłaBates, Colin Robert. "Macroalgae as microhabitat : seaweed traits and wave action as predictors of invertebrate epifaunal diversity". Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/31214.
Pełny tekst źródłaScience, Faculty of
Botany, Department of
Graduate
Villeneuve, Valérie. "Algues benthiques du haut Arctique canadien, microhabitat et évaluation des facteurs de contrôle chimiques". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0017/MQ53987.pdf.
Pełny tekst źródłaBoyce, Sean. "Microhabitat selection and characterization of the Woolly Beech Scale, «Cryptococcus fagisuga», in Southern Quebec". Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=40686.
Pełny tekst źródłaLa maladie corticale du hêtre est une maladie répandue et mortelle du hêtre à grandes feuilles (Fagus grandifolia Ehrh.). Une infestation par le puceron laineux du hêtre, (Cryptococcus fagisuga Lind.) représente la première étape dans la progression de la maladie (Ehrlich 1934). Sa propagation sur l’arbre est affectée par l’exposition et la hauteur. Nous avons caractérisé ces patrons spatiaux en mesurant la température, la résistance, la rugosité et l'humidité de l'écorce des arbres. Ces mesures ont été prises dans deux forêts de la région de Montréal, Québec entre Juin et Septembre à deux hauteurs différentes (1.3 et 2.5 m) et du côté nord et sud des arbres. Nous avons également installé des colliers aux arbres pour empêcher l'écoulement sur le tronc du côté nord des arbres. Les pucerons étaient plus nombreux sur le côté nord et plus haut (2.5-2.8 m du sol) sur l’arbre . La température moyenne de l’écorce était 0.5oC plus élevée à 2.5 m. Le contenu en eau de l’écorce était 3% plus élévé à la hauteur de 2.5 m. Le résistance de l’écorce était plus haute sure les côtés nord des arbres. Les collets ont diminué la colonisation par le puceron laineux pendant l'été d’environ 80%. Nos résultats suggèrent que l’écoulement sur le tronc est une source d'humidité importante pour l'insecte, ou une méthode de transport, qui peut expliquer les plus grandes populations observées du côté nord des arbres. En bref, nos résultats démontrent que les populations du puceron laineux du hêtre varient avec la qualité du microhabitat.
Sakai, Osamu. "Personality of a clonal gecko Lepidodactylus lugubris: developmental mechanism and relation to microhabitat use". Kyoto University, 2019. http://hdl.handle.net/2433/242641.
Pełny tekst źródłaNishi, Hirotaka. "Divergence of Euhadra land snails associated with differentiation in microhabitat, shell morphology and behavior". 京都大学 (Kyoto University), 2007. http://hdl.handle.net/2433/136804.
Pełny tekst źródłaDebortoli, Jully Anne. "Preferência de monogenéticos por microhabitat branquial em jundiá Rhamdia quelen sob condições de laboratório". reponame:Repositório Institucional da UFSC, 2013. https://repositorio.ufsc.br/handle/123456789/107329.
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Hunter, Anne Katherine. "Longitudinal Patterns of Community Structure for Stream Fishes in a Virginia Tailwater". Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/31656.
Pełny tekst źródłaMaster of Science
Melo, Lilian Sayuri Ouchi de [UNESP]. "A similaridade no uso do microhabitat por girinos (Amphibia, Anura) reflete processos ecológicos ou filogenéticos?" Universidade Estadual Paulista (UNESP), 2014. http://hdl.handle.net/11449/110980.
Pełny tekst źródłaFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Inúmeros processos tem sido sugeridos para explicar a estruturação de comunidades, como por exemplo competição, predação, dispersão, deriva continental, filtragem ambiental, especiação. A compreensão da influência desses processos em escala local é capaz de possibilitar uma melhor compreensão dos determinantes da composição e riqueza de espécies em comunidades, especialmente as bem delimitadas fisicamente, como é o caso das comunidades de girinos. Nosso objetivo neste estudo foi investigar a influência de características ambientais na estruturação de comunidades de girinos em corpos d'água lênticos e lóticos. Realizamos as amostragens em uma área de Mata Atlântica no sudeste do Brasil. Este trabalho está dividido em dois capítulos. No primeiro capítulo verificamos quais características ambientais dos microhabitats de corpos d'água lênticos e lóticos influenciam positivamente a riqueza de espécies. Além da riqueza, avaliamos ainda a composição de espécies nos microhabitats, testando se ela é determinada pelas características ambientais ou um reflexo da estrutura espacial dos corpos d'água. No segundo capítulo, investigamos a relação entre os gradientes ambientais contínuos e descontínuos - considerando as características ambientais de corpos d'água lênticos e lóticos - com a diversidade taxonômica, filogenética e funcional de girinos em escala local. Os resultados do primeiro capítulo demonstram que a riqueza de espécies nos microhabitats dos corpos d’água lênticos e lóticos foi influenciada, respectivamente, pela quantidade de vegetação e de areia. A vegetação aquática influenciou positivamente a riqueza, provavelmente por proporcionar maior quantidade de alimento e de refúgios contra predadores. Nos ambientes lóticos, a relação positiva da riqueza de espécies com o substrato arenoso provavelmente decorre da seleção de microhabitats com menor correnteza, onde a areia fica ...
Inumerous processes have been suggested to explain the community structure, such as competition, predation, dispersal, continental drift, environmental filtering, speciation. To comprehend the influence of these processes on a local scale provide a better understanding of the composition and species richness determinants in communities, especially physically well defined communities, as is the case of the communities of tadpoles. Our goal in this study was to investigate the influence of environmental characteristics in communities structures of tadpoles in lotic and lentic water bodies. We conducted sampling in an area of Atlantic Rain Forest in southeastern Brazil. This work is divided into two section. In the first chapter we verified which environmental microhabitat characteristics of lotic and lentic water bodies positively influence species richness. Besides species richness, we evaluated species composition in microhabitats, testing if it is determined by the environmental characteristics of microhabitats or a consequence of water bodies spatial structure. In the second chapter, we seek to investigate the relationship between continuous and discontinuous environmental gradients - considering the environmental characteristics of lotic and lentic water bodies - with the taxonomic, phylogenetic and functional diversity of tadpoles on a local scale. The results of the first chapter show that species richness in microhabitats in lentic and lotic water bodies was influenced, respectively, by the amount of vegetation and sand. The aquatic vegetation had a positively relationship with tadpoles richness, probably due to the greater amount of food and refuge from predators provided. In lotic environments, the positive relationship of species richness with sand probably due to the selection of microhabitats with lower currents, where the sand is accumulated. In contrast, species composition in lentic and lotic microhabitats was mainly ...
FAPESP: 12/09243-0
Van, Overdijk Colin D. A. "Microhabitat selection by the amphipods Echinogammarus ischnus and Gammarus fasciatus in laboratory and field experiments". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0033/MQ62296.pdf.
Pełny tekst źródłaMelo, Lilian Sayuri Ouchi de. "A similaridade no uso do microhabitat por girinos (Amphibia, Anura) reflete processos ecológicos ou filogenéticos? /". São José do Rio Preto, 2014. http://hdl.handle.net/11449/110980.
Pełny tekst źródłaBanca: Ricardo Janinni Sawaya
Banca: Fabrício Barreto Teresa
Resumo: Inúmeros processos tem sido sugeridos para explicar a estruturação de comunidades, como por exemplo competição, predação, dispersão, deriva continental, filtragem ambiental, especiação. A compreensão da influência desses processos em escala local é capaz de possibilitar uma melhor compreensão dos determinantes da composição e riqueza de espécies em comunidades, especialmente as bem delimitadas fisicamente, como é o caso das comunidades de girinos. Nosso objetivo neste estudo foi investigar a influência de características ambientais na estruturação de comunidades de girinos em corpos d'água lênticos e lóticos. Realizamos as amostragens em uma área de Mata Atlântica no sudeste do Brasil. Este trabalho está dividido em dois capítulos. No primeiro capítulo verificamos quais características ambientais dos microhabitats de corpos d'água lênticos e lóticos influenciam positivamente a riqueza de espécies. Além da riqueza, avaliamos ainda a composição de espécies nos microhabitats, testando se ela é determinada pelas características ambientais ou um reflexo da estrutura espacial dos corpos d'água. No segundo capítulo, investigamos a relação entre os gradientes ambientais contínuos e descontínuos - considerando as características ambientais de corpos d'água lênticos e lóticos - com a diversidade taxonômica, filogenética e funcional de girinos em escala local. Os resultados do primeiro capítulo demonstram que a riqueza de espécies nos microhabitats dos corpos d'água lênticos e lóticos foi influenciada, respectivamente, pela quantidade de vegetação e de areia. A vegetação aquática influenciou positivamente a riqueza, provavelmente por proporcionar maior quantidade de alimento e de refúgios contra predadores. Nos ambientes lóticos, a relação positiva da riqueza de espécies com o substrato arenoso provavelmente decorre da seleção de microhabitats com menor correnteza, onde a areia fica ...
Abstract: Inumerous processes have been suggested to explain the community structure, such as competition, predation, dispersal, continental drift, environmental filtering, speciation. To comprehend the influence of these processes on a local scale provide a better understanding of the composition and species richness determinants in communities, especially physically well defined communities, as is the case of the communities of tadpoles. Our goal in this study was to investigate the influence of environmental characteristics in communities structures of tadpoles in lotic and lentic water bodies. We conducted sampling in an area of Atlantic Rain Forest in southeastern Brazil. This work is divided into two section. In the first chapter we verified which environmental microhabitat characteristics of lotic and lentic water bodies positively influence species richness. Besides species richness, we evaluated species composition in microhabitats, testing if it is determined by the environmental characteristics of microhabitats or a consequence of water bodies spatial structure. In the second chapter, we seek to investigate the relationship between continuous and discontinuous environmental gradients - considering the environmental characteristics of lotic and lentic water bodies - with the taxonomic, phylogenetic and functional diversity of tadpoles on a local scale. The results of the first chapter show that species richness in microhabitats in lentic and lotic water bodies was influenced, respectively, by the amount of vegetation and sand. The aquatic vegetation had a positively relationship with tadpoles richness, probably due to the greater amount of food and refuge from predators provided. In lotic environments, the positive relationship of species richness with sand probably due to the selection of microhabitats with lower currents, where the sand is accumulated. In contrast, species composition in lentic and lotic microhabitats was mainly ...
Mestre
Rocha, Clarisse Rezende. "Utilização de microhabitat por três espécies de roedores cricetídeos em um cerrado do Brasil central". reponame:Repositório Institucional da UnB, 2007. http://repositorio.unb.br/handle/10482/3397.
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O objetivo deste trabalho foi analisar a utilização de microhabitat por Calomys tener, Necromys lasiurus e Thalpomys lasiotis e os fatores que mais influenciam a abundância destas três espécies de cricetídeos em áreas abertas de campo com murundus. O estudo foi realizado na Estação Ecológica de Águas Emendadas, Planaltina, DF, entre julho e setembro de 2004. Foram estabelecidas duas grades com 100 pontos de amostragem cada, em que foram colocadas armadilhas e para os quais foram registrados os dados de oito variáveis de microhabitat e das capturas dos roedores. A abundância de Calomys tener foi associada negativamente com o número de árvores e positivamente com a quantidade de gramíneas e de número de cupinzeiros. Foi encontrada diferença significativa entre as variáveis de microhabitat utilizadas por esta espécie quando comparados os machos com as fêmeas. Necromys lasiurus apresentou abundância diretamente proporcional à densidade de árvores no microhabitat. Thalpomys lasiotis apresentou associação negativa com o diâmetro de árvore e associação positiva com a variável distância da árvore mais próxima, o que indica ter associação inversamente proporcional à densidade de árvores. Calomys tener e T. lasiotis parecem ter maior especificidade aos gradientes de microhabitat quando comparado com N.lasiurus, considerada uma espécie generalista de habitats. A Análise de Correspondência Canônica sugeriu que as variáveis de microhabitat não são bons indicadores para predizer a composição da comunidade em áreas de campo cerrado com murundus durante a estação seca, entretanto foi encontrado que estas variáveis são de fato selecionadas pelos indivíduos e espécies. _______________________________________________________________________________ ABSTRACT
The aim of the present study was to investigate the utilization of microhabitat by Calomys tener, Necromys lasiurus and Thalpomys lasiotis, and the factors that affect the abundance of these cricetid species in open areas of fields with “murundus”, a kind of vegetation of the Central Brazil Cerrado. The study was conducted in a conservation area (Estação Ecológica de Águas Emendadas), Planaltina town, Federal District, from July to September, 2004. Population densities of the three animal species and eight microhabitats variables were recorded in two grids with 100 trapping station each. Calomys tener was negatively associated to the number of trees and positively to grass percentage and numbers of termite nest. It was found a significant difference among used microhabitat variables for this species by comparing males and females. For Necromys lasiurus the most important variables were proximity between trees and number of trees. Thalpomys lasiotis was negatively associated to tree diameters and had a positive association to proximity between trees. Calomys tener and T. lasiotis seemed to have more specificity to microhabitat gradients than N. lasiurus. Canonical Correspondence Analyses suggest that microhabitat variables are not good to predictors of community’s composition in “murundus” fields of the Cerrado areas, during the dry season. However, it was found that these microhabitats variables are in fact selected by individuals and species.
Viljoen, Jan-Adriaan. "Distribution of leaf dissection and sclerophylly along microhabitat gradients in pteridophytes of the Cape peninsula". Bachelor's thesis, University of Cape Town, 2010. http://hdl.handle.net/11427/25976.
Pełny tekst źródłaJacob, Suellen A. "Effects of microhabitat and temporal factors on foraging behavior of white-footed mice (Peromyscus leucopus)". University of Cincinnati / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1337888535.
Pełny tekst źródłaBoley, Ryan Michael. "Relative species abundance and microhabitat preferences of larval Scaphirhynchus sturgeon in the middle Mississippi River". OpenSIUC, 2010. https://opensiuc.lib.siu.edu/theses/195.
Pełny tekst źródłaNitta, Carlos Hiroshi. "Uso de hábitat por tatus em área de floresta de restinga do sul do Brasil". Universidade do Vale do Rio dos Sinos, 2008. http://www.repositorio.jesuita.org.br/handle/UNISINOS/3128.
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Os tatus (Cingulata: Dasypodidae), apesar da diversidade de espécies, 21 espécies, e ampla distribuição, da Argentina até a metade sul dos EUA, passando pela América Central, as informações sobre a utilização dos ambientes por estes animais é escassa. A escavação e utilização de buracos no solo é uma característica ecológica relevante para o grupo, podendo estas estruturas serem consideradas indicadores conspícuos da presença desses animais. No presente estudo investiguei a densidade, direção, morfometria e microhabitat das tocas, em diferentes tipos de formação vegetal. O trabalho foi desenvolvido durante 13 meses (Out/06 a Nov/07) no Parque Estadual de Itapuã, na Grande Porto Alegre, RS, Brasil. O tatu-galinha (Dasypus novemcinctus) parece ser a espécie mais abundante neste local, onde ainda ocorre ao menos uma outra espécie, tatu-de-rabo-mole-grande (Cabassous tatouay). As características físicas e ambientais de 72 tocas, no campo (n = 31), mata (n = 22) e Restinga (n = 19), encontradas foram analisadas. A densidade de tocas não variou significativamente entre estes ambientes. Embora o tatu-galinha seja apontado como uma espécie de áreas florestadas no presente estudo, as áreas abertas foram utilizadas com a mesma intensidade que mata e restinga. Dentre as variáveis ambientais o número de árvores e porcentagem de cobertura de solo por arbustos tiveram influência no número de tocas encontradas em mata. A direção das tocas foram predominantemente sul nas áreas de floresta (mata e restinga) e significativamente diferentes das áreas de campo (campoXmata p = 0,002; campoXrestinga p = 0,001). Sugerindo que esta espécie possa mudar o comportamento e aumentar o nicho na ausência ou relaxamento de predadores e competidores.
Armadillos ( Cingulata : Dasypodidae ), despite the diversity of species , 21 species , and wide distribution , from Argentina to the southern half of the United States through Central America, information on the use of animals in these environments is scarce. The excavation and using holes in the ground is an important ecological nature of the group, these structures may be considered conspicuous indicators of the presence of these animals. In the present study I have investigated the density, direction, morphometric and microhabitat of the burrows in different types of plant formation. The study was conducted during 13 months (Oct/06 to Nov/07) in Itapuã State Park, in Porto Alegre , RS , Brazil . The nine-banded armadillo (Dasypus novemcinctus) seems to be the most abundant species at this site, which is still at least one other species, the greater naked-tailed armadillo (Cabassous tatouay). The physical and environmental characteristics of 72 holes, fields (n = 31), forest (n = 22) and Restinga (n = 19), found were analyzed. The density of burrows did not vary significantly between these environments. Although the nine-banded is touted as a kind of wooded areas in the present study, the open areas were used with the same intensity that forest and dunes. Among the environmental variables the number of trees and percentage of ground cover shrubs influenced the number of burrows found in the woods. The direction of the burrows were predominantly southern areas of forest (forest and Restinga) and significantly different from field areas (fieldXforest p = 0.002; fieldXrestinga p = 0.001). Suggesting that this species can change behavior and increase the niche or relaxation in the absence of predators and competitors.
Larrieu, Laurent. "Les dendro-microhabitats : facteurs clés de leur occurrence dans les peuplements forestiers, impact de la gestion et relations avec la biodiversité taxonomique". Thesis, Toulouse, INPT, 2014. http://www.theses.fr/2014INPT0130/document.
Pełny tekst źródłaTree microhabitats, such as cavities, are diverse and abundant in natural forests. A literature review revealed that they are dynamic and temporary key habitat resources for the complexity of forest ecosystems. However, since their study is recent, they are still poorly known. In harvested forest, tree microhabitats are well categorized as silvicultural items, mostly as wood defaults decreasing its commercial value. Therefore, how to reconcile the retention of ecological objects crucial for biodiversity and the production of high‐quality timber? This PhD thesis aimed, on the one hand, at participating to better qualify the ecological roles of tree microhabitats for forest biodiversity and, on the other hand, at giving practical recommendations to forest managers who integrate the conservation of species diversity in their usual management. 1028 plots were set up in 210 French forests to observe about 55,000 trees. We studied the relationships between tree microhabitats and species richness and composition of 9 taxa. Through the analysis of key features for tree microhabitats at the tree and stand levels, we showed that tree species and diameter at breast height explain 26 and 31 % of the variations in microhabitat occurrence and diversity, respectively, in beech‐fir forest unlogged for more than 100 years. We highlighted significant diameter thresholds for the occurrence and diversity of microhabitats borne by beech (Fagus sylvatica L.) and silver fir (Abies alba Mill.). Furthermore, tree microhabitat density, deadwood volume and their diversity were shown to be roughly constant throughout the silvigenetic cycle in mountain mixed forests. Secondary tree species play a crucial role in the regulation of deadwood and microhabitat pools, especially during the phases where the dryad trees supply a low amount of microhabitats and deadwood. A surface of unharvested forest more than 10 hectares in area is necessary to observe the whole microhabitat diversity. Microhabitat occurrence patterns in logged forests were drastically different from those observed in forests unlogged for more than one century: tree microhabitats were systematically less diverse and the relative density of microhabitat types was modified. Moreover, the restoration of tree microhabitat pools was slow in set‐aside plain broadleaved forests. More than 30 years without harvests were not sufficient to observe the restoration of the tree microhabitat pool and significant changes in saproxylic beetle communities in all forest contexts. We measured the contribution of tree microhabitats to biodiversity, and we observed that the density of cavity‐ and fungus‐bearing trees were significant drivers for species richness and composition of saproxylic beetle assemblages. The density of trees bearing microhabitats, especially bark losses, significantly influenced the species richness of polypores. The stand openness and local climatic conditions affected these relationships in several forest‐taxon cases. We proposed a reference hierarchical typology of tree microhabitats in order to harmonize survey protocols and to facilitate data sharing in the future. Furthermore, we improved the consideration of tree microhabitats in an integrated management tool, i.e. the Potential Biodiversity Index (PBI). We also included the tree microhabitat pool into a simulation model of mountain forest dynamics (Samsara 2). Apart from being relevant management tools in conservation biology, tree microhabitats stand for natural microcosms available to further fundamental ecological researches. We hope that our work will help foresters to have a new insight on their managed forests
Tolimieri, Nicholas. "Effects of microhabitat characteristics and spatial scale on recruitment and adult abundance in Caribbean reef fishes". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq30297.pdf.
Pełny tekst źródłaVirillo, Carolina Bernucci. "Influência do microhabitat e da densidade e distância de vizinhos na demografia de populações espécies arbóreas". [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/315004.
Pełny tekst źródłaTese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: Os mecanismos responsáveis pela alta diversidade de espécies arbóreas em florestas tropicais têm sido alvo de intenso debate na literatura, e dentre os inúmeros mecanismos propostos, dois deles têm encontrado relativo suporte empírico: a dependência de densidade e a diferenciação de nichos. O objetivo deste trabalho foi investigar a ocorrência destes mecanismos na Floresta Ombrófila Densa Atlântica, que apresenta uma enorme diversidade de espécies vegetais, que variam em abundância, e uma grande diversidade de habitats, o que faz deste bioma um local apropriado para buscar evidências da ocorrência desses mecanismos. Foi investigada a influência da densidade de coespecíficos, da vizinhança e do microhábitat na demografia de quatro espécies arbóreas, e esperava-se que estes fatores atuassem de maneira conjunta na determinação da demografia das espécies estudadas. Em cinco áreas de 0,25 ha, duas na Floresta Ombrófila Densa de Terras Baixas (TB) e três na Floresta Ombrófila Densa Submontana (SM), foram marcados e medidos os indivíduos destas espécies, e um recenso foi realizado após dois anos para obtenção de taxas de mortalidade e recrutamento. Indivíduos com PAP (perímetro a altura do peito) > 15 cm foram acompanhados mensalmente para a avaliação da fenologia reprodutiva e do incremento diamétrico. Foi avaliada a influência da densidade de indivíduos e da distância e número de vizinhos coespecíficos na demografia das espécies. Também foi avaliada a relação da demografia com habitats específicos, dados pela declividade e pela porcentagem de abertura de dossel, assim como da fenologia reprodutiva e do incremento diamétrico com a cota de altitude e com o índice de iluminação da copa (IC). Para nenhuma das espécies estudadas foi encontrada relação entre a densidade total de indivíduos e as taxas de mortalidade e de recrutamento. Entretanto, nas áreas de maior abundância, foram encontradas associações entre os indivíduos mortos e os demais indivíduos da população, assim como diminuição da agregação conforme se considera classes de tamanho maiores, que podem ser interpretadas como evidências dos processos dependentes de densidade, indicando que os processos dependentes de distância ou densidade só se mostram importantes em situações de densidade elevada. Houve relação do número de indivíduos com a declividade para a maioria das espécies, mas foram poucas as relações significativas com a abertura de dossel. A mortalidade, o recrutamento e o crescimento dos indivíduos com PAP < 15 cm apresentaram poucas relações significativas com as variáveis ambientais (IDP e abertura do dossel), provavelmente devido ao baixo número de eventos registrados. Para duas das espécies, a fenologia reprodutiva se relacionou com a cota de altitude, mas não com o IC, indicando um aspecto da preferência de hábitat. Já o incremento diamétrico variou muito dentro de uma mesma cota altitudinal, se relacionando, para duas das espécies, com o IC, mas para as outras duas espécies nem a altitude e nem a iluminação das suas copas explicou a variação observada no crescimento. Recomenda-se que um maior número de variáveis ambientais sejam utilizadas para caracterizar os microambientes quando se busca evidências de preferências de hábitat. É provável que os mecanismos estudados não sejam mutuamente exclusivos e que eles atuem em conjunto na determinação dos processos demográficos populacionais, e assim influenciando conjuntamente na manutenção da grande diversidade de espécies arbóreas em florestas tropicais.
Abstract: The mechanisms that are responsible for the high tree species diversity in tropical forests have been intensively debated on literature, and among the several proposed mechanisms, two of them have been relatively empirically supported: the density-dependence and the niche differentiation. The aim of this work was to investigate the occurrence of these mechanisms on the Atlantic Ombrophilous Dense Forest, that has a huge plant species diversity, that vary on their abundance, and a high diversity of habitats, what makes this biome an appropriate place to seek for the existence of these mechanisms. We investigated the influence of conspecific density, neighborhood and microhabitat on the demography of four tree species, and we expected these factors to act together on determining the demography of the studied species. On five 0.25 ha area, two on the Lowland Ombrophilous Dense Forest and three on the Lower-montane Ombrophilous Dense Forest, we tagged and measured all the plants of the studied species; the plants were re-censused after two years so we obtained the mortality and recruitment rates. Plants with perimeter at breast height (PBH) > 15 cm were monthly observed to evaluate their reproductive phenology and diameter increment. We evaluated the influence of the density of plants and the number and distance of conspecific neighbors on the demography of the studied species. We also evaluated the relationship of the demographic rates with specific habitats, given by canopy openness and declivity, and of the reproductive phenology and diameter increment with the altitude and the crown illumination index (IC). We found no relationship between the total density of individuals and the mortality or recruitment rates, but on the areas of high abundance we found associations between the dead plants and the other plants of the populations, as well as lower aggregation as we considered bigger size classes, which could be interpreted as evidences of the density dependent processes, indicating that the density or distance-dependent processes are important only on high density situations. We found significant relationships between the number of individuals and declivity for the majority of species, but there were few significant associations with the canopy openness. Mortality, growth and recruitment of plants PBH < 15 cm have few significant correlations with environmental variables (declivity and canopy openness), probably because of the low number of events registered. For two of the studied species, the reproductive phenology was related to the altitude but not with IC, indicating one aspect of the habitat preference. The diameter increment showed great variation on the same altitude, and for two species it was related with IC, but for the other two neither the altitude nor the IC explained the observed variation on growth. We recommend the use of more environmental variables to characterize the microenvironments when seeking for evidence of habitat preference. It's possible that the studied mechanisms are not mutually exclusive and that they act together on determining the demographic processes, and so, influencing together the maintenance of the high tree species diversity on tropical forests.
Doutorado
Mestre em Biologia Vegetal
Farquhar, Michael Robert. "Interspecific interactions of the sea urchin Parechinus angulosus and the effect of variations in microhabitat availability". Thesis, Rhodes University, 1995. http://hdl.handle.net/10962/d1005406.
Pełny tekst źródłaMergo, John Carl. "Studies on the life history, development, occurrence, and microhabitat of Microcotyle spinicirrus, (Monogenea: Microcotylidae) Maccallum 1819 /". The Ohio State University, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487588939090221.
Pełny tekst źródłaCross, Amy Suzanne. "MICROHABITAT USE BY GOLDEN MICE (OCHROTOMYS NUTTALLI) AND WHITE-FOOTED MICE (PEROMYSCUS LEUCOPUS) IN SOUTHERN ILLINOIS". OpenSIUC, 2013. https://opensiuc.lib.siu.edu/theses/1094.
Pełny tekst źródłaSilva, Adilson de Oliveira. "Análise comparativa dos nichos espacial e alimentar de anuros em áreas de Caatinga e Mata Atlântica de Sergipe, Brasil". Universidade Federal de Sergipe, 2014. https://ri.ufs.br/handle/riufs/4404.
Pełny tekst źródłaDistinct environmental characteristics can directly affect community structure, they offer varying conditions and resources, which allows each area to establish different groups of species. In this study we analyzed two amphibian assemblages between October 2012 and September 2013 in two areas with different degrees of environmental heterogeneity, one in the Caatinga (Monument Natural Grota do Angico - MNGA ) and the other in the Atlantic Rainforest (Refugio de Vida Silvestre Mata do Junco - RVSMJ), both in the state of Sergipe. We used information about the spatial and food niches and their relationships with ecological and historical factors. We analyzed 1,332 records (999 - RVSMJ 333 - MNGA) of 28 species (22 - RVSMJ and 15 - MNGA, nine common to both areas). The food and space niche overlap was relatively high in both study sites. Nine types of microhabitats were used by the species being the most common, regardless of the area, soil (45.1 %), water (23.7 %) and leaflitter (8.6%). The most important preys in their diets were Formicidae and Coleoptera in both areas. Individuals in the Atlantic rainforest were relatively smaller than those of the Caatinga area suggesting differentiated investments between reproduction and growth between the areas. The results suggest that the assemblages from both areas are influenced by historical or phylogenetic factors only in the use of space assets. Their diets are strongly influenced by the availability of resources the environment offers.
Características ambientais distintas podem afetar diretamente a estruturação das comunidades, pois oferecem recursos e condições variadas, o que permite que em cada área, grupos diferenciados de espécies se estabeleçam. Nesse estudo duas taxocenoses de anfíbios anuros foram analisadas entre outubro de 2012 e setembro de 2013, em duas áreas com diferentes graus de heterogeneidade ambiental, uma na Caatinga (Monumento Natural Grota do Angico MNGA) e outra de Mata Atlântica (Refugio da Vida Silvestre Mata do Junco RVSMJ), ambas no estado de Sergipe. Foram utilizadas informações sobre os nichos espacial e alimentar e suas relações com fatores ecológicos e históricos. Foram tomados 1.332 registros (999 - RVSMJ e 333 - MNGA) pertencentes a 28 espécies (22 RVSMJ e 15 MNGA, sendo nove comuns as duas áreas). A sobreposição de nicho espacial e alimentar foi relativamente alta em ambas as áreas. Nove tipos de microhábitats foram utilizados pelas espécies sendo os mais comuns, independente da área, solo (45,1%), água (23,7%) e folhiço (8,6%). As presas mais importantes das dietas foram Formicidae e Coleoptera em ambas as áreas. Os indivíduos da Mata Atlântica foram relativamente menores que os da Catinga sugerindo investimentos diferenciados em reprodução e crescimento entre as áreas. Os resultados obtidos sugerem que as taxocenoses de ambas as áreas são influenciadas por fatores históricos ou filogenéticos somente na utilização dos recursos espaciais. Suas dietas são fortemente influenciadas pelas disponibilidades de recursos que o ambiente oferece.
Ditterich, Franziska [Verfasser], i Ellen [Akademischer Betreuer] Kandeler. "Microbial community structure and function is shaped by microhabitat characteristics in soil / Franziska Ditterich ; Betreuer: Ellen Kandeler". Hohenheim : Kommunikations-, Informations- und Medienzentrum der Universität Hohenheim, 2016. http://d-nb.info/1118571665/34.
Pełny tekst źródłaLandry-Cuerrier, Manuelle. "From habitat to energetics : eastern chipmunk burrow microhabitat selection and fine-scale variation in winter torpor expression". Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=112530.
Pełny tekst źródłaGuerra, Giraldez Mabel. "Alteración en la elección de microhabitat de Acyrtosiphon pisum (Hemiptera: Aphididae) parasitado por Aphidius ervi (Hymenoptera: Braconidae)". Tesis, Universidad de Chile, 2000. http://www.repositorio.uchile.cl/handle/2250/106673.
Pełny tekst źródłaDuchemin, Gérald. "Ecologie des foraminifères benthiques du Golfe du Morbihan et de la Grande Vasière : variabilité temporelle et microhabitat". Angers, 2004. http://www.theses.fr/2004ANGE0014.
Pełny tekst źródłaThis thesis on benthic foraminiferal ecology presents two parts, one on a high marsh of the Gulf of Morbihan, and the other on the continental shelf of the Bay of Biscay (in the context of the French national program PNEC). The aim of this thesis is the same for both environments: to define the foraminiferal behaviour in response to the environmental variations. In the high marsh of the Gulf of Morbihan, our observations indicate that foraminiferal faunas present a strong short-term (weekly) variability and a well established microhabitat succession in the first 9 cm of sediment. Furthermore, this study highlights some poorly known phenomena, such as possible migrations and/or transport of foraminifera, the refuge effect of the vegetation and the potential impact of the rainfall. On the continental shelf, foraminiferal faunas are mainly under the influence of the variations of matter organic fluxes. These fluxes determine the composition, the spatial distribution and the seasonal variations of density of the benthic foraminiferal faunas
Legras, Elaine C. "Microhabitat is critical for sugar pine seedlings emergence and survival in a xeric Jeffrey pine dominated forest /". abstract and full text PDF (UNR users only), 2008. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1455660.
Pełny tekst źródła"May, 2008." Includes bibliographical references (leaves 39-44). Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2009]. 1 microfilm reel ; 35 mm. Online version available on the World Wide Web.
Ortiz, Durà Jesús. "Response of the benthic macroinvertebrate community to a point source in La Tordera stream (Catalonia, NE Spain)". Doctoral thesis, Universitat de Girona, 2005. http://hdl.handle.net/10803/7901.
Pełny tekst źródłaAigües avall de la font puntual, concentració de nutrients, cabal i conductivitat eren majors que al tram d'aigües amunt, mentre que oxigen dissolt era menor. La densitat de macroinvertebrats era més elevada al tram d'aigües avall però la biomassa era similar als dos trams. La riquesa taxonòmica al tram de dalt era un 20% més alt que al tram de baix. Els anàlisis d'ordenació separen clarament els dos trams en el primer eix, mentre que els dos trams presentaven una pauta temporal similar en el segon eix. La similaritat entre els dos trams en composició taxonòmica, densitats i biomasses després de les crescudes d'abril i maig de 2002, indiquen que les pertorbacions del cabal poden actuar com a un mecanisme de reinici de la comunitat bentònica i jugar un paper important per a la restauració d'ecosistemes fluvials.
Els dos trams presentaven una biomassa de perifiton, plantes vasculars, CPOM i FPOM similars, mentre que clorofil·la a, algues filamentoses, molses i SPOM eren majors al tram d'aigües avall. La densitat relativa de trituradors era menor sota la font puntual mentre que col·lectors i filtradors van ser afavorits. La biomassa relativa de trituradors també era menor sota la font puntual, però la biomassa de col·lectors i depredadors va augmentar. Les relacions entre densitat de grups tròfics i els seus recursos eren rarament significatives. La relació s'explicava millor amb la biomassa de macroinvertebrats. Els dos trams compartien la mateixa relació per raspadors, col·lectors i filtradors però no per trituradors i depredadors.
La densitat i la biomassa de macroinvertebrats es trobaven positivament correlacionades amb la quantitat de recursos tròfics i la complexitat d'habitat, mentre que la riquesa taxonòmica es trobava negativament relacionada amb paràmetres hidràulics. La influència dels substrats inorgànics prenia menor rellevància per a la distribució dels macroinvertebrats. Els anàlisis d'ordenació mostren com les variables del microhabitat de major rellevància eren CPOM, clorofil·la a, algues filamentoses i velocitat. La cobertura de sorra només era significativa per al tram d'aigües amunt i les molses, al d'aigües avall. El número de correlacions significatives entre macroinvertebrats i les variables del microhabitat era més elevat per al tram de dalt que per al de baix, bàsicament per diferències en composició taxonòmica. La biomassa de macroinvertebrats va aportar una informació semblant a la obtinguda per la densitat.
Perifiton i molses tenien uns continguts de nutrients similars en els dos trams. Els %C i %N d'algues filamentoses també eren similars en els dos trams però el %P sota la font puntual era el doble que al tram de dalt. Les relacions estoquiomètriques en CPOM, FPOM i SPOM eren considerablement menors sota la font puntual. Els continguts elementals i relacions van ser molt variables entre taxons de macroinvertebrats però no van resultar significativament diferents entre els dos trams. Dípters, tricòpters i efemeròpters presentaven una estoquiometria similar, mentre que el C i el N eren inferiors en moluscs i el P en coleòpters. Els depredadors presentaven un contingut en C i N més elevat que la resta de grups tròfics, mentre que el P era major en els filtradors. Els desequilibris elementals entre consumidors i recursos eren menors en el tram d'aigües avall. A la tardor i l'hivern la major font de nutrients va ser la BOM mentre que a la primavera i a l'estiu va ser el perifiton.
We monitored physical and chemical parameters, benthic macroinvertebrates, chlorophyll a, primary producers, and organic matter for one year (2001-2002) to assess the effect of a point source input on the taxa composition, community structure, functional organization, microhabitat distribution, and elemental stoichiometry in La Tordera stream (Catalonia, NE Spain).
Below the point source, nutrient concentrations, discharge, and specific conductance were higher than at the upstream reach, while dissolved oxygen decreased. Total macroinvertebrate density was higher at the downstream reach than at the upstream reach. The two reaches did not differ in macroinvertebrate total biomass. On average, taxa richness at the upstream reach was 20% higher than at the downstream reach. Ordination analysis clearly separated the samples of the two reaches in the first axis and corroborated the effect of the point source on the benthic community. The two reaches followed a similar temporal pattern with respect to the distribution of taxa along the second axis. Higher similarities between the two reaches in taxa composition, densities and biomass after the spates of April and May 2002, suggest that flooding events may act as a reset mechanism for benthic communities and play an important role in stream restoration.
The two reaches did not differ in standing stocks of periphyton, vascular plants, CPOM and FPOM. Chlorophyll a, filamentous algae, mosses, and SPOM concentrations were increased by the point source. Relative density of shredders was reduced at the downstream reach, whereas gatherers and filterers were enhanced. Relative biomass of shredders decreased below the point source as well, but gatherers diminished and predators increased. The relationships between density of functional feeding groups and their presumed food resources were rarely significant. The relation between consumers and their food resources was best explained through macroinvertebrate biomass. The two reaches had the same relationship for scrapers, gatherers, and filterers, but differed for shredders and predators.
Macroinvertebrate density and biomass were positively correlated with food resources and complexity of habitat architecture while taxa richness was negatively correlated with hydraulic parameters. Inorganic substrate exerted a lesser influence on macroinvertebrate distribution. Ordination analysis revealed that the microhabitat variables of major relevance at the two reaches were CPOM, chlorophyll a, filamentous algae, and maximum water velocity. Sand coverage was only retained at the upstream reach and moss, at the downstream reach. The number of significant correlations between macroinvertebrates and microhabitat variables was higher at the upstream reach than at the downstream reach mainly because of higher taxa richness. Macroinvertebrate biomass provided similar information to that obtained from density in our study case.
Periphyton and mosses had similar nutrient contents in the two reaches. The %C and %N filamentous algae was also similar in the two reaches, but %P below the point source was two times higher than that at the upstream reach. Stoichiometric ratios for CPOM, FPOM, and SPOM decreased considerably below the point source. Elemental contents and ratios were highly variable among macroinvertebrate taxa but did not differ significantly between the two reaches, indicating homeostatic regulation. Dipterans, caddisflies, and mayflies had similar elemental contents and stoichiometry, whereas C and N were lower in mollusks and P in beetles. Predators had the higher C and N contents, while %P was higher in filterers and lower in scrapers. Elemental imbalances between consumers and resources were amended at the downstream reach relative to the upstream reach. Macroinvertebrates represented, on average, relatively low nutrient storage in the ecosystem. At the upstream reach, autochthonous production represented the major input of nutrients into the ecosystem food web, whereas the major source of P for heterotrophic production at the downstream reach was represented by allochthonous inputs.