992 resultados para inter-generational succession


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Resumen tomado de la publicación

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Resumen basado en el de la publicaci??n

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Resumen basado en el de la publicaci??n

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Man-made wetlands are often created to compensate for the loss or degradation of natural wetlands, but little is known about the processes taking place in these artificial environments, especially at the community level. Throughout this thesis, we have assessed the phenomena of primary succession over different time (short-, mid- and long-term) and spatial scales (local, regional, interregional levels), applying different approaches (taxonomic and functional) and subject groups (invertebrates and amphibians). Our main findings regarding time scales show a 3-phase successional pattern in Mediterranean man-made wetlands’ communities, where at the short term (1 year) colonization processes dominate; at mid term perspectives (2 to 7 years) succession signs begin to be conspicuous, and later on (≥ 10 years) parameters such as species richness reach an asymptote. At that moment, some biological strategies dominate, and biodiversity surrogates indicate that communities are indistinct between man-made and natural wetlands. Regarding spatial effects, we corroborated that both local and regional factors affect the establishing communities. Particularly, the low hydrological stability of the Mediterranean region has enhanced biological traits favoring resilience and resistance to disturbances when comparing Mediterranean and cold temperate aquatic communities. Even within the Mediterranean region, low levels of hydrological stability have significant effects on the successional dynamics. In these cases, local communities are highly nested within regional natural ones, and so are not able to make net contributions to regional richness. We also showed the influence of the regional pool of recruiters over local communities, both in the case of invertebrates and amphibians. Especially for the latter group, man-made Mediterranean temporary ponds (MTPs) can play an important role in their conservation.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

O objectivo deste estudo é considerar a possibilidade e exigências de um diálogo e de uma espiritualidade inter e trans-religiosos a partir das propostas de Sua Santidade o Dalai Lama e Agostinho da Silva.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

O tema deste trabalho é a (in)disciplina em contexto de sala de aula, colocando - se o enfoque nas representações alunos do 3º ciclo, pais e professores sobre esta problemática e as suas perceções sobre o tipo de ocorrências e causas. Este estudo de caso procura um entendimento da indisciplina, reconhecendo-se a existência de uma miríade de fatores subjacentes a este conceito, cruzando diferentes olhares da psicologia, sociologia e pedagogia. O conceito de indisciplina é definido com referência ao conceito de disciplina traduzindo um comportamento disruptivo que emerge na relação pedagógica. A construção da relação interpessoal entre professor/aluno e a gestão do comportamento dos alunos assegura a manutenção de um clima que permite a efetividade do processo ensino – aprendizagem. Realiza-se uma abordagem numa perspetiva conceptual, procurando-se o conhecimento e natureza do conceito, a identificação das causas centrados no aluno desde as suas características psicológicas, sócio – económicas, de contexto familiar e culturais, as causas centradas no professor e na organização escolar, bem como as causas sociais que influenciam a ocorrência de (in)disciplina. Explanam-se formas de gestão e resolução de comportamentos disruptivos, atendendo a diferentes e possíveis abordagens. Efetua-se, numa perspetiva empírica, na tentativa de compreender o impacto da interação pedagógica na ocorrência de atos disruptivos, a análise e interpretação de dados obtidos por triangulação de métodos, a partir de uma população de alunos de 3ºciclo, professores e pais, permitindo uma reflexão e confrontação sobre as representações destes atores e as realidades observadas.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This paper discusses a study undertaken to test various speech discrimination tests.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In recent decades, many early-succession songbird species have experienced severe and widespread declines, which often are related to habitat destruction. Field borders create additional or enhance existing early-succession habitat on farmland. However, field border shape and the landscape context surrounding farms may influence the effectiveness of field borders in contributing to the stabilization or increase of early-succession bird populations. We examined the influence of linear and nonlinear field borders on farms in landscapes dominated by either agriculture or forests on nest success and Brown-headed Cowbird (Molothrus ater) brood parasitism of Indigo Bunting (Passerina cyanea) and Blue Grosbeak (Passerina caerulea) nests combined. Field border establishment did not affect nest survival probability and brood parasitism frequency of Indigo Bunting and Blue Grosbeak nests. Indigo Bunting/Blue Grosbeak nest success probability was more than twice as high in agriculture-dominated landscapes (39%) than in forested landscapes (17%), and brood parasitism frequency was high (33%) but did not differ between landscapes. Edges in agriculture-dominated landscapes can be higher-quality habitats for early-succession birds than edges in forest-dominated landscapes, but our field border treatments did not enhance nest success for these birds on farms in either landscape.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Predicting metal bioaccumulation and toxicity in soil organisms is complicated by site-specific biotic and abiotic parameters. In this study we exploited tissue fractionation and digestion techniques, combined with X-ray absorption spectroscopy (XAS), to investigate the whole-body and subcellular distributions, ligand affinities, and coordination chemistry of accumulated Pb and Zn in field populations of the epigeic earthworm Lumbricus rubellus inhabiting three contrasting metalliferous and two unpolluted soils. Our main findings were (i) earthworms were resident in soils with concentrations of Pb and Zn ranging from 1200 to 27 000 mg kg(-1) and 200 to 34 000 mg kg(-1), respectively; (ii) Pb and Zn primarily accumulated in the posterior alimentary canal in nonsoluble subcellular fractions of earthworms; (iii) site-specific differences in the tissue and subcellular partitioning profiles of populations were observed, with earthworms from a calcareous site partitioning proportionally more Pb to their anterior body segments and Zn to the chloragosome-rich subcellular fraction than their acidic-soil inhabiting counterparts; (iv) XAS indicated that the interpopulation differences in metal partitioning between organs were not accompanied by qualitative differences in ligand-binding speciation, because crystalline phosphate-containing pyromorphite was a predominant chemical species in the whole-worm tissues of all mine soil residents. Differences in metal (Pb, Zn) partitioning at both organ and cellular levels displayed by field populations with protracted histories of metal exposures may reflect their innate ecophysiological responses to essential edaphic variables, such as Ca2+ status. These observations are highly significant in the challenging exercise of interpreting holistic biomarker data delivered by "omic" technologies.