Suchergebnisse

Floodplains are ecosystems which are driven by periodic inundation and oscillation between terrestrial and aquatic phases. An understanding of such pulsing systems is only possible by studying both phases and linking the results into an integrated overview. This book presents the results of a 15-year study of the structure and function of one of the largest tropical floodplains, the Amazon River floodplain. It covers in 23 chapters hydrology, hydrochemistry, climatology, soil science, and the ecology of various groups of aquatic and terrestrial plants and animals. In the botanical section, emphasis is given to aquatic algae (phytoplankton and periphyton), aquatic macrophytes, terrestrial herbaceous plants and the floodplain forest. The zoological section covers common terrestrial invertebrates (i.e. spiders, collemboles, termites, oribatid mites, tiger beetles, millipedes), aquatic invertebrates (zooplankton, perizoon, benthos), fishes, birds, mammals, amphibians and reptiles. Data are presented on the biomass of plants and animals, on primary production and decomposition of algae, herbaceous plants and trees of the floodplain forest. The amounts of bioelements stored in different compartments of the system during the aquatic and the terrestrial phases are quantified and fluxes between the phases are described. The authors interpret their findings and the most important data from other studies under an integrating scientific concept, the Flood Pulse Concept

The role of climate as a speciation driver in the Amazon has long been discussed. Phylogeographic studies have failed to recover synchronous demographic responses across taxa, although recent evidence supports the interaction between rivers and climate in promoting speciation. Most studies, however, are biased toward upland forest organisms, while other habitats are poorly explored and could hold valuable information about major historical processes. We conducted a comparative phylogenomic analysis of floodplain forest birds to explore the effects of historical environmental changes and current connectivity on population differentiation. Our findings support a similar demographic history among species complexes, indicating that the central portion of the Amazon River basin is a suture zone for taxa isolated across the main Amazonian sub-basins. Our results also suggest that changes in the fluvial landscape induced by climate variation during the Mid- and Late Pleistocene drove population isolation, leading to diversification with subsequent secondary contact. Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).

Understanding how floodplain communities of the Brazilian Amazon respond to the impacts of extreme flooding induced by hydroclimatic variability and how learning supports these responses are the dual focus of this thesis. The UN Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report (2014) demonstrates that rural communities in developing countries are among those most impacted by extreme climatic events, which are likely to increase in frequency and intensity in the near future. However, the community-based adaptations (CBA) literature indicates that rural communities have coped with climate variability by using a range of local assets, especially when governments have failed to provide proper assistance. My study followed a qualitative approach, employing semi-structured interviews with community members and institutional agents, participant observation, participatory mapping exercises, and validation workshops. Findings demonstrate that the repeated occurrence of extreme floods between 2009 and 2015 resulted in severe impacts, including some that had never been experienced by the local communities, such as the complete loss of perennials. Utilizing the sustainable livelihoods and resilience lenses, I investigated the locally-devised short-term and long-term responses to these impacts. Results revealed a wide range of responses, some of which I placed in a newly-proposed category of annual responses. Data about the capacity to absorb impacts without responding and about transformative responses were also provided. I also found that much of the learning that was foundational to the responses was instrumental in nature. The learning outcomes for individual participants resulted in proposing two new learning domains –introspective and emancipatory learning. Transformative outcomes were revealed for some participants who found that the intensity and repetition of extreme flooding drove them to leave the floodplain for upland or urban areas. Findings also revealed a wide array of learning domains ...

A pesca fica prejudicada quando as várzeas sofrem crescentes pressões de infraestrutura, poluição, mudanças climáticas e sobrepesca. Para comunidades ribeirinhas da Amazônia, isso pode significar menos peixes nos rios e lagos, o que leva a bolsos e estômagos vazios. Este artigo usa a teoria dos recursos comuns para analisar as origens e o funcionamento dos acordos coletivos de pesca assinados por habitantes das várzeas da Amazônia brasileira. Como a pesca comercial se expandiu em meados dos anos 1990, as experiências envolvendo lagos geridos pelas comunidades locais surgiram em vários locais, como um exemplo promissor de gestão participativa de base. Os resultados mostram que os acordos geraram melhorias consideráveis, embora a sua eficácia esteja ameaçada pela fraqueza do monitoramento e da fiscalização e pela falta de eficácia da regulamentação da posse da terra. O artigo sugere que as agências governamentais devem apoiar estes acordos por meio do desenvolvimento (ou adaptação) dos mecanismos que visam a descentralização das decisões públicas e da gestão. O fracasso deles pode levar a mudanças nos processos ecológicos, à redução dos estoques pesqueiros e a conflitos sócio-ambientais. ; Fisheries become undermined as floodplains suffer increasing pressure from infrastructure, pollution, changes in climate and over-extraction. For Amazonian riverside communities, less fish in the rivers and lakes means empty pockets and empty stomachs. This article uses common pool resource theory to analyze the origins and workings of collective fishing agreements in the Brazilian Amazon floodplains. As commercial fisheries expanded in the mid-1990s, experiences in community-managed lakes emerged in several locations, as a promising example of participatory grassroots management. Findings show that agreements yield considerable improvements, although their effectiveness is threatened by the weak vigilance and monitoring and by the lack of effectiveness of land tenure regulation. The article suggests that governmental agencies should support these agreements by developing (or adapting) mechanisms aiming at the decentralization of public decisions and management. Their failure may lead to changes in ecological processes, reduction of fishing stocks, and social-environmental conflicts. ; La pesca se ve perjudicada cuando las llanuras de inundación sufren presiones crecientes de infraestructura, contaminación, cambio climático y sobrepesca. Para las comunidades ribereñas de la Amazonía, esto puede significar menos peces en los ríos y lagos, lo que provoca bolsos y estómagos vacíos. Este artículo usa la teoría de los recursos comunes para analizar los orígenes y el funcionamiento de los acuerdos colectivos de pesca firmados por habitantes de las llanuras de inundación de la Amazonía brasileña. Como la pesca comercial se expandió a mediados del los años 1990, en varios lugares surgieron experiencias de lagos gestionados por las comunidades locales, como un ejemplo prometedor de gestión participativa. Los resultados muestran que los acuerdos generaron mejoras considerables, aunque su eficacia esté amenazada por la debilidad del control y vigilancia y por la falta de eficacia de la regulación de la tenencia de tierras. El artículo sugiere que las agencias gubernamentales deben apoyar estos acuerdos mediante el desarrollo (o adaptación) de los mecanismos que buscan la descentralización de las decisiones públicas y de la gestión. El fracaso de dichos acuerdos puede desencadenar cambios en los procesos ecológicos, la reducción de los estoques pesqueros y conflictos socioambientales.

Research on community-based management system has been oftengrounded on monolithic institutional, social and ecological perspective withfocus on the commoners as the only local actor, collective territorial rights asthe only local tenure system, and the managed resource unit or ecosystem asthe only contested resource driving collective action. However, CBMSs areembedded in local social-ecological systems usually characterized by multipleruling systems, different local groups, and heterogeneous ecological systems. Inthis paper I discuss how the floodplain tenure system is negotiated and rearrangedbetween two local groups – community residents and large landholders. Thiscomplex and dynamic arrangement comprises three layers of property rightswhich are combined according to changing ecological and social context. Basedon longitudinal empirical data spanning 20 years of research, I describe thehistory of contemporary human occupation, and the most recent socioeconomicand institutional changes in the region in order to unpack the dynamics of thefloodplain tenure in the region. I conclude that assumptions that integration of localmanagement system into a formal legal framework suffices to achieve an efficientco-management system is rather simplistic. Despite major structural changes inthe formal tenure framework, power relations between different local users mayremain unchanged unless local perceptions and everyday life practices of powerrelations are changed. Unpacking the multiple ruling systems and everyday lifepractices that mediate interactions between different local actors is fundamentalto understanding how the commons are appropriated at the local level. Therefore,a local contextualization of the social and ecological structure is crucial to revealpotential barriers to the development of an inclusive and sustainable productionsystem.