118 research outputs found

    Mapping and characterization of vegetation units by means of Landsat imagery and management recommendations for the Pantanal of Mato Grosso (Brazil), north of Poconé

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    In the present study, remote sensing in the northern region of Poconé-MT was used to identify vegetation categories, which were then mapped and characterized. The goal in generating the map was to provide information needed to support sustainable use and to formulate conservation policies. Vegetation units were identified and classified using digital images that were taken in 1990 by the Landsat Thematic Mapperc Satellite and then processed using ERDAS software. First, the vegetation classes were systematically defined. In a preliminary interpretation of the image data, Landsat-TM bands that allowed the best visual differentiation of these classes were selected and the image was georeferenced. Routes for trips to the study area to collect truth data (training samples) for further supervised classification were then determined. These data were subsequently classified according to The System of Classification of Brazilian Vegetation (VELLOSO et al. 1991), which has been used in other physiognomic maps of the Pantanal, in order to make our results comparable to those from other mappings. In addition, some modifications of this system were made due to the particular characteristics of the Pantanal and the scale used for this map. Six classes and 16 subclasses were defined for part I of the vegetation map of Pantanal, Mato Grosso, Brazil, specifically, the area north of Poconé. A distinction was made between the vegetation units of the Paraguayan Depression and those of the Pantanal due to the different characteristics of the vegetation from these two regions, and particularly the role played by inundation. The phytoecological region savanna (cerrado) covers a large part of the total area (53.05%) and consists of five sub-classes. Two forest classeswere identified: seasonal semideciduous forest and seasonal deciduous forest. These two phytoecological classes occupied 16.21 % of the total mapped area; 14.45% of the area has been strongly modified by humans (agriculture, pasture, gold mine, and construction); 0.80% is covered during the dry season by perennial water bodies. Based upon ground truth data and regional field experience, ten eco-zones are proposed and suggestions for sustainable management and conservation measures are discussed

    Fish Structure in Channel Networks of a Large Anabranching Floodplain: Effect of Isolation/Connection Processes

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    Channel networks of floodplain rivers are the main routes for water, sediment, organic matter, and aquatic organisms between main channels and lakes, playing a substantial role in floodplain dynamics. Despite their importance most investigations in large floodplain rivers focus on main channels and lentic water bodies. This research deals with fish assemblage variations in different lotic sites (scour holes and straight reaches) of one of the many channels which shape the wide anabranching floodplain of the middle reach of the ParanĂĄ River. We considered the influence of environmental factors, such as hydro-geomorphological features and water quality of the channel, connections with surrounding lentic water bodies, seasonality, and interannual flow variations. The results showed two main ecological patterns closely related to floodplain connectivity. In-channel habitat heterogeneity has low influence on fish assemblages when minor channels are connected to significant flooded areas (sampling period 2013–2016). Spatial or temporal predictions of fish structure during these stages are not easy due to the interaction of several environmental factors. However, during very low water levels (winter of 2018) most lentic areas become isolated from the nearby channel network, and floodplain fish are forced to move into the numerous scour holes of the floodplain channels where water conditions resemble those in lentic habitats. Our work highlights the importance of in-channel characteristics of floodplain river networks and their crucial role for fish conservation, particularly during very low water stages.Fil: Abrial, Elie. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Santa Fe. Instituto Nacional de LimnologĂ­a. Universidad Nacional del Litoral. Instituto Nacional de LimnologĂ­a; ArgentinaFil: EspĂ­nola, Luis Alberto. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Santa Fe. Instituto Nacional de LimnologĂ­a. Universidad Nacional del Litoral. Instituto Nacional de LimnologĂ­a; ArgentinaFil: Amsler, Mario Luis. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Santa Fe. Instituto Nacional de LimnologĂ­a. Universidad Nacional del Litoral. Instituto Nacional de LimnologĂ­a; ArgentinaFil: Rabuffetti, Ana Pia. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Santa Fe. Instituto Nacional de LimnologĂ­a. Universidad Nacional del Litoral. Instituto Nacional de LimnologĂ­a; ArgentinaFil: Latosinski, Francisco Guillermo. Universidad Nacional del Litoral. Facultad de IngenierĂ­a y Ciencias HĂ­dricas. Departamento de HidrĂĄulica; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Santa Fe; ArgentinaFil: Szupiany, Ricardo Nicolas. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de IngenierĂ­a y Ciencias HĂ­dricas. Departamento de HidrĂĄulica; ArgentinaFil: Eurich, MarĂ­a Florencia. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Santa Fe. Instituto Nacional de LimnologĂ­a. Universidad Nacional del Litoral. Instituto Nacional de LimnologĂ­a; ArgentinaFil: Blettler, Martin Cesar Maria. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Santa Fe. Instituto Nacional de LimnologĂ­a. Universidad Nacional del Litoral. Instituto Nacional de LimnologĂ­a; Argentin

    Riverhood: political ecologies of socionature commoning and translocal struggles for water justice

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    Mega-damming, pollution and depletion endanger rivers worldwide. Meanwhile, modernist imaginaries of ordering ‘unruly waters and humans’ have become cornerstones of hydraulic-bureaucratic and capitalist development. They separate hydro/social worlds, sideline river-commons cultures, and deepen socio-environmental injustices. But myriad new water justice movements (NWJMs) proliferate: rooted, disruptive, transdisciplinary, multi-scalar coalitions that deploy alternative river–society ontologies, bridge South–North divides, and translate river-enlivening practices from local to global and vice-versa. This paper's framework conceptualizes ‘riverhood’ to engage with NWJMs and river commoning initiatives. We suggest four interrelated ontologies, situating river socionatures as arenas of material, social and symbolic co-production: ‘river-as-ecosociety’, ‘river-as-territory’, ‘river-as-subject’, and ‘river-as-movement’

    The role of organisms in hyporheic processes : gaps in current knowledge, needs for future research and applications

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    Fifty years after the hyporheic zone was first defined (Orghidan, 1959), there are still gaps in the knowledge regarding the role of biodiversity in hyporheic processes. First, some methodological questions remained unanswered regarding the interactions between biodiversity and physical processes, both for the study of habitat characteristics and interactions at different scales. Furthermore, many questions remain to be addressed to help inform our understanding of invertebrate community dynamics, especially regarding the trophic niches of organisms, the functional groups present within sediment, and their temporal changes. Understanding microbial community dynamics would require investigations about their relationship with the physical characteristics of the sediment, their diversity, their relationship with metabolic pathways, their inter- actions with invertebrates, and their response to environmental stress. Another fundamental research question is that of the importance of the hyporheic zone in the global metabolism of the river, which must be explored in relation to organic matter recycling, the effects of disturbances, and the degradation of contaminants. Finally, the application of this knowledge requires the development of methods for the estimation of hydro- logical exchanges, especially for the management of sediment clogging, the optimization of self-purification, and the integration of climate change in environmental policies. The development of descriptors of hyporheic zone health and of new metrology is also crucial to include specific targets in water policies for the long-term management of the system and a clear evaluation of restoration strategies
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