Deploy diverse renewables to save tropical rivers.

A strategic mix of solar, wind and storage technologies around river basins would be safer and cheaper than building large dams, argue Rafael J. P. Schmitt, Noah Kittner and colleagues

PROCESS BASED CLASSIFICATION OF SEDIMENT CONNECTIVITY AT THE RIVER BASIN SCALE.

Novel modelling approaches allow to trace the fate of sediment contributions from individual river reaches throughout the river network and to assess the resulting sediment connectivity at the basin scale. The derived information is an unprecedented source of information to assess from where and over which times a downstream river reach recruits its sediment. This information links strongly to the reach sensitivity to anthropic disturbance or restoration efforts. In this paper, we demonstrate how to make the complex data-sets resulting from basin scale connectivity models accessible for river basin management applications. We introduce the concept of “connectivity signatures” that epitomizes the timing, magnitude, and quality (grain size) domain of connectivity at the reach scale. We use data driven classification techniques to identify a reduced set of typical connectivity classes. Spatial distribution of connectivity classes reveals that these classes represent specific, functional “connectivity styles” with specific locations and functions for sediment routing in the river network. Results concretize the interpretation of sediment connectivity from an operational perspective and open the way for its application to large river basins

Uso de microhabitats por imaturos de Ephemeroptera, Plecoptera e Trichoptera em riachos de clima subtropical

TCC(graduação) - Universidade Federal de Santa Catarina. Centro de Ciências Biológicas. Biologia.Ao longo de um ambiente aquático há diferentes microhabitats, ambientes com características particulares que direcionam o estabelecimento da fauna. Dentre a comunidade de insetos associadas a esses ambientes, Ephemeroptera, Plecoptera e Trichoptera (EPT) são os que apresentam maiores especificidades com relação ao habitat, sendo constituídos por numerosos grupos taxonômicos, cada um com suas particularidades e são considerados bons indicadores da qualidade do ambiente. Diante disso, o objetivo do presente estudo foi avaliar a diversidade e associação dos insetos aquáticos (EPT) aos microhabitats em riachos subtropicais. O estudo foi desenvolvido no Parque Municipal da Lagoa do Peri e a amostragem dos organismos foi realizada durante o inverno de 2011 e verão de 2012. Os insetos foram amostrados nos quatro tipos de microhabitats predominantes, Pedra/Corredeira, Folha/Corredeira, Folha/Remanso e Pedra/Remanso, localizados em seis riachos de baixa ordem em duas microbacias (Cachoeira Grande e Ribeirão Grande) com distintos estádios de integridade da vegetação ripária. Em cada um dos pontos amostrados foram mensuradas as variáveis da água, assim como matéria orgânica retida. Dos 2574 imaturos de EPT identificados, a ordem Ephemeroptera foi a mais abundante, seguida por Trichoptera e Plecoptera. A estrutura da comunidade apresentou variação significativa quanto a sua composição taxonômica tanto para escala temporal quanto espacial, sendo similares entre as microbacias e as diferentes ordens dos riachos. A maior abundância de organismos foi observada na microbacia do Ribeirão Grande e pode ser reflexo das características do entorno. Os grupos alimentares funcionais (GAFs) apresentaram variação significativa apenas na escala de microhabitat. As diferenças com relação à abundância dos mesmos durante o período de estudo são reflexos da disponibilidade de detritos no sistema, a qual é direcionada pela sazonalidade ambiental, como precipitação e temperatura. Além disso, os GAFs apresentaram distribuição condizente nos microhabitats de acordo com a preferência alimentar

Tracking multiple sediment cascades at the river network scale identifies controls and emerging patterns of sediment connectivity

Sediment connectivity in fluvial networks results from the transfer of sediment between multiple sources and sinks. Connectivity scales differently between all sources and sinks as a function of distance, source grain size and sediment supply, network topology and topography, and hydrologic forcing. In this paper, we address the challenge of quantifying sediment connectivity and its controls at the network scale. We expand the concept of a single, catchment-scale sediment cascade toward representing sediment transport from each source as a suite of individual cascading processes. We implement this approach in the herein presented CAtchment Sediment Connectivity And DElivery (CASCADE) modeling framework. In CASCADE, each sediment cascade establishes connectivity between a specific source and its multiple sinks. From a source perspective, the fate of sediment is controlled by its detachment and downstream transport capacity, resulting in a specific trajectory of transfer and deposition. From a sink perspective, the assemblage of incoming cascades defines provenance, sorting, and magnitude of sediment deliveries. At the network scale, this information reveals emerging patterns of connectivity and the location of bottlenecks, where disconnectivity occurs. In this paper, we apply CASCADE to quantitatively analyze the sediment connectivity of a major river system in SE Asia. The approach provides a screening model that can support analyses of large, poorly monitored river systems. We test the sensitivity of CASCADE to various parameters and identify the distribution of energy between the multiple, simultaneously active sediment cascades as key control behind network sediment connectivity. To conclude, CASCADE enables a quantitative, spatially explicit analysis of network sediment connectivity with potential applications in both river science and management

The static allometry of sexual and non-sexual traits in vervet monkeys

Sexual traits vary tremendously in static allometry. This variation may be explained in part by body size-related differences in the strength of selection. We tested this hypothesis in two populations of vervet monkeys, using estimates of the level of condition dependence for different morphological traits as a proxy for body size-related variation in the strength of selection. In support of the hypothesis, we found that the steepness of allometric slopes increased with the level of condition dependence. One trait of particular interest, the penis, had shallow allometric slopes and low levels of condition dependence, in agreement with one of the most consistent patterns yet detected in the study of allometry, namely that of genitalia exhibiting shallow allometries.This research was supported by NIH grant R01RR0163009

Accounting for river morphology in the management of red river (vietnam): a numerical modeling approach

During last 15 years, the Red River in northern VietNam has experienced severe river bed degradation along its lower course. The continued decrease of the minimum water levels aggravated water scarcity for agriculture. These outcomes can be attributed to strong in stream sediment mining, major upstream impoundments, climatic and land use changes. The aim of this work is to provide a valuable tool to assess the effects of different reservoir water releases and sediment mining policies on river reach morphology. A 1D mobile bed finite volume numerical model has been set up and preliminary results on the recent 2000-2009 period are presented and discussed. The model features facilitate its integration in optimization algorithms devoted to water management strategies

Rede Neural para a Detecção de Comunidades em Grafos

In the literature, there are several approaches to the problem of identifying communities in graphs, due to their importance in a wide range of scientific fields. A less explored approach is the application of expert systems, which can be trained to recognize patterns. This work proposes the use of artificial neural networks to recognize the patterns that characterize the communities, allowing their identification