Protection of spawning habitat for potamodromous fish, an urgent need for the hydropower planning in the Andes

Because dams block migratory routes of potamodromous fish to their spawning areas, and energy generation changes natural flow seasonality, it is necessary to identify spawning areas and their conditions. This information will help in management decisions in the Magdalena River basin regarding the future hydropower development. We identified which characteristics of the tributaries to the Magdalena River are important for determining potamodromous fish spawning grounds, and we estimated the percentage of future loss of spawning areas because of dam development. Ichthyoplankton density is directly related to the floodplain area, and inversely related with channel slope. Low channel slopes offer adult fish a longer distance for their upstream migration and a longer time for embryo development during their drift downstream from the spawning areas to nursery habitats (floodplain lakes). These features could increase the migration distance of the adults, the time for initial embryo development, and, because of its relationship with nursery habitats access, the offspring survival. The potential loss of the actual spawning grounds in the river network was estimated to be nearly 70% because of new dams. Our findings will help to reduce conflicts between hydropower and ecological interests.(AU)

La construcción de hidroeléctricas puede afectar la reproducción de los peces migratorios potamódromos, ya sea porque las represas bloquean las rutas migratorias a sus áreas de desove, o porque la generación de energía cambia la estacionalidad del flujo natural. Esto hace necesario generar información sobre las áreas de desove y sus características, que permitan tomar decisiones de manejo, teniendo en cuenta el desarrollo hidroeléctrico propuesto a futuro en la cuenca del río Magdalena. Identificamos qué características de algunos afluentes del río Magdalena son importantes para los desoves y estimamos el porcentaje de pérdida futura de áreas de desoves debido al desarrollo hidroeléctrico. La densidad del ictioplancton se relacionó directamente con el área de la llanura aluvial e inversamente con la pendiente del canal. Estas características aumentan la distancia de migración de los adultos maduros, el tiempo para el desarrollo inicial del embrión y la supervivencia de la descendencia debido a la proximidad y/o conectividad con los hábitats de cría. La pérdida potencial de las zonas de desove en la red fluvial se estimó en casi el 70% debido a las nuevas presas. Nuestros hallazgos ayudarán a tomar decisiones sostenibles para reducir los conflictos entre intereses de desarrollo hidroeléctrico y ecológicos.(AU)

Humedales del Parque Nacional Chirripó, Costa Rica: características, relaciones geomorfológicas y escenarios de cambio climático / Wetlands of the Chirripó National Park, Costa Rica: characteristics, geomorphological relationships and climate change scenarios

Resumen Los humedales, también llamados altoandinos, han sido poco estudiados y caracterizados en Costa Rica. En este estudio se analizan las características geomorfológicas, climatológicas e hidrológicas de los humedales altoandinos del Parque Nacional Chirripó (PNCh), ubicado al centro-sur de Costa Rica, América Central. Para ello se parte de un levantamiento geomorfológico a escala 1:25 000 de formas de relieve particularmente de origen glaciar, el Inventario Nacional de Humedales llevado a cabo por el Proyecto Humedales (PNUD-SINAC-GEF), y la determinación de distintos escenarios de cambio climático para los periodos 2039-2059 y 2079-2099. El objetivo de este trabajo es caracterizar el estado actual de estos ecosistemas, explicar cómo y porqué se forman, así como valorar las posibles implicaciones en el ciclo hidrológico y la provisión de agua de estos reservorios debido a las variaciones del clima a futuro. Los resultados denotan la gran importancia de estos humedales para mantener la dinámica ecológica en el PNCh, así como los servicios de provisión de agua y regulación del ciclo hidrológico en las cuencas que derivan de esta área protegida.(AU)

Abstract The geomorphological, climatological and hydrological characteristics of the high Andean wetlands of the Chirripó National Park (PNCh) are analyzed. The PNCh is located in south-central Costa Rica, Central America. This analysis includes a geomorphological survey on a 1: 25 000 scale of the relief forms and processes, particularly those of glacial origin. The National Wetland Inventory carried out by the Wetlands Project (UNDP-SINAC-GEF) was also used, along with different climate change projections corresponding to the scenarios for the 2039-2059 and 2079-2099 horizons. The main objective is to characterize the current state of these ecosystems, to explain how and why they are formed, as well as to assess the possible implications in the hydrological cycle and the water supply of these wetlands due to future climate variations. The results showed the relevance of these natural reservoirs in maintaining the ecological dynamics of the PNCh. We also studied the services of water provision and regulation of the hydrological cycle in the basins that compose this protected area.(AU)

Implementación del mapa de geopedología como base para la delimitación de unidades de ecosistemas a nivel nacional en colombia

Geopedología corresponde a la integración entre geomorfología y pedología; es el concepto que se aplica en Colombia, para interpretar la información de los suelos y, a través de ella, generar cartografía temática, que pueda ser representada en diferentes escalas. Una aplicación reciente de la geopedología es la definición del medio pedológico como sustrato, que soporta ecosistemas terrestres y que hace parte del ambiente, debido a que cumple la función de permitir los flujos de energía entre coberturas vegetales y seres vivos. En este artículo, se realiza una reflexión sobre el papel que, históricamente, ha tenido la información de los suelos en el contexto colombiano y su aporte a las ciencias del ambiente; se muestra un desarrollo histórico, que permite analizar cómo se ha integrado la información de suelos realizada en el Instituto Geográfico Agustín Codazzi (IGAC), por más de setenta años y cómo el mejoramiento continuo ha permitido el acercamiento teórico a la delimitación de ecosistemas para dos escalas: la nacional y la general. La ciencia del suelo ha tenido poco reconocimiento en la elaboración de informes recientes relacionados con el ambiente, por ello, es importante que se muestren conceptos y trabajos realizados por expertos en suelos y se divulgue la labor de quienes la desarrollan, así como los resultados obtenidos en la investigación realizada por Progasp, relacionado con el tema de escalas y de representación de variables, que permiten mostrar la realidad ambiental y avance en los procesos que, actualmente, se llevan a cabo en Colombia.

Geopedology corresponds to the integration between geomorphology and soil science and this concept is applied in Colombia to interpret the information of soil for generating thematic maps that can be displayed on different scales; a recent application of the geopedology is the definition of pedological zone as the substrate that supports terrestrial ecosystems and is part of the environment because it serves to allow the energy flows between mulches and living things. This article presents a reflection on the role that historically has had the soils information in the Colombian context and its contribution to environmental science; a historical development is done about soil information to analyze its integration in the Instituto Geográfico Agustín Codazzi (IGAC) for over seventy years and how the continuous improvement has allowed the theoretical approach and the delimitation of ecosystems are close to each other to two scales: national and overall. Soil science has had little recognition in the development of recent reports related to the environment, so it is important that concepts and work done by experts in soils are shown; it is equally important that result obtained in the investigation performed by the research group Progasp, related to the topic of scales and representation of variables which allow display environmental reality and the processes that are advancing in Colombia.

Influence of Natural and Anthropogenic Processes in the Coastline Evolution at the Doce River Mouth (Espírito Santo, Brazil).

Aims and Place: The Doce River is one of the largest rivers of southeastern Brazil, and has been target of strong environmental impact in recent decades due to mining and farming activities. Influenced by lithological factors and human disturbance, the Doce River has brought changes on the vegetation of the deltaic plain and increased the local sediment load transported Methodology: Limnological analysis, textural characteristic of soils and sediments and TOC, TON and TP (ppm) were determined at the Doce River mouth during the dry and rainy seasons between 1993 and 2008. Cluster analysis, analysis of the sediment dynamic and bed topography of the mouth were applied to the results. Results and Conclusion: The river shows accelerated bank erosion, especially during the rainy season. Near the mouth, erosion processes are enhanced by sediment dynamics, obstructing the main channel and modifying the coastal landscape. This research aims to contribute to a better understanding of fluvial geomorphology near the mouth of the Doce River, from nutrients flow analyze and sediment dynamics, without discarding the anthropogenic influence in the region.

Geomorfología, zonas de erosión y sedimentación costera de la Península de Burica, Costa Rica / Geomorphology, erosion and sedimentation in coastal zones of the Burica peninsula

Resumen Se efectuó una evaluación geomorfológica y de zonas de erosión y sedimentación del sector oeste de la Península, desde punta Banco hasta punta El Mangle, con el fin de determinar aspectos relevantes desde el punto de vista geológico. El estudio se llevo a cabo durante 9 días en enero del 2008, tiempo en el cual, se realizó el estudio geológico, geomorfológico y de zonas de erosión-sedimentación costera, presentándose en este trabajo solamente los resultados relevantes de los últimos dos aspectos. Geomorfológicamente, se reconocen una predominancia de morfologías de origen estructural, y en menor grado de origen marino, fluvial y denudacional. Se definieron cuatro zonas de erosión-sedimentación, zonas de erosión intensa, de erosión moderada a leve, de erosión y sedimentación y zonas de depositación. Los procesos geológicos más importantes son los deslizamientos, la erosión costera y la alta sismicidad del área, factores que deben ser tomados en cuenta para una adecuada planificación rural de la península

Abstract The present work describes a geomorpholopic evaluation of the Burica peninsula, during 9 days in January 2008. Coastal geomorphology, erosion and depositional zones were evaluated between punta Banco and punta El Mangle. The most important morphologies found were structural origin morphologies, represented by active tectonic deformation, produced by the Panamá Fracture Zone, and the subduction of the Cocos ridge. The structural origin morphologies identified were, structural-denudational zones which dominate the study area, homocline in the south of the peninsula and structural terraces, that are observed easily between punta El Mangle and La Peña, and in punta Banco. Other morphologies were identified, such as marine, fluvial and denudational morphologies. The marine-origin morphologies include the beach, subdivided in subareas, separated due to the waves dynamic, the cliffs, that dominate the area between La Peña river and punta Banco, and the shore platforms in the area between punta El Mangle and La Peña. The denudational morphology is represented by landslides, which area present mainly in the cliffs. In the other hand, the fluvial origin morphologies, include La Peña, Peñita, Caña Blanca and Coco mouths and the floodplain of La Peña river. Intense erosional, slight to moderate erosional, sedimentational, and erosion and sedimentational zones were identified, having a great importance the coastal erosion, especially observed in the central and south of the peninsula. Considering the results and the interaction of them, the main hazards found are landslides, coastal erosion and the high seismicity of the area, which should be taken into account and studied in detail for a proper planning of the rural development. Rev. Biol. Trop. 63 (Suppl. 1): 407-416. Epub 2015 April 01.

Land-sea interface features of four estuaries on the South America Atlantic coast

The Brazilian coastal zone extends from 4º N to 34º S latitude and because of its long extension, the interface zone from continent to ocean includes a high diversity of geomorphologic and oceanographic characteristics. The rivers from the Northeast and East regions are marked by a typical unimodal seasonal flux patterns but with different amplitudes. As the climate indicates, the rivers from the Northeast are subject to an accentuated seasonal variability with an elevated input and flood pulses during the rainy season and low to negligible fluxes during the dry season. Small-scale rivers usually present typical torrential behaviour. In the humid eastern region, the unimodal seasonal cycle is dampened with a more constant input supply. Recently, some studies have shown that the material supply from rivers along the Northeast and Eastern coasts is diluted by surface tropical waters of oceanic currents and that the estuarine plume dispersal is restricted to a narrow coastal belt. However, human impacts of course mask or even override both natural hydrological cycles and CO2 emissions from terrestrial biomes, or depending on the nature of the human impact, can even increase extreme events. Henceforth this contribution addresses the typological, hydrological and biome diversity of the four estuarine systems fed and affected by the respective Amazon, São Francisco, Paraíba do Sul and Plata watersheds.

A zona costeira brasileira se estende de 4º N a 34º S de latitude. Por causa de sua longa faixa de zona de interface do continente com o oceano, é encontrada uma grande diversidade nas características geomorfológicas e oceanográficas. Os rios das regiões nordeste e leste mostram um padrão de fluxo sazonal normalmente unimodal, mas diferentes em amplitude. Conforme o clima indica, os rios do nordeste estão sujeitos a uma acentuada variabilidade sazonal, com elevação da vazão em forma de pulsos de inundação durante a estação chuvosa e fluxos muito baixos ou mesmo negligentes durante a estação seca. Em rios de pequena escala, a vazão costuma apresentar um típico comportamento de eventos torrenciais. Na região leste, com clima tropical úmido, o ciclo unimodal sazonal se apresenta amortecido com uma entrada mais constante. Recentemente, alguns estudos mostram que a exportação de materiais pelos rios ao longo da costa leste e do nordeste é diluída a partir de águas tropicais superficiais de correntes oceânicas e que a dispersão das plumas estuarinas é restrita a uma estreita faixa costeira. No entanto, os impactos humanos mascaram ou mesmo substituem ambos os ciclos hidrológicos naturais e as emissões de CO2 dos biomas terrestres ou, dependendo da natureza, podem até aumentar os eventos extremos. Doravante, esta contribuição aborda a diversidade, a tipologia hidrológica e os biomas dos quatro sistemas estuários.

Land-sea interface features of four estuaries on the South America Atlantic coast / Características da interface continente-oceano de quatro estuários da zona costeira da America do Sul

The Brazilian coastal zone extends from 4º N to 34º S latitude and because of its long extension, the interface zone from continent to ocean includes a high diversity of geomorphologic and oceanographic characteristics. The rivers from the Northeast and East regions are marked by a typical unimodal seasonal flux patterns but with different amplitudes. As the climate indicates, the rivers from the Northeast are subject to an accentuated seasonal variability with an elevated input and flood pulses during the rainy season and low to negligible fluxes during the dry season. Small-scale rivers usually present typical torrential behaviour. In the humid eastern region, the unimodal seasonal cycle is dampened with a more constant input supply. Recently, some studies have shown that the material supply from rivers along the Northeast and Eastern coasts is diluted by surface tropical waters of oceanic currents and that the estuarine plume dispersal is restricted to a narrow coastal belt. However, human impacts of course mask or even override both natural hydrological cycles and CO2 emissions from terrestrial biomes, or depending on the nature of the human impact, can even increase extreme events. Henceforth this contribution addresses the typological, hydrological and biome diversity of the four estuarine systems fed and affected by the respective Amazon, São Francisco, Paraíba do Sul and Plata watersheds.

A zona costeira brasileira se estende de 4º N a 34º S de latitude. Por causa de sua longa faixa de zona de interface do continente com o oceano, é encontrada uma grande diversidade nas características geomorfológicas e oceanográficas. Os rios das regiões nordeste e leste mostram um padrão de fluxo sazonal normalmente unimodal, mas diferentes em amplitude. Conforme o clima indica, os rios do nordeste estão sujeitos a uma acentuada variabilidade sazonal, com elevação da vazão em forma de pulsos de inundação durante a estação chuvosa e fluxos muito baixos ou mesmo negligentes durante a estação seca. Em rios de pequena escala, a vazão costuma apresentar um típico comportamento de eventos torrenciais. Na região leste, com clima tropical úmido, o ciclo unimodal sazonal se apresenta amortecido com uma entrada mais constante. Recentemente, alguns estudos mostram que a exportação de materiais pelos rios ao longo da costa leste e do nordeste é diluída a partir de águas tropicais superficiais de correntes oceânicas e que a dispersão das plumas estuarinas é restrita a uma estreita faixa costeira. No entanto, os impactos humanos mascaram ou mesmo substituem ambos os ciclos hidrológicos naturais e as emissões de CO2 dos biomas terrestres ou, dependendo da natureza, podem até aumentar os eventos extremos. Doravante, esta contribuição aborda a diversidade, a tipologia hidrológica e os biomas dos quatro sistemas estuários.

Environmental assessment of the area surrounding Dam Rio Verde – Parana, Brazil. An overview of environmental geomorphology.

This paper presents a brief essay on the situation in which the environment of the dam of the Rio Verde Basin- Paraná, from the vision of environmental geomorphology. The area is located between the cities of Campo Magro and Campo Largo, Paraná plateau in the first part of the Alto Iguaçu basin. This study aims to raise the concepts relating to environmental geomorphology, to identify the anthropogenic impacts caused in the reservoir areas, identify the environmental compartments found around the dam and characterize the geologic and physiographic region. It was found that the area has intense anthropogenic influence, as urban growth is present in areas and wavy and rough terrain, subject to mass movements and floods. Besides these aspects, the use of land for agriculture contributes to fragility of the area.

Geologia e geomorfologia da estação ecológica Serra Geral do Tocantins / Geology and geomorphology of Serra Geral do Tocantins ecological station

Este trabalho trata de descrição básica da paisagem existente na Estação Ecológica Serra Geral do Tocantins, localizada na porção oriental do Estado do Tocantins e extremo oeste do Estado da Bahia, Brasil Central. Dois fatores do meio físico são abordados: a geologia, composta por litotipos sedimentares, e as formas de relevo, dada a predominância de chapadões e morros testemunhos na região, famosa pela presença das Dunas do Jalapão ao norte. Tal interação, esculturada sob clima típico de savana, produziu uma série de mosaicos com imensas peculiaridades paisagísticas. A Serra Geral do Tocantins é um planalto sedimentar esculpido na Bacia Sedimentar do Parnaíba. A área da Estação é caracterizada por pacotes de sedimentos predominantemente continentais, posteriores ao derrame basáltico ocorrido durante a Reativação Wealdeniana Juro-Cretácea. São arenitos de colorações brancas a vermelhas, extremamente friáveis, oriundos das acumulações de paleoclimas secos (áridos a semi-áridos) do Mesozóico, possivelmente contemporâneos ao Deserto Botucatu existente na Bacia do Paraná, embora as camadas mais superiores possam estar associadas a ambiente flúvio-lacustre. As formas de relevo envolvem uma seqüência de chapadas e patamares caracterizando formas estruturais com rebordos festonados e rampas escalonadas em formas erosivas. As chapadas são constituídas por sedimentos cretáceos e configuram grandes unidades de relevo em mesa penetradas por vales pedimentados, com bordas escarpadas e anfiteatros largos, que atacados por ciclos de erosão pós-cretáceos resultaram em patamares escalonados e arrasados em pediplanos que descem rumo ao curso do Rio Tocantins. A presença de inúmeros relevos residuais colabora nos contrastes geomorfológicos. Os processos morfogenéticos predominantemente mecânicos podem ser divididos em quatro fases de esculturação que resultaram na dissecação diferenciada. A compartimentação do relevo permite apontar algumas considerações sobre a distribuição geográfica da fauna na área da Estação Ecológica e seu entorno, pois em parte esta relação pode ser determinada pelos escalonamentos topográficos decorrentes do aparecimento das unidades geomorfológicas. A maior barreira geográfica foi criada durante o Neoproterozóico, separando as formas de relevo dos patamares escalonados; os basculamentos mesozóicos produziram os chapadões que, pela erosão mecânica, formaram pedimentos que foram aos poucos coalescidos durante o Cretáceo Superior até o Terciário Superior; tal processo resultou nos relevos residuais que, juntamente com a reativação de falhas antigas, favoreceu o isolamento entre os compartimentos biológicos; este processo continuou durante o Quaternário em razão das alternâncias climáticas de períodos semi-áridos a úmidos, promovendo a retomada da erosão mecânica e a formação de planícies fluviais.

This work presents a basic description of Serra Geral do Tocantins Ecological Station, located in the eastern part of Tocantins State and western part of Bahia State, Central Brazil. Two main factors of physical environment are treated: geology, composed by sedimentary litotypes, and the relief forms, due to predominance of mesetas and inselbergs in the region, famous for Jalapão Dunes in the north. This interaction, sculpted under typical savanna climate, has turned out into a mosaic series with immense landscape peculiarities. Serra Geral do Tocantins is a sedimentary plateau sculpted at Sedimentary Basin of Parnaiba. The Ecological Station's area is featured by sedimentary packs mainly continental, subsequent from basaltic extrusion that occurred during Wealdenian Reactivation in the Jura-Cretaceous period. It is composed by sandstones whose colors changes from pale to red ones, extremely friable, originated from dry paleoclimate accumulations (arid to semi-arid ones) of Mesozoic. It is possible to be related to contemporary dry Mesozoic period of Parana's Basin (Botucatu Desert), though upper layers can be from fluvial-lake environment. The relief forms involve mesetas and level sequences characterized by structural features with retreated edges and step levels into erosive forms. The mesetas are filled with cretaceous sediments and configure great plateau relief units penetrated by pedimented valleys, with scarped edges and large amphitheatres. Its attack by post-cretaceous erosion resulted into step levels whose softened surface produced pediplains that run to Tocantins River course. The very existence of considerable numbers of residual landforms contributes to the geomorphologic contrast. The predominance of the mechanical morphogenetic process can be divided into four sculptural phases resulting in differential dissection. Based on relief compartments it is possible to point out some considerations about the geographical distribution of the fauna in the Ecological Station's area and its surroundings, because at least part of it can be related to the topographic step-levels forms originated from geomorphological units. The biggest geographical barrier was created during Neoproterozoic, dividing the step-levels relief forms; the Mesozoic tilting produced the mesetas which by mechanical erosion formed pediments that suffered coalescence from Upper Cretaceous to Upper Tertiary. This process resulted into residual landforms, whose action in combination with ancient faults reactivations helped the isolation of biological compartments; continuing during Quaternary due to alternations of semi-arid to humid periods, mechanical erosion was initiated again and fluvial plains were formed.

Geomorphology and habitat diversity in the Pantanal

The present study deals with the inter-relations in the relief which forms the Bacia do Alto Rio Paraguay (BAP) in mid-west Brazil. The overall aim is to discuss the relationship between relief forms and the biodiversity of the Pantanal. The BAP is a natural environmental system with contrasts in two of the compartments on which it is formed: the plateau, the most elevated compartment, highly transformed by human activities, and the plain which forms the Pantanal, which is more preserved and less transformed in relation to productive activities. The analysis was performed based on publications with a geomorphologic focus, examining the different relief units of the BAP and the dynamics of the revealing processes of landscape change which the Pantanal has undergone since the end of the Pleistocene.

O presente estudo tem como objetivo abordar a inter-relação entre os compartimentos do relevo brasileiro que compõem a Bacia do Alto Paraguai - BAP, para discutir as formas de relevo e a biodiversidade do Pantanal. A abordagem fundamenta-se na compreensão das diferentes formas do terreno, associando ao fato que a BAP é um sistema ambiental natural que tem contrastes nos dois compartimentos que a compõem: o planalto, o compartimento mais elevado, fortemente transformado por atividades humanas; e a planície, que constitui o Pantanal mato-grossense, mais conservada e pouco transformada, quanto ao uso com atividades produtivas. A análise foi realizada a partir de publicações com enfoques geomorfológicos, abordando as diferentes unidades do relevo da BAP e o entendimento da dinâmica dos processos reveladores de que o Pantanal passa desde o fim do Pleistoceno, com processos de mudanças da paisagem.

Characterization of abiotic conditions affecting vegetation distribution in the river Plate coastal plain, Argentina - DOI: 10.4025/actascibiolsci.v30i4.5875

The river Plate coastal plain is located in northeastern Buenos Aires province, where geological events such as sea transgressions and regressions in the Holocene have produced a stratigraphic column with marine-estuarine, fluviatile and continental sediments, as well as a variety of landforms and soils. The aim of this paper is to describe these different coastal settings and their influence in the distribution of plant communities.