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A inserção de impactos ambientais cumulativos em Estudos de Impacto Ambiental: o caso do setor sucroenergético paulista; The inclusion of cumulative environmental impacts in Environmental Impact Statements: the case of São Paulo sugarcane industry

Dibo, Ana Paula Alves
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 04/10/2013 PT
Relevância na Pesquisa
56.66%
O etanol de cana-de-açúcar tem se destacado no cenário mundial como uma potencial fonte de energia alternativa aos combustíveis fósseis. Entretanto, sua produção é fortemente baseada na monocultura, intensificando os impactos adversos nos recursos ambientais. Esses impactos podem se combinar e persistir ao longo do tempo, possibilitando o acúmulo destes nos recursos ambientais, tornando-se necessário um planejamento mais adequado da produção do bioetanol, para que uma abordagem mais sistêmica seja integrada a esse processo. Em meio a esses fatores, a consideração de impactos cumulativos é um elemento essencial para a sustentabilidade do etanol, por conseguir avaliar de maneira mais holística as implicações da monocultura, sendo obrigatória durante o processo de licenciamento ambiental do setor. Essa prática pode ser viabilizada por meio da AIA, possibilitando que esses impactos possam ser identificados e avaliados para que a viabilidade ambiental dos empreendimentos do setor possa ser atestada, principalmente pela elaboração de um EIA. Apesar da exigência, há indícios de que a prática da inserção destes impactos não tem sido realizada adequadamente. Diante do exposto, a pesquisa teve como objetivo analisar de que maneira os impactos ambientais cumulativos estão sendo inseridos em Estudos de Impacto Ambiental do setor sucroenergético paulista...

Impactos sociais e efeitos cumulativos decorrentes de grandes projetos de desenvolvimento: aplicação de rede de impactos e sobreposição de mapas em estudo de caso para o Litoral Norte Paulista; Social impacts and cumulative effects derived from large projects: impact network and map overlay application in North Coast of São Paulo, Brazil, study case

Utsunomiya, Renata
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 18/06/2014 PT
Relevância na Pesquisa
36.58%
A prática de Avaliação de Impacto (AI) mostra-se consolidada como elemento de suporte ao processo decisório ao redor do planeta. No entanto, apresenta uma série de limitações relacionadas à inclusão dos impactos sociais e efeitos cumulativos como objeto de análise, que se mostram mais intensas no contexto da implantação de grandes projetos de desenvolvimento. No Estado de São Paulo, a região do Litoral Norte se destaca pela perspectiva de intensificação dos processos de desenvolvimento econômico a partir da implantação de projetos ligados à exploração de óleo e gás e seus empreendimentos derivados. Ainda que as mudanças de caráter socioambiental venham sendo analisadas em estudos ambientais estratégicos e estudos de impactos ambientais de projetos, planos diretores municipais, dentre outros instrumentos, verifica-se uma lacuna em termos de seus aspectos cumulativos que, associada ao baixo grau de integração entre os instrumentos de planejamento aplicados na região, tem limitado a sua capacidade de influenciar as decisões tomadas. Nesse contexto, a presente pesquisa se utiliza de métodos de Avaliação de Impactos para a verificação de impactos sociais e seus efeitos cumulativos sobre o Litoral Norte paulista...

Avaliação de impactos ambientais de um projeto de mineração: um teste metodológico baseado em serviços ecossistêmicos.; Assessing environmental impacts of mining projects: a methodological test based on the ecosystem services approach.

Rosa, Josianne Claudia Sales
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 12/05/2014 PT
Relevância na Pesquisa
36.2%
A aplicação do conceito de serviços ecossistêmicos à avaliação de impactos ambientais (AIA) pode resultar em uma análise integrada dos efeitos sociais e ambientais de projetos e contribuir para solução de algumas das deficiências recorrentes da prática de AIA. Com objetivo de testar a aplicabilidade de uma abordagem de serviços ecossistêmicos (ASE) foi selecionado um projeto de uma nova mina de ferro, em Minas Gerais. O estudo de impacto ambiental (EIA) desse projeto foi elaborado segundo uma perspectiva tradicional, focada nas perdas ou danos potenciais aos recursos ambientais e culturais e suas respectivas mitigações. O projeto está localizado em uma região prioritária para conservação da biodiversidade e a sua população afetada é principalmente composta por agricultores de subsistência sem acesso a saneamento básico e outros serviços públicos. A coleta de dados foi feita mediante análise documental (EIA e seus complementos) e avaliações expeditas de campo (observação direta e mini surveys). A análise dos resultados se deu por meio da comparação entre os resultados obtidos pelo teste e as etapas do processo de AIA. Os resultados apontam que a ASE: (1) proporciona uma análise integrada dos impactos sobre os meios físico...

Playing It Safe: Assessing Cumulative Impact and Social Vulnerability through an Environmental Justice Screening Method in the South Coast Air Basin, California

Sadd, James L.; Pastor, Manuel; Morello-Frosch, Rachel; Scoggins, Justin; Jesdale, Bill
Fonte: Molecular Diversity Preservation International (MDPI) Publicador: Molecular Diversity Preservation International (MDPI)
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
36.26%
Regulatory agencies, including the U.S. Environmental Protection Agency (US EPA) and state authorities like the California Air Resources Board (CARB), have sought to address the concerns of environmental justice (EJ) advocates who argue that chemical-by-chemical and source-specific assessments of potential health risks of environmental hazards do not reflect the multiple environmental and social stressors faced by vulnerable communities. We propose an Environmental Justice Screening Method (EJSM) as a relatively simple, flexible and transparent way to examine the relative rank of cumulative impacts and social vulnerability within metropolitan regions and determine environmental justice areas based on more than simply the demographics of income and race. We specifically organize 23 indicator metrics into three categories: (1) hazard proximity and land use; (2) air pollution exposure and estimated health risk; and (3) social and health vulnerability. For hazard proximity, the EJSM uses GIS analysis to create a base map by intersecting land use data with census block polygons, and calculates hazard proximity measures based on locations within various buffer distances. These proximity metrics are then summarized to the census tract level where they are combined with tract centroid-based estimates of pollution exposure and health risk and socio-economic status (SES) measures. The result is a cumulative impacts (CI) score for ranking neighborhoods within regions that can inform diverse stakeholders seeking to identify local areas that might need targeted regulatory strategies to address environmental justice concerns.

A Screening Method for Assessing Cumulative Impacts

Alexeeff, George V.; Faust, John B.; August, Laura Meehan; Milanes, Carmen; Randles, Karen; Zeise, Lauren; Denton, Joan
Fonte: MDPI Publicador: MDPI
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.65%
The California Environmental Protection Agency (Cal/EPA) Environmental Justice Action Plan calls for guidelines for evaluating “cumulative impacts.” As a first step toward such guidelines, a screening methodology for assessing cumulative impacts in communities was developed. The method, presented here, is based on the working definition of cumulative impacts adopted by Cal/EPA [1]: “Cumulative impacts means exposures, public health or environmental effects from the combined emissions and discharges in a geographic area, including environmental pollution from all sources, whether single or multi-media, routinely, accidentally, or otherwise released. Impacts will take into account sensitive populations and socio-economic factors, where applicable and to the extent data are available.” The screening methodology is built on this definition as well as current scientific understanding of environmental pollution and its adverse impacts on health, including the influence of both intrinsic, biological factors and non-intrinsic socioeconomic factors in mediating the effects of pollutant exposures. It addresses disparities in the distribution of pollution and health outcomes. The methodology provides a science-based tool to screen places for relative cumulative impacts...

Methodological Considerations in Screening for Cumulative Environmental Health Impacts: Lessons Learned from a Pilot Study in California

August, Laura Meehan; Faust, John B.; Cushing, Lara; Zeise, Lauren; Alexeeff, George V.
Fonte: MDPI Publicador: MDPI
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
36.32%
Polluting facilities and hazardous sites are often concentrated in low-income communities of color already facing additional stressors to their health. The influence of socioeconomic status is not considered in traditional models of risk assessment. We describe a pilot study of a screening method that considers both pollution burden and population characteristics in assessing the potential for cumulative impacts. The goal is to identify communities that warrant further attention and to thereby provide actionable guidance to decision- and policy-makers in achieving environmental justice. The method uses indicators related to five components to develop a relative cumulative impact score for use in comparing communities: exposures, public health effects, environmental effects, sensitive populations and socioeconomic factors. Here, we describe several methodological considerations in combining disparate data sources and report on the results of sensitivity analyses meant to guide future improvements in cumulative impact assessments. We discuss criteria for the selection of appropriate indicators, correlations between them, and consider data quality and the influence of choices regarding model structure. We conclude that the results of this model are largely robust to changes in model structure.

Cumulative Human Impacts on Mediterranean and Black Sea Marine Ecosystems: Assessing Current Pressures and Opportunities

Micheli, Fiorenza; Halpern, Benjamin S.; Walbridge, Shaun; Ciriaco, Saul; Ferretti, Francesco; Fraschetti, Simonetta; Lewison, Rebecca; Nykjaer, Leo; Rosenberg, Andrew A.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 04/12/2013 EN
Relevância na Pesquisa
36.44%
Management of marine ecosystems requires spatial information on current impacts. In several marine regions, including the Mediterranean and Black Sea, legal mandates and agreements to implement ecosystem-based management and spatial plans provide new opportunities to balance uses and protection of marine ecosystems. Analyses of the intensity and distribution of cumulative impacts of human activities directly connected to the ecological goals of these policy efforts are critically needed. Quantification and mapping of the cumulative impact of 22 drivers to 17 marine ecosystems reveals that 20% of the entire basin and 60–99% of the territorial waters of EU member states are heavily impacted, with high human impact occurring in all ecoregions and territorial waters. Less than 1% of these regions are relatively unaffected. This high impact results from multiple drivers, rather than one individual use or stressor, with climatic drivers (increasing temperature and UV, and acidification), demersal fishing, ship traffic, and, in coastal areas, pollution from land accounting for a majority of cumulative impacts. These results show that coordinated management of key areas and activities could significantly improve the condition of these marine ecosystems.

Quantifying Process-Based Mitigation Strategies in Historical Context: Separating Multiple Cumulative Effects on River Meander Migration

Fremier, Alexander K.; Girvetz, Evan H.; Greco, Steven E.; Larsen, Eric W.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 25/06/2014 EN
Relevância na Pesquisa
36.51%
Environmental legislation in the US (i.e. NEPA) requires defining baseline conditions on current rather than historical ecosystem conditions. For ecosystems with long histories of multiple environmental impacts, this baseline method can subsequently lead to a significantly altered environment; this has been termed a ‘sliding baseline’. In river systems, cumulative effects caused by flow regulation, channel revetment and riparian vegetation removal significantly impact floodplain ecosystems by altering channel dynamics and precluding subsequent ecosystem processes, such as primary succession. To quantify these impacts on floodplain development processes, we used a model of river channel meander migration to illustrate the degree to which flow regulation and riprap impact migration rates, independently and synergistically, on the Sacramento River in California, USA. From pre-dam conditions, the cumulative effect of flow regulation alone on channel migration is a reduction by 38%, and 42–44% with four proposed water diversion project scenarios. In terms of depositional area, the proposed water project would reduce channel migration 51–71 ha in 130 years without current riprap in place, and 17–25 ha with riprap. Our results illustrate the utility of a modeling approach for quantifying cumulative impacts. Model-based quantification of environmental impacts allow scientists to separate cumulative and synergistic effects to analytically define mitigation measures. Additionally...

Assessing environmental impacts of offshore wind farms: lessons learned and recommendations for the future

Bailey, Helen; Brookes, Kate L; Thompson, Paul M
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
Publicado em 14/09/2014 EN
Relevância na Pesquisa
36.13%
Offshore wind power provides a valuable source of renewable energy that can help reduce carbon emissions. Technological advances are allowing higher capacity turbines to be installed and in deeper water, but there is still much that is unknown about the effects on the environment. Here we describe the lessons learned based on the recent literature and our experience with assessing impacts of offshore wind developments on marine mammals and seabirds, and make recommendations for future monitoring and assessment as interest in offshore wind energy grows around the world. The four key lessons learned that we discuss are: 1) Identifying the area over which biological effects may occur to inform baseline data collection and determining the connectivity between key populations and proposed wind energy sites, 2) The need to put impacts into a population level context to determine whether they are biologically significant, 3) Measuring responses to wind farm construction and operation to determine disturbance effects and avoidance responses, and 4) Learn from other industries to inform risk assessments and the effectiveness of mitigation measures. As the number and size of offshore wind developments increases, there will be a growing need to consider the population level consequences and cumulative impacts of these activities on marine species. Strategically targeted data collection and modeling aimed at answering questions for the consenting process will also allow regulators to make decisions based on the best available information...

Assessment of the Impacts of Climate Change on Mountain Hydrology : Development of a Methodology through a Case Study in the Andes of Peru

Vergara, Walter; Deeb, Alejandro; Leino, Irene; Kitoh, Akio; Escobar, Marisa
Fonte: World Bank Publicador: World Bank
Relevância na Pesquisa
36.25%
The objective of study of the impacts of climate change on mountain hydrology is to develop a methodology to assess the net impacts of climate change on the hydrological response in mountainous regions. This is done through a case study in the Peruvian Andes. There are few examples of predictions of the impact of climate change on resource availability and even fewer examples of the applications of such predictions to planning for sustainable economic development. This report presents a summary of the efforts of a Bank energy and climate change team to develop methodological tools for the assessment of climate impacts on surface hydrology in the Peruvian Andes. The importance of analyzing the potential climate impacts on hydrology in Peru arises in part from concerns about the retreat of tropical glaciers, the drying of unique Andean wetland ecosystems, as well as increased weather variability and weather extremes, all of which will affect water regulation. The study, together with a recently published report by the World Bank...

Biofuels : Markets, Targets and Impacts

Timilsina, Govinda R.; Shrestha, Ashish
Fonte: Banco Mundial Publicador: Banco Mundial
Relevância na Pesquisa
36.39%
This paper reviews recent developments in biofuel markets and their economic, social and environmental impacts. Several countries have introduced mandates and targets for biofuel expansion. Production, international trade and investment have increased sharply in the past few years. However, several existing studies have blamed biofuels as one of the key factors behind the 2007-2008 global food crisis, although the magnitudes of impacts in these studies vary widely depending on the underlying assumptions and structure of the models. Existing studies also have huge disparities in the magnitude of long-term impacts of biofuels on food prices and supply; studies that model only the agricultural sector show higher impacts, whereas studies that model the entire economy show relatively lower impacts. In terms of climate change mitigation impacts, there exists a consensus that current biofuels lead to greenhouse gas mitigation only when greenhouse gas emissions related to land-use change are not counted. If conversion of carbon rich forest land to crop land is not avoided...

Using Forests to Enhance Resilience to Climate Change : What Do We Know About How Forests Can Contribute to Adaptation?

World Bank
Fonte: Washington, DC Publicador: Washington, DC
EN_US
Relevância na Pesquisa
36.13%
The global dialogue surrounding the United Nations framework convention for climate change has focused on two strategies for addressing challenges associated with climate change: (1) mitigation (reducing the accumulation of greenhouse gases (GHG) in the atmosphere); and (2) adaptation (reducing the vulnerability of societies and ecosystems to the impacts of climate change). Forests feature in both of these strategies. The role of forests as stores of carbon and therefore in reducing GHG emissions has been captured in the efforts associated with reducing emissions from deforestation and degradation and enhancing carbon stocks (REDD+). The report points to how forests will respond to climate change, and advocates strengthening the ability of institutions to deliver on sustainable forest management, which will help with the resilience of forest systems. This working paper presents a review of relevant work on forests and the services, and the use of forests and trees in adaptation. The paper starts with a brief discussion about climate change. It also provides a conceptualization of how to link forest services with their use for adaptation (more specifically...

A National Biodiversity Offset Scheme

World Bank Group
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Relatório
EN_US
Relevância na Pesquisa
36.13%
Liberia had an estimated 4.3 million hectares of forests in 2011, comprising approximately 50 percent of Liberia’s landmass. These forests support very high levels of biodiversity, provide a wide range of ecosystem services (for example, bush meat, medicines, construction materials, and charcoal), and generate employment and revenue from commercial and chainsaw logging. Encouraging inward investment while striking a sound balance between different interests, respecting the legal and customary rights of local people, and conserving biodiversity represents a major challenge. This project focuses on the mining sector, which has the potential to become a significant engine for growth and broader-based development. It explores the feasibility of implementing a national biodiversity offset scheme in Liberia to help minimize adverse impacts on biodiversity and ecosystem services resulting from mining. A Liberian national offset scheme will entail the application of a common methodology to ensure that conservation benefits are at least equivalent to biodiversity losses due to mining investments. The report is presented in seven chapters. Chapter one gives introduction. Chapter two discusses the conservation imperatives for Liberia and conveys a sense of the quality and extent of biodiversity within Liberia. Chapter three describes the challenge of securing conservation outcomes in Liberia as well as the prevalence of threats to biodiversity. Chapter four discusses the potential for biodiversity offsets to help secure conservation outcomes. Chapter five covers the legal...

Cumulative Human Impacts on Mediterranean and Black Sea Marine Ecosystems: Assessing Current Pressures and Opportunities

MICHELI Fiorenza; HALPERN Benjamin; WALBRIDGE Shaun; CIRIACO Saul; FERRETTI Francesco; FRASCHETTI Simonetta; LEWISON Rebecca; NYKJAER Leo; ROSENBERG Andrew A.
Fonte: PUBLIC LIBRARY SCIENCE Publicador: PUBLIC LIBRARY SCIENCE
Tipo: Articles in Journals Formato: Online
ENG
Relevância na Pesquisa
36.44%
Management of marine ecosystems requires spatial information on current impacts. In several marine regions, including the Mediterranean and Black Sea, legal mandates and agreements to implement ecosystem-based management and spatial plans provide new opportunities to balance uses and protection of marine ecosystems. Analyses of the intensity and distribution of cumulative impacts of human activities directly connected to the ecological goals of these policy efforts are critically needed. Quantification and mapping of the cumulative impact of 22 drivers to 17 marine ecosystems reveals that 20% of the entire basin and 60-99% of the territorial waters of EU member states are heavily impacted, with high human impact occurring in all ecoregions and territorial waters. Less than 1% of these regions are relatively unaffected. This high impact results from multiple drivers, rather than one individual use or stressor, with climatic drivers (increasing temperature and UV, and acidification), demersal fishing, ship traffic, and, in coastal areas, pollution from land, accounting for a majority of cumulative impacts. These results show that coordinated management of key areas and activities could significantly improve the condition of these marine ecosystems.; JRC.H.1-Water Resources

Simulation of the cumulative impacts of CO2 geological storage and petroleum production on aquifer pressures in the offshore gippsland basin

Michael, K.; Bunch, M.; Varma, S.
Fonte: Elsevier Ltd Publicador: Elsevier Ltd
Tipo: Artigo de Revista Científica
Publicado em //2013 EN
Relevância na Pesquisa
46.37%
Geological carbon dioxide storage (GCS) has been identified as an important strategy for reducing greenhouse gas emissions. Due to their potentially large CO₂ storage capacity, deep saline aquifers have been investigated globally with respect to storage suitability, injectivity and potential impact on the environment and other basin resources. The relatively large area of pressure impacts associated with large-scale GCS has been identified previously as an important issue. One aspect of GCS in saline aquifers that has previously not been considered widely in the assessment of injection impacts and storage capacity is the history of regional production-induced underpressuring in many petroleum-producing sedimentary basins. The Latrobe aquifer in the Gippsland Basin in southeastern Australia is a potential candidate for large-scale GCS. The Latrobe Group forms a major freshwater aquifer in the onshore Gippsland Basin and contains hydrocarbon reservoirs in the offshore parts of the basin up to 6000m below the seafloor. The emphasis of the current modelling was to examine the cumulative impacts of CO₂ injection and petroleum production on the regional flow and displacement of formation water. With respect to the Gippsland Basin specifically...

Cumulative Impact Assessment and Management : Guidance for the Private Sector in Emerging Markets

Cardinale, Pablo; Greig, Lorne
Fonte: International Finance Corporation, Washington, DC Publicador: International Finance Corporation, Washington, DC
Tipo: Publications & Research :: Working Paper; Publications & Research
ENGLISH; EN_US
Relevância na Pesquisa
46.5%
The major environmental and social management challenges that we face today, climate change, loss of biodiversity, the decline of ocean fisheries, limitations on food security, the scarcity of usable freshwater resources, displacement of communities with consequent increases in urban poverty, and inviability of traditional local livelihoods, are all the result of cumulative impacts from a large number of activities that are for the most part individually insignificant, but together have had regional or even global repercussions. The importance of understanding the cumulative environmental and social impacts from multiple projects, actions, or activities, or even from the same actions over an extended period of time, located in the same geographic region or affecting the same resource (e.g., watershed, airshed) has been acknowledged for decades. In some cases, the most ecologically devastating environmental effects and subsequent social consequences may result not from the direct effects of a particular action...

Exploring the social dimensions and complexity of cumulative impacts: a case study of forest policy changes in Western Australia

Loxton, Edwina; Schirmer, Jacqueline; Kanowski, Peter
Fonte: Beech Tree Publishing Publicador: Beech Tree Publishing
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.3%
Social impacts resulting from policy changes and other interventions interact and aggregate, and are influenced by additional interventions and exogenous factors, leading to cumulative social impacts. We explored these complex impacts through a case study

Development of a Cumulative Impacts Management Plan

May, Philip
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Relatório
Publicado em 25/11/2012 EN_US
Relevância na Pesquisa
66.61%
The City of High Point developed an Environmental Assessment and Secondary and Cumulative Impacts Management Plan to assess environmental issues associated with a sewer line replacement in High Point, North Carolina. The project began as an EA addressing the potential impacts of construction and operation of a sewer line that would replace an existing line. The existing line had numerous issues including exposed sections in the stream, leakage and infiltration of groundwater. As the EA was developed and reviewed by regulatory agencies, the focus of concern became the increased capacity of the new line and its potential to promote development and associated environmental impacts. Rather than revise the EA to comprehensively address secondary and cumulative impacts, it was proposed to address direct impacts of the line replacement in the EA while developing a separate Management Plan for cumulative impacts within the entire treatment plant service area. This allowed for the EA to be processed relatively quickly and the replacement sewer line construction to begin, while also providing time for the City to comprehensively address cumulative impacts on a service area scale and limit comments on future projects within the same service area. As the City was not only the project owner...

Ecological impacts of small dams on South African rivers Part 1: drivers of change - water quantity and quality

Mantel,Sukhmani K; Hughes,Denis A; Muller,Nikite WJ
Fonte: Water SA Publicador: Water SA
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2010 EN
Relevância na Pesquisa
56.58%
Impacts of large dams are well-known and quantifiable, while small dams have generally been perceived as benign, both socially and environmentally. The present study quantifies the cumulative impacts of small dams on the water quality (physico-chemistry and invertebrate biotic indices) and quantity (discharge) of downstream rivers in 2 South African regions. The information from 2 South African national databases was used for evaluating the cumulative impacts on water quality and quantity. Physico-chemistry and biological data were obtained from the River Health Programme, and discharge data at stream flow gauges was obtained from the Hydrological Information System. Multivariate analyses were conducted to establish broad patterns for cumulative impacts of small dams across the 2 regions - Western Cape (winter rainfall, temperate, south-western coast) and Mpumalanga (summer rainfall, tropical, eastern coast). Multivariate analyses found that the changes in macroinvertebrate indices and the stream's physico-chemistry were more strongly correlated with the density of small dams in the catchment (as a measure of cumulative impact potential) relative to the storage capacity of large dams. T-tests on the data, not including samples with upstream large dams...

Ecological impacts of small dams on South African rivers Part 2: biotic response - abundance and composition of macroinvertebrate communities

Mantel,Sukhmani K; Muller,Nikite WJ; Hughes,Denis A
Fonte: Water SA Publicador: Water SA
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2010 EN
Relevância na Pesquisa
56.34%
This paper investigates the cumulative impacts of small dams on invertebrate communities in 2 regions of South Africa - the Western Cape and Mpumalanga. Previous research found reduced discharge, increased total dissolved salts, and a decrease in average score per taxon (ASPT; collected using SASS4 methods) at sites with high density of small dams in their catchment. These changes in ASPT are investigated using the invertebrate abundance data available in the River Health Programme. Multivariate analyses found differences in invertebrate communities in rivers with high densities of small dams in their catchment in foothill-gravel streams (in both Western Cape and Mpumalanga) and in foothill-cobble streams (in Western Cape only). Opportunistic taxa that are tolerant of pollution, and capable of exploiting various habitats, and those that prefer slower currents increased in numbers, while other taxa that are sensitive to pollution and disturbance declined in numbers. Some regional differences were noted possibly reflecting climatic differences between the regions. Since the results of this study are correlative, it highlights the need for a systematic (by sites and seasons) and detailed (at species level) collection of data to verify the results of cumulative effects of small dams. This can further the development of a framework for small-dam construction and management that will limit their impact on river catchments.