نتایج جستجو برای: river ecosystem

تعداد نتایج: 162076  

    Ecologically-based Management Factors and criteria of River-Valleys in Tehran metropolis-Case Study: River-Valleys of Kan   Abstract: Iran has seasonal rivers because of dry climate, low rainfall and different topography. These river- valleys have main role in forming, genesis, and sustainability of human settlements and provide different ecological services. The main services include...

2008
Roger G. Young Christoph D. Matthaei Colin R. Townsend

River health monitoring traditionally has made use of structural measurements (water quality or taxonomic composition of aquatic organisms). We argue that a more complete assessment of river health should include functional metrics, such as rates of organic matter decomposition and ecosystem metabolism. Leaf breakdown links the characteristics of riparian vegetation with the activity of both aq...

2013
Xiaoyan Chen Huiwang Gao Xiaohong Yao Zhenhua Chen Hongda Fang Shufeng Ye

Marine ecosystem is a complex nonlinear system. However, ecosystem health assessment conventionally builds on a linear superposition of changes in ecosystem components and probably fails to evaluate nonlinear interactions among various components. To better reflect the intrinsic interactions and their impacts on ecosystem health, an ecosystem coordination index, defined as the matching level of...

2015
Caryn C. Vaughn Carla L. Atkinson Jason P. Julian

Extreme hydro-meteorological events such as droughts are becoming more frequent, intense, and persistent. This is particularly true in the south central USA, where rapidly growing urban areas are running out of water and human-engineered water storage and management are leading to broad-scale changes in flow regimes. The Kiamichi River in southeastern Oklahoma, USA, has high fish and freshwater...

2002

This paper presents the results of analysis of samples of river water and bottom sediments for PAH and PCB content using previously developed analytical procedures. Conclusions are drawn as to the form and main places of occurrence of the above analytes in the various elements of the river ecosystem (water phase, suspension, bottom sediments). The dependencies which were found between the PAH a...

1999
RICHARD H. NORRIS

1. Traditionally the assessment of river water quality has been based solely on the measurement of physical, chemical and some biological characteristics. While these measurements may be efficient for regulating effluent discharges and protecting humans, they are not very useful for large-scale management of catchments or for assessing whether river ecosystems are being protected. 2. Measuremen...

2016
Syed Hafizur Rahman Md. Towfiqur Rahman

This study aims to set up a comprehensive approach to the Vulnerability and Impact Assessment (VIA) of river erosion and to suggest Ecosystem-based Adaptation (EbA) practices. Based on the analysis of vulnerability using the Driver-Pressure-State-Impact-Response (DPSIR) framework, this paper discusses some of the significant climatic (rainfall pattern, temperature, seasonal drift, cold wave and...

Journal: :Conservation biology : the journal of the Society for Conservation Biology 2009
David J Hoeinghaus Angelo A Agostinho Luiz C Gomes Fernando M Pelicice Edson K Okada João D Latini Elaine A L Kashiwaqui Kirk O Winemiller

Applying the ecosystem services concept to conservation initiatives or in managing ecosystem services requires understanding how environmental impacts affect the ecology of key species or functional groups providing the services. We examined effects of river impoundments, one of the leading threats to freshwater biodiversity, on an important ecosystem service provided by large tropical rivers (...

2007
Jackson R. Webster

The spiraling concept provides an explicit approach to modeling the longitudinal linkages within a river continuum. I developed a spiraling-based model for particulate organic C dynamics in the Little Tennessee River to synthesize existing data and to illustrate our current understanding of ecosystem processes in river ecosystems. The Little Tennessee River is a medium-sized river flowing ;100 ...

H. Arabi S. Haghighi,

Heavy metal pollution dispersion simulation in rivers and predicting spatial and temporal variations of pollutants can be used to determine the precise place and to schedule water withdrawal time for drinking, agriculture, aquaculture and ecosystem studies. To study the movement of heavy metal pollution through Karoon flow model, MIKE 11 was employed fpr simulation of the flow model of Karoon R...

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