نتایج جستجو برای: river ecosystem

تعداد نتایج: 162076  

2003
H. Yang

The Haihe River basin is one of the most developed regions in China. With the rapid economic development and associated increases in water demand, the river basin has been enduring increasing water stress. Water for the ecosystem use has been compromised and the environment has been deteriorating. Water shortage has become a bottleneck to the further development of the economy and grain product...

Journal: :international journal of environmental research 2012
y. x. feng g.p. luo c.f. li l. dai l. lu

this study aims to quantify the impacts of land use changes on ecosystem service value during large scale land development, and to provide key information for both economic development and policy makers for eco-environmental protection. the study area locates in manas river watershed which is a typical land development region in northwest china. landsat mss/tm/etm+ images in 1976, 1989, 1999 a...

2018
Elizabeth P Anderson Clinton N Jenkins Sebastian Heilpern Javier A Maldonado-Ocampo Fernando M Carvajal-Vallejos Andrea C Encalada Juan Francisco Rivadeneira Max Hidalgo Carlos M Cañas Hernan Ortega Norma Salcedo Mabel Maldonado Pablo A Tedesco

Andes-to-Amazon river connectivity controls numerous natural and human systems in the greater Amazon. However, it is being rapidly altered by a wave of new hydropower development, the impacts of which have been previously underestimated. We document 142 dams existing or under construction and 160 proposed dams for rivers draining the Andean headwaters of the Amazon. Existing dams have fragmente...

Journal: :Emerging Infectious Diseases 2009
Pedro Luiz Tauil

The Amazon River basin region is a vast territory with an area >7 million km2, encompassing parts of 9 South American countries: Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname, and Venezuela. The Amazon River, the longest river in the world, traverses the region from west to east, fed by multiple tributaries. The region also contains the largest tropical rainforest in...

Journal: :Softw., Pract. Exper. 2016
Robert Soulé Martin Hirzel Bugra Gedik Robert Grimm

This paper presents both a calculus for stream processing, named Brooklet, and its realization as an intermediate language, named River. Because River is based on Brooklet, it has a formal semantics that enables reasoning about the correctness of source translations and optimizations. River builds on Brooklet by addressing the real-world details that the calculus elides. We evaluated our system...

2012
Charles W. Schmidt

The “Flume Room” The University of Michigan has created a specialized laboratory containing 150 artificial mini-streams, or “flumes,” that mimic a variety of river conditions as closely as possible. The flumes are populated with rocks, sediment, biota, and more than 3,000 gallons of water from the Huron River. The goal is to better understand how different stressors—nutrient and chemical pollut...

1999
FERDINAND C. DE MOOR

The tributaries of the Olifants River draining the Cedarberg Mountains in the Western Cape are well known for their diverse fauna of endemic freshwater fish. Aquatic ecosystems in the region have also been identified as being particularly important in terms of ecosystem conservation. Recent surveys of aquatic macroinvertebrates have indicated that the region is rich in Trichoptera, with a numbe...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2000
I Cassens S Vicario V G Waddell H Balchowsky D Van Belle W Ding C Fan R S Mohan P C Simões-Lopes R Bastida A Meyer M J Stanhope M C Milinkovitch

The four species of "river dolphins" are associated with six separate great river systems on three subcontinents and have been grouped for more than a century into a single taxon based on their similar appearance. However, several morphologists recently questioned the monophyly of that group. By using phylogenetic analyses of nucleotide sequences from three mitochondrial and two nuclear genes, ...

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 beauty, store of green spaces, water supply, reduce and create temperature differences, local air flow and natural ventilation which are part o...

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