Wyniki wyszukiwania - Biblioteka Nauki

1

Fish habitats in a small, human-impacted Sibunag mangrove creek (Guimaras, Philippines): a basis for mangrove resource enhancement

100%

Abroguena J. B. R. , Bagarinao T. U. , Chicharo L.

International Journal of Ecohydrology and Hydrobiology

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2012

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tom 12

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nr 4

2

Fish diversity in different habitats in the streams of lower middle Western Himalayas

86%

Johal M. , Krishan-Tandon K. , Kumar-Tyor A. , Kumar-Rawal Y.

Polish Journal of Ecology

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2002

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tom Vol. 50, nr 1

45-56

EN

The present study was carried out in the lower middle Western Himalayan streams in the Indian state of Himachal Pradesh of the three river basins namely the Ghaggar, the Sutlej and the Yamuna. The main aim was to study fish assemblage structure/composition, fish diversity in different habitats and the habitat preference of the fishes. The different habitats like pools, riffles, runs and rapids were sampled over a 2 km stretch at all the sites with the help of cast net of 1 cm mesh size having a diameter of 1-2 meter on a fixed day every month between mid morning and late afternoon. All the sites when broadly delineated at level-1 fall into type - B except site II that is an F - type stream. A total of 23 species belonging to four orders were recorded of which the cyprinids were the most dominant group. According to Shannon-Weawer diversity index, the pool habitat supports greater diversity (H' = 0.72-0.97), Runs (H' = 0.24-0.87) and riffles (H' = 0.22-0.81) have diversity very near to each other at all the sites whereas rapids have significantly lower fish diversity (H' = 0.00-0.58). The pool is the preferred habitat for most of the cyprinid fishes recorded in the present study especially the minnows.

3

Changes in the biotope quality unfavourable to ichthyofauna of the Szczecin Lagoon during the flood crest outflow in summer 1997

72%

Poleszczuk G.

Baltic Coastal Zone. Journal of Ecology and Protection of the Coastline

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2003

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tom 06

4

The effects of small-scale impoundments and bank reinforcing on fish habitat and composition in semi-natural streams

72%

Monaghan K. A. , Fonseca M. M. , Domingues I. , Soares A. M. V. M.

Polish Journal of Ecology

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2008

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tom 56

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nr 4

647-657

EN

We studied the fish assemblages of thirty one, 2nd–4th order “least-impacted” streams with a varying degree of low-level management in central Portugal, using a standardised survey to document the river habitat. Channel, banks and riparian landuse, described separately according to principal component scores, were significantly related to altitude, slope and management intervention. Species diversity was low, represented by four endemic, four pan-European and one exotic species. TWINSPAN classification distinguished 3 community types, characterised by their dominant species: trout (Salmo trutta L.), chub (Leuciscus carolitertii Doadrio) and “roach” (Squalius alburnoides Steindachner and Chondrostoma oligolepis Robalo). Community types were associated with environmental differences with PC Channel scores higher at trout sites compared to other classification groups, whilst PC Bank-1 scores, temperature and conductivity were significantly different at trout compared to “roach” sites. Ecologically important habitat features were, in turn, related to landscape (map-derived) parameters and the extent of channel and bank management. The mis-classification of sites in discriminant analysis was related to management intervention, indicating the potential difficulty in the assignment river-community types for the biological monitoring of fish communities in these stream types.

5

Restoration of sustainability of physically degraded fish habitats - The Model of Intermediate Restoration

72%

Zalewski M. , Welcomme R.

International Journal of Ecohydrology and Hydrobiology

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2001

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tom 01

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nr 3

EN

The Restoration Ecohydrology Concept integrates two approaches to restoration and mitigation of physically modified freshwater habitats. Firstly actions at the catchment level connected with integrated management of abiotic factors including, landscape planning, catchment management, forestation, phytotechnologies and hydrology by impoundment. Secondly actions at the level of the aquatic ecosystem itself, particularly those linked to fisheries management. The highest biodiversity and productivity of fish assemblages appears at an intermediate level of human disturbances, which, in the case of the biogeochemical cycle, has usually been connected with limited degradation of catchment cover. The increase of fish biomass and diversity under these conditions apparently results firstly from nutrient enrichment and improved energy influxes to the stream arising from the more rapid cycling of nutrients of terrestrial origin cycling, and secondly from the intermediate complexity of the riparian ecotones. The maximum of biomass might appear under different conditions than those that favour maximum biodiversity due to this ecosystem enrichment and amplified access to energy. The data presented at the symposium lead to following conclusions: 1. Restoration of river systems to pristine conditions is not realistic but is also not necessary. 2. The target of restoration of physically degraded habitats should lie somewhere in the range between maximum biodiversity and maximum productivity of fish communities.

6

Aquatic habitat inventories using remote sensing

72%

Armantrout N. B.

International Journal of Ecohydrology and Hydrobiology

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2001

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tom 01

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nr 1-2

EN

Increasing emphasis is being placed on managing aquatic resources on an integrated, basinwide basis. Traditional ground inventory methods are time-consuming and expensive, and are not easy to integrate over large areas. Remote sensing, combined with Geographic Information Systems (GIS) and Geographic Positioning System (GPS) technology, offers a more flexible, cost-effective method for gathering and integrating information. Digital terrain models, spectral separations, and microwaves can be used to define physical and biological features. Habitat conditions in a basin can be defined by four basic elements: climate, geomorphology, vegetation and human activities. All of these can, to different degrees, be directly inventoried by remote sensing. When used with GPS and GIS systems, remote sensing information can be merged with field data and other sources of information to create an integrated summary of resource conditions. Information can be summarized on a range of scales, from local to region-wide, and can be compared over time as a monitoring and evaluation tool.

7

Geomorphic and hydraulic influences on the abundance and distribution of stream centrarchids in Ozark USA streams

58%

Rabeni C. F. , Jacobson R. B.

Polskie Archiwum Hydrobiologii

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1993

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tom 40

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nr 1