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  • 1
    Electronic Resource
    Electronic Resource
    River Dan, headwater of the Jordan, an aquatic oasis of the Middle East (1986)
    Springer
    Hydrobiologia 134 (1986), S. 121-140 
    Details
    ISSN: 1573-5117
    Keywords: Jordan River ; Freshwater biogeography ; Stream typology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract River Dan is the largest of the headwater rivers of the Jordan. The karstic exsurgence of the Dan has a seasonally stable output, a long stretch of strongly turbulent flow, stable temperature around 15.5°C and high oxygen saturation. A total of 156 taxa, mainly at the species level, were identified from the river. These species are almost exclusively of Palearctic origin. About half of the species are limited to the northernmost part of Israel. The faunal complex described, does not present any longitudinal zonation for the 5 kilometers of turbulent flow; neither does it present seasonal changes in species composition. River Dan is considered to be a post-Pleistocenic river which has an important function of refugium for a wide area of aquatic water-bodies in the area, including the presently drained Lake Hula. It is suggested that in the Illies scheme of stream classification, River Dan might represent a type of stream belonging to a ‘pseudorhithral’ along with other stenothermic warm water torrents of the tropical-subtropical climatic belt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00006736
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Invertebrate drift in the Dan River, Israel (1988)
    Springer
    Hydrobiologia 160 (1988), S. 155-163 
    Details
    ISSN: 1573-5117
    Keywords: invertebrate drift ; aquatic insects ; river ecology ; Gammarus ; Baetidae ; environmental impact ; Israel ; Jordan River
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The Dan river, a principal source of the Jordan River, Israel, is unusually constant in discharge (∼8 m3·s−1) and water temperature (15–16 °C). The Jordan headwaters constitute the southernmost oasis of a palearctic north temperate fauna, and presumably the very constancy of the Dan contributes to its important role as a regional refuge. However, little is known of river ecology from this region. We report a twelve month study of drift, undertaken to assess diel, seasonal, and spatial patterns of the abundance of drifting invertebrates. Diel periodicity in drift was detectable but minimal. Baetidae nymphs showed a pronounced nocturnal increase, gammarid amphipods a modest, twofold increase, while dipteran larvae showed no diel variation. Seasonal variation likewise was minimal and due principally to the Baetidae, while gammarid amphipods showed no significant seasonality. The notably small diel and seasonal variation in aquatic drift in the Dan may be attributable to the extremely constant physical regime. Spatial variation was substantial. Two stations located 30 and 200 m below the karstic exsurgence of the Dan provided drift densities among the lowest reported anywhere, whereas two stations located 1 and 4.5 km downstream had more typical drift densities. A water diversion project completed halfway through the study resulted in a 50% reduction in flow at the most downstream stations, but had no discernible effect on drift.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00015478
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Faunal relationships to abiotic factors along the River Dan in northern Israel (1992)
    Springer
    Hydrobiologia 246 (1992), S. 69-82 
    Details
    ISSN: 1573-5117
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A 4.5 km section of the River Dan in northern Israel was sampled at intervals of 6 weeks, between April 1983–March 1984, using standardized mesh bags. The river is characterized by extremely stable temperature and other physical and chemical conditions. The effects of a water diversion project 2400 m from the spring were investigated. The relationships between fauna and depth, current velocity and distance from the spring sources were evaluated. Of 48 common taxa analyzed, 27 showed relativity to the distance from the sources, 18 to current velocity and 12 to depth. The lowest density of invertebrates, but the highest number of taxa and highest variety of species were found at the spring sources. The sampling site immediately downstream from the water diversion project was characterized by intermediate densities, lowest varieties of species and highest evenness of distribution. Results are compared with the predictions of the Intermediate Disturbance Hypothesis; but the influence of invertebrate drift caused this hypothesis to be inapplicable to lotic waters. Invertebrate drift is in addition suggested as an important factor governing the structure of the fauna at the spring sources.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00005623
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Relationship between current velocity, depth and the invertebrate community in a stable river system (1993)
    Springer
    Hydrobiologia 263 (1993), S. 163-172 
    Details
    ISSN: 1573-5117
    Keywords: Invertebrates ; current velocity ; depth preference ; turbulence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The relationship between invertebrate densities, current velocity and water depth was studied in the Dan River, northern Israel. Maximum current preferences ranged from 5–120 cm sec−1, and depth preferences ranged from 5–60 cm. Thirty-five taxa of invertebrates were collected by means of colonization cages. Larval and adult stages of 3 Elmidae (Coleoptera) species were treated separately: Limnius letourneuxi, Grouvellinus caucasicus and Elmis rioloides. Differences in current preference were observed between larval and adult stages of the same species of Elmidae. Taxa were also grouped according to preference for turbulence. Wide ranges of depth and current velocity preferences were observed. Most of the taxa were found at between 80–100 cm sec−1 and at depths of less than 30 cm. A correlation between species diversity and current velocity was established. Velocities of 60–80 cm sec−1 contained the greatest overlap of faunal preference. The sensitivity of selected species to stream flow reduction is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00006267
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Interactions among Scientists, Managers and the Public in Defining Research Priorities and Management Strategies for Marine and Coastal Resources: Is the Red Sea Marine Peace Park a New Paradigm? (2000)
    Springer
    Water, air & soil pollution 123 (2000), S. 581-594 
    Details
    ISSN: 1573-2932
    Keywords: coral reef ; Gulf of Aqaba ; management ; marine protected area ; Red Sea ; research ; sustainable use
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract It has been assumed that marine habitats and resources, especially, are almost unlimited, and that if one habitat became degraded or a particular fisheries resource depleted, there always would be another to replace it. Therefore, natural resource management principals are beginning to include human motivation and responses as part of the marine and coastal systems that are being studied and managed. Managers of marine resources face the challenge of balancing conservation and development objectives in the context of the inherent uncertainty of natural systems and the political and social pressures of human systems. Natural resource managers, scientists and the general public seem to share a vision for the future as a world in which societal and economic decisions will be strongly coupled with an increasingly comprehensive understanding of the environment. This in turn will lead to both socio-economic health and ecosystem health. A paradigm shift is being seen in the evolution of the role of scientists in society from simply observers of the natural world with tenuous linkages to resource managers and the public, to partners in modern society's quest for answers to pressing questions related to sustainable use and conservation of natural resources. A US Agency for International Development supported, joint effort between the US National Oceanic and Atmospheric Administration, the Government of Israel and the Hashemite Kingdom of Jordan to conduct a comprehensive research and monitoring program directed at the new Binational Red Sea Marine Pearce Park will be a pioneering effort to employ and test this new paradigm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005281403279
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    Paper (German National Licenses)
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