Distributional patterns and habitat characteristics of Amphipoda (Crustacea) in the inland waters of Israel and Sinai

Ten amphipod (Crustacea) species from the inland waters of Israel and Sinai have been identified (Gammarus syriacus, G. pseudosyriacus, Echinogammarus n. sp., E. foxi, E. veneris, Corophium orientalis, Orchestia cavimana, O. platensis, Bogidiella hebraea and Metacrangonyx n. sp.). These species display two principal distribution patterns: a marine origin derived pattern and a north-south pattern typical of the freshwater fauna of the Levant. The understanding of these patterns aids in the elucidation of the zoogeography of the region. Within their ranges the common Gammarus and Echinogammarus species display differences in preference for current velocities, salinities and habitat types. The influence of man-induced habitat destruction on the amphipod fauna is also discussed.     

Distribution and habitat characteristics of Naididae and Tubificidae in the inland waters of Israel and the Sinai Peninsula

Nineteen species of Naididae and fourteen species of Tubificidae were found in collections from inland waters in Israel and Sinai. The local distribution patterns of the majority of these species were determined. The ranges of several physical and chemical variables characterizing the habitats of each species were defined. A correlation was found between the distribution patterns of some species and the following variables: salinity, temperature, dissolved oxygen, current velocities and stability of the habitats.     

Foraging,roosting, and nesting habitats of the avian fauna of the Agmon wetland,northern Israel

The foraging, nesting and roosting habitats of the avian fauna of a newly created Agmon wetland and surrounding cultivated peat land (5 km2) in the Hula Valley, northern Israel, were evaluated (January 1996–February 1997) to assess the value as a habitat and for wildlife tourism. We recorded 180 bird species (herons, dabbling ducks, kingfishers, waders, wagtails and raptors) in different habitats (the lake, shores, cattail and reed-bed stands, trees, temporary inundated areas). The most heavily used habitat for foraging, breeding, and roosting was a large cattail stand in the southern third of the lake. The foraging habitat and diet data of 97 avian species were determined. The most intensively used foraging habitats were cultivated fields, lake shore reed-beds, shallow canals and the cattail stand. Forty six species nested in the wetland during March-October, with 2,040 colonial and solitary nests mostly in the cattail stand, near-shore reed-beds and young trees. Roosts, also mostly in the cattail and reed-bed stands and in trees, were used by 55 species. Based on this survey of available habitats, we identified several key habitats that are either missing or require further development (e.g., temporarily inundated mud flats, reed-beds and bare islands). We also provide suggestions for improving the delicate balance between requirements of this developing wetland ecosystem and of the adjacent agricultural areas.     

Physiological mechanisms of color constancy

Color constancy is the term given to the ability to recognize the color of objects correctly under different conditions of illumination. For this purpose the visual system must determine the character of the illumination, introduce a correction for it into the spectal composition of the light received from the object, and hence recreate the true color of its surface. Behavioral experiments on fish showed that they possess constant color vision of objects. Electrophysiological experiments on ganglion cells of the color type showed that the simplest mechanisms of correction for illumination are found at the retinal level. An investigation of model algorithms providing for color constancy showed thatthe presence of color vision makes it much easier to recognize the three-dimensional form of objects. This fact compels a reexamination of established views regarding the place and role of color vision in functions of the animal visual system as a whole.Institute for Problems in Information Transmission, Academy of Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 7, No. 1, pp. 21–26, January–February, 1975.     

Predation of Arternia cysts by water-tiger larvae of the genus Anacaena (Coleoptera,Hydrophilidae)

Artemia cysts are preyed upon by the larvae of Anacaena (Coleoptera, Hydrophilidae) in the wet supralittoral of the hypersaline Solar Lake near Elat. The larvae are specialized feeders of the cysts, as shown by laboratory experiments.     

River Dan,headwater of the Jordan,an aquatic oasis of the Middle East

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.     

Diaptomidae (copepoda,calanoida) of Israel and Northern Sinai

A study on the morphology, biology, distribution and habitat characteristics of inland water diaptomids of Israel and Northern Sinai is presented. Taxonomic status, seasonal colour change and adaptations of these species for living in temporary waters are discussed. Two new subspecies are established, namely Arctodiaptomus (Arctodiaptomus) similis irregularis n.ssp and Hemidiaptomus (Hemidiaptomus) gurneyi canaanita n.ssp.     

Cyclopoid diversity in the basin of Lake Hula (Israel), after its partial reflooding

In a relatively small area of 60 km² which corresponds to the basin of the presently drained Lake Hula and its swamps (Upper Jordan Valley), 22 species of Cyclopoida are on record, with two more species reported in the pre-drainage times. The basin of Lake Hula is the southernmost enclave of permanent fresh waters in the Levant Province of Southwest Asia. Lacustrine and swamp environments existed in the area uninterruptedly for at least 700 000 years. A partial restoration project created a new lake. The basin is situated right in the middle of a main bird migration route. The fact that no less than 15 species were recorded from a set of small artificial and isolated experimental ponds seems to indicate that migrating birds and stocks of resting eggs are to account for this high diversity. Cyclops vicinus, Mesocyclops arcanus and Eucyclops serrulatus are the most common species. The success of the restoration is discussed.