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Background: The present study examined genetic variations of the green toad Pseudepidalea viridis from different breeding sites throughout Israel and in Egypt, Turkey, Iran, and Germany (out-groups).Results: Comparison of Cyt b and D-loop fragments from Israeli sites with those from the four out-groups showed that analysis of molecular variance (AMOVA) was greatest among regions. Values of proportion of the total genetic variance among regions (PhiRT) in Israeli sites were relatively low and not statistically significant. A cluster analysis of RAPD for classifying P. viridis revealed a subgroup comprising seven northernmost populations and three populations near the southern and eastern deserts surrounding Israel. AFLP analysis defined all individuals in a single cluster. Variations in P. viridis according to AMOVA test of Israeli sites using GenAl were 2% among regions, 8% among populations, and 90% within populations. Conclusions: These findings support the hypothesis that various ecological conditions in a relatively small area have little effect on genetic variations.

A mediterranean-type climate exists in five widely separated regions; the Mediterranean basin, parts of western North America, parts of western and southern Australia, southwestern South Africa and parts of central Chile. Streams in these regions feature seasonal disturbances of contrasting hydrology with high predictability of the timing of flooding and drying but low constancy. We would expect fish living in these streams to avoid scouring flow and breed after cessation of the flood period. The aim of the present study was to examine the adaptation of the Yarqon bleak, Acanthobrama telavivensis, an endemic cyprinid in the coastal streams of Israel, to mediterranean-type stream 1 conditions. For that we studied its reproductive strategy (age at maturity and life span, gonad activity, oocyte maturation, spawning activity and habitats, appearance of juveniles), in a major costal stream (Yarqon). Our findings show that the Yarqon bleak exhibits life history traits attuned with a mediterranean-climate hydrologic regime. It breeds in late winter and early spring, a window of opportunity between flash floods and habitat desiccation. Being a multiple spawner allows the fish to compensate for the potential loss of part of its reproductive output due to scouring flows of late floods. The ability of the Yarqon bleak to spawn on different substrate-types enables it to take advantage of different stream conditions that pertain in different years. The fish attains preadult size (ca. 33-42 mm) within the first year, prior to drying out of most stream reaches, and matures by the beginning of the second year (males >41; females >42 mm). The cost of these tactics is a short life span (4-5 age groups). The reproductive strategy of the Yarqon bleak falls into the category of in-channel breeding but, unlike the case suggested by a low flow recruitment model, the fish breed during the period of flood cessation, a transitional time between high and low flows, rather than at the time of low flow. Breeding at this time of the year in mediterranean-type streams puts early stages somewhat at risk of being washed away by late floods, but gains them a longer period of growth under favorable conditions. We suggest an additional positive tradeoff that should be investigated: the reduced competition with age 0 of other fish that breed later in the season. This suggested model of recruitment during the period of flood cessation seems appropriate for fish in streams with 1 mediterranean-written with a small m, is used in connection with climate or ecological region and is distinguished from Mediterranean that is used in a geographical context, referring to the Mediterranean basin.

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