Introduction
Along the coastal plain of Israel, a few hundred meters east of the Mediterranean shore, extends a strip of sand-dunes and chalksandstone hills . This strip is interrupted by the courses of several streams flowing into the Mediterranean .
Some of the hills in this land strip are considerably higher than the coastal plain so that rainpools form behind them during the winter . Most typical are the pools of Birkat el Faza, 4 km south of Natanya (7 in Map 1 ; Map 2) and at Ga'ash (10 in Map 1 ; Map 3) about 16 km north of Tel-Aviv .
Elsewhere along the coastal plain, rainpools are formed as a result of encroachment by civilization, e.g ., road ramparts that block the drainage of small valleys into the rivers and wadis . Thus, for instance drainage of the Holon Pool into the Wadi Musrara has been blocked by a number of roads (17 in Map 1 ; Map 4) .
Although temporary rainpools constitute a special habitat, characteristic to this part of the country, only few investigators have paid much attention to them .
The fauna of the local temporary pools, however, has been studied by various authors : GURNEY (1913) ; KRAMPNER (1928) ; LEPSI (1929) ; KIEFER (1930) ; BODENHEIMER (1935); BREHM (1937); WIERZUBSKI (1944) ; FISCHER (1953) .