Palestinian Painted Frog

The Palestinian painted frog (Discoglossus nigriventer) formerly inhabited Lake Huleh (Lake Hula) in Israel and has not been recorded since the lake was drained in the 1950s. This species is known only from two adult and two tadpole specimens collected in 1940 on the lake's eastern shore in what was then Palestine (Mendelssohn and Steinitz, 1943) and a single adult specimen reported by Steinitz in 1955 (Werner, 1988). This species was the first of its genus to be reported on the eastern shore of the Mediterranean (Mendelssohn and Steinitz, 1943).

D. nigriventer was a small frog (4 cm in length) colored in shades of brown and gray with many white dots on its underside, marking the glandular openings in its skin. Nothing is known of its habits, food preferences, or life cycle. Of the two specimens collected by Mendelssohn and Steinitz, the smaller was eaten by the larger while they were housed in a terrarium for study.

Lake Huleh, the northernmost lake in the Jordan valley, was formerly one of the few large freshwater habitats in the Near East. The shallow pear-shaped lake extended over 12 square kilometers, with swampy meadows and dense stands of papyrus at its borders. In total, the lake and swamps covered up to 60 square kilometers, with significant seasonal and interannual variations caused by changes in water level. These wetlands provided vital wintering grounds and stops along migration routes for many bird species. Prior to the lake's drainage, surveys found several species of endemic fish and invertebrates. The primary source of the water in the lake was the Jordan River, and beyond Lake Huleh this water flowed onward to Lake Kinneret (the Sea of Galilee).

In an attempt to tame the environment and make it more hospitable and profitable for its human inhabitants, plans were proposed to drain Lake Huleh with the goals of eradicating malaria, creating land suitable for agriculture, and safeguarding the water for human use. Although the plans were proposed in the 1930s, World War II, the Israeli War of Independence, and other pressing domestic concerns delayed action until the 1950s. The scientific community pleaded for more extensive study of the lake and the impacts of the proposed drainage, but difficult working conditions and political instability impeded their efforts. The drainage plans went forward in 1951 and were completed in 1958 (Dimentman, Bromley, and Por, 1992).

Public and scientific concern prompted the government to set aside a portion (3.1 square kilometers) of the Huleh swamp and lake as the Huleh Nature Reserve, which was formally established in 1964 (Ashkenazi and Yom-Tov, 1997). The actual area that remained as a wetland following the drainage turned out to be significantly smaller than had been planned because of unanticipated drainage, evapotranspirational losses, and seasonal drying. In addition, the water that fed the reserve was primarily the effluent from neighboring fish farms. This water contained high levels of nitrogen and suspended organic matter that promoted eutrophication (the proliferation of algae and associated decreased oxygenation). Settling ponds were incorporated in the 1970s to improve the quality of the water entering the reserve (Dimentman, Bromley, and Por, 1992).

In retrospect, the drainage project was a limited success. The incidence of malaria was reduced, and more water was made available for human use. Initially the land was fertile, but soil subsidence and erosion led to diminished productivity within a few years (ibid.). In addition, decomposition of the peat soils in the Huleh lakebed released large amounts of nitrates and sulfates, which were washed by the rains into Lake Kinneret, leading to eutroph-ication and reduced water quality in that lake.

The Hula Restoration Project, overseen by a scientific advisory committee, was initiated in the 1980s. Rather than trying to achieve the impossible goal of restoring Lake Huleh to its pristine state, the committee formulated a plan to create a carefully engineered system of wetlands, lake, and agricultural areas. The plan aimed to restore wildlife habitat, control erosion, maintain the security of the water supply, provide alternative income for displaced farmers, and create ecotourism-oriented economic opportunities. The original course of the Jordan River was reopened, and a new, smaller lake, named Lake Agmon, was established in 1994.

Although it was hoped that many native plant and animal species would gradually recol-onize the area by migration from adjoining remnants of the native habitat, intentional reintroductions were also performed. Migrating birds and other wildlife were attracted to the area by the re-established plant community. Nesting colonies of some bird species have been established. Following the draining of Lake Huleh, many birds discovered the commercial fishponds as an alternate source of food, causing extensive economic losses for farmers. To reduce this problem with the newly increased bird population, natural fish populations are being supplemented by artificial stocking (Zohary and Hambright, 2001).

The main water source for the new lake is the relatively pure water of the Jordan River, but the nitrogen and other nutrients that con tinue to be leached from the peat have contributed to the growth of plant matter that provides the basis for the food chain in the lake. In the drainage canals, however, the dense stands of plant growth impede water movement and make it more difficult to manage the water table elevation. The stagnant water in these canals may encourage the return of malaria-transmitting mosquitoes.

The results of the hurriedly conducted surveys of the 1950s, which attempted to document the biota of Lake Huleh, were not collated and published for more than forty years. Using these data, Dimentman, Bromley, and Por (1992) compiled a list of more than 100 species that have not been recorded in the Huleh valley since the drainage. Some of these species have never again been recorded anywhere in Israel. Several species that were endemic to Lake Huleh are now extinct. The Palestinian painted frog, not reported since 1955, was one of the inhabitants of Lake Huleh that did not survive to populate Lake Agmon (Werner, 1988).

—Julie Pomerantz

See also: Amphibians; Draining of Wetlands; Interior Wetlands; Lakes

Bibliography

Ashkenazi, S., and Y. Yom-Tov. 1997. "The Breeding Biology of the Black-crowned Night Heron (Nycti-corax nycticorax) and the Little Egret (Egretta garzetta) at the Huleh Nature Reserve, Israel." Journal of Zoology, London. 242:623-641; Dimentman, Ch., H. J. Bromley, and F. D. Por. 1992. Lake Hula: Reconstruction of the Fauna and Hydrobiology of a Lost Lake. Jerusalem: Keterpress; Mendelssohn, Heinrich, and Henry Steinitz. 1943. "A New Frog from Palestine." Copeia 1943:231-233; Werner, Y. L. 1988. "Her-petofaunal Survey of Israel (1950-1985), with Comments on Sinai and Jordan and on Zoogeographic Heterogeneity." In The Zoogeography of Israel, edited by Y. Yom-Tov and E. Tchernov. 355-388. Dordrecht: Dr. W. Junk; Zohary, T., and K. D. Ham-bright. 2001. "Lake Hula—Lake Agmon," http://www.israel-mfa.gov.il/mfa/home.asp (accessed April 4, 2001).

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