Extinction of water plants in the Hula Valley: Evidence for climate change.

We describe two events of water plant extinction in the Hula Valley, northern Israel: the ancient, natural extinction of 3 out of 14 extinct species at Gesher Benot Ya'aqov, which occurred some 800-700 k.yr., and an anthropogenic, near contemporary extinction of seven species in the artificial drainage of the Hula Lake in the 1950s. We conclude that the considerable fraction of water plants that disappeared from the Hula Valley in the Early-Middle Pleistocene was the result of habitat desiccation and not global warming. Thus, there is evidence that the hominins who lived in the Hula Valley inhabited a comparatively dry place. The disappearance of water plant species was partially the result of reduced seed dispersal by birds (ornitochory) as a result of the shrinkage of water bodies and their number along the Rift Valley. We suggest that the disappearance of a group of rare, local water plants can be used as an indicator of climate drying and impacts on the local vegetation.