The little creatures have been found nowhere else in the world and show how their ancestors looked millions of years ago
Zafrir Rinat Apr. 16, 2021
A cave in central Israel boasts “living fossils” of species that went extinct millions of years ago, but scientists fear that invasive species and a plan to turn the area into a floodwater reservoir will do in the unique scorpions and crabs that dwell there.
Living fossils are species that resemble extinct species that are only known from fossils. At Ayalon Cave near Ramle, the researchers want to turn the site into a nature reserve as soon as possible.
The 2.7-kilometer-long (1.7-mile) cave sits in the middle of a quarry used by the company Nesher Israel Cement Enterprises. The cave and its species were discovered 15 years ago; since then, only researchers have been allowed in.
The previously unknown scorpions, crabs and other animals were found both inside and outside the cave, their ancestors having entered millions of years ago, before the Mediterranean Sea covered the region.
After the water receded around 7 million years ago, the animals remained “living fossils” that provide evidence of the region’s hot and damp climate at the time. Even earlier, related species entered the area of Lake Kinneret – the Sea of Galilee – and the Dead Sea, which were then connected to the Mediterranean. Similar but distant species have been found in springs along the shores of the Kinneret and near the Dead Sea.
Unlike most animals, which exploit the sun’s energy, the species in the cave gain energy from the site’s groundwater. The water contains sulfur compounds and creates a bed of bacteria that serve as food. A summary of the findings has been published in the journal Quaternary International by Amos Frumkin, Chanan Dimentman and Israel Naaman of the Hebrew University of Jerusalem.
The future of the animals in the cave is very much in doubt, Frumkin said. “We have documentation of the entrance of invasive species that weren’t in the cave before, including bats and a species of small crab,” he said.
“The original animals are disappearing. There’s also a plan to turn the area into a reservoir to control floodwaters … the water could very well contain pollutants that penetrate into the cave.”
Five years ago, Hebrew University experts recommended that the entire cave area be declared a nature reserve as soon as possible – a formal process to fully protect it.
Other recommendations included blocking the floodwaters, sealing the land above the cave and sealing its mouth with concrete to keep out invasive species. “It’s possible to consider other alternatives to deal with the floodwater to protect the site, which is unique by world standards,” Frumkin said.
The scientists say the process has taken too long, and when it’s completed, the unique animals might no longer exist.
The Israel Nature and Parks Authority is responsible for declaring the site a nature reserve. The authority said it the cave is being monitored to see if anything has changed since the last ecological survey there. “This is an important site and we will continue to act to declare it a nature reserve,” it said.