HA’ARETZ (Tel Aviv, Israel) 10 January 07 Humans burrow too deep into lizards' turf (Zafrir Rinat)
For millennia the Egyptian mastigure (uromastyx aegyptius), a large and impressive lizard indigenous to Israel, has lived in peace and security in burrows about nine meters (29 feet) long, which it digs and even bequeaths to its offspring. The mastigure, however, is no match for humankind, which is spreading into the lizard's territory and causing significant drops in the species' population. To combat the trend, the Israel Nature and National Parks Protection Authority (INNPPA) has recently undertaken preventative measures to save the lizard population and its habitat.
A population study conducted near Idan, a moshav semi-cooperative farming community in the northern Arava desert, revealed that over the past 20 years there has been a 60-percent decline in the number of actively used mastigure burrows. The study, completed recently by INNPPA, found that the main causes for fewer burrows were the expansion of land cultivation and other human activities such as all-terrain vehicle traffic.
The researchers, ecologist Dror Hawlena and INNPPA rangers Harel Ben Shahar and Einav Vidan, identified the active and inactive burrows by brushing away any lizard tracks at entrances to burrows, and returning a few days later to see if there were fresh tracks.
The study's results clearly show a declining number of active burrows in the area near agricultural land, and an increasing number farther away. The lizards are harmed not only by the cultivation of the land, but also by the hunting activities of Thai workers and by the introduction of such animals as dogs, which chase away the lizards.
"There is a danger of the total collapse of the population," says Hawlena. "When one family of mastigures is destroyed, another moves into the burrows, and they are harmed, too."
INNPPA personnel have recently undertaken to save these lizards, by luring them out of burrows in areas designated for agriculture and transferring them to abandoned burrows in safer areas. Getting a mastigure out of its burrow is no easy task; when it feels threatened, the lizard inhales extra air to puff up its body and wedges itself into its home.
Hawlena feels that in addition to transferring some lizards to safer places, the habitats of other lizards must be preserved via a land exchange. Under Hawlena's proposal, farmers would be given alternative lands from nature reserves that have no burrows or other animals, and the agricultural areas containing active burrows will be declared nature reserves.
One of the most surprising findings of the INNPPA study was the indirect effects of ATVs. Until now, INNPPA rangers had thought that the main damage caused by nature tourists was the destruction of the burrows by the vehicles. It turns out, however, that the worst damage is caused by driving past burrow openings, leaving deep tracks. With heavy rainfall, the tire tracks become channels that drain the water into the burrows, flooding them and killing the lizards.
Some lizards have even dug new burrows in the ATV tracks, as the vehicle's passage makes the ground easier for digging.
"This exposes the lizards to fatal flooding later on," explains Hawlena.
Humans burrow too deep into lizards' turf