28 wild asses were released into Israel’s Negev from a captive herd between 1982 and 1987, according to a 2018 study in Conservation Biology . Another ten were released in 1992 and 1993. Few animals vanish from a desert and then find their way back. The Asiatic wild ass did, with human help. But a growing herd is not always a healthy one.
Since then, the herd has grown, which sounds like a clear win.
The comeback began with a small herd that survived in the Shah of Iran’s zoo. The captive group did well. Shirli Bar David of Ben-Gurion University recognized the parallel to Templeton’s work with collared lizards in Missouri. Numbers are as important as genes. Genetic data were collected non-invasively, and computer modeling was used. This number tells us how fast a group loses genetic diversity by chance. Among the factors the team examined, uneven mating had the strongest effect on how fast the herd loses genetic diversity. The authors call the low number a concern, even though the herd keeps growing.
In 1968, animals from that herd were brought to the Hai-Bar Yotvata Reserve in Israel and bred there. Both species were reintroduced beginning in the early 1980s from small founding populations: 29 lizards and, eventually, 38 wild asses. A 2015 study in Molecular Ecology examined the mating habits of asses. It found that fewer than 25% of males participate in mating each generation. The 2018 Conservation Biology study then measured the herd’s effective population size. The result was 24.3, far below the herd’s total population .
The same article says blood tests showed very high genetic diversity.
