HA'ARETZ (Tel Aviv, Israel) 27 March 08 Salamanders travel far and wide between breeding sites (Zafrir Rinat)
Until recently, the common salamander, Salamandra salamandra, was considered loyal to his pool. However, according to a recent study on the Carmel by researchers at the University of Haifa, salamanders travel great distances between several pools. This means that if the territory that lies between the pools is damaged as a result of development and building in the area, the population could dwindle and the species could die out. The study will be published in The Israel Journal of Ecology and Evolution.
The Carmel range is the world's southernmost salamander habitat. The salamander belongs to the taxonomic class of Amphibia, cold-blooded, four-legged vertebrate animals that live on land and in water. Amphibia are in the greatest danger of extinction of any animal class. The salamander develops as a tadpole in pools, puddles and springs and at three months leaves the water source and lives in burrows and caves during dry seasons. Upon reaching sexual maturity at age 3 to 5, it returns to the water source to reproduce.
During 1999-2006, Dr. Shirli Bar-David and two other researchers, Uri Segev and Nir Peleg, spent 60 nights finding salamanders on paths and in a number of pools in the Carmel area. They captured mature salamanders, released them after documenting the idiosyncratic marks of each individual and identified the salamanders that were captured more than once.
According to the places they were captured, the researchers were able to estimate the distance the salamanders had traveled from the pools. Of the 72 salamanders captured the second time around, most were close to the pools where they had been captured the first time. In eight cases, salamanders had moved more than 400 meters from the site where they had been captured first - some even at a distance of more than a kilometer. In two cases, salamanders were captured at a different breeding site from the one where they had been captured initially.
These findings prove that salamanders are able to cover long distances and to move from one breeding site to another. The researchers believe that in this way they strengthen populations in neighboring breeding sites, and they call this "the rescue effect." "The study proves salamanders do not live in isolated groups in each pool but rather as 'supra-populations' that spread over a number of breeding sites among which there is a connection," says one of the participants in the study, Dr. Leon Blaustein.
The researchers note their estimates are conservative. In fact, apparently, there were many more instances of migration among the various breeding sites. According to a study Peleg conducted in the area, there are only small genetic differences between the salamanders from different pools, which testifies to a connection between the various areas.
Plans are in the works to expand Carmel agricultural lands, Usifiyeh and Daliat al Carmel and Haifa, and to pave more roads. The researchers argue that such development will damage the areas that link the breeding sites and could lead to the salamanders' extinction. One proof of the expected damage is that one of the salamanders that had been captured was later found after being run over on a road in the Carmel. Other salamanders were found injured in the area. The researchers are proposing not only preserving the pools but also the terrain that links them. Another means is to establish artificial pools at a suitable distance from existing pools. In this way, the possibilities for movement will be maintained even if the connection to natural pools is cut off because of the construction.
Salamanders travel far and wide between breeding sites