Several times each year, dozens of volunteers set out on designated trails around the country and search for butterflies as part of a national monitoring project designed to identify types of butterflies. To the chagrin of the volunteers and the researchers, this identification work has in recent months revealed that many species of butterflies are imperiled, and will face extinction in coming years.
Next week, Dr. Rahel Schwartz-Tzahor, a researcher at the Ramat Hanadiv nature park, will disclose recent findings of this national butterfly watching project at the annual conference of the Israel Society of Ecology and Environmental Sciences.
These findings will focus on the monitoring of 14 protected species today, out of 141 known butterfly types in Israel. The national monitoring project is the initiative of Israel's Association of Butterfly Lovers, and is supported by Ramat Hanadiv. "Up to the last years, we based our work on sightings of enthusiasts at various locales around the country," states Dovi Binyamini, who heads the association. "We are now engaged in an orderly monitoring project with guidelines that set out the trails or areas where butterfly watching is to take place."
Without financial resources, but with considerable knowledge and ingenuity, the butterfly watching project took flight three years ago.
Schwartz-Tzahor says that the project has some 40 volunteers, some of whom are scientists. "We never received authorization from any national agency that deals with nature protection, but we define this as a national project because it is being undertaken in all parts of the country, and we are the only ones who are doing this work," relates Schwartz-Tzahor. "In countries such as Britain, this work has gone on for thirty years. There, the monitoring work has indicated that global warming affects the distribution and diversity of butterflies. Animals and insects are measures of the state of the environment, and so it is very important to monitor how they are doing."
The close monitoring of protected butterfly species shows that some of them are in danger of extinction. "There are some types which are disappearing right before our eyes," says Binyamini. In many cases, the threat of extinction stems from harm down to vegetation and flora which serve as hosts for female butterflies' eggs. A female butterfly locates a host plant for its eggs via its sense of smell. It lays eggs on the host plant, and the plant becomes a source of food for the young insects that hatch from the eggs, until they become caterpillars and butterflies. In many areas, host plants have been damaged by livestock grazing or agricultural work involving the use of insecticides. In some areas, construction work damages the plants.
The dangers are illustrated by the case of the Melitaea arduinna, a strikingly beautiful butterfly which, the monitoring project has established, can be found solely in the Safed area today; in this solitary habitat, the Melitaea arduinna is endangered by plans to build a new neighborhood. Also, local cattle feed on the knapweed plant (Centaurea triumfettii ), which serves as the host plant for the melitaea arduinna.
South of the Safed region, in the Ramat Menashe area, another species of butterfly, Tomares nesimachus, survives tenuously. "We don't know why this type has mostly disappeared, but the problem is apparently connected to the disappearance of its host plant, the milk-vetch (Astragalus macrocarpus )," states Schwartz-Tzahor. One of the causes of the milk-vetch plant's disappearance is the construction of roads and neighborhoods that disrupt the continual flow of open spaces in which this butterfly host plant grows. "I see milk-vetch plants at Ramat Hanadiv, but I can't find butterflies around them," notes Schwartz-Tzahor.
At present, she adds, "we are trying to encourage the planting of milk-vetches on the sides of roads, in order to enlarge the number of butterflies. The Trans-Israel Highway Company has contributed to this effort, and planted milk-vetch plants near one of its exit ramps. In the Hermon region, another type of butterfly, the olive grizzled skipper, has been harmed by infrastructure development work and tourism. Bulldozer work caused severe harm to this butterfly's host plants, which are found exclusively in the Hermon region, claim workers in this butterfly monitoring project.
Another endangered butterfly is the Apharitis cilisae, which is found today only in two areas in Israel. In one area, close to Hadera, the butterfly is threatened by plans to build a residential neighborhood. Butterfly enthusiasts are hoping that the neighborhood will be built in a way that does not impair the Apharitis cilisae's natural habitat. A building company involved in the neighborhood's construction has agreed to set aside one area, partly for the protection of this butterfly.
Discussion of butterfly extinction is not idle talk. The Colotis chrysonome, a butterfly that lived in the Ein Gedi region, became extinct in the 1960s. Most of the types of trees that served as its host plant vanished as a result of agricultural work in the area. In recent years, the Israel Nature and Parks Authority has planted a grove of one such host plant, Maerua crassifolia, at the Ein Gedi reserve. Butterfly enthusiasts are hoping that this return of a host plant will spark a rebirth of the Colotis chrysonome at Ein Gedi, but so far this has not happened.