CHELONIANS IN JORDAN
Testudo Graeca Terrestris
Spur-thighed Mediterranean Tortoise
T. g. terrestris is characterized by a moderately domed carapace. In hatchlings and juveniles the shell is more flattened. The nuchal scute is narrow and increase in width posteriorly in 37 specimens of 42 examined. The cutting edge of the upper jaw is not concealed by fleshy lips. The superacaudal plate is undivided except in two specimens. The number of marginals ranges from 10 to 12, the mode being 11 (10,n = 4; 11,n=39; 12,n=5). The latero-posterior periphery of the carapace is bent clearly outwards in some specimens. The hind plastral lobe is rigid in juveniles. However, in mature females it is movable, but not in all males. The hind lobe is broadly notched posteriorly, especially in males. The tail lacks a spur and is shorter in females than in males. Males have slightly concave plastron. The dorsal surface of the forelimbs is covered with numerous heavy pointed scales, A spur is obvious on the thigh.
The carapace of adult specimens is yellowish or olive-green, with an irregular back blotch in the areola of each scute. The anterior and lateral periphery of each scute is tinged with varying shades of black. The plastron is olive-yellow with more or less yellow on the periphery, with or without black blotches of different sizes. The intensity of darkness seems to be correlated with the type of habitat. In areas with dense vegetation, the black colouration is intense, similarly in areas covered by black rocks as in Zarqa Ma’in.
The habitat of T. g. terrestis is highly variable. It was collected from open forested areas as well as sparsely vegetated areas, and from the Jordan Valley (300m below sea level) up to an elevation of 1,600 m above sea level.
T. g. terrestris is almost entirely herbivorous, utilizing fleshy leafed herbs mainly with preference to yellow flowers. In captivity they feed on green plants (lettuce, cabbage, cucumber), tomatoes and other vegetables.
Based on collected and observed specimens, it could be concluded that T. g. terrestris starts its activities in March with the highest peak in April and May with a second, lesser peak in September. The nadir of activity was observed in August, Beyond November, no specimens were collected or seen.
T. g. terrestris lays two to three clutches per season and the number of eggs clutch varies between 3-6 eggs in Jordan. This indicates that T. g. terrestris is characterized by a high reproductive potential.
T. g. terrestris divides its mature eggs at one time in two or three interrupted clutches, perhaps this egg laying behavior is related to minimizing the effect of predation on the nests or hatchlings. Indeed, having clutches laid at different nests will eventually reduce the risk of predation.
Threats in Jordan:
1. Rapid population growth and expansion:
During 50 Years the human population of Jordan has increase four times. With increased demands accompanying this growth (i. e. water consumption, waste products, etc.) the various ecological indicators show that natural habitat destruction is increasing. This rapid growth leads to expansion of cities and urban centers in order to accommodate the growing population. These processes had a negative impact on the limited habitats suitable for wildlife.
In Jordan, open forests are the main biotope harbouring Testudo graeca terrestris. But forests in Jordan are under heavy pressure from several negative aspects (cutting of trees to produce charcoal or to replace the forests by farms, fires, grazing and agricultural projects). Establishing new road systems through the natural habitats of T. g. terrestris is another major threat. On several occasions many tortoises were killed on roads by cars. Also, establishing tourist hotels and other projects in the natural habitats of tortoises may destroy the original habitat of T. g. terrestris.
It has a detrimental effect on tortoise populations. Sheep, goats and tortoises may compete for the same plant. Also, the composition of plant cover changes as a result of intensive grazing. This result in erosion of the upper fertile layer of soil, which may decrease the diversity of plant species and end in one plant species dominating. This happened in Jordan in the Irano-Turanian biotope where Anabasis articulate dominates the area and this plant is not utilized by tortoises. Also in overgrazed habitats the tortoises travel a long distance to find food, which may expose them to predation. This consideration is supported by the correlation between the colour of the tortoises and their habitat.
In Jordan there is heavy use of chemical fertilizers, insecticides and herbicides: more than 1,200 tons are used annually. There are more than 500 different kinds on the Jordan market which are freely available to farmers and almost without restriction of use. Moreover, farmers use wide-spectrum pesticides, different types of pesticides are mixed together, and sprayed in agricultural areas against crop pests. Natural habitats are close to agricultural areas, so the biodiversity of certain sensitive terrestrial groups may be affected. Pesticide run-off enters the River Jordan and the surface water may be contaminated by drift during aerial spray operations. Pesticides residues, especially organochlorines, are also able to enter food chains through bioconcentration in the terrestrial fauna. Agriculture has a negative impact on the natural habitat of T. g. terrestris, because it changes the substrates suitable for tortoises, changes their available shelter, and effects the disappearance of vegetation composition preferably utilized by them. It was reported that mechanical ploughing takes its toll of the tortoises. Also, soil mixing may interrupt egg incubation and cleared soils may expose them for predation, since there is no shelter to hide in. it was stated that the type and quantity of vegetation and aridity seem to be limiting factors of T. graeca growth. This notion is supported by high growth rates of tortoises raised in captivity.
5- Commercial exploitation:
Tortoise populations may affected by ground density, abundance of tortoise and by the age distribution in the population which may be distorted as a result of a tendency to capture desirable sizes. This is believed to be an important factor limiting the productivity of the population, especially if the main reproductive size. Class is removed. It may take a long time for the population to restore its balance, because of the time lag until the juveniles mature and are able to reproduce.
All species of chelonians in Jordan are in need of immediate protection. Further detailed studies on the ecology and population dynamic of tortoises are needed.