THREATS TO AN ISLAND'S HERPETOFAUNA


The Maltese archipelago situated almost in the centre of the Mediterranean Sea consists of three main islands and a number of associated islets together occupying not more than 200 sq.kilometres. With a population of more than 300,000 it is understandable that man has had a great influence on the natural environment with a subsequent decrease in the animal populations.This alarming decline in animal life now includes not only the birds and mammals but also amphibians and reptiles, creatures whichhave hitherto received little attention by the general public and whose proper study is difficult because of their retiring habits.

The herpetofauna of the Maltese Islands is not very rich, consisting only of ten terrestrial species. Of these only seven can definitely be said to form part of our natural fauna. These include the endemic Maltese Wall Lizard of which there are a number of subspecies endemic to the various islets. The rest, like the Chameleon and the Algerian Whip Snake, have been imported by man, the former directly and the latter indirectly by continual trade contact during the First World War. These two species have now become naturalized. The origin of the Cat Snake recorded from Maltais still obscure since its apparent localization in the NE part of Malta may be simple a feature of its shy nocturnal nature. To the list of Maltese herpetofauna may be added four species of marine turtles which have been reported from time to time around Maltese shores.

The population of each species has been markedly decreased due to a variable number of factors all centred on human influence.

HABITAT DESTRUCTION
In the forefront of those factors which have been influential indecreasing species population number is habitat destruction. Withan average population density of one per 700 sq. meters it is expected that advances in society are paralleled by destruction of natural habitat. The expanding building programme together with road-laying has in Malta decreased significantly the natural areas to small pockets. The few remaining natural areas are all in dire peril. Wetlands have been developed to suit mans requirements altering the natural ecology of the area. The gradual disappearance of wetland habitat in the Maltese Islands has decreased the spawning grounds of the only amphibian on the islands, the Painted Frog.

The decrease of spawning grounds for the frog is also a by-productof the continuous drive towards exploitation of fresh water. Rainfall run-off and fresh water streams are now being channelled through man-made waterways into reservoirs, again contributing towards a decrease in natural fresh water pools and ponds with a continuous or intermittent supply of water. Man-made reservoirs open to the environment may be considered as serving as an alternate site for spawning. However, it must be remembered that unless the topography or chemistry of this man-made pond is suited for the species, the animal wanders off in search of a more suitable habitat and perhaps perishes in an unnatural environment.The idea of breeding goldfish in these reservoirs is also a factor against these man-made ponds ever serving as alternate spawning grounds for the frog.

LOSSES DUE TO ROAD TRAFFIC
The building of houses is slowly followed by the laying down of roads and footpaths. Frequent use of these roads and footpaths by humans is detrimental to the reptile population of the area. Reptiles, particularly lizards, require an optimum temperature for their biology. The frequent interruptions while the lizards are sunning themselves would prevent the animals from attaining this temperature and thus serve to make that habitat unsuitable. Road traffic may also be a factor in directly decreasing the populations, particularly of slow moving animals by their being rundown while crossing roads.

MALTESE ECONOMY
Two items of importance in Maltese economy are tourism and agriculture. Both have contributed towards decreasing the reptile population of the Islands. The constant drive to promote tourism coupled with the easy accessibility of sandy beaches by the development of roads has led to a crowding of beaches in the summer months by tourists and inhabitants. These now oft frequented beaches cannot conceivably serve as egg-laying sites for the Loggerhead Turtle as they used to in the past. This coupled with the capture of this animal for food and for its ornamental shell has helped decrease the Loggerhead Turtle population in the Mediterranean.

The agriculture industry has also contributed towards decreasing the reptilian population, not so much because it contributes towards decreasing natural habita as through the use of pesticides and herbicides. These chemicals particularly the organochlorine and organophosphorus compunds may directly or unselectively through the food chain, harm all animal species living in the affected area. Unfortunately, precise quantitative data from field experiments on the effect of biocides is still lacking.

INTRODUCTION OF EXOTIC ANIMAL SPECIES
Various reptilian and amphibian species have been introduced in the past, however only those noted previously have become naturalized, fitting very well in the ecological setup of the Maltese environment. At present the species which are being introduced include land and freshwater tortoises which exert very little effect on the native species. However, as noted earlier, the introduction of goldfish in man-made or natural ponds constitutesa serious threat to the frog population. Pets, particularly cats,also constitute an added predator to those animals attempting to live in the altered and unsuitable environment created by man.

CAPTURE AND TRADE
It has already been noted that the Loggerhead Turtle is exploited as an item of food and for its shell which is used as an ornament.If this is to be condemned, the capture of the Leatherback Turtleis to be deplored even more. This animal is occasionally encountered by Maltese fishermen who then try their best to prove their superiority over large animals by capturing this turtle. They are often at a loss at what to do with the remains. Their efforts reflect the suffering of frogs at the hand of children who blow theanimals up to enormous sizes with football pumps.

The capture of individual animals for purposes of temporary observation or study does not effect a stable population, particularly if a school furthers conservational ends by doing so. However the capture of individual Chameleons whose population is far from stable constitutes a definite hazard to this species, particularly since captured specimens often end up dead after a few months. The same may be said of the uncontrolled capture of frogs and tadpoles by children and others, the animals often ending upbeing killed or starved to death.

An aspect of trade which in the past served as a detriment to the Ocellated Skink was the belief that the oil extract from this animal had medicinal properties. Children used to capture this reptile to sell it to pharmacists and doctors who prepared the required extract.

LOSSES DUE TO HUMAN PREJUDICE
Since earlier times reptiles and amphibians were commonly regarded as undesirable animals and there is no lack of examples to show that these lower vertebrates fall mass victims to human prejudice. Even today direct persecution at the hands of man seems to be on every definite reason for the diminishing numbers of all reptile species particularly the snakes. Throughout the world snakes have long been associated with superstitions and folklore and this is not lacking in Malta. The advent of St Paul in Malta in the first century A.D. and his supposed miracle of remaining unharmed after being bitten by a snake has led to a variety of folk beliefs. An unassociated belief regarding snakes is that these animals may enter a baby's mouth to get at the mother's milk. Though the latter belief is not prevalent, it made the headlines in a local newspaper a few years ago. The two species of gecko have suffered direct persecution particularly in the past since they were at one time associated with leprosy and other skin disease.

Conservation of Maltese amphibian and reptilian species must start with education. The introduction of units on Maltese natural life into the civics and biology curricula of schools would do much to eliminate the mystery and ignorance regarding our few local species.

The amphibian and reptilian species have now been declared to be protected by the Environment Protection Act, 1991 (Act No. V of 1991) and the Reptiles (Protection) Regulation, 1992. This legal notice makes it an offence punishable by a fine, the capture, killing or trading of any member of the herpetofaunal species. These enactments will have an eventual desirable effect of limiting the threats afforded to the local herpetofauna.