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A Biologists view on the wildlife habitats of Skopelos

Directing the winds of change
A Biologists view on the wildlife habitats of Skopelos

The Mediterranean region contains some of the most intensely damaged environments on our planet. Skopelos has managed to avoid much of this destruction, but the pace of change seems to be accelerating.

There is potential damage to wild life habitats on Skopelos that is easily recognised and may be resisted by co-ordinated action. Unfortunately there is also damage – potentially greater damage – that can be caused by the unwary and uninformed actions of those who love the island and would fight for its conservation. All types of danger must be understood.

Much of Skopelos is formed from Dolomite – calcium and magnesium carbonate sediments lain down in the shallow seas of the upper Triassic period, and converted into limestone over many millions of years. Later sediments have largely weathered away although there are still some Cretaceous limestones and other more recent rocks exposed. Two major mountain building episodes have shaped the island. The first caused great folds of the earth’s crust to be thrust over the south-east part of the island (Palouki nappe), and the second folds of deep sea sediments over the north end (Glossa nappe). The vast tectonic forces involved converted the sedimentary rocks in and around these regions into metamorphic schists, marbles and phyllites. The central Dolomite is now mostly covered with pine forest whilst the metamorphic regions are coated with maquis (vegetation no taller than 5-7 metres) and garrique (vegetation no taller than 1 meter). These latter are semi-natural habitats, composed of herbs, evergreen shrubs and spiny plants that have largely evolved through the fuel requirements of man and the food requirements of his goats.

The composition of the original forest on these islands is difficult to deduce after thousands of years of mans activities. Classical authors give interesting descriptions but names are based on the use as timber so that a type of tree may have a different name depending on the straightness of its trunk. Nevertheless there is general agreement that the dominant trees were probably pine and oaks so that the current allepo (Pinus halepensis) pine forests provide an echo of the past that has perhaps survived largely because of ship building. Forest and maquis are generalised habitats that we may encroach upon but probably will not destroy. The most fragile and important environments are the wetlands and springs, which may be ruined by a single thoughtless action.

There are few remaining wetlands on Skopelos. The most recent loss seems to have been the reed bed on the harbour beach. This was an excellent little habitat that was cleared to leave a patch of useless wet sand. The most important is undoubtedly the reed beds at Milia, which were saved from destruction but are now accumulating rubbish. One mans fragile ecosystem remnant is another mans wasted beach area, but we cannot argue for conservation if our own actions are equally – though innocently – destructive. The introduction of a vigorous alien plant, insect or animal into a wet land or spring could cause as much environmental damage as a mechanical digger.

A pond at Ditropon provides a useful example of introduced creatures. This contains a population of Greek Marsh frogs (Rana balcanica) and a few adult Balkan terrapins (Mauremys rivulata). The frogs belong in the pond but the terrapins were rescued and introduced when an area of wetland was filled in. This was a good idea, but amongst the Balkan terrapins is an American Red-eared terrapin. Red-eared terrapins are popular pets, but they cease to be so attractive as they grow larger. It might seem to be a good idea to release them where they can live amongst friends but they are more vigorous breeders than the European terrapins and easily displace these indigenous species. This is not a problem at Ditropon because there is only one Red-eared terrapin and the Balkan terrapins are not a breeding population. A handful of unwanted pets released into he breeding colony in the Milia reed beds, however, would probably exterminate the Skopelos population of these terrapins. The introduction of alien species, accidentally, via the pet trade, or perhaps a packet of seeds because of a desire to grow the plants that grew at home, has caused massive environmental damage around the world.

An unexpected variation on this is the belief that rare indigenous creatures must be escaped pets and can be captured. This has occurred with the Greek Tortoise (Testudo marginata). A small population still survives in the Stafilos valley and it’s numbers should not be depleted as pets.

Skopelos is an important island for natural history with delicate ecosystems that have not all been ruined by development and greed. It is possible for changes to occur side-by-side with conservation, but we must learn the significance of habitats that remain so that informed decisions can be made. We have a responsibility to understand the wildlife and its requirements on these islands so that as much as possible is retained for future generations.

Brian V. Ridout