Comparative studies of lizard populations on small islands provide far reaching insigths into the evolution of genetic diversity as well as the history of the islands in focus (changes of sea level,land bridges).
The main aim during the two herpetological expeditions to the Northern Sporades Archipelago was a complete assessment of the distribution pattern and variation range of the lizard species Podarcis (=Lacerta) erhardii subspec., on the 48 islands which provided suitable habitats. As a rule, all islands that sustained the shrub Pistacia lentiscus were inhabited by the lizards. We found small populations only on a very few isles without the shelter of the evergreen Pistacia, e.g. on Strongylò off Skantzoura (cf. the article Strongylò – the living dead). Of particular interest was the territorial behaviour of male lizards on these very confined patches of inhabited land. Again the bushes of Pistacia designated the size and distribution of these territories. Cannibalism was observed at several occasions; it is seen as another behavioural adaptive consequence of the very confined living conditions on small islands.
The lizards on Piperi Island were described as a new subspecies, Potarcis erhardii weigandi.
Our survey included also the other reptiles of the Northern Sporades, green lizards (Lacerta trilineata), geckos, snakes and tortoises.
A selection of scientific papers which describe the results:
Gruber, U. und T. Schultze-Westrum. 1971. Zur Taxonomie und Ökologie der Cycladen-Eidechse (Lacera erhardii) von den Nördlichen Sporaden. Bonner Zoologische Beiträge.
Schultze-Westrum, T. und K. Buchholz.1964. Zur Kenntnis der Schlangenfauna der Nördlichen Sporaden. Zoologischer Anzeiger.
Beutler, A. und U. Gruber. 1977. Intraspecifische Untersuchungen an Cyrtodactylus kotschyi (Steindachner 1870). Reptilia: Gekkonidae. Spixiana – Zeitschrift für Zoologie.