Diversity and conservation of the non-marine molluscs of the Maltese Islands

Abstract

The Maltese archipelago, occupying an area of c.316 km2 and situated in the central Mediterranean, consists of the inhabited islands of Malta and Gozo and a number of uninhabited islets and rocks. The islands are composed mainly of limestones of Oligo-Miocene age. Soils are young, show little horizon development, and are very similar to the parent rocks. There are no mountains, streams or lakes, but only minor springs. The main geomorphological features are karstic limestone plateaux, hillsides covered with clay taluses and gently rolling limestone plains. The southwest coast is mainly steep sea-cliffs and the land tilts gently seawards to the northeast. The islands are riven by valleys which drain runoff during the wet season. The average annual rainfall is c.530mm of which 85% falls during the period October to March. The mean monthly temperature range is 12-26oC. The flora and fauna are rich with c.2000 species of plants and more than 3000 species of animals recorded to date; a relatively large number of species are endemic. The main ecosystems are maquis, garigue and steppe. Minor ones include patches of woodland, coastal wetlands, sand dunes, freshwater and rupestral communities and those of caves. Human impact is significant. The islands have been inhabited since c.7000BP. The current resident population density is 1095 per km2. Some 38% of the land area is cultivated and c.15% is built up.