Organisms, together with the environment they inhabit, constitute an ecosystem. Malta has a number of major ecosystems which are widespread, such as garigue, as well as minor ecosystems which are rare, like sand dunes and freshwater pools. Ecosystems can be classified according to their vegetation.

Malta´s vegetation, the nature of which is determined principally by the climate, the soil and the degree of disturbance, is typical of low-lying areas of the Mediterranean. The mild temperatures are not detrimental to the flora, but the lack of water has a marked negative impact. The plants growing in Malta are therefore adapted to endure a long dry season.

The most typical vegetation of the Mediterranean is dominated by hard-leaved evergreen trees and shrubs. Woodland , with trees such as Evergreen Oak and Aleppo Pine, is the climax of the vegetation series. In Malta this habitat was virtually exterminated following the arrival of humans on the islands. Only some remnants are still to be found in a few areas with small copses of Evergreen Oak. Some of these trees, still existing at Wardija, are possibly between 500 and 900 years old.

Buskett, the major part of which was planted by man, has now acquired the character of a semi-natural woodland, where the trees regenerate naturally. The dominant trees here are Aleppo Pine, together with Evergreen Oak, Olive and Carob. The smaller trees and shrubs include Lentisk, Mediterranean Buckthorn and Hawthorn, as well as a large number of other species. This is the only locality in Malta which represents a mature woodland ecosystem.



Another ecosystem is the maquis, characterised by small trees and large shrubs such as Carob, Olive, Lentisk and Bay Laurel, together with climbers which include Ivy, Smilax, Spiny Asparagus and Wild Madder, and a large herbaceous species like Bear´s Breeches and Lords-and-Ladies. Maquis is typically found on the sides and bottoms of the deeper valleys (widien), and at the base of cliff formations.

The garigue is an ecosystem which develops on large expanses of limestone bearing numerous depressions and fissures. Here one finds dense, low-growing shrubs, often aromatic, such as Mediterranean Thyme, Mediterranean Heath, Germander, White Hedge Nettle and Maltese Spurge. Several types of garigue exist, each characterised by different dominant plant species.

The widespread steppe is characterised by herbaceous plants, especially grasses (Poaceae), umbellifers (Apiaceae), legumes (Fabaceae) and tuberous or bulbous species like Squill and Asphodel.

The steppe is derived from maquis and garigue which have been degraded through various causes, including fire and grazing. Other types of steppe are encountered, including some natural ones formed through climatic factors. These include the rocky steppe ( a sort of shrubless garigue) and the clay slope steppe.

The cliffs, found mainly along the southern and western shores, harbour many species of flora and fauna. The plants growing here include various interesting species, among them some endemic forms (occurring in the Maltese Islands and nowhere else in the world).

Two of these are the Maltese Rock-centaury and the Maltese Cliff-orache, both belonging to monospecific genera.

In several coastal localities, one finds a number of shallow areas which fill up with water during the winter. Admixture with the salt found in the mud renders the water brackish, leading to the formation of saline marshlands. Evaporation during the dry season increases the salinity further and even causes them to dry up completely. In spite of the harshness of such conditions, certain species of plants and animals are restricted to these saline marshes. A short distance inland from the few sandy beaches, the last remaining sand dune systems struggle to survive against human interference. These too harbour specialised plants and animals.

Freshwater habitats are also scarce in Malta, especially during the summer months. In winter, water collects in small rock pools, and freshwater species live here, albeit for a limited time. A few freshwater pools and springs are also found in certain valleys, and these are enriched by a number of species, considered rare owing to the scarcity of these habitats.

In spite of the calcareous nature of Malta´s rocks, deep caves are not frequent. The few examples are home to some specialised organisms. The most well-known are bats, but there are other cave-dwelling species, especially invertebrates. Some are endemic and of great scientific interest.

One must also mention ecosystems which are found on disturbed ground. When one considers the high human population density, as well as the extensive land use, one can easily understand why these are widespread. Abandoned fields and countryside road verges fall into this category.