Ecosystems undergo ecological succession, which refers to the natural process of change over time brought about by progressive replacement of one plant (or animal) community with another in response to changes in environmental conditions. This process starts off with the pioneer community and eventually leads to the development of a stable mature community, referred to as the climax community. The process of succession can halt in a pre-climax stage when some factor is limiting, such as when the organism needed to bring about the necessary changes that lead to the creation of the following community, is absent. Limiting factors may also be abiotic (non-living), such as lack of water.
Succession can be of two types. Primary succession begins with the colonisation, by pioneer species (such as mosses and lichens) of barren substrate (rock, sand or soil), which has never supported any vegetation. On the other hand, secondary succession occurs in areas where natural vegetation has been disturbed or destroyed. The latter type is generally less species rich.
Maquis (Maltese: Makkja)
Maquis is the stage following that of garrigue in the ecological succession, and consists mostly of an evergreen shrub community, where shrubs reach a height ranging from 1-3m Frequently, this is the climax stage.
Local maquis is characterised by small trees and large shrubs such as the Carob (Scientific: Ceratonia siliqua; Maltese: Ħarruba), the Olive (Scientific: Olea europaea; Maltese: Żebbuġa), the Lentisk (Scientific: Pistacia lentiscus; Maltese: Deru), the Wild Fig (Scientific: Ficus carica; Maltese: Siġra tat-Tin), the Wild Almond (Scientific: Amygdalus communis; Maltese: Siġra tal-Lewż), as well as the Bay Laurel (Scientific: Laurus nobilis; Maltese: Randa). In order to be able to support such trees, there must be enough water and soil depth for the maquis to develop. Maquis occurs in a semi-natural state at the sides of steep valleys and rdum, which are inaccessible to man. Various subtypes of maquis occur, some of which, such as those based upon the Myrtle (Scientific: Myrtus communis; Maltese: Riħan), and the National Tree of Malta, the Sandarac Gum Tree (Scientific: Tetraclinis articulata; Maltese: Siġra ta' l-Għargħar), are very rare and threatened.
This habitat type is also rich in plants namely climbers including the Ivy (Scientific: Hedera helix; Maltese: Liedna), the Common Smilax (Scientific: Smilax aspera; Maltese: Pajżana), the Spiny Asparagus (Scientific: Asparagus aphyllus; Maltese: Sprag Xewwieki) and the Wild Madder (Scientific: Rubia peregrina; Maltese: Robbja Salvaġġa), as well as large herbaceous species like the Bear's Breeches (Scientific: Acanthus mollis; Maltese: Ħannewija) and the Italian Lords-and-Ladies (Scientific: Arum italicum; Maltese: Garni).