Concepts and Methodology

Concepts

The coastal zone of the Maltese Islands is colonised by a community of halophytic vegetation. Perennial members of this community are capable of tolerating the abiotic stresses associated with the coastal zone (saline soil, exposure to wind, sparse soil) through the use of specialised structures (succulent leaves, low profile, and efficient osmoregulation).

The specialised perennial community is frequently invaded by species less characteristic of this habitat: opportunistic annual generalists. Generalist species would not usually be capable of tolerating the characteristic abiotic stresses on a long-term basis, and therefore utilise a strategy of avoidance in order to survive.

Such plants would only grow in a vegetative state in winter and spring, when climatic conditions are less hostile, and survive as seeds in the seed bank throughout the dry season.

 


 

Moreover, such vegetation generally invades the community following disturbance which would have vacated habitat-space.

These two broad groups of species coexist within this community and therefore utilise common resources. One such resource is space, which, for the purposes of this investigation, is being defined as perpendicular distance from the shoreline. Colonisation at increasing perpendicular distance from the shoreline implies decreasing exposure to saline spray and wave action and increased access to deeper soil. Since the upper reaches of rocky shores are easily accessible to human activity, increasing perpendicular distance from the shoreline also implies increasing risks of anthropogenic disturbance (encroachment, traffic, dumping, species introduction etc.) >>next