Zonation of macrophytic vegetation on rocky shores of the Maltese Islands

Abstract

The zonations of macrophytic vegetation present on the rocky shores of Għallis Point, iż-Żellieqa (Żonqor Point area) and Xatt l-Aħmar were studied in relation to abiotic factors, namely orientation and slope. These coasts were sampled using quadrats and belt transects. A total of three belt transects, which extended from the shoreline till the road, were analysed in each location. Quadrats placed near each transect and flipped three times to the right were also analysed. All the macrophytic vegetation present in the framed area was recorded in terms of the area occupied by each species. This resulted in a total of 68 species, which included annuals, perennials, and also biennials. The raw data, which was analysed and recorded into percentage coverage, produced biplots, which revealed the most significant species of each transect, convex hulls, which revealed species variations between transects, and weighted averaging graphs, which revealed the optimum distances of plants in each area. Results from this study show that Għallis Point was mostly dominated by Inula crithmoides in summer and Anthemis urvilleana in winter. On the other hand, Xatt l-Aħmar and iż-Żellieqa were mostly covered by Inula crithmoides in both seasons. This shows that Inula crithmoides is the most adaptable plant on rocky shores, since it grows nearer to the seashore and further inland. Abiotic factors are important in determining the types and quantities of species present in an area. In response to these abiotic factors, plants form zones. The general zonation scheme found in these locations showed that areas nearer the seashore were dominated by succulents and semi-succulents, the middle areas were mostly occupied by annuals, perennials, and a few succulents, while the rear parts of the areas contained species specially adapted to live in disturbed ground.