Investigating aerohaline plant distribution on northern and southern coastal locations

Abstract

The purpose of this dissertation is to assess the difference in the distribution of vegetation between the northern and southern coastal locations of Malta. This study also aims at identifying any differences in vegetation within these locations which result from the composition of the substratum of these areas – namely whether the substratum is composed of Globigerina Limestone or Lower Coralline Limestone. The process applied to carry out this assessment involved the line transect methodology, which entails measuring line transects within each area being studied and recording the flora species located within these transects. This study involved the measuring of three line transects at each location being investigated, namely Marsaskala, Kalkara, Birżebbuġa, and Ħal Far. The line transect distance applied in this study was that of 30 metres, starting from the point closest to the coastline where vegetation occurs. A distance of 5 metres was allowed between each transect in the same location. These line transects were used to identify the type of flora species that occurred over the measured distance. Following, the extent of coverage of each of the identified flora species was measured. Upon investigation of the data collected from the four locations which were studied, a number of observations were made. Firstly, it was evident that the data collected from Birżebbuġa and Ħal Far, both sites occurring on the southern coastal location, showed a higher floral coverage and biodiversity of flora species than Marsaskala and Kalkara, which occur on the northern coastal location. Moreover, it emerged that the sites composed of Lower Coralline Limestone substratum, which comprised Ħal Far and Kalkara, showed a higher floral coverage and biodiversity than the sites which were located on a Globigerina Limestone substratum, which were Marsaskala and Birżebbuġa. The outcome of this study suggests that the levels of biodiversity and floral coverage are affected by the altitude of the point where the vegetation occurs. In particular, sites which had a higher altitude also had higher levels of floral coverage and biodiversity when compared to sites with lower altitudes. Moreover, the type of soil found on the sites also appears to have an effect on the vegetation in the area. Distinctly, the Terra Rossa soil which is found in sites composed of a Lower Coralline Limestone substratum was identified to be one of the main reasons for a higher biodiversity and floral coverage levels witnessed in these sites. A final conclusion derived from the gathered results was that disturbed grounds, such as the site investigated in Marsaskala, also impact the level of vegetation occurring in the area. Such disturbed grounds appeared to impact more heavily the level of floral coverage within the site than the level of biodiversity. Indeed, the levels of floral coverage recorded in this site were shown to be abnormally higher than those of sites which demonstrated a lower extent of human intervention.