Vegetation along valley sides : an investigation of the transition from the urban-fringe to the valley base

Abstract

This dissertation focused on the change in type and abundance of macrophytes, as one proceeds from the plateaux overlooking a valley to the valley sides and valley bed. The plateaux often represent an urban fringe whilst the beds and sides may be less disturbed. This study tried to identify any factors that may have correlated with observed changes in the species richness and species abundance of the vegetation. This study involved sampling of vegetation in Wied Babu, Wied Anġlu, Wied Qirda and Wied Binġemma using walkthrough surveys belt transects. All transects were linear starting from the valley-urban fringe and ending right at the bed of the valley. Transects were established at different points in each valley, and data such as species, slope inclination and soil depth were recorded. Overall, 11 transects were sampled, in which 83 different species were recorded. Species richness and diversity were analysed and the changes observed were correlated with percentage cover, slope inclination and soil depth. A relationship between species diversity and slope inclination was discovered, and also between both species richness and species diversity with the distance away from the valley-urban fringe. All other correlations were statistically insignificant. Species diversity was also analyzed by categorising the species found according to the area they were found in. The results of the study suggested that there was a change in both species richness and diversity from the valley-urban fringe towards the valley bed. The large number of ruderal species found also suggested that anthropogenic disturbance was a major factor in creating the difference in vegetation communities found in the different parts of the valley.