Mapping the distribution of selected flora of scientific importance found on the northern coast of Malta : an exercise in species' vulnerability

Abstract

By the end of 2008, the Maltese Islands had 20.5 percent of their land area under a form of legal recognition and protection. Despite the introduction of such legal protection measures most of Malta’s biodiversity remains threatened. Consequently, 64% of Maltese habitats and 44% of Maltese species, listed in the Habitat Directive, are considered to have an unfavourable-conservation status. There is now a need to assess the vulnerability of plant species within protected areas and in the process determine the conservation status of species that are also not covered by said directive. The aim of this study was to map the distribution of 10 floral species and the respective assemblages that they form within the existing network of protected Natura 2000 sites. In the process their relation with the surrounding landscape was to be evaluated and their vulnerability deduced from observed criteria like conflicting land uses, identifiable threats and the extent of habitat fragmentation at the local and landscape level. The floral species that were mapped in this study were chosen to reflect the diversity of habitats that can be found within the northern coast of Malta. They were also picked because of their limited geographical distribution and their important ecological contribution to the Maltese natural environment. A total of 8 sites where chosen in correlation with designated Special Protected Areas and assessed by means of walk over surveys and spatial mapping. With the spatial data collected during fieldworks the relation of surveyed floral communities with surrounding land use/land cover could be depicted by means of digitized maps. Once this holistic view was achieved a proposal based on integrated landscape ecology was constructed to further improve upon the protected area approach undertaken in Malta for the protection of biodiversity. Overall it was found that almost half of the species surveyed in this study are restricted to very specific locations, with very limited linkage between populations. This level of fragmentation ultimately renders said species vulnerable to future isolated threats due to a decreased resilience of the meta-population as a whole. The remaining species exhibited varying distribution patterns throughout the protected areas, with greater connectivity for populations at the local and landscape level.