The infralittoral marine biotopes of the Maltese islands : identification, characterisation, classification and conservation

Abstract

Some of the major requirements necessary for effective and long-lasting marine conservation include up-to-date knowledge and inventories ot the d1vers1ty ot the manne environments present, together with a framework in which to install and analyse existing and new data. The primary objective of this study was to provide such a framework by proposing a classification scheme for the marine biotopes of the infralittoral zone of Maltese territorial waters. Given the international use of .such classification schemes, throughout this study, great care was taken not to propose a classification scheme that was incompatible with (or replaces) the Class1!1ca1101J sc11eme 01 Ma1711o Habitat typos !Ot tho lfhdltotmno<111 Rog/on Thi:. mgion:il cl1:1s:.iflc:rition ;,c;t1r.rne, Is important because its primary aim 1s to serve as a common reference tor the establishment ot national inventories of marine and coastal natural sites of conservation interest. Although the use of this marine habitat classlflcatlon scheme Is mandatory for Malta, the Mediterranean Action Plan's Regional Activity Centre for Specially Protected Areas (RAC/SPA) acknowledges the fact that, by its very nature, the classification scheme takes into account the habitat types which are the most general case and that therefore the specifisities of each country must be dealt with at the national level. The classification scheme proposed here is therefore an extension of that already available for the Mediterranean region, focusing on local requirements. The marine biotope classification scheme proposed in this study consists of a hierarchically arranged framework with the 'biotope', (being the largest unit), at the uppermost level. Below the biotope level, the scheme is split into two major components; Environmental units, which essentially include abiotic factors and the biocoenotic units, which include the biotic features of biotopes. Substratum type and water depth wem identified ris heing the most important abiotic attributes and were given the rank of parameters, while all other abiotic attributes, (energy, turbidity, temperature, salinity and nutrient concentration), appeared to be of secondary importance for the local infralittoral and were given the rank of modifiers (of existing environmental conditions). Seven biocoenotic units were identified for this scheme. Each biocoenotic unit was further sub-divided into biocoenoseis/ecomorphoseis, which may in turn contain a number of associations and facies. The classification scheme proposed was applied in the field during benthic surveys carried out at a site that is currently a candidate marine protected area.