The role of 'naturalness' and seral stage in the assessment and management of coastal sites

Abstract

Conservation and restoration of Mediterranean coastal habitats often requires rapid assessment of the ‘state of health’ of the environment. A potential solution to this issue may be represented by the implementation of a method for rapid assessment of the ‘naturalness’ of coastal areas. The degree of naturalness of a site is diagnosed by sampling and analysing the anthropogenicity of the ecosystem in the area, and, from its inverse interpretation, the naturalness grade that characterises the habitat may be deduced. We are suggesting that the principal criterion for defining values of naturalness in the upper part of the scale should be the position of a terrestrial plant community along a sere. Using species richness as a criterion for naturalness would probably not be suitable, as this value is fundamentally a statistic and does not give any information regarding the ‘state of health’ of the ecosystem. As such, the identity of the species, rather than their number would be a better indicator of naturalness. A natural habitat, one that has been undisturbed by human actions, would be characterized by a primary climax community. Disturbances (man-made and otherwise) would act to erode the integrity of the climax community and would introduce other species (usually opportunistic species) which would occupy disturbed patches and coexist with the climax vegetation. A disturbance of very large magnitude would revert the succession to early seral stages which would subsequently proceed (if undisturbed) through a secondary succession, reaching a secondary climax. When actively managed sites were compared to unmanaged coastal areas in the Maltese islands, it was found that the former were statistically more likely to show a higher position in the seral stage of the vegetation community. This emphasizes the fact that some kinds of human disturbances do not reduce the naturalness value of a site. In fact, active management and conservation practices that entail a proper strategic plan should be considered. This allows managers to spatially and temporally determine the position of a plant community along a sere and would provide them with a rapid indication of how different types and intensities of negative human disturbance affect coastal vegetation.