Latest Trends in Engineering Mechanics, Structures, Engineering Geology Coastal vertical cliffs of the National Park of Cilento: reservoirs of endemic species ARONNE G.1*, DE MICCO V.1, SANTANGELO A.2,SANTANGELO N.3, SANTO A.4, BUONANNO M. 5 1Department of Agricultural and Food Sciences, University of Naples Federico II (UNINA), 2Department of Biology, UNINA; 3Department of Earth Sciences, Environment and Resources, UNINA; 4Department of Civil, Architectural and Environmental Engineering, UNINA; 5 Institute for Agricultural and Forest Systems in the Mediterranean, CNR-ISAFoM, *Via Università, 100, Portici, (NA), ITALY [email protected] Abstract: - Vertical cliffs are widely distributed, are characterized by peculiar environmental characteristics and are generally acclaimed for their flora rich of phylogenetic relicts and rare species. Many vertical cliffs occur along the coastline of the National Park of Cilento (Tyrrhenian coast of Southern Italy), an area highly affected by human impact. Using a multidisciplinary approach we aimed at verifying in this habitat the occurrence of a set of features repeatedly reported for vertical cliffs worldwide. The overall analysis of information available in literature and newly elaborated data showed that geological, geomorphological and structural features of coastal cliffs of Cilento and the number of endemic species, much higher than in the surrounding areas, are consistent with those reported for cliffs in other geographical region. Biological and ecological traits of one of the relict species, Primula palinuri Petagna, highlighted that not all the sites on the cliffs are equally suitable for life requirements of the species; moreover, long term survival of the populations is at risk due to large failure in generation turnover. Coastal cliffs of Cilento act as refuge of endemic species and deserve special concern for biodiversity conservation. Key-Words: - Vertical cliffs, cliff ecology, endemic species, Mediterranean species, Primula palinuri 1 Introduction access may be considered the main constrain limiting the amount of studies and experiments on High and very steep rock walls are generally the biotic communities of cliffs. However, referred to as cliffs or vertical cliffs [1]. Their inaccessibility is reported to have protected these extension is difficult to quantify on geographical ecosystems in historical time from direct and maps because vertical surfaces are not easily indirect impact of anthropogenic disturbances [2]. detected by aerial photographs. Nevertheless Cliffs are asserted ecological islands because vertical cliffs occur at any latitude and elevation in peculiar abiotic characteristics of their environments all geographical regions of the world. Their very are also associated to a distinct fauna and flora [1]. steep orientation affects physical factors such as Plants growing among rocks are generally defined incident radiation, wind speed and direction, amount as saxicolous; however, those living in narrow holes of direct precipitation, soil availability and water and crevices, often associated with vertical angle of retention. Specific studies on factors such as local slope, are classified as chasmophytes. Among many temperature, light, air humidity and underground others factors, chasmophytes have to deal with low water availability, showed that these environments availability of nutrients, very limited space for root are distinct from the nearby habitats and that development and scarce shelter sites for biotic seasonal fluctuations of the physical components are recruitment. often significantly more moderate on cliffs than on Despite environmental conditions are considered the surrounding level grounds [1]. harsh for plant growth, an amazing phenomenon has Despite they are commonly diffuse and provide a been reported for worldwide geographical regions: distinctive habitat, cliffs have been rarely the number of phylogenetic relicts and of rare investigated from an ecological view point. Difficult species is much higher on cliffs than in the flora of ISBN: 978-960-474-376-6 77 Latest Trends in Engineering Mechanics, Structures, Engineering Geology the surrounding areas [2-9]. Geographical isolation of them verified the presence of specific features and selective pressure towards evolution of adaptive generally reported as life strategies for cliff species features to peculiar conditions of cliffs, are basic or emphasized the co-occurrence of other relict considerations to explain the occurrence of species. numerous endemic species on cliffs all over the The aim of this work is to verify if the main world [1]. Richness of rare relict species is reported features reported for vertical cliff worldwide, occur also for cliffs of Eastern Mediterranean region [2]. also for the habitat of P. palinuri. Specific aims are: The phenomenon is considered as a result of both a) to analyse geological, geomorphological and environmental and anthropogenic pressure: in structural features of coastal cliffs of Cilento addition to past climatic changes, new supporting P. palinuri; b) to verify the richness in anthropogenic factors, such as fire, grazing and relict and endemic plant species of the same habitat; changes in land use, affected much less cliffs than c) to check if the life strategy of P. palinuri is in their surrounding areas because of their conformity with that of other cliff-hangers. To inaccessibility. Among them, grazing, especially by achieve these goals, we used a multidisciplinary goats, might have determined a selective pressure approach based on critical analyses of the available exterminating the plants living at the accessible sites literature as well as on new data elaboration. Results [2]. are discussed altogether in terms of biodiversity We have focused our scientific interest on cliffs conservation. of the Cilento’s shoreline that extends about 100 km along the Tyrrhenian coast of Southern Italy. Most of this area is within the boundaries of the National 2 Geomorphological, geological and Park of Cilento (Parco Nazionale del Cilento, Vallo structural features of coastal cliffs di Diano e Alburni, PNCVDA). This area attracts a large number of tourists, especially during the The distribution of P. palinuri along the Cilento summer, and is then affected by high anthropogenic coastline shows a lithological control (Fig. 1). impact. Despite the presence of coastal cliffs carved on Our work has been based on three main sandstone (Punta Licosa), on marl (Punta del considerations. Firstly, along the Cilento coast, Telegrafo) and carbonate rocks, all but one vertical cliffs and coastal slopes are frequent. populations live on carbonate cliffs. The only Studies on geomorphological, geological and exception is the population at Palinuro (Ficocelle) structural features of the Cilento coastline are that lives on pleistocenic cemented marine sands reported in the international literature [10, 11]. They and represents also the northern limit of the focus on geological phenomena, such as rock-falls geographical range of the species. and slides, and are aimed at identifying causes of All the others, as in the case of Capo Palinuro these phenomena and foreseen their future and Marina di Camerota coast, are on cliffs made up evolution. In these studies, environmental by Jurassic limestones and dolostones. As regards parameters are taken into account but there is no the origin and age of the carbonate cliffs, several mention of biological components. Secondly, studies have been carried out in the area establishing although several works have been done on the that the present day planar outline of the coast was Cilento’s flora [12-19], floristic knowledge of this defined at the end of middle Pleistocene (around area is still inadequate due to its naturalistic 300ka) [28-30]. In this period, the last climate complexity [20]. Regarding coastal cliffs, an oscillations determined both transgressions and exhaustive flora is not available. Thirdly, north- regressions of the coast line. During the facing vertical cliffs of a narrow area of the Cilento transgressions (OIS7 and 5), beach sediments, coast are habitat for Primula palinuri Petagna, a abrasion platforms and notches formed along the sea paleoendemic species, symbol of the National Park cliffs at elevations higher than the present sea level. of Cilento. It survives in a few sites between Capo During regressive phases (OIS6 and 3), the coastline Palinuro (Campania) and Capo Scalea (Calabria), a migrated seaward, and wider and thicker debris coastal area of about 80 km. P. palinuri is reported cones and talus formed at the base of the cliffs, as endangered in the Red List of threatened species testifying for cold and dry climate conditions which compiled by the International Union for the enhanced physical degradation of the cliffs. Conservation of Nature (IUCN) [21]. Several studies on the biology and ecology of this species are reported in literature [22-27]. Nevertheless, none ISBN: 978-960-474-376-6 78 Latest Trends in Engineering Mechanics, Structures, Engineering Geology Fig. 1. Geological sketch of Cilento coastline. Sandstones (orange), clayey-calcareous flysch (dark yellow), sandy beaches (yellow), carbonate rocks (violet). Geographical distribution of P. palinuri in the PNCVDA (red). (modified from Budetta et al. 2008) Two configurations of rocky coasts occur in the natural arch [31], deep bays and allows the geographical range of P. palinuri: a) vertical cliffs continuous evolution of the coastline. with sloping