Sea cliffs and rocky coastlines 7
Transcription
Sea cliffs and rocky coastlines 7
I TA L I A N H A B I TAT S Sea cliffs and rocky coastlines 7 Italian habitats Italian Ministry of the Environment and Territory Protection / Ministero dell’Ambiente e della Tutela del Territorio Friuli Museum of Natural History / Museo Friulano di Storia Naturale · Comune di Udine I TA L I A N H A B I TAT S Scientific coordinators Alessandro Minelli · Sandro Ruffo · Fabio Stoch Editorial committee Aldo Cosentino · Alessandro La Posta · Carlo Morandini · Giuseppe Muscio "Sea cliffs and rocky coastlines · Life between cliffs and saltiness" edited by Alessandro Minelli Texts Carlo Nike Bianchi · Ferdinando Boero · Luigi Carobene · Giuseppe Carpaneto · Simonetta Fraschetti · Carla Morri · Simonetta Peccenini · Margherita Solari English translation Elena Calandruccio · Gabriel Walton Illustrations Roberto Zanella Graphic design Furio Colman Photographs Archive of Circolo Speleologico e Idrologico Friulano 83, 138 · Archive of Unione Speleologica Bolognese (photo: E. Altara) 102 · Roberto Argano 73 · Claudio Aristarchi 33, 35/3, 37/2, 40/1, 43, 46, 49, 53, 58/3 · Mauro Arzillo 91, 94, 97, 98, 101/2 · Paolo Audisio 71, 146 · Flavio Bacchia 104, 115, 124, 126, 132/2, 149 · Pietro Baccino 34, 35/1, 37/1, 37/3, 38/1, 38/3, 39/3, 40/2, 40/3, 44/1, 44/2, 45/1, 45/2, 47/1, 48/1, 48/3, 48/4, 50, 62, 67/2 · Giuseppina Barberis 41/2, 47/2, 58/1, 58/2 · Enrico Benussi 84, 85 · Carlo Nike Bianchi and Carla Morri 109, 111, 112, 116, 118, 119/1, 119/2, 119/3, 120/1, 120/2, 120/3, 121, 123, 125, 130/1, 130/4, 132/1, 133/1 · Ferdinando Boero and Simonetta Fraschetti 106, 113, 117, 119/4, 120/4, 127, 128, 130/2, 130/3, 132/3, 132/4, 133/2 · Eugenio Busetto 59, 63, 64, 65 · Luigi Carobene 7,10, 11/1, 11/2, 12, 27, 28, 29, 69, 108, 141 · Giuseppe Carpaneto 79, 80, 81 · Fabio Conti (Archive of Centro Ricerche Floristiche dell’Appennino) 35/2, 48/6 · Adalberto D’Andrea 30, 54 · Domingo D’Avenia 42 · Paolo Fabbro 68, 147 · Tiziano Fiorenza 78, 87, 93, 96 · Gianluca Governatori 60 · Luca Lapini 82, 86, 101/1 · Daniele Macale 88, 89/1 · Ugo Mellone 6, 9, 22, 32, 137, 142, 144, 145 · Luigi Minuto 41/1· Giuseppe Muscio 20, 75/2, 134, 148 · Francesco Orsino 36, 45/3, 48/2, 51, 67/1 · Paolo Paolucci 100/2, 101/1 · Roberto Parodi 90, 99 · Simonetta Peccenini 52 · Paola Sergo 136 · Daniela Tinti (Archive of Centro Ricerche Floristiche dell’Appennino) 38/2, 39/1, 39/2, 47/3, 48/5, 56, 57, 66 · Paolo Utmar 70 · Augusto Vigna Taglianti 72, 75/1, 76, 77/1, 77/2, 77/3, 89/2, 92, 95 Sea cliffs and rocky coastlines Life between cliffs and saltiness ©2004 Museo Friulano di Storia Naturale, Udine, Italy All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form, or by any means, without the prior permission in writing of the publishers. ISBN 88 88192 15 8 ISSN 1724-6539 Cover photo: vertical layers of sandstone, path to Cinque Terre, Liguria (photo by L. Carobene) M I N I S T E R O D E L L’ A M B I E N T E E D E L L A T U T E L A D E L T E R R I T O R I O M U S E O F R I U L A N O D I S T O R I A N AT U R A L E · C O M U N E D I U D I N E Italian habitats Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Carlo Nike Bianchi · Ferdinando Boero · Luigi Carobene · Giuseppe Carpaneto · Simonetta Fraschetti · Carla Morri · Simonetta Peccenini Morphology, processes and dynamics. . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Luigi Carobene 1 Caves and karstic phenomena 2 Springs and spring watercourses 3 Woodlands of the Po Plain 4 Sand dunes and beaches 5 Mountain streams Terrestrial flora and vegetation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Simonetta Peccenini Terrestrial fauna . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 Giuseppe Carpaneto Submerged communities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 Carlo Nike Bianchi · Ferdinando Boero · Simonetta Fraschetti · Carla Morri 6 The Mediterranean maquis 7 Sea cliffs and rocky coastlines 8 Brackish coastal lakes 9 Mountain peat bogs 10 Realms of snow and ice Conservation and management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 Carlo Nike Bianchi · Ferdinando Boero · Luigi Carobene · Giuseppe Carpaneto · Simonetta Fraschetti · Carla Morri · Simonetta Peccenini Suggestions for teaching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141 Margherita Solari Select bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 11 Pools, ponds and marshland 12 Arid meadows 13 Rocky slopes and screes 14 High-altitude lakes 15 Beech forests of the Apennines Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153 Index of species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154 Introduction C. NIKE BIANCHI · FERDINANDO BOERO · LUIGI CAROBENE · GIUSEPPE CARPANETO · SIMONETTA FRASCHETTI · CARLA MORRI · SIMONETTA PECCENINI A coastline more than 7450 km long surrounds Italy, the Mediterranean outlining the familiar “boot” slanting on the pale blue background on maps and satellite photographs. From Ventimiglia near France to Trieste in the east, through the Strait of Messina and Santa Maria di Leuca, almost all the regions of the Italian peninsula have coastal access, as, of course, do its large and small islands. Coastlines on maps usually have two different colours, some are green and others brown, in lighter or darker shades. Green corresponds to low, flat, generally sandy shores, shades of brown identify high, usually rocky Irregular morphology of limestone coast in Cirella (Calabria): these sharp, spiky forms are coasts. These two types have differing due partly to karstism, partly to the action of ecological, geological, historical and sea water economic importance. This volume treats only rocky coastlines which, as we shall see, are very different in both geological and vegetational terms, as well as in the use to which humans put them. High coastlines are produced by lengthy interactions between water masses (here we consider only sea water) and rocky blocks (islands or continents). Both masses move: the former undergo long-term variations in level (e.g., glacio-eustatic oscillations) and short-term ones (tides, swell, seiche, seaquakes); the latter may slowly slide upwards in tectonically active areas; move occasionally (bradyseism) in volcanic areas; jerk suddenly for more than one metre in seismic areas; or the entire coast, even its submerged part, may slowly rise in areas of isostatic adjustment, etc. (see table “Changes in shoreline position”, page 11). Inlet along a rocky coast in Salento (Apulia) 7 8 These interactions underlie the morphogenesis of high coasts and also interact with exogenous processes, independent of marine ones. In Italy, high, rocky coastlines prevail over low, sandy or gravelly ones, and are therefore very important in determining coastal environments. Their origin may be traced back to the Holocene rise of the sea after the most recent glaciation. However, many high coasts date back to previous high sea levels during interglacial periods or, as in lowering (or submersion) coasts, to morphologies of continental origin. Glacio-eustatic oscillations cause marine moulding of high coasts during interglacial periods and subaerial moulding (therefore not marine) during glaciations. It may also be inferred that climatic variations play a fundamental role in the creation and evolution of high rocky coasts, causing alternating marine and continental erosion, acting in different ways. When examining high coasts, we must always take into account that their present condition is the product of lengthy evolution (thousands or even hundreds of thousands of years), so that a simple correlation between visible aspects and the processes now operating would be misleading. High coasts often have cliffs plunging into the sea, sometimes vertically. They may be active or inactive. The coastal dynamics giving rise to the formation of cliffs is complex - the result of many causes which produce movements of the Earth’s crust and water, and to the large number of processes (both marine and subaerial) which take place. These, in turn, are influenced by a series of factors (lithology, rock structure, local geodynamics, physical characteristics of water, etc.), which contribute to the production of different results according to area. It is difficult to find two high coasts with similar morphology and biological habitats. The main morphological situations in Italy will be described later: highgradient cliffs receding suddenly or gently; steep flanks covered with vegetation; seabeds which may be deep, or feature large, shallow erosion platforms; high shores protected from direct sea action by deposits of debris, landslides, strips of beach, etc.. In each one of these are differing animal and plant populations, both under and above water. In subaerial environments, the steeper the cliff, the more difficult it is for plants to colonize the area. Cliff vegetation is highly specialized, and species with particular soil and climatic requirements are absent. Hard, submerged seabeds, i.e., the continuation of rocky land, host the most spectacular subterranean seascapes. 9 Rocky coastline of island of Marettimo (Sicily) This is why most Protected Marine Areas are near high, rocky coasts. On land, organisms attached to the substrate are almost exclusively plants, mushrooms and lichen. But submerged rocks are covered by highly differing animal and plant communities. The erosive action of waves is often enhanced by perforating organisms, or may be mitigated by the protective effect of bioconstructors, organisms which create calcareous bodies. Coral limestone is the most important product of bio-constructive phenomena along Italian shores. The flora and fauna which colonize these borderline environments, dominated by lack of productive soil, high saltiness, and both sea and wind erosion, are poor and more or less specialized. Land and sea communities are always closely associated, and energy continually flows between these two bordering habitats. Abiotic factors, like wind and waves, and biotic ones such as the activity of seabirds and other organisms, provide a constant exchange of organic matter between land and sea. Morphology, processes and dynamics LUIGI CAROBENE High coastlines are treated here very simply, without any further classification, although the topic is very complex. It is essential to bear in mind that the study of high coasts implies analysis of coastal surfaces (flanks, cliffs, seabeds), i.e., erosion surfaces which developed over time as the consequence of events of regional and global importance related to tectonics, eustatism and climate. High coasts are therefore unstable and changeable features of the landscape, characterized by a great variety of aspects. Let us thus begin our study of high shores with their morphological characteristics, their dynamic ones, which control their development, and the evolution of cliffs over time. CHANGES IN SHORELINE POSITION COASTAL HINTERLAND C O A S TA L HINTERLAND MOVEMENTS OF THE SEA SURFACE MOVEMENTS OF THE EARTH’S SURFACE Fast (local scale) earthquakes bradysism landslides Slow (regional scale) subsidence tectonics isostasy High cliff on island of Palmaria (Portovenere, Liguria) Short-term tides waves storms Long-term eustatism (of various kinds) variations in geoid’s shape SEA 11 ■ Types of high coasts 12 13 High coasts have a large number of characteristics which do not depend only on the main geological features of the formations constituting inland areas and the climatic and meteo-marine aspects of the area, but also on many other factors. The main morphological aspects which describe emerging surfaces (flanks, scarps or cliffs) are: gradient, height, shape, and regularity of surfaces. Main emerging morphologies. High coasts may be divided into three main morphologies: coastal flanks, flank-cliffs and cliffs. Coastal flanks. These are sloping COASTAL FLANK flanks, up to hundreds of metres high, the gradient of which is less than 45°. They are covered with debris and the products of weathered substrates, and are usually carpeted with vegetation. Although the steepness of Processes: subaerial processes (weathering, flanks depends on the geo-technical erosion, etc.) affect foot of cliff more than marine ones characteristics of rocks, weathering is Morphologies: high, steep flanks covered by also very important. These shores are debris, weathering products and vegetation typical of tropical regions, where the warm-humid climate contributes to intense chemical alteration. Here, powerful weathering of rocks hinders the formation of steep cliffs, and produces large quantities of debris which, through various means (solifluction, landslides) may fall to the foot of the flanks, thus contrasting the erosive action of waves. ● Flank-cliffs. Shores vary in profile, i.e., the upper portion is called a flank and the lower one a cliff. These two sections are separated by clearly different gradients. Flanks were formed by mainly subaerial processes of weathering and erosion, which produced great quantities of debris and lowered the flank gradient after the Holocene rise in sea level, which caused erosion of ● High limestone cliffs, plunging into deep water, slowly retreat, mainly due to external forces; the sea’s action at the base of the cliff is strong (Capo Caccia, Sardinia) FLANK-CLIFF Processes: strong subaerial processes along flank; at cliff foot, action of sea prevails and gives rise to platforms Morphologies: flanks covered by debris and vegetation; cliffs with fast-receding rock 14 the flank base. These coasts are typical of areas where periglacial activity was intense and moulded the flanks during glaciations; later, in interglacial periods, the flanks were covered with vegetation, and high eustatic levels gave rise to the formation and recession of cliffs. also due to latitude, which influences the height of waves: at high latitudes, ice may protect shores in certain periods of the year. Generally speaking, maximum removal of base debris occurs in temperate areas, and is minimum in tropical and polar regions. Cliffs. These steep rocky flanks CLIFF show the powerful action of the sea at their base (drawing c, page 15). They are subvertical, sometimes even overhanging, rocky walls of heights varying between a few to hundreds of metres (e.g., lava cliffs in Tenerife). Cliffs cut deposits of any origin, from Processes: subaerial and marine on cliff, with semi-incoherent (coastal deposits, powerful sea action at foot alluvial cones, etc.), to extremely hard, Morphologies: rock walls at angles of more compact rocks (granite, limestone, than 45°, steep, subvertial, overhanging; variable retreat, according to lithology and etc.). This influences the velocity of water depth their recession but also their shape, verticality and height. Verticality is not a constant characteristic of cliffs, because intense exogenous action may lower their gradient. Cliffs are therefore “free surfaces” without debris produced by weathering, but if gradients are not too high, debris remains on the surface and vegetation may grow. The formation and recession of cliffs are due to the indirect action of the sea, as waves have an effect only at the cliff base. In actual fact, the evolution of cliffs is mainly caused by rock falls and the erosion by exogenous agents. The recession velocity of cliffs is extremely variable, between a few millimetres to tens of centimetres a year, but it may even exceed one metre: in the former case, cliffs are stable and marine and subaerial processes are weak; in the latter, cliffs are unstable, so that marine and subaerial erosive phenomena are very severe. The extent of erosive effects largely depends on local factors, such as the type of rock, its structure and exposure to waves. Active cliffs owe their condition to the ongoing capacity of waves to remove the debris accumulating at their base. This supply-removal balance depends on climatic variations, tectonics, and variations in sea level. If removal is greater than supply, cliffs remain the same and even recede; if the opposite occurs, alluvial cones are deposited and beaches form at the base of cliffs, thus lowering their gradient. Differences are Main submerged morphologies. High rocky coasts occur in two typical morphologies, cliffs and shore platforms opposite, although along some coasts cliffs may rise from deep seabeds and are thus called plunging cliffs. Shore platforms are subhorizontal surfaces entering the sea (slope less than 3°), tens or even hundreds of metres wide. They have various names: shore platforms, underwater platforms, abrasion or erosion platforms, cut by waves, storm platforms, etc.. Here we use the terms “marine” or “shore” platforms. They are divided into Type A and Type B platforms. ● Type A platforms gently slope into the sea and join the base of cliffs at high tide level. They are formed by the continual regression of cliffs, and their width and gradient depend on the velocity of shore recession and thus on the erosion resistance of cliffs and wave energy. These platforms may be tens of metres deep off the coast. ● a MSL h b MSL h c MSL h According to geographical position, geological composition of coastline, and meteo-marine and climatic characteristics, high rocky coasts have different morphologies: a. cliff-platforms type A b. cliff-platforms type B c. immerging cliffs in deep water Type B platforms have two levels: an upper high tide level, and a lower level under the low tide mark. The two surfaces are separated by a step a few metres high; the high-tide surface is sub-horizontal. Although the formation of the upper surface is mainly due to subaerial weathering, there may be other factors at stake, such as differences in height between high and low tides. ● 15 16 1. High coasts without cliffs, protected Processes: flanks undergoing subaerial modelling, unstable, with falling debris at foot - scarce removal of debris by waves - shores protected from waves Morphologies: landslide deposit, human interventions (banks, roads, reclaimed land) 2. High coasts without cliffs, unprotected Processes: evolving flanks, unstable, subjected to landslides, with little vegetation - removal of fallen debris by waves and currents near shoreline Morphologies: detrital seabeds - possible narrow, unstable beaches 3. Active cliffs, platforms, breakers Processes: strong waves which produce conspicuous recession of cliffs Interactions between subaerial and marine processes. These are divided as follows: High coasts without cliffs. High shores with flanks of varying steepness but without cliffs at their base have two different aspects. - the former type (1) is subjected to intense subaerial flank moulding. This produces large quantities of accumulated debris at the flank base. Wave action is unable to remove these deposits completely and, over time, beaches of varying width develop, protecting the flanks from the direct action of the sea and making them stable. Human interventions, such as beach defences, protected sea fronts, etc., may produce the same effects. - In the latter type of shore (2), debris produced by subaerial processes and falling into the sea is completely removed by waves. The sea therefore erodes the base and flanks become unstable and active, i.e., a dynamic balance arises between flank evolution and removal of debris by waves and shore currents. ● Morphologies: unstable, subvertical cliffs and sea platforms (shallow water) Processes: transport and sedimentation of debris along shores - subaerial modelling of cliffs High coasts with cliffs. The erosion/sedimentation balance along coasts influences the evolution of cliffs greatly, causing various situations, the most important of which are shown (3, 4, 5, 6). - The first case (3) describes maximum erosion (see following paragraph), whereby waves break because of deep seabeds, giving rise to maximum erosion at the cliff base. This makes cliffs recede quickly, particularly if the rock is poorly coherent and soft. Most debris is removed by waves, and abrasion platforms and unstable, subvertical cliffs develop. - In the second case (4), seabeds are deeper and waves do not break, but reach the rocky cliff and are reflected. Erosion and production of debris are reduced, and cliffs are therefore active but recede slowly, especially if their rock is hard and compact. - In the third case (5), the shore has large amounts of debris, produced both by erosion of flanks and by shore current transport. Small deposits of debris may form and give rise to narrow beaches. The cliffs are partially protected and are only eroded by strong sea-storms, so that they recede gradually. - In the fourth case (6), the amount of debris transported by shore currents, rivers or flanks is such that large, stable beaches are formed, protecting the cliffs from the force of waves. They become stable, i.e., inactive. Morphologies: inactive cliffs - stable beaches - deep water ● ● 4. Slightly active cliffs, reflected waves Processes: little erosion of cliffs Morphologies: high, stable cliffs - deep water 5. Protected cliffs, beaches, poor sedimentation Processes: limited sedimentation along coasts - occasional erosion of cliffs Morphologies: limited recession of cliffs - narrow, unstable beaches - deep water 6. Inactive cliffs, stable beaches, intense sedimentation High coasts with inherited morphology. Analysis of high coasts shows both present processes and the effects they have produced in time. However, the 17 18 High coasts with continental flanks Processes: flanks undergo subaerial modelling -sea action at foot Morphologies: these coasts often have plunging cliffs in deep water without littoral platforms Sinking coastline High coasts with flanks of marine origin Processes: flanks undergo subaerial modelling -sea action at foot Morphologies: old marine terraces outcropping along coast -present receding cliffs -formation of littoral platforms Uprising coastline shapes and deposits of coastlines often have ancient causes. In this case, it is essential to reconstruct the geological history of the region to determine the succession of past events and gain a clear understanding of the present-day coastal dynamics. There are many possibilities, two of which are shown in the figure. - Above: shores are submerged by concomitant tectonic lowering of the coastline and a rise in sea level. Submersion coasts develop, which have inherited flanks of continental origin (e.g., rias and coasts of Dalmatian type). However, the two movements may be relative, not absolute. In northern regions which were covered by ice during the most recent glaciation, the glacio-eustatic rise in sea level (about 100-120 m) formed the well-known fjords, which are valleys previously filled with tongues of ice. In this case, the coasts too underwent an isostatic rise, which was, however, smaller than the eustatic one. - Below: the rise in the coastline is greater than the eustatic rise and therefore coastlines have inherited flanks of marine origin. Along Italian shores, where tectonic and isostatic processes have produced rises of about 0.5-1 mm/year, the coasts may have several tiers of marine terraces up to hundreds of metres above the present sea level, which are now moulded by subaerial processes. ■ Coastal processes 19 Coastal morphogenesis derives from a series of actions produced by water masses which move for various causes and in different ways. Analysis of waves is particularly important, as they are certainly the main morphogenetic agent. Waves can transform energy accumulated offshore which is sufficient to destroy high coasts, but they also carry and accumulate rocky debris (see chart below). Only the causes which produce movements of water are discussed here. Masses of moving water are the agents, which are identified according to their type of movement. Moving water has kinetic energy which is expended to carry out processes, i.e., work, which in turn depends on the water mass and its velocity and duration in time. Direct and indirect actions performed by agents are processes; they are influenced by factors which modify them according to place and time, resulting in differing effects. The erosive process is highly important in the evolution of high coasts, and occurs in various ways (see chart below). Waves, currents and tides produce results, i.e., the shapes and deposits which characterize both high and low coasts. They, in turn, are influenced by other factors, among which of particular importance are the transgressive and regressive phenomena caused by eustatism, and vertical movements of the coast due to tectonics, isostasy, and diagenetic and volcanic processes. CAUSES pressure gradient thermal gradient salt gradient gravity earthquakes These provide potential energy to the system, causing enormous masses of water to move Moving water mass: waves currents tides tsunami The agent may be quantitatively described with typical parameters AGENTS PROCESSES erosion transport sedimentation RESULTS Erosion: high coasts, sea platforms rocks, faraglioni, arches grooves, grottoes corrosion forms These produce coastal morphogenesis through direct and indirect action. They are controlled by a series of factors.1 Erosion occurs in different ways. 2 Sedimentation: beaches, bars, barrier spits, pendent terraces, storm deposits These make up forms and deposits which characterize both high and low coasts. They are controlled by a series of factors. 3 1. Geographical features of basin, orientation and contour of coasts, climate, presence of terrestrial or marine glaciers, anthropic works, river debris, role of organisms, geological features of rock. 2. Abrasion, mechanical erosion, cavitation, leaching, bio-erosion, marine corrosion. 3. Eustatic oscillations, Quaternary tectonics and dynamics, volcanic activity, subaerial exogenous processes 20 Types of erosive sea action Luigi Carobene Abrasion. Mechanical erosion caused by mutual collision or friction of pieces of rocky debris against each other or between debris and substrate rock (rasping effect). This causes the smoothing of hard rock surfaces (e.g., limestone). Abrasion is similar to corrasion caused by moving water in rivers and winds in deserts. Mechanical erosion by waves. Caused by physical actions in general, and particularly by the collisional power of waves against cliffs and in shallow water. This causes the rock to break and chip, followed by excavation and removal of debris, understood as removal of rocky fragments produced by the collision of waves. It is similar to the quarrying action (block erosion) caused by tongues of ice. Cavitation. Phenomenon whereby air bubbles (water vapour) formed by wave turbulence (where waves break) implode (collapse) due to increased pressure deriving from the collision of waves against rocky walls. Water bubbles (cavities) dissolve rapidly and noisily, producing mechanical effects. Leaching. Action of water against soft rock (e.g., limestone, gypsum), leading to production of ions. Bio-erosion. Biochemical or biomechanical actions directly or indirectly caused by living organisms. In the intertidal zone, bivalves, gastropods, limpets, barnacles, algae, sponges, worms, sea urchins, etc. contribute to rock erosion, by means The sea cliff on the top of which Vieste (Gargano, Apulia) is built of boring (e.g., date mussels), scraping, uprooting and crumbling. Marine corrosion. Series of mainly chemical actions which produce progressive weathering of rock surfaces and debris (solution, hydrolysis, hydration, carbonation, oxidation). Here, rock weathering is favoured by alternating phases of wetting and drying associated with tides or storms (direct action). Weathering is also caused by windblown water splashing against high areas of cliffs. Corrosion therefore occurs both in intertidal zones, and in higher areas which are not splashed by waves directly. Here, salty spray may cause salt weathering of the cliff flank, weathering in general and, in cold climates, even congelifraction (mechanical action). The transformation of waves. When waves reach shallow water, i.e., when their half-length exceeds their depth, they become deformed: their height and steepness increase, and their length and speed decrease, but they maintain their period. At a certain depth, called breaking depth, they break, and their crests roll forward. Waves which oscillated in deep water now become translational, and the water mass “works” both on the sea bed and against cliff walls. Only when waves exceed a certain height (critical value) do they have erosive effects. The figure below shows the important role played by the depth of seabeds in transforming waves approaching cliffs. The splashing of waves against the sea bottom produces the important phenomenon called diffraction. If coastlines are irregular, waves tend to concentrate their power on protruding sections (promontories) which they erode, and deposit debris, which supplies beaches in indented areas such as bays and inlets. ● r d r d r Reflection of waves on flank in deep seabeds. Flanks undergo hydrostatic pressure variations, not shock pressure. Energy is mostly transmitted to reflected waves. There is little erosion of seabeds and flanks. Symbols: d = crest of direct wave; r = crest of reflected wave; dotted line: shape of wave when two waves overlap. Depth is such that it produces intense wave deformation and breakers roll forwards against flanks. Maximum shock pressure. Energy is expended on weathering of rocks and turbulence. Maximum erosion at cliff foot. Shallow water causes breakers to form offshore. Most energy is expended before reaching cliff foot. Maximum seabed abrasion. Different effects of waves against a vertical rock wall, at varying depths 21 ■ Cliff dynamics 22 23 The flanks and cliffs of high coasts change over time, sometimes slowly and continually, at others intermittently or quickly. It is therefore necessary to speak of the mean speed of these transformations, which is calculated in the long term (generally more than 50 years). These mean values, which are now calculated by analysing topographic and bathymetric maps and by comparing photographs taken over the years, tend to change with the changing climate, as shown by palaeo-climatological studies. In addition, also the breaker zone - the point at which waves strike the shore – changes over time, due to upward tectonic movements on emerging coasts and to glacio-eustatic oscillations in sea level, i.e., shoreline changes (see chart below). These factors determine cliff dynamics. only subaerial processes: weathering, pedogenesis, flow, river ravinement, solifluction, etc. cliff edge action of exogenous agents supply of debris RECENT AND PRESENT ANCIENT AND PRESENT Cliff dynamics FLANK CLIFF recession indirect marine action indirect marine action at cliff foot TECTONICS PRESENT EUSTATISM debris removal foot of cliff SEABED High coast near San Cesareo (Salento, Apulia) The present contour of high coasts is due to the various groups of processes shown in the figure. These processes occur over time in different ways, and with varying intensity and effects, according to climatic changes. -Flank, cliff and seabed are the three main forms of coastal profiles; they change continually over time. -Tectonics and eustatism produce “changes in shoreline position” (see chart, page 11). -Variations in the ratio supply/removal of debris changes erosion at cliff foot over time. Processes affecting cliffs are shown in the figure “Cliff modelling” (page 24). 24 CLIFF MODELLING subaerial processes: weathering decalcification exfoliation wind abrasion runoff ravinement falls AGENTS PROCESSES RESULTS Cliff evolution. Analysis of cliffs has led to the identification of three evolutionary stages in their development: active, inactive, and fossil cliffs (see figures on this page). Active cliffs are exposed to attack by subaerial and marine processes, and therefore they continually recede over time, supplying the sea with debris. Their steepness shows the homogeneity of their rocks and variations in relations between subaerial and marine erosion. 1. Active subaerial and marine processes platform formation ● taphons: alveolar cavities caused by wind unstable zone due to erosion at foot cliff recedes (due to falls, overturning, sliding, landslides) wetting weathering salt weathering WI ND waves breaking towards shore salty spray erosion abrasion corrosion leaching bio-erosion compression cavitation grooves hollows grottoes Inactive cliffs have bases covered with and therefore protected by flank debris (scree, alluvial cones, landslides), and therefore are not subjected to marine erosion. Their steepness tends to decrease and their peaks round off. This is due both to the lowering of sea level and to the advance of the shoreline caused by large deposits of rock and soil. 2. Inactive stable abandoned subaerial modelling begins gradient decreases ● salty aerosol receding debris and alluvial cones lowering of sea level 3. Ancient fossil, degraded palaeo-cliff modelling of cliffs and flanks alluvial cones BREAKING WAVE hydraulic, mechanical, chemical action water vapor bubbles water bubbles suspended debris debris deposited at foot of cliff due to collapse transport of rocks: shorewards offshore along coast CURRENTS weathering of granules dragged along seabed abrasion of rocky seabed Fossil cliffs are no longer subjected debris flows to any form of marine process (e.g., due to tectonic rises or eustatic emersion of area lowering), and are therefore eroded and moulded by subaerial processes. Watercourses flow through them and deposit alluvial cones at their base. ● The main factors which control these stages are vertical tectonic movements, eustatism, climatic variations, and, locally, human activities. Cliff stability. Cliff dynamics often cause instability and hazard. It is therefore necessary to describe what is involved, the actual possibility of collapses and rock falls, and what can be done to avoid danger. 25 26 The figure below shows a very simple situation: a cliff of height H between the surface of a flank and that of the seabed. Taking into account some geometric parameters (angles, depth, height), the geotechnical parameters of the rocky mass and wave characteristics, we identify cliff stability by means of two indexes: stability (s) and breaking (lb). If ls = about 1, the cliff is unstable; recession is quick and landslides are a likely hazard. If ls = about 0, the cliff is stable; recession is very slow, and hazardous situations are unlikely. If we consider the breaking index, cases are: lb = 1, which corresponds to maximum wave pressure on cliffs, implying erosion, cavitation, absence of beaches, and formation of shore platforms. lb > 1 corresponds to little or no mechanical erosion. Waves are reflected on cliffs, which are subjected to hydrostatic pressure only. If lb = 0, the cliff is protected. However, in reality situations may be very complex and different, and may involve not only cliffs, but also flank-cliffs and flanks. These require specialized geological research on the following: - Structure of the rock behind the cliff, up to perhaps hundreds of metres or a few kilometres; - Quaternary tectonics; - Detailed stratigraphic analysis, to show stratification and lithological changes, particularly the overlap of rocks with differing deformability and erodibility; - The position of the surface separating the two bodies; - Analysis of rock weathering and permeability; - Evaluation of the state of vegetation cover and infiltration of water in the subsoil; - Morphological study to identify superficial breaks in the soil, which show rotational movements of the substrate or deep gravitational movements caused by the cutting of cliffs. D = depth of cliff foot Db = breaking depth H = cliff height FLANK β upper cliff edge CLIFF H features of rocky mass features of breaking waves D θ foot of cliff Db SEABED α Geotechnical and geometrical elements of a cliff: taking into account only the geometrical aspects of a cliff, the nature of waves and the characteristics of the rocky mass, cliff stability is defined by two indexes: stability (ls = H/Hc) and breaking (lb = D/Db). The rocky mass is composed of: c’ = cohesion; ϕ = angle of internal friction; γ = specific weight of rock. Breaking waves are characterized by: direction; offshore height Ho; offshore length Lo. Critical height Hc depends on rock parameters and cliff gradient. Present-day notch in Jurassic limestone at Maladroxia (Sardinia) 27 28 Erosion forms of cliffs and platforms Marine grooves. Horizontal cavities in cliff flanks at sea level. The shape of the cavity is generally asymmetrical; the base is often flat and the vault hyperbolic (see figure). The shape and dimensions of grooves depend on the type of cliff, rock, tide variations, wave energy, and debris suspended in water. Generally, grooves form on limestone cliffs, which sometimes contain “fossil” grooves, many metres above the present sea level, formed through leaching, bioerosion and abrasion. underground karstic cavities. The size and shape of grottoes depend on these characteristics, but also on variations in sea level. In this case, the development of cavities is heterogeneous and occurs over hundreds of thousands of years. Ancient sea levels inside limestone grottoes produced typical grooves due to boring action by date mussels. Grottoes, like grooves, are also frequently found in compact, resistant limestone, implying the importance of chemical processes and bio-erosion. Grottoes. Cavities sometimes characterizing cliff flanks, which were excavated by the sea in areas where the rock broke, near faults or soft rock layers. Grottoes may also be found where there are pre-existing Ramps. These are often found at the foot of receding cliffs. They slope towards the sea (a sort of slide) and link the cliff flank with the sloping surface of the platform in front. They are formed by the abrasive action of waves rich in debris (abrasion ramps). Natural arches. Passages formed by waves near rocky projections (small promontories) along high coasts. They form along particular erosion planes, such as layers or fractures. The erosive cavity acquires a more stable arched shape over time. Arches, particularly in soft rock, are ephemeral in coastal landscape. Stacks. Column-shaped rocks, isolated or in small groups, which are found along cliffs not far from the shore. They are relicts of part of the rocky coast which receded over time due to marine erosion. The genesis of faraglioni is favoured by faults and systems of fractures which, subjected to erosion, are then separated from the mainland. Grottoes, developing as a result of fractures in Mesozoic limestone (Sardinia) Rocks. Rocky masses which emerge for a few metres from the sea and are Luigi Carobene intensely degraded by waves and weathering. They may be rocky emersions, relicts of coastal recession, or fallen rocks not truly attached to the seabed. Bastions. Long, narrow ridges, a few metres above sea level, formed by the selective erosion of waves and arranged at the seaward limit of sea platforms. Their formation is favoured by resistant, sloping layers and fractures. As they rise parallel to the coast, they modify the action of waves and currents. Erosion kettles. These generally form on the surface of platforms and are due to the action of waves on pebbles trapped in the uneven seabed. The pebbles are continually moved and rounded by the waves and excavate circular cavities by means of abrasion. The shapes of kettles vary, and they may be up to 1-2 metres wide. Pools. Cavities a few centimetres or decimetres deep, and several dozens of centimetres wide, with a flat bottom which is larger than the opening. They widen by means of chemical and biochemical processes, favoured by water stagnation. Domed forms. Elevated forms with thin stalks supporting domed shapes. They may be some decimetres high. Domed shapes form in the intertidal belt of platforms. Pinnacles. These are rocky crests with irregular, sharp surfaces full of small cavities. They are formed by corrosion caused by salt splash and rain in the area above the high-tide mark. Limestone bored by date mussels (Sardinia) Pit (honeycomb). Small, hemispherical or spherical cavities, usually less than 1 cm across, typical of pinnacle and pool surfaces. Trottoirs. Narrow platforms sometimes found in intertidal zones, between shoreline and sea. They are divided into: 1) corrosion trottoirs - flat, horizontal surfaces at high-tide level, cut into the substrate surface and ending seawards with an intertidal organogenic shelf; 2) bio-constructed trottoirs - the flat upper surface of organogenic bodies (covered with vermetids, serpulids and calcareous algae), generally at low-tide level or at mean sea level. Sometimes centimetres of bioherm cover corrosion trottoirs. Organogenic frames may extend seawards for over one metre. 29 30 ■ Characteristic aspects of rocky coasts Rocky shores sometimes have peculiar eroded forms or deposits which are due to many coastal processes, the sea level and its variations, type of rock, the activity of certain organisms, cliff recession and climatic conditions. Major forms. The transition from platform to cliff is often marked (especially in carbonatic rock) by grooves, indicating a period of steady sea level; certain structural conditions give rise to gullies sometimes several metres deep, called sea grottoes. Relative variations in sea level may widen these grottoes, making them dozens of metres deep. Ramps, with slightly concave surfaces, may form between platforms and cliffs. In other cases, and in particular climatic conditions, the transition between cliff Natural arch at Capo Palinuro (Campania) and sea is marked by narrow subhorizontal surfaces (platforms, banks, ledges) of mainly organogenic origin. The area in front of cliffs may contain monolithic rocks (faraglioni), emerging rocks and arches, which highlight the dynamics of the coastal environment and particularly cliff recession. Shore platforms sometimes have rocky bastions on their seaward side. Minor forms due to karstic erosion. These are found along certain high coasts on carbonatic rocks (limestone, calcarenite, or cemented carbonatic sand). They are produced by the mechanical action of waves, but particularly by marine corrosion enhanced by alternating periods of emersion and submersion, besides stagnation of plant matter inside hollows in the rock. Maceration of organic matter acidifies water, favouring the solubility of calcium carbonate. Living organisms also contribute to erosion, as they burrow small hollows in the rocky walls. An important factor controlling and further developing these forms is climate. Research shows zoning of forms from the coast seawards with small pools, pinnacles with holes on cliff surfaces (a few metres high); hollows, niches dug out by organisms and small pools on cliffs; kettles and grooves at the cliff base, and domed surfaces and asymmetrically shaped pools on abrasion platforms. a b c d Some of the erosive forms found along coasts between high and low tide, or in the upper area which is affected by storms and salt spray. These forms may change according to position, tides, and type of rock. a. Corrosion pools (biochemical processes, with dissolved calcium carbonate due to stagnating water inside); b. Kettles (abrasion carried out by pebbles); c. Domed surfaces (abrasion by waves); d. Pinnacles (corrosion, bio-erosion, leaching) 31 Terrestrial flora and vegetation SIMONETTA PECCENINI ■ Living conditions The main limitation to the life of plants on cliffs and detrital coastal slopes, subjected as they are to the direct effects of the sea, is the high concentration of salt in the soil. Plants which can withstand or even prefer high salt concentrations are called halophilous. Their tissues often have cells rich in mucilage, which retains water. Other species, non-exclusive to Tyrrhenian cornflower (Centaurea aplolepa this environment, develop these ligustica) characteristics when they grow here. When Tyrrhenian knapweed (Centaurea aplolepa ligustica) colonizes rocks covered with salt, it turns into a kind of succulent plant: its leaves become thick and fleshy, its parenchyma swells with water, and the outer surface of its epidermis thickens. If there were no transition between these halophilous forms and those with normal structures, one might even think they were different species. Another factor which hinders life on rocks is the lack of substrate, which accumulates only in a few cracks. Here we find only chasmophytes, i.e., plants adapted to life in cliff cracks. Protracted exposure to sun and salt often determine arid conditions, and living species therefore feature xerophilous adaptations (from the Greek xeròs = dry, arid), such as small leaves covered with hairs or wax to limit transpiration. Substrates on detrital slopes are incoherent, and landslides often hinder vegetation. In these conditions, only species with robust root systems can survive. The distribution of vegetation also depends on weather phenomena, among which wind is one of the most important. The resulting vegetation is composed mainly of chamaephytes, i.e., small, woody, prostrate or pulvinate (cushion- Rocky coastline near Santa Cesarea (Salento, Apulia) 33 34 Sea fennel (Crithmum maritimum) shaped) plants which grow flat on rocks to maximize their resistance to the strong sea winds. The plant cover near the sea is therefore usually composed of species belonging to all these categories at the same time: halophilous chasmophytes, and xerophilous and pulvinate or prostrate chamaephytes. The species most resistant to saltiness, those which colonize areas nearest to the sea, creeping into cracks or consolidating landslide debris, are sea fennel (Crithmum maritimum), sea lavender (Limonium spp.) and a few other species; however, the greater the distance from the sea, the larger the number of species. ■ Flora Let us now list the most interesting or most frequent species found on Italian rocky shores. Among conifers are Aleppo pine (Pinus halepensis), with its light foliage and pale bark, cluster pine (Pinus pinaster), with hard needles, sharp cedar (Juniperus oxycedrus), with sharp needles and red berries, and Phoenician juniper (Juniperus phoenicea), its branches covered with small, imbricate, squamiform leaves. Camphor tree (Camphorosma monspeliaca), a small chamaephyte with a woody base, prostrate-ascending stalks bearing thin, linear leaves, and spikes with clusters of tiny flowers, may be also found inland, in sub-salty, silty areas. Caryophyllaceae are common on rocky coasts, e.g., Paronychia capitata, found in western Liguria and Sicily, and strong-rooted spurrey (Spergularia macrorhiza), endemic to cliffs in Sardinia and Corsica. Then there is campion with gaudy flowers: nodular campion (Silene nodulosa), with pinkish-white petals, is endemic to cliffs in Sardinia and Corsica; fruticose campion (Silene fruticosa), with pink flowers, lives on limestone cliffs in Sicily; hairless catchfly (Silene vulgaris ssp. angustifolia), a subspecies associated with cliffs and arid areas by the sea along all Italian coasts, has white flowers with a typical swollen calyx and fleshy, blue-green, opposite leaves; and sedum-leafed campion (Silene sedoides), an annual with tiny rosy-white flowers borne on reddened undeveloped stalks, lives in Tuscany, Apulia, Sicily and Sardinia. Cracks in coastal cliffs host the beautiful flowers of various species of wild pinks, e.g., Balbis pink (Dianthus balbisii) in Liguria and cliff pink (Dianthus rupicola) in southern Italy and Sicily. The latter species is a perennial with blue-green, sharp, coriaceous, fleshy leaves attached at the base and clusters of rosy flowers. This is a suffruticous chamaephyte which blossoms in summer and is found in Cilento, southern Calabria and Sicily; it is also a mesophilous and 35 Paronychia (Paronychia capitata) Sedum-leafed campion (Silene sedoides) Balbis pink (Dianthus balbisii) 36 Common caper (Capparis spinosa) thermophilous chasmophyte and lives, as its name suggests, on limestone cliffs and sometimes on old walls, such as those of the castle at Milazzo, on the northern Sicilian coast. The pinks commonly grown in the nursery hot-houses along the Ligurian Riviera seem to derive from cliff pink. Cliffs in Sardinia and on the tiny island of Lampedusa are the only places where Egyptian St. John’s wort (Hypericum aegypticum) grows - a small, woody, steno-Mediterranean shrub. Capers are very often found on old walls and limestone cliffs. Common caper (Capparis spinosa) lives throughout Italy, and hairy caper (Capparis ovata) is found in southern Italy, from Calabria to Gargano, and in Sicily. It is used as a savoury seasoning obtained from the buds or early fruit of these climbing shrubs. Caper flowers are white, very large and showy with many long stamens, blossoming in spring-summer. Its deciduous leaves are round with long stalks. There are also many crucifers. Hoary stock (Matthiola incana), a stenoMediterranean crucifer, with reddish-purple or white flowers, is found on all rocky cliffs throughout Italy, from Liguria to the Conero promontory. Malcolmia (Malcolmia flexuosa) lives only on the Tremiti islands. Lesser vesicaria (Alyssoides sinuata) and white alyssum (Alyssum leucadeum) which are grey, downy chamaephytes with large yellow flowers, are amphi-Adriatic species, i.e., they live on both shores of the Adriatic. They may also be found in Dalmatia, but in Italy the former colonizes only the limestone cliffs of Gargano and Murge, and the latter the areas around Otranto, Gallipoli, Castro, and the Tremiti islands (Apulia). Common alyssum (Lobularia maritima), with honey-scented white or sometimes purplish-red flowers, is found all over Italy, not only near the sea but also in dry areas and on walls. Candytuft (Iberis semperflorens) forms hemispheric, evergreen shrubs, with strong, woody twigs covered with the scars of its fallen leaves. The cuneatespatulate leaves are smooth, fleshy, with short stalks, completely covered with clusters of flowers which form a thick umbrella-shaped corymb. Its scented flowers have an irregular corolla, as the two external petals are three times as large as the others, which are white, sometimes rosy, spatulate, and contracted at their base. This is a suffruticous chamaephyte which blossoms in mid-winter, forming beautiful white cushions on rocky flanks. It is an endemic species and its distribution is similar to that of cliff pink (at Capo Palinuro in Campania, in Sicily, and on the island of Zembra in the Gulf of Tunis). It is a meso-xerophilous chasmophyte living on limestone cliffs up to 1400 m. Sea kale (Brassica oleracea ssp. robertiana), the spontaneous ancestor 37 Hoary stock (Matthiola incana) Common alyssum (Lobularia maritima) Sea kale (Brassica oleracea ssp. robertiana) 38 “Carrubazzo” (Anagyris foetida) Bird’s-foot trefoil (Lotus cytisoides) Jupiter’s beard (Anthyllis barba-jovis) of cabbage grown as a vegetable, is endemic to the north-western Mediterranean, from Catalonia in Spain to the Conero promontory near Ancona on the eastern Adriatic. There are also other coastal kale species - big-fruit kale (Brassica macrocarpa), Trapani kale (Brassica drepanensis), white kale (Brassica incana), Sardinian kale (Brassica insularis) - which are less widely distributed. Kale is a perennial plant the stalks and twigs of which are woody at the base and herbaceous at the top. Its bottom leaves are large, lyrate, with slightly amplexicaul base earlets and irregularly crenate edges. Its blossoms form thick clusters of yellow flowers. Kale is a suffruticous chamaephyte with robust foliage and large flowers which bloom between February and April. It is also a mesophilous and thermophilous chasmophyte, typically found along both limestone shores and inland. A new species of kale, the scientific name of which is Brassica tyrrhena, has recently been found on limestone shores in central-western Sardinia, between Baunei and Dorgali. It grows in calcareous cracks exposed to the sun, from sea level up to 500 m, and its large cobs of yellow, scented flowers bloom in February-March. Tyrrhenian and southern Italian regions, particularly thermophilous maquis, host carob (Ceratonia siliqua), which may also be shrub-like, with its shiny, coriaceous, paripinnate leaves. Its long, leathery pods contain a sweet, edible pulp and very hard seeds, which were used in the past as units of measure for gold: the term “carat” derives from the Arabic for carob. In winter and spring, “carrubazzo” (Anagyris foetida) blooms and sets fruit. This is a heliophilous and thermophilous shrub with deciduous, trifoliate leaves and yellow flowers. It occasionally grows along Italian coasts from Liguria to the Marches and the islands. Among the most localized species is Aeolian cytisus (Cytisus aeolicus), endemic to the Aeolian islands north of Sicily, Nurra broom (Genista acanthoclada ssp. sardoa), typically found in northern Sardinia, Corsica broom (Genista corsica), in Corsica and Sardinia, Moris broom (Genista morisii), typical of southern Sardinia, and Cilento broom (Genista cilentina), on Tyrrhenian shores in Campania and Sicily. Bird’s-foot trefoil (Lotus cytisoides), with a woody base, hairy, silvery trifoliate leaves and golden yellow flowers, covers cliffs or appears from cracks in cliffs along Tyrrhenian and Apulian coasts. Cracks in higher coastal cliffs, which are not splashed by the sea, contain Jupiter’s beard (Anthyllis barba-jovis), a slender shrub with ash-grey leaves and white flowers, shrubby scorpion vetch (Coronilla valentina) and rush-like scorpion vetch (Coronilla juncea). Cliffs also host tree spurge (Euphorbia dendroides), a shrub or small tree with blue-green leaves which turn red 39 Shrubby scorpion vetch (Coronilla valentina) Tree spurge (Euphorbia dendroides) Large Mediterranean spurge (Euphorbia characias) 40 Aleppo rue (Ruta chalepensis) Tree-mallow (Lavatera arborea) Cliff tree-mallow (Lavatera maritima) before falling in early summer. Large Mediterranean spurge (Euphorbia characias) is also a large shrub, which is found in maquis and coastal garrigue along the Italian peninsula and its islands. Wulfen’s spurge (Euphorbia wulfenii), with its funnel-shaped flower bracts, grows near Trieste, Conero and Ventimiglia. Then there are the dense cushions of strawberry spurge (Euphorbia fragifera) on limestone screes in Istria, Bivona’s spurge (Euphorbia bivonae) on Sicilian coastal cliffs, sea cliff spurge (Euphorbia pinea) with herbaceous branches, spiny spurge (Euphorbia spinosa), the thorny cushions of which colonize coastal screes and cliffs throughout Italy and Sardinia, and Balearic spurge (Euphorbia pithyusa), a small shrub with a woody base and dense oval leaves, which, like all spurge leaves, contain a poisonous milky latex. Coastal garrigue contain the aromatic Aleppo rue (Ruta chalepensis), and Sardinian granite cliffs host the endemic Corsican rue (Ruta corsica). Spurge olive (Cneorum tricoccon), a shrub the flowers of which have three petals, is only found in a few locations along northern Tyrrhenian and Sardinian shores. In spring and summer, mallow blossoms lushly. Species include: treemallow (Lavatera arborea), with purple flowers, which is spontaneous on coastal cliffs in southern Italy and its islands, and runs wild in vegetable gardens; cliff tree-mallow (Lavatera maritima), found on cliffs in western Liguria, Sardinia and on the island of Gorgona, with downy-grey leaves and large pink flowers; and Hyères treemallow (Lavatera olbia) found along western coasts in Apulia and on Italian islands. Sericeous daphne (Daphne sericea), with its twisted twigs and tiny white flowers, grows on limestone cliffs from Piombino on Elba to the Tremiti “Spazzaforno” (Thymelaea hirsuta) islands; “spazzaforno” (Thymelaea hirsuta), with yellow flowers and branches completely enveloped by small, imbricate leaves, lives in cliff garrigue along western Italian coasts and islands; thymelaea (Thymelaea tartonraira) is only found in Campania, Sicily and Sardinia. The cliffs at Capo Mannu (Sardinia) host the rare bushy violet (Viola arborescens), a steno-Mediterranean species with woody stalks and white, pale blue or violet flowers. Woody frankenia (Frankenia laevis) The colourful, yellow flowers of rockroses bloom for a short period on cliffs and garrigue: yellow rockrose (Halimium halimifolium) from Tuscany to Molise and Sardinia; cat’s head rockrose (Helianthemum caput-felis) at Capo Mannu in Sardinia; Ionian rockrose (Helianthemum jonium), which is endemic to coasts from Romagna to Basilicata; Mediterranean rockrose (Fumana arabica), from Tuscany to Apulia and Sicily and Sardinia; thyme-leaved rockrose (Fumana thymifolia) and Fumana laevipes, which are also found in Liguria. Cliffs with salty pools are colonized by small sprawling shrubs of sea heath (Frankenia laevis) and hairy frankenia (Frankenia hirsuta). Sea fennel is a densely branched, glabrous, blue-green, perennial umbellifer with a woody base, and fleshy stalks and leaves. In late summer, it is covered by large yellow umbels composed of tiny flowers; it bears fruit in September. 41 42 The umbellifer family is characterized by the presence of aromatic substances often used in cooking; the fleshy leaves of sea fennel are also pickled and used in salads. This coastal, cliffloving species grows along rocky shores and on cliffs, but may also adapt to life in debris, pebbles, consolidated sand, and even in ballast. It typically associates with other halophilous plants along the seasplashed coasts of the Mediterranean, Atlantic, Canary Islands, and as far as the Black Sea. In June, the large white umbrellashaped clusters of sea cliff carrot (Daucus gingidium) dangle from long Palinuro primrose (Primula palinuri) scapes surrounded by light, lace-like segmented leaves. The white umbels of Boccone’s moon carrot (Seseli bocconi), a perennial, branched plant with a woody base and blue-green lanceolate or linear lacinia, blossom on limestone cliffs in Sicily and Sardinia. Mediterranean moon carrot (Seseli tortuosum) is also found along Italian coastal cliffs and on garrigue. The rare Lucania moon carrot (Portenschlagiella ramosissima), with linear, segmented leaves and yellow flowers forming elegant umbels, lives only on the cliffs of Mt. Bulgheria near Sapri. Among umbellifers is Macedonian atamantha (Athamanta macedonica), Sicilian atamantha (Athamanta sicula), a few hare’s ears (Bupleurum elatum, B. dianthifolium, B. fruticosum), honewort (Trinia glauca), etc.. The most thermophilous heather species (Erica sicula, E. terminalis) colonize very dry, limestone cliffs in Sicily and shady, humid ones in Campania and Sardinia, respectively. Palinuro primrose (Primula palinuri) blooms lushly on Capo Palinuro between February and March. It is a very rare species, found only on a few north-facing limestone cliffs between Capo Palinuro and Scalea. It is a suffriticous plant, with woody stalks and viscous, fleshy, dentate leaves; its yellow flowers form umbels and have white, floury, bell-shaped calyxes. The most interesting of the madder family are stinking madder (Putoria calabrica), rock crosswort (Crucianella rupestris), a few woodruff (Asperula Ferns Although the ideal environment for most types of fern is damp, shady undergrowth, a few species do live on coastal cliffs, in particular habitats. Woodwardia (Woodwardia radicans) lives in damp ravines and caves in the Mediterranean area. It has a northernsubtropical distribution, but in Italy it is only found on the island of Ischia, Sorrento peninsula, Calabria and Sicily. Its name derives from the fact that the axis of its long leaves may bear new plants as soon as they find soil. This phenomenon occurs in deeply shaded areas where this fern grows lushly together with other, more frequent varieties, as occurred in the Tertiary epoch, of which woodwardia is a relict. Tyrrhenian shield fern (Dryopteris tyrrhena) is less frequent. It is found only in the western Mediterranean, in a few areas in southern Spain and France, Liguria, Sardinia, Corsica and the Tuscan Archipelago. It lives in cliff cracks, rocky inlets, at the foot of cliffs, and also on dry walls, but only on silicic substrates. It is very similar to the common male fern but its leaves are more triangular, with smaller sori (spore clusters). Madeira lady fern (Cheilanthes maderensis) also prefers silicic substrates. It is found in cliff cracks, on minute debris and dry walls everywhere in Liguria, on Capraia in the Tuscan Archipelago, on Vesuvius, in Sicily, on the small Aeolian island of Alicudi, on Pantelleria, and in Sardinia. It has small, horny leaves, the margins of which curl over their undersides, protecting the spore-bearing structures. Sunny limestone or volcanic cliffs in Simonetta Peccenini Acquafredda between Sapri and Maratea, near Gallipoli, in Sicily, on the islands of Linosa and Pantelleria, and southern Sardinia host Catania lady fern (Cheilanthes vellea). It has fronds of segmented leaves, with linear-lanceolate margins and short petioles. The undersides of its leaves are covered with scales which form a rusty felt extending to the sori. Glandulose spleenwort (Asplenium petrarchae), a small fern with delicate pinnate fronds with lanceolate margins, is completely covered by gland hairs. It lives in cliff cracks, coarse debris and limestone. It is a Mediterranean species and, in Italy, is found in Liguria, between Sapri and Maratea in southern Campania, in Sicily and eastern Sardinia. The Latin name of the species recalls the wellknown poet and humanist Francesco Petrarca (Petrarch), because it was picked and described for the first time in France, near the “clear, fresh waters” in Vaucluse which he celebrated. Madeira lady fern (Cheilanthes maderensis) 43 44 crassifolia, A. garganica, A. rupestris), tiny bedstraw (Galium minutulum) and hairy crosswort (Valantia hispida). Turkish convolvulus (Convolvulus cneorum) is a shrub up to 30 cm high, the stalks of which are silvery, enveloped in silky hairs, and leafy, particularly on sterile twigs. Its acute, lanceolate-spatulate leaves with entire margin and short leafstalks are white, downy, and covered in thick hairs. The many flowers at the tips of its stalks Savona convolvulus (Convolvulus sabatius) have hairy calyxes with sharp, rigid teeth and white, lilac-streaked corollas which, initially twisted, become conical and bell-shaped in full bloom. It is a fruticose chamaephyte which blossoms in spring (April-May). Its fragmented, relict distribution includes Dalmatia, Albania, central-southern Italy and Sicily. In Italy, it lives on Tyrrhenian shores (Massa Marittima, M. Argentario, Gaeta, Sorrento Peninsula, Capri, near Palermo at Monte Catalfano, Monte Pellegrino Tree germander (Teucrium fruticans) and Monte Gallo, and near Trapani at Monte Cofano and Capo San Vito). It is a thermo-xerophilous and heliophilous chasmophyte found on limestone cliffs up to 700 m. Endemic to Liguria, Savona convolvulus (Convolvulus sabatius) is even rarer, and has pale blue-violet flowers, yellow inside. Its scientific name derives from the old name of Savona: Vada Sabatia. It is spontaneous only at Capo di Noli, near Savona, on inaccessible dolomitic cliffs plunging into the sea. As it has beautiful flowers, it is often grown in gardens, and also tends to run wild in Apulia and Sicily. Among plants of the mint family are tree germander (Teucrium fruticans), yellow germander (Teucrium flavum), cat-thyme (Teucrium marum), Mediterranean prasium (Prasium majus), sticky hedge nettle (Stachys glutinosa), Sardinian savory (Satureja thymbra), micromerias (Micromeria filiformis, M. microphylla, M. nervosa, M. graeca, M. canescens, M. cosentina, M. fruticosa) and streaked thyme (Thymus striatus). White henbane (Hyosciamus albus), a poisonous member of the potato family, with pale yellow, bell-shaped flowers in spikes, is slightly nitrophilous and is therefore found on cliffs and walls, especially where seagulls nest and tourists sunbathe. Among the figworts are fruticose figwort (Scrophularia frutescens) and snapdragon, which are usually grown in gardens for their colourful flowers. Yellow snapdragon (Antirrhinum latifolium) lives on shores in Liguria, Tuscany, and Latium; bushy snapdragon (Antirrhinum tortuosum) and Sicilian snapdragon (Antirrhinum siculum) live on the Tyrrhenian shores of Latium, Calabria and Sicily; common snapdragon (Antirrhinum majus) everywhere, usually escaping from gardens. Snapdragon is a perennial herbaceous plant, shrubby and woody at its base, with straight stalks, linear or elliptical leaves, opposite at the bottom and alternating in the upper part. According to species, their pale yellow, pink or purple-red corollas have that typical shape which gives the common name to the plant. Their fruit is a capsule, and they bloom and fructify almost all year round. The cliffs and walls of the Italian peninsula and Sicily host purple toadflax (Linaria purpurea); Capraia toadflax (Linaria capraria) is endemic to the Tuscan Archipelago. Sicilian 45 Mediterranean prasium (Prasium majus) White henbane (Hyosciamus albus) Yellow snapdragon (Antirrhinum latifolium) 46 Savona bellflower (Campanula sabatia) toadflax (Cymbalaria pubescens) is endemic to Sicily, and Tyrrhenian toadflax (Cymbalaria pilosa) lives on cliffs from the Circeo promontory near Rome to Calabria. Salty cliffs host plantain (Plantago coronopus), with rosettes of fleshy, laciniate leaves. Red valerian (Centranthus ruber) is found everywhere, whereas cliff scabious (Scabiosa cretica) of Calabria and Sicily and Trapani scabious (Scabiosa limonifolia), endemic to Sicily, are rare. Sicilian bellflower (Trachelium lanceolatum) with beautiful corymbs of violet flowers, is endemic to shady Sicilian cliffs. Savona bellflower (Campanula sabatia), endemic to calcareous rocks in western Liguria, lives in coastal garrigue. Limestone cliffs host endemic bellflowers with small, cordate or reniform leaves and cascades of pale blue, star-shaped flowers: Bethlehem stars (Campanula isophylla), endemic to limestone rocks in western Liguria; Adria bellflower (Campanula garganica), endemic to the Gargano (the “spur” of the Italian boot); Neapolitan bellflower (Campanula fragilis) endemic to southern Italy; and Apulian bellflower (Campanula versicolor), which belongs to the same group and lives in Apulia and Greece. On cliffs of the Italian islands are delicate daisies, the heads of which are yellow, surrounded by white or pink ligular petals: tiny daisy (Bellium minutum) on Pantelleria, Linosa and Lampedusa, is annual. False daisy 47 Bethlehem stars (Campanula isophylla) Neapolitan bellflower (Campanula fragilis) Phagnalon (Phagnalon graecum illyricum) 48 Strawflower (Helichrysum stoechas) Porto Venere knapweed (Centaurea veneris) Maritime aster (Asteriscus maritimus) Gargano knapweed (Centaurea subtilis) Dusty miller (Senecio cineraria) Tremiti knapweed (Centaurea diomedea) (Bellium bellidioides) and thick-leaved daisy (Bellium crassifolium) are perennial and live in Sardinia. Cliffs, walls and garrigue host the greyish cushions of phagnalon (Phagnalon sordidum, P. rupestre, P. saxatile) and the large, yellow flowers of strawflower (Helichrysum stoechas, H. saxatile, H. rupestre, H. siculum). Maritime aster (Asteriscus maritimus) grows in dense shrubs with hairy stalks and spatulate leaves. In spring, it is covered with large yellow flowers. The large shrubs of groundsel (Senecio cineraria, S. bicolor) are often to be found. White, woolly hairs cover their twigs and leaves, which Common reichardia (Reichardia picroides) are indented to the central nervation, and corymbs have yellow heads with white, woolly bracts. Coastal groundsel (Senecio leucanthemifolius) is a small, annual plant, the yellow flowers of which blossom in winter. Dusty miller (Centaurea cineraria) and the similar Centaurea gymnocarpa, Porto Venere knapweed (Centaurea veneris), Aeolian knapweed (Centaurea aeolica), Leuca knapweed (Centaurea leucadea) and Ucria knapweed (Centaurea ucriae) of western Sicily, are a group of meso-xerophilous and heliophilous chasmophytes endemic to coastal and subcoastal cliffs. They are ash-grey, downy perennial plants with straight stalks, woody at the base, laciniate leaves, and rosy or purple flowers in small heads. They are suffruticous chamaephytes which blossom in summer. Limestone cliffs also host other species of knapweed, such as Taormina knapweed (Centaurea tauromenitana), endemic to eastern Sicily, spiny knapweed (Centaurea horrida), of northern Sardinia, Oliena knapweed (Centaurea filiformis), endemic to eastern Sardinia, Tyrrhenian knapweed, which lives along the Ligurian and Tuscan shores, Karst knapweed (Centaurea kartschiana), endemic to the karst, Gargano knapweed (Centaurea subtilis), typical of Apulia and Basilicata, Parlatore’s knapweed (Centaurea parlatoris), in Sicily, Tenore’s knapweed (Centaurea tenorei), on the Sorrento peninsula, and Tremiti knapweed (Centaurea diomedea) on the Tremiti islands. There are also members of the chicory family, such as smooth cat’s ear (Hypochoeris laevigata), marine sow thistle (Sonchus asper ssp. nymani), a 49 51 50 Tyrrhenian iris (Iris chamaeiris) Dwarf palm (Chamaerops humilis) biennial or perennial plant with thorny, blue-green leaves and large, yellow heads; common reichardia (Reichardia picroides), with yellow flowers and green leaves with red and pale blue shades; spiny chicory (Cichorium spinosum), a hemi-spherical shrub with pale blue flowers; sea cliff chicory (Hyoseris taurina); wild chicory (Hyoseris radiata) and Spanish chicory (Hyoseris baetica). In the iris family are several endemic and steno-Mediterranean irises of heliophilous, thermo-xerophilous habit. They colonize rocky limestone substrates and garrigue: Tyrrhenian iris (Iris chamaeiris), on the western coast; Salentine iris (Iris revoluta) in Apulia; Todaro’s iris (Iris todaroana) in Sicily and on the island of San Pietro, off Sardinia; and Sicilian iris (Iris pseudopumila) in Apulia and Sicily. The last is a perennial plant with short, horizontal rhizomes, and cylindrical stalks enveloped by the sheathing base of the leaves. Its single, scented flowers are yellow with violet edges or vice versa, and are enveloped by membranous spathes. Its spatulate laciniae have a central line of dense hairs: the three external laciniae are turned out- and downwards, the three internal ones converge, hoodlike. Its leaves are blue-green, sharp and lanceolate. It is a rhizomatous geophyte with persistent leaves, which blossoms in spring. Shore cliffs often host gramineae such as curved ryegrass (Parapholis incurva), slender barb grass (Lepturus incurvatus), orchard grass (Dactylis glomerata ssp. hispanica), lamarckia (Lamarckia aurea), ryegrass (Catapodium marinum), and Oryzopsis coerulescens. Dwarf palm (Chamaerops humilis), small, with fanned leaves, is the only species of the palm family to grow spontaneously in Italy. It may be found on limestone shore cliffs and in thermophilous maquis. This short list shows how rich, especially in endemic plants, is flora living on coastal cliffs, and one may wonder why, in view of the apparent harshness of the habitat. The answer, as often happens when discussing biological phenomena, is complex, because it implies the interaction of many factors. One of the most important ones is the history of vegetation in Italy. In the early Tertiary, the vegetation was probably tropical, with large, tree-like ferns and lush palms, which were then replaced by laurels and magnolias when changed climatic conditions made tropical vegetation migrate south. In the Pliocene, therefore, vegetation became xerophilous and evergreen, similar to the present one. The variety of border environments along rocky shores may be a refuge for many plant species which have alternated over time. A classic example is dwarf palm. Links between emerging lands were different from today’s in both the Tertiary and Quaternary, perhaps explaining now disjunct distributions such as the amphi-Adriatic one of white alyssum, or the western Mediterranean of bushy violet, found in France, Spain, the Balearic Islands and Sardinia. The subdivision of widely distributed species caused the birth of new species confined to restricted areas, starting from populations which were isolated from the mother species. For example, Bethlehem stars, Adria, Neapolitan and Apulian bellflowers all belong to the same group of species, originating from a common ancestor. 52 Exotic plants The ecological conditions of rocky shore habitats enable the development of plants native to foreign countries with a similar climate. These exotic plants were intentionally or unintentionally brought to these areas by man. They are obviously adapted to Mediterranean or tropical climates and come from various countries: South Africa, Central and South America, Asia Minor, etc.. Many of them are succulents, i.e., they contain water-retaining mucilage, as water is always insufficient in their native environment. One of the most well-known is agave, or century plant (Agave americana) which, as its scientific name suggests, comes from Central America. It was introduced into Italy (Tuscany) in the 16th century and from there spread throughout the Mediterranean - to such an extent that it is now a typical feature of the landscape. It spreads mostly through vegetative reproduction, but it also produces many seeds before dying. Century plants are monocarpic, i.e., they flower only once in their lives, bear fruit, and then die. Their long, rigid, thorny leaves envelop a single scape - a leafless stalk - which may be several metres long, bearing a greenish-yellow flower spike. Aloe (Aloe barbadensis) is similar to century plant, although smaller and less widespread. It is a woody plant with fleshy, toothed, spiked leaves, in the middle of which grows a scape bearing yellow bell-shaped flowers. The introduction of aloe into Europe was very complicated: native to eastern Africa, Saudi Arabia and India, it was later grown in the Caribbean, where it ran wild, and from there it was introduced into Europe with the name “barbadensis”, suggesting that it Simonetta Peccenini Agave (Agave americana) Hottentot fig (Carpobrotus edulis) originated in Barbados. Gardens near cliffs in Liguria, Campania, Calabria and Sicily also host other aloe species, some of which have interesting medical proprieties and are used for their antitumoral effects. Another exotic species, now a common sight in the Mediterranean, is prickly pear (Opuntia ficus-indica). It belongs to the cactus family and is native to Central America. It was introduced into Europe by Christopher Columbus, and since then has been grown for its edible fruit and also to create impenetrable hedges. Its fleshy, flat, segmented joints, called cladodes, are covered with thorns. Hottentot figs (Carpobrotus acinaciformis, C. edulis) are native to South Africa, but find Italian climatic conditions along the coasts so favourable that they have become invasive. They have long, creeping stalks with opposite, triangular, fleshy leaves, with large purple flowers in the former species and yellow or red in the latter. Yellow sorrel (Oxalis pescaprae) is also native to South Africa, but has spread in the Mediterranean over the last two centuries and is now found in olive groves and orange orchards, on uncultivated land and along roads. In Italy, it spreads by means of bulbils, whereas in its native country it reproduces sexually. It blooms with spectacular yellow flowers in winter and spring. In summer, both its trifoliate leaves, rich in oxalic acid, and its stalks, dry up completely. Heart-leaf ice plant (Aptenia cordifolia) is native to South Africa and is grown in gardens along the coast. It often escapes from them and covers shores, rocks and old walls with its small, heart-shaped fleshy leaves and tiny purple flowers which bloom throughout the year. A few groundsels (Senecio angulatus, S. mikanioides) also come from South Africa, and are called ornamentals because they flower in November and December. S. angulatus, more common than S. mikanioides, grows spontaneously on cliffs, walls and sunny slopes along Tyrrhenian, Ionian and southern Adriatic shores. They both have lianoid habitus, with yellow flower heads arranged in corymbs, and small fleshy leaves which resemble ivy. Castor-oil plant (Ricinus communis) has been cultivated since ancient times to extract oil from its seeds, and it soon escaped from gardens. It is a member of the spurge family, native to the tropical European belt. It has large shield-shaped leaves, i.e., round, with petioles inserted in laminas, and many toothed lobes. In favourable climatic conditions, as in Sicily, its herbaceous or trunk-like stalk may be several metres tall. Garden waste is sometimes completely covered by the yellow and reddishorange flowers of nasturtium (Tropaeolum majus). This is an annual, with creeping stalks and almost round, shield-like leaves, native to South America. It is commonly grown in pots on balconies and in gardens, and its greyish, wrinkly seeds germinate very easily, colonizing the environment. Tree tobacco (Nicotiana glauca) is a small tree with bluish leaves and yellow trumpet-shaped flowers which bloom throughout the year. Native to South America, it is pot-grown or runs wild on cliffs, old walls or debris near gardens, and all along the Italian coastline. Much rarer is the shrub Wigandia caracasana of the waterleaf family, which grows only in gorges and uncultivated land in Sicily and the western Ligurian coast. Native to Central-South America (from Mexico to Venezuela and Colombia), it is grown as an ornamental for its dichotomous tips, pretty lilacwhite flowers, and large leaves with yellowish, hairy undersides. Tree alfalfa (Medicago arborea) has become spontaneous in Italy, but is certainly native to Greece and Asia Minor. Study of its distribution reveals that it is found where ancient Greek colonies arose, and therefore, although we may call it an exotic plant, it was introduced in ancient times. It is a shrub up to 4 m high, with silvery, hairy trifoliate leaves and yellow flowers. 53 ■ Vegetation 54 Golden samphire (Inula crithmoides) on the carbonatic rocks of Cilento (Campania) Bare soil is colonized by pioneering plant species which have few requirements, are only slightly competitive with others, and are replaced by more demanding species as soon as a sufficient amount of substrate forms. As regards cliffs - of any sort - this does not occur: pioneering vegetation remains stable over time because environmental conditions cannot change to enable, for example, maquis or even just garrigue to establish themselves. These are only found in a few locations which feature cracks or clefts in rocks where soil can accumulate. This gives rise to a mosaic of fragmented plant associations which replace each other in time and space. Coastal cliffs are therefore characterized by large surfaces of completely barren rock alternating with strips of vegetation which follow the direction of the cracks and rock layers. When cliffs have detritus slopes, vegetation is sparse and covers the surface irregularly, according to the higher or lower gradient and stability of the substrate. The lithology and geomorphology of cliffs, their position, type of degradation, micro-morphology, and possible debris and soil accumulation can influence plant colonization. Cliffs are therefore a series of microhabitats which are variously influenced by ecological factors, as shown by the different plant species. CLIFF OF SCILLA 3 4 3 1 METAMORPHITES NEAR FAVAZZINA 3 4 7 5 4 3 GRANITE AT BAGNARA 8 6 4 6 2 Types of vegetation on Tyrrhenian coast in Calabria 1: 2: 3: 4: 5: Limonietum calabri Limonietum brutii Oleo-Euphorbietum dendroidis Erucastretum virgati Calicotomo infestae-Ericetum arboreae 6: Erico arboreae-Myrtetum communis 7: Erico-Quercetum virgilianae 8: Erico-Quercetum ilicis 55 ■ Halophilous cliff vegetation 56 Halophilous vegetation living on cliffs splashed by seawater is called Crithmo-limonietum from the name of its typical plants, mainly sea fennel and several species of sea lavender. The distribution of these plants is determined by coastal morphology. Halophilous vegetation is more developed where flanks slope gently seawards, or along wind-exposed shores. Typical species of halophilous vegetation - sea lavender and sea fennel - on coastal cliffs are island garlic (Allium commutatum), sea cliff Island garlic (Allium commutatum) carrot, common reichardia, prickly sow thistle (Sonchus asper), golden samphire (Inula crithmoides) and dusty miller. This vegetation typically lives on Mediterranean rocky shores, shows an open and irregular structure, and often contains small, woody species. Most of these plants are highly specialized, as they are associated with very salty soils. ■ Annual halophilous vegetation Small cliff terraces sprayed by marine aerosol host associations of annual species belonging to the class Saginetea maritimae. These grow on thin detrital substrates, together with other halophilous cliff communities or coastal garrigue. These small meadows are colonized by sea pearlwort (Sagina maritima), ryegrass, curved ryegrass (Parapholis incurva) and plantain. ■ Sub-halophilous cliff vegetation Golden samphire (Inula crithmoides) Wind blowing over cliff tops is less rich in salt water and aerosol from the sea, and vegetation is therefore less halophilous, often occurring inland. Gentle slopes may host maquis of Pistacio Rhamnetalia alaterni, which is replaced on cliffs by fragmented, chasmophilous plants of the same class. Areas linking halophilous cliff vegetation with that of maquis or similar, is characterized by garrigue, and woody plants with salt-tolerant cushions. 57 58 Sea lavender The small, round cushions of sea lavender characterize rocky shores. They are annual or perennial herbs, suffruticous or shrub-shaped, with woody bases and rosettes of horny leaves, and shooting scapes ending with spikes of pale blue flowers enveloped by papery bracts. Their fruit are small achenes. They colonize coasts all over the world, but sometimes have extremely localized distribution. They are often endemics which, for their ecological and phytogeographic significance, play the role of characteristic species of plant associations. Almost every rock hosts a particular species of sea lavender that can only be found in that spot! This is due to their type of reproduction - called apomixis whereby embryos develop without fertilization, so that populations are formed of equal individuals, all slightly different from those of other populations. Sea lavender (Limonium sinuatum) grows in sand, rock, rocky grassland and brackish lagoons in Calabria, Sicily and Sardinia. It has winged branches, sinuate leaves, flowers with bluish-violet persistent calyx and whitish-yellow corolla. It is grown as an ornamental, and used in dry flower arrangements. The persistent calyx has lasting intense colours. Sea lavender is usually sold in colours that are different from their natural ones, obtained by soaking the plant in special dyes. Simonetta Peccenini The more mature and less halophilous associations which colonize areas far from the beach, but always sloping, are made up of “spazzaforno”, thymelaea, Jupiter’s beard, dusty miller, strawflower, etc.. ■ Non-halophilous cliff vegetation Salerno sea lavender (Limonium remotispiculum) Ligurian sea lavender (Limonium cordatum) Cliffs host thermophilous, chasmophilous formations of Asplenietalia glandulosi with glandulose spleenwort, yellow germander, cliff tree-mallow, snapdragon, phagnalon, red valerian and Oryzopsis coerulescens. Natural rocky flanks influenced by human intervention are colonized by associations of the class Parietarietea judaicae, which also grow on walls. The dominating synanthropic (associated with man’s activities) and nitrophilous species are white henbane, caper, red valerian, fig (Ficus carica), hoary stock, common reichardia, snapdragon, navelwort, stock (Erysimum cheiri), wild chicory, finger fern (Ceterach officinarum) and toadflax (Cymbalaria muralis). Here, there are also fragments of garrigue, maquis with tree spurge and oleaster, ampelodesmetum, rockroses, maquis with holm oak or heather and myrtle, and particularly pine woodland. Although the most extensive Aleppo pine woodland derives from old reafforestation, communities that colonize coastal slopes may be considered as natural. Pine mixes with other tree species, such as buckthorn, lentisk and juniper, forming heliophilous maquis with a natural structure. Northern Tyrrhenian, Sardinian and Pantelleria coasts host spontaneous cluster pine woodland, which has been greatly extended for reafforestation purposes. ■ Hygrophilous vegetation Sea lavender (Limonium sinuatum) Watercourses, springs and trickling water, even a few metres from the sea, give rise to particular conditions which enable the colonization of a type of hygrophilous vegetation, Adiantetea. It is characterized by maidenhair fern (Adiantum capillus-veneris), brookweed (Samolus valerandi), liverworts and mosses, such as bog rush and other species of rush. Stock (Erysimum cheiri) 59 ■ An overall view of Italian rocky coasts 60 Coastal vegetation on the island of Ponza (Latium) Let us imagine a voyage round the whole Italian peninsula to examine the vegetation along rocky coastlines, starting from Liguria, in the west. Here, the mountains almost reach the coastline, offering shelter against cold northerly winds and giving rise to the typical mild climate of this region, and coastal vegetation is limited to a narrow strip. This vegetation is highly impoverished in comparison with that described previously. Sometimes, the Crithmo-limonietum (sea fennel and sea lavender meadows) hosts only one of the typical species, i.e., sea fennel. However, proceeding upwards and inland on a few promontories, coastal vegetation is followed by garrigue, Mediterranean maquis, holm oak and pine woodland, or grassland. Impressive limestone cliffs are found near Balzi Rossi and Capo Mortola. Here, between the sea and the Hanbury Botanic Gardens, calcareous rock rich in nummulites hosts sea fennel, dusty miller, curved ryegrass, and also one of the many Italian sea lavender species: Limonium cordatum. This attractive plant, with dense rosettes of spatulate leaves and spikes of tiny pale blue flowers, is only found on cliffs in Liguria and southern France. At Finale Ligure, the coast between the promontories of Caprazoppa and Capo di Vado hosts interesting vegetation, which is similar to that more highly developed found inland. The limestone substrate, little summer rain, intense, protracted exposure to the sun, and action of south-westerly (libeccio) and south-easterly (sirocco) winds create an ideal environment for more thermophilous and xerophilous Mediterranean plants, e.g., Bethlehem stars and Savona convolvulus. The dolomitic cliffs on the Bergeggi promontory host Crithmo-limonietum, with Ligurian sea lavender, sea fennel and prickly sow thistle near the sea and, farther inland, dusty miller and stock, which dominate the cliff tops. Where salty soil rich in animal nitrates can accumulate, are various nitrophilous species which withstand saltiness, such as spurrey (Spergularia media), pigweed (Chenopodium album) and scarlet pimpernel (Anagallis arvensis). Cliff tops still have halophilous vegetation such as sea fennel and dusty miller, gradually changing into garrigue with pink (Dianthus sylvestris), a relative of primrose (Coris monspeliensis), “spazzaforno”, and glaucous fescue (Festuca gracilior), followed by maquis with buckthorn and lentisk. In eastern Liguria, the mountains are even nearer the coast, which is therefore higher, rockier and less altered, especially near the promontories of Portofino, Punta Manara, Punta Baffe, Punta Mesco, along the five villages of the Cinque 61 62 Terre, Portovenere, and between Lerici and Bocca di Magra. These cliffs host sea kale with its bluegreen leaves and the hemispheric shrubs of tree spurge, a plant which can live in extremely arid and sunny cliff environments because in summer it sheds its leaves, i.e., its transpiring surfaces. The promontory of Portofino, formed of a layer of marly limestone surmounted by a thick layer of conglomerate in its southern part, has several spurs and ridges plunging into the sea, which create inlets and small bays. Altitude, sunlight, substrate and soil humidity combine in various ways to Saxifrage (Saxifraga cochlearis) give rise to small, grassy meadows spangled with anemone, primrose, lungwort and orchid, or covered with precocious Mediterranean flora; steep slopes carpeted with impenetrable maquis or scented garrigue; and inaccessible vertical flanks colonized by a few shrubs and slopes, beaten by the wind or scorched by sun and salt. Shady cliffs on south-western and northern flanks host saxifrage (Saxifraga cochlearis), which lives only here and on the French Maritime Alps. Where conglomerate outcrops, near the sea, are interesting halophilous populations of sea fennel, seashore wild carrot, sea lavender, sea ryegrass and sea bird’sfoot trefoil. Higher cliffs are colonized by spiny spurge, thick-leaved stonecrop and dwarf palm, of which this is the northernmost location. At Portovenere, the cliffs host sea fennel, strawflower and wild pink, especially near narrow ridges where soil is deposited, together with cliff associations with kale and Porto Venere knapweed (which lives only on this promontory and on the nearby islands of Palmaria, Tino and Tinetto), and fragmented formations of tree spurge, juniper, Aleppo pine, Ampelodesmetum, rockrose, garrigue, and maquis with lentisk, buckthorn, tree heather and strawberry tree. A peculiar sea lavender (Limonium multiforme), together with other species of the Crithmo-limonietum, colonize the Tuscan cliffs of Ardenza, Antignano, Calafuria, Romito, Castiglioncello, Baratti, Cala Moresca, Punta Ala, Talamone, Porto Santo Stefano, Port’Ercole and Ansedonia. Higher cliffs, on the promontory of Piombino, at Uccellina, and Argentario, host dwarf palm, a relict of warm-loving flora which lives in cracks in rocks with dusty miller, Jupiter’s beard, Phoenician juniper and tree spurge. In the Circeo National Park, on the promontory of the same name, is a calcareous massif composed of crystalline and marly limestone, white flint, marl, sandstone and scaly clay. Cliffs with caves which sheltered prehistoric man host cliff vegetation such as the endemic Circe’s knapweed, dwarf palm, Jupiter’s beard and Phoenician juniper. Cliff bases splashed by seawater are covered with Crithmo-limonietum like Circe’s sea lavender, sea fennel, sea bird’s-foot trefoil, seashore wild carrot, Nyman’s prickly sow thistle, cocksfoot, common reichardia and coastal groundsel. On the rocky peninsula of Gaeta lives an endemic sea lavender (L. amynclaeum), which only grows here, at Sperlonga and Terracina. Proceeding southwards is the high, rocky coast of the Campi Flegrei (Phlegraean Fields) and the peninsula of Sorrento, which enclose the Gulf of Naples. Here we may find four different species of sea lavender: on the volcanic rock of Capri, Posillipo, Gaiola and Sorrento is Limonium johannis, Aleppo pine on conglomerate cliff on Monte di Portofino (Liguria) 63 64 dedicated to the botanist Giovanni Gussone; on the inaccessible calcareous rocks between Castellamare di Stabia and Vico Equense grows Limonium tenoreanum, dedicated to the botanist Michele Tenore; at Belvedere, near Castellamare, Ischia sea lavender (Limonium inarimense) also grew in the past, but was probably destroyed by human intervention along the Neapolitan coast; on the limestone rocks of Sorrento is Salerno sea lavender (Limonium remotispiculum), which is also found near Salerno and in Calabria as far as the Gulf of Policastro. The higher cliffs of the peninsula of Sorrento host the endemic Neapolitan mourning bride (Globularia neapolitana), a crawling plant with beautiful pale blue heads which form dense clusters on limestone rocks. High cliffs and steep slopes alternate all along Cilento, the Gulf of Policastro and the Calabrian coast. In Cilento, together with Palinuro primrose are other rare cliff species, such as cliff pink and candytuft, made up of small, hemispheric bushes which bear corymbs of tiny white flowers throughout winter. Seashores at Marina di Ascea, Marina di Pisciotta and Caprioli host ephedra-leaved broom, its bare twigs like those of ephedra, with yellow flowers. This plant may only be found in the three locations above and on the islands along the Tyrrhenian (Sicily, Sardinia, Corsica, and the islands making up the Ponza group). Along the Salento coast is a short, rocky scarp where endemic Apulian sea lavender (Limonium japygicum) grows. This plant only lives at altitudes ranging from sea level to 6-8 m, on both steep and gently sloping flanks, from Porto Cesareo to Otranto. The high, limestone cliffs at Capo di Leuca host precious flora, such as Apulian bellflower (Campanula versicolor), an amphi-Adriatic species, i.e., distributed on both Adriatic shores. Its pale blue flowers with dark centres bloom in late August. There is also one alyssum species (Alyssum leucadeum), which is covered with small, yellow flowers in March, and Leuca knapweed, endemic to this area. The Adriatic coast is often crowded with people and their numerous artefacts, so that there are only a few halophilous cliff species. The uniformity of this coastline is interrupted only by the rocky promontories of Gargano (Apulia) and Conero (Marches). Limestone cliff on Capri: cliff vegetation grows only in crevices and soil deposits Tree spurge and prickly pear along Calabrian coast 65 66 On the Gargano promontory, high cliffs plunging into the sea alternate with very short stretches of dune beaches. This promontory is similar in its geological, environmental, floral and faunal characteristics to the Dalmatian coast, with which it is associated. The coastline between Mattinata and Peschici is a series of high limestone cliffs with bays, inlets, small beaches, monolithic rocks and grottoes. Here live Phoenician juniper, Jupiter’s beard and, further down, where the shore is splashed by seawater, species of the Crithmo-limonietum. Sunny cliffs host mullein-leaf samphire (Inula verbascifolia), an amphi-Adriatic Mullein-leaf samphire (Inula verbascifolia) species, which is completely covered by white, woolly down. It has yellow flowers in heads surrounded by white scales. On rocks and walls in more shaded areas at Peschici, Rodi Garganico, Cagnano, Monte S. Angelo and Mattinata grows the beautiful Adria bellflower (Campanula garganica), endemic to this promontory. Its rosettes of crenateserrated leaves bear on their axils stalks rich in star-shaped corollas of pale blue-violet or white flowers. Monte Conero is composed of high cliffs of various rock types. Marly sandstone cliffs, formed of layers of clay and subject to frequent landslides, mainly host Plinius’ reed (Arundo pliniana), which consolidates slopes by covering them with a dense net of rhizomes and roots. Calcareous rocks near the sea or debris with the same ecological position have typical halophilous vegetation with sea fennel, common reichardia, and wild kale. Debris falling from higher rocky flanks is colonized by white-flower cephalaria (Cephalaria leucantha), bedstraw (Galium lucidum), wild madder (Rubia peregrina) and, if splashed by water, sea fennel. A few rocky flanks have tree spurge and hoary stock; consolidated debris contains buckthorn (Ampelodesmus mauritanicus), broom (Spartium junceum) and shrubby scorpion vetch (Coronilla valentina). The coast between Duino and the border with Slovenia is high and rocky. Spontaneous succulent plants Coasts host many plants of the mesembryanthemum, stonecrop and saxifrage families, which feature xerophytic and halophytic adaptations which enable them to live in these environments, generally shunned by other species. The most conspicuous are the Crassulaceae, among which are perennial stonecrops, such as orpine (Sedum telephium), with purple flowers, great stonecrop (Sedum maximum) with greenish-white flowers, Nice stonecrop (Sedum sediforme), white stonecrop (Sedum anopetalum) with whitish flowers, cliff stonecrop (Sedum rupestre), Sedum tenuifolium with yellow flowers, and annual stonecrops (Sedum stellatum, S. litoreum, S. caespitosum, S. andegavense, S. caeruleum). Annual stonecrops are very ephemeral, and in April-May their tiny flowers cover the arid cliff cracks in which these plants live, set fruit and dry up in early summer. Anjou and azure stonecrop are calciphobes, and therefore live on silicic walls or acid red soil, whereas bushy stonecrop lives on limestone cliffs. Three species of navelwort (Umbilicus rupestris, U. erectus, U. horizontalis) live on Italian coasts on damp cliffs and old walls with some water trickling down them. The first is the most common and the second, reniform navelwort, the rarest. This is an eastern Mediterranean species which, in Italy, only lives in Gargano and Sila. All three navelworts have round, fleshy, shieldshaped leaves, arranged around scapes bearing clusters of erect, yellow flowers on their tips. The flowers may be spreading or hanging according to species. Simonetta Peccenini Saxifragaceae typically live in the mountains, although Saxifraga cochlearis, endemic to the Maritime Alps, also grows on conglomerate cliffs facing north-west on the Portofino promontory. Its small, teaspoonshaped leaves (as its Latin name suggests) have edges dotted with white. These are calcareous crusts due to the discharge and evaporation of calcium carbonatic water from their pores, called hydathodes. Of the Aizoaceae (mesembryanthemum family) are Hottentot figs and two rare species of ice plant (Mesembryanthemum nodiflorum, M. crystallinum). These small, halophytic annuals have creeping stalks and fleshy leaves, linear in the former and oval in the latter. They have a peculiar distribution, being found in the Mediterranean, South Africa, and the latter also in Australia. Cliff stonecrop (Sedum rupestre) Navelwort (Umbilicus rupestris) 67 On the limestone cliffs of Trieste, the Crithmo-limonietum is even poorer in typical species, which are sometimes restricted to sea fennel alone. However, there are other interesting cliff species, such as the endemic Karst knapweed, which may be found up to 50 m from sea level in Duino and Sistiana. Here also are the feathery, cob-like flowers of Venetian sumac (Cotinus coggygria). In Sicily, many cliff species are found in the Riserva dello Zingaro (Trapani). The Crithmo-limonietum contains Limonium flagellare, sea fennel, ryegrass, sea cliff carrot, Spanish chicory, grey bird’s-foot trefoil, common reichardia, golden samphire and stock; cliff associations of Dianthion rupicolae with cliff pink, Todaro’s sea lavender (Limonium todaroanum), Boccone’s moon carrot and candytuft; and Lomelosio creticae-Centaureetum ucriae with cliff strawflower, Ucria knapweed and Turkish convolvulus. Limestone or granite cliffs in Sardinia contain Crithmo-limonietum with various endemic species of sea lavender, woody frankenia and camphor-scented sea heath. Cliff tops host associations of endemic species such as Boccone’s moon carrot and Sardinian kale or, in the Nurra region, fragmented garrigue with spiny knapweed. 68 The rocky spur of Monte Conero (Marches) interrupts the long series of sandy Adriatic beaches Deep inlets along rocky coastline in hard, resistent granite (northern Sardinia) 69 71 Terrestral fauna GIUSEPPE CARPANETO ■ Fauna: invertebrates The windiness, saltiness and high summer temperatures typical of rocky shores make life impossible for small animals, incapable of efficient thermoregulation and lacking suitable protection against loss of water from their tissues. This is why there are only a few terrestrial invertebrates which permanently live in these environments where there is little or no soil. The largest taxonomic groups comprising species associated with cliff phytocenoses are gastropod molluscs and arthropods. Rock pools along Sicilian coastline Molluscs. Gastropod molluscs generally spend the day in cracks or hollows in rocks and move during the night, to feed on plants. Obviously, they are more numerous where vegetation is thicker. A few species are found under deposits of algae and sea plants carried on to rocks by storms. Among the most frequent marine species found along cliffs, in areas splashed by the sea, are those of the genera Patella and Littorina (periwinkle). Species typical of salty waters are Truncatella subcylindrica, Paludinella littorina and Caracollina lenticula. The first is found along the Mediterranean and Atlantic coasts of Europe and Africa; the second along Mediterranean coasts and Macaronesia; the third on the western Mediterranean. Molluscs which are often found on cliffs are clausiliids of the genera Lampedusa and Muticaria, endemic to Sicily and nearby islands. These small snails have elongated, spindle-shaped shells, and live in cracks in limestone rocks. Other clausiliids living in rocky environments are species of the genus Siciliaria, in the Balkans, Italy and Sicily. More frequent are species of the genus Peregrine (Falco peregrinus) on cliffs near Trieste (Friuli Venezia Giulia) 72 Papillifera, which belong to the same family and are associated with the same habitats. One of the most typical animals found on cliffs is Papillifera solida, a western Mediterranean species. Another important species, although less widespread, is Marmorana saxetana, endemic to the Tyrrhenian. Rocky coasts also host many terrestrial gastropods, which are not typical of these environments but are Littorina (Melaraphe) neritoides euryoecious, i.e., widespread in various types of habitats, and generally associated with cliffs. All these species make up large populations and are therefore important sources of food for many animals, such as arthropod predators, lizards and migrant birds resting along the shores. Arachnids. Among arthropods are many arachnid species, especially spiders, harvestmen and mites. A few species of spiders spin their webs on plants or across rock hollows hoping to catch small insects. A few species of spiders spin their webs on plants or across rock hollows. The most widespread webspinners in coastal environments are dictynids, orb spiders and sheet-web weavers. Only orb spiders weave wide, regular webs between empty spaces in the vegetation. Dictynids (genera Argenna, Lathys) and sheet-web weavers spin irregular webs at the tips of dry plants or between cavities in the ground. Some dwarf spiders are even carried by the wind, which blows them on their tiny “flying mats”, thus enabling them to colonize islands. Several species of jumping spiders (e.g., those of the genera Marpissa, Euophrys, Sitticus) move swiftly on the ground, actively searching forˇ prey, on which they pounce with sudden leaps. Other species, like crab spiders, stalk their prey on cliff plants, waiting until flying insects mistake them for petals. Many species of spiders, such as gnaphosids, sac spiders and liocranids are nocturnal and spend the day in their cocoons, from which they emerge after sunset. This is the case of the tiny gnaphosid Haplodrassus minor, the sac spider Clubiona frisia and the liocranid Agroeca lusatica, typical of coastal environments. Spiders are often confused with harvestmen, an arachnid order whose members have compact, generally unsegmented bodies. Metaphalangium propinquum, a widespread Mediterranean species, lives in warm, arid environments on all Italian islands. Sedimentary cliffs host various families of mites, which wander in search of lichen, insect eggs and tiny animals. A few species are parasitic on the skin of lizards, on which they form large patches. Those of the halacarid family are aquatic and live in both cliff pools and coastal water. In Italian fauna, they include about 50 species belonging to Ligia italica 17 genera. A few false scorpions also live on rocky shores, e.g., Neobisium maritimum, and those of the genus Roncus even live on rocks near the water. Crustaceans. Isopods, better known as woodlice, are the only crustaceans adapted to terrestrial environments and may be found in cracks in rocks, where they hide during the day. Here are various species of armadillidiids, the armourlike tegument of which makes them resistant to xero-thermal conditions, as it prevents them from losing water from their tissues. Some of these species are endemic to the Italian islands, such as Armadillidium pseudassimile on Capraia, A. oglasae of Montecristo and A. tyrrhenicum on Giglio. However, the most typical species is undoubtedly Ligia italica, which may be seen even during daytime, scuttling on rocks, hiding in cracks, or even sheltering in water. During their reproductive period, the females plunge into the sea, where their eggs are laid and hatch. Centipedes and millipedes. Species of centipedes and millipedes are not exclusive inhabitants of rocky coasts. In this environment, the two classes are generally associated with cliff habitats. For instance, a common centipede is Scutigera cleoptrata, frequently also found in houses. A swift predator, it has a short body and very long legs, the number of which is smaller than that of other members of this class. Among millipedes are various species of julids, typical millipedes with cylindrical bodies. They are slow, nocturnal detrivores, which spend the day in cracks in rocks. Cliffs near the sea, splashed by seawater and covered at high tide, house some very characteristic specimens. 73 74 Fauna in cliff pools Cliff pools are very interesting microhabitats. These small reservoirs in the rock may contain either seawater or rain. The former are filled during storms, and the latter collect water during Mediterranean spring or autumn. Their closeness to the sea, and the rainfall, seasonality, depth and extension of these hollows all give rise to a complex series of situations according to saltiness. During summer, intense exposure to the sun increases the evaporation of seawater in the pools, and they therefore become saltier. This salt precipitates, and later rainfall decreases the saltiness, giving rise to brackish or even freshwater habitats. Cliff pools host marine or brackishwater planktonic biocenoses made up of flagellate protists, rotifers, small crustaceans (isopods, amphipods, copepods, etc.) and insects. Typical are the hydraenid beetles of the genus Ochthebius. The adults of these tiny, black, shimmering bronze insects (Ochthebius quadricollis, O. subinteger) are about 2 mm long. They are phytophagous and detrivorous: they feed on algae and vegetal remains in the pools. The adults slowly tread the bottom and walls of pools, but must emerge to breathe. They store water in a very curious way: they detach themselves from the bottom, turn upside-down, rise vertically to the surface and adhere to the underside of the surface with their legs. The dense, short hairs covering their bellies touch the air and capture it, forming a silvery film. Once sufficient air is stored, the insects continue their upside-down walk as far as the pool walls, where they start descending again. Their larvae live on the bottom and feed on Giuseppe Carpaneto organic matter. In summer, when evaporation is intense and salt concentration too high, these beetles fly away in search of pools that suit them better. A few species of dragonflies may also visit pools, particularly those containing freshwater. Eggs are laid in the water and voracious larvae are born, which feed on any tiny animal colonizing these microhabitats. When stalking their prey, dragonfly larvae move slowly on the bottom, whereas aquatic heteropterans (water bugs), especially water striders, water boatmen and back swimmers, move swiftly. Water striders scuttle on the water surface; water boatmen and back swimmers are very skilful swimmers. These bugs catch small invertebrates and suck their body fluids through the powerful piercing suckers in their mouths. In a few water strider species, colonization is carried out by macropterous (long-winged) individuals, which reproduce forming populations air of brachypterous (small-winged) specimens. Other predators in pools are true water beetles, particularly those of the genera Agabus, Coelambus and Hydroporus. Whirligig beetles twirl on the water surface. Among dipterans are non-biting midges, gnats and mosquitoes. Mosquitoes can adapt to life in salty water, although most of them prefer freshwater pools with rainwater. These micro-environments, which are isolated in the rock and without fish, are ideal for the development of mosquitoes, which can reproduce without having their numbers controlled by predators. The only mosquitoes specializing in life in hot, salty pools are Aedes mariae and A. zammitii. These two species, the former particularly, are very aggressive towards man. They can fly into houses and bite, both during the day and at night, thus constituting a problem for summer tourists. Other species living in salty or brackish Patella ferruginea water are Culex modestus, Culiseta litorea, Anopheles sacharovi, Aedes detritus, etc., although they are not typical of coastal pools. Only in particular situations, large pools containing rain and sheltered by hanging rocks are inhabited by amphibians (green toad, tree frog, green frog), which find here ideal living conditions. But water temperature must not be too high and the area must be protected from predators - requirements difficult to meet due to the lack of vegetation. 75 76 The genus Thalassisobates includes tiny millipedes specializing in life in these habitats, such as Thalassisobates adriaticus, generally found only a few metres from the sea. Among centipedes are species living under algal debris and the remains of Posidonia, on various types of shores: Hydroschendyla submarina, Geophilus poseidonis and G. fucorum are found along both sandy and rocky coasts. Insects. Very few species of insects live near the sea, practically along the shoreline. In the intertidal zone, in addition to several species of springtails, which are often associated with cliff pools, one of the most exclusive species is the bristletail Petrobius maritimus, which lives on rocks splashed by water. This delicate hexapod may be seen running jerkily along rocks and hiding in cracks. Where pebbles and coarse sand form small deposits between rocks, we find the cricket Pseudomogoplistes squamiger, an orthopteran species exclusive to this environment throughout the Mediterranean. The earwig Anisolabis maritima also lives along the coast, especially where algae and debris are washed ashore. Anisolabis maritima The role of predators is played by carabid beetles, such as the metallic blue Ocydromus (Omoperyphus) steinbuehleri, typical of rocky shores and cliff pools. It lives in small areas along the Mediterranean coast. In Italy, it has only been collected in a few isolated places, along both Tyrrhenian and Adriatic shores. Cricket Pseudomogoplistes squamiger Another halobious (associated with coastlines) carabid is Lymnaeum nigropiceum, which lives along European Atlantic coasts and the Mediterranean, as far as the Black Sea. It is found in the intertidal zone under rocks and in cracks at the foot of cliffs. In Italy, it was mostly found in Sardinia, on some Tyrrhenian islands and in the northern Adriatic. Even rarer is Lymnaeum abeillei, only found in a few Ground beetle Limnaeum nigropiceum sites in southern France, Corsica, Liguria, Latium and Abruzzi. However, most insects living along rocky shores are associated with plant communities, such as the Crithmolimonietum of rocks and the Mediterranean maquis, which thickens proceeding inland. Among phytophagous species associated with rocky coasts is the Ground beetle Ocydromus (Omoperyphus) brown long-horned beetle Parmena steinbuehleri pubescens, which is about 1 cm long and parasitic on the umbellifer Crithmum maritimum, a guide-species of the Crithmo-limonietum. Few phytophagous insects are exclusive to rocky coasts, as they also live inland, in the evergreen Mediterranean maquis, deciduous woodland and pastureland farther from the coast. Together with phytophagous insects are other more or less specialized or euryoecious predators, i.e., indifferent to the type of environment. 77 ■ Fauna: vertebrates 78 Amphibians and reptiles. Amphibians are seldom seen on rocky coasts, unless they live in salty or freshwater pools in rocks. Species which may inhabit these environments are green toad (Bufo viridis), tree toad (Hyla intermedia and H. sarda) and frogs of the esculenta group (Rana hispanica, R. bergeri). The presence of amphibians implies that of their predators, i.e., reptiles, such as grass snake (Natrix natrix) and viper snake, especially near large freshwater pools. A more frequent snake along rocky shores is rat snake or green and yellow coluber (Hierophis viridiflavus), which crawls on steep slopes in search of birds’ eggs and nests. However, its usual prey are lizards, which are the most frequent and numerous reptiles in these environments. Rocky cliffs near Trieste still house cat snake (Telescopus fallax), which moves as far as the shoreline hunting for lizards. Various widespread species belong to the lizard family and live both inland and along rocky coasts, such as common wall lizard (Podarcis muralis) and wall lizard (Podarcis sicula). These two species constitute morphologically differing populations on the islands and therefore, in the past, many geographical subspecies were described according to their external features (colour, size, shape of body and scales). Viperine snake (Natrix maura) Rat snake or green and yellow coluber (Hierophis viridiflavus) 79 80 A few of these subspecies are clearly differentiated, such as the blue wall lizard (Podarcis sicula cerulea), which lives on the plunging cliffs of the “faraglioni” of Capri. It has a typical dark blue back and deep turquoise belly. Another beautiful type of lizard, as a separate subspecies, is Isola Bella wall lizard (Podarcis sicula medemi), with a brick-red belly. It is found on the tiny island of the same name, near Taormina, Sicily. The rocky coastline of Duino-Aurisina (Trieste) hosts Melisello lizard (Podarcis melisellensis), which sometimes reaches the shoreline. As regards lizards, it is difficult to separate the fauna of rocky coasts from that living on islands, because many endemic subspecies live exclusively on small islands and archipelagos. Among wall lizards are Podarcis sicula aemiliani (Scogli di Apani, near Brindisi), P. s. trischittai (Isolotto Bottaro, Aeolian Islands), P. s. calabresiae (Montecristo), P. s. klemmeri (Licosa, in the Gulf of Salerno), P. s. lanzai (Isolotto Gavi, islands of the Ponza group), P. s. liscabiancae (Isolotto Lisca Bianca, Aeolian Islands), P. s. pasquinii (Scoglio Cappello, Ponza group) and P. s. roberti (Formica Grande di Grosseto, Tuscany). Among wall lizards are Podarcis muralis beccarii (Isolotto Porto di Ercole, Tuscany), P. m. marcuccii (Isolotto Argentarola, Tuscany), P. m. muellerlorenzii (Isolotto La Scola, Tuscany) and P. m. tinettoi (Isolotto Tinetto, eastern Liguria). Research on the thermoregulation of the Argentarola lizards, which are dark in colour, has shown that, after these animals have basked in the sun and started moving, their body temperature is higher than that of the normal spotted population of nearby Monte Argentario. Sardinia hosts large numbers of Tyrrhenian lizard (Podarcis tiliguerta) and other, more localized species like Bedriaga’s rock lizard (Archaeolacerta bedriagae) which, in the past, was believed to be associated with rocky, mountain environments in Sardinia, such as Gennargentu and Monte Limbara, where these animals may be found up to 1800 m. Later, coastal and even insular populations were discovered, e.g., on Folaca, a small granitic island of only 3700 sqm and only 11 m in altitude. On this tiny island, Bedriaga’s rock lizard lives alone, probably due to the absence of competitors. In Sicily we find wall lizard (P. sicula) and Italian wall lizard (P. wagleriana), living in almost all environments, although the latter species seems to be associated with meadowland rather than rocky substrates. Instead, Aeolian wall lizard (Podarcis raffonei) is typical of the rocky habitats of a few small islands of the Aeolian archipelago, such as Vulcano (restricted to the Vulcanello peninsula and nearby rocks), Strombolicchio, Scoglio Faraglione Wall lizard (Podarcis sicula) Bedriaga’s lizard (Archaeolacerta bedriagae) 81