Included here is virtually all of the maritime zones surrounding the Adriatic Sea, most of which has a Mediterranean climate.

Adriatic Mega Sea Cliff Formations

This is a province of gigantic cliffs the largest of which occur along the Velebit channel in the northeastern Adriatic. These huge cliffs can reach heights of 1200 m, while the adjacent cliffed islands of Krk, Pag and Rab have escarpments up to 460 m. But these are far from being straight up and down and have ledges ranging from a few square metres to several hectares many of which have retained their natural vegetation due to their inaccessibility. Some of the best examples of these isolated shelves can be found on the escarpments of the Velebit and Biokovo mountains, the Konavl coast, the Boka canyon, and on the islands of Svetac, Krk and the Senj archipelago.

In the northeast, the maritime vascular plant assemblages of exposed windswept cliffs form three main vegetation belts. A lower hygrohaline belts, regularly sprayed by surf - a middle much dryer (xerohaline) belt - and an upper subhaline belt only affected by the strongest aerosaline hurricanes. The lower belt is characterised by a succulent rock scrub comprising a canopy of endemic taxa such as Astragalus curictanus, A. dalmaticus, A. uraganicus, Meliotus turbulentus (Fabaceae), Aurinia media (Brassicaceae), Centaurea procellaria (Asteraceae), Silene microloba (Caryophyllaceae), and an under story also largely composed of endemic taxa such as Allium horvattii (Liliaceae), Asperula dalmatica (Rubiaceae), Corydalis acaulis (Fumariaceae) and Limonium antractum (Plumbaginaceae). In the open windswept middle belt herbaceous elements like Crithmum maritimum, Iris cengialtii subsp. illyrica, Euphorbia epithymoides, Limonium cancellatum and the endemic taxa Campanula fenestrellata subsp. istriaca (Campanulaceae)and Centaurea dalmatica (Asteraceae), while the upper belt comprises a semi-evergreen scrub. Here endemic or near endemic taxa include Anthyllis montana subsp. atropurpurea (Fabaceae), Campanula subalpine (Campanulaceae), Cyathoselinum tomentosum (Apiaceae), Dianthus sylvestris subsp. nodosus (Caryophyllaceae), Iris rothschildii (Iridaceae), Micromeria kerneri (Lamiaceae), Onosma croatica (Boraginaceae) and Sedum dinaricum (Crassulaceae). Other formations include ‘guano’ vegetation dominated by tall columnar nitrophilous forbs such as the endemic Peudedanum pachyphyllum and Seseli varium subsp. promonense (Apiaceae), and shady cave communities with the endemic moss Barbula adriatica, the endemic fern Adianthum capillus-veneris subsp. visianii (Adianthaceae) and the endemic flowering plants Campanula fenestrellata subsp. debarensis (Campanulaceae) and Centaurea dalmatica subsp. rabensis (Asteraceae).

In the southeastern Adriatic on the Konavli coast of southern Dalmatia another stretch of megacliffs can be found reaching heights of up to 1050 m. Here a different assemblage of species occur, but can still be divided into a lower, middle and upper belt. In the lower zone up to about 70 m an unusual candelabriform rock scrub with rosette tuft-treelets has developed growing up to about 3 m tall. The canopy includes Cephalaria mediterranea, Coronilla valentina subsp. glauca and the endemic Cyathoselinum palmoides (Apiaceae), while sub-canopy species typically comprise Allium cornutum, Cheilanthus perisica and the three endemic species Centaurea adriatica (Asteraceae), Iris dalmatica (Iridaceae) and Limonium japygicum (Plumbaginaceae). This gives way to an evergreen rock scrub in the middle zone with taxa such as Lavandula latifolia, Phlomis fruticosa, Putoria calabrica and the endemic Brassica incana subsp. mollis (Brassicaceae). The upper belt above about 350 m is semi-evergreen rock scrub up to 1 m tall. It is usually dominated by Moltkia petraea and Potentilla speciosa, but also includes endemic or near endemic taxa such as Campanula pocharskyana, Edraianthus baldaccii (Campanulaceae), Centaurea incompta (Asteraceae), Dianthus sanguineus, Heliosperma tommesinii, Petrorhagia illyrica (Caryophyllaceae) and Scabiosa leucophylla (Dipsacaceae).

Adriatic Mobile Coastal Scree Slopes

These structures are found on many of the oblique coastal slopes and as with mega cliffs, the vascular plant vegetation can be broadly divided into three belts: lower ultrasaline scree (up to 120 m), middle xerosaline scree (between 120-300 m) and upper sub saline scree  (between 300-700 m). The lower belt, which tends to be covered with salt crust from aerosaline storms, supports a halophytic, succulent community characterized by species such as Atriplex prostrata, Centaurium pulchellum subsp. meyeri, Daucus carota subsp. hispanicus, Salsola kali subsp. pontica, Suaeda maritima subsp. sola and the endemic taxa Limonium visianii (Plumbaginaceae), Microrhinum litorale (Scrophulariaceae) and Senecio fluminensis (Asteraceae).  The middle belt is usually powdered by salt crystals and supports a xerohalophytic, echinate, cushion community of Drypis spinosa, Echium pustulatum, Sedum brevifolium and the endemic taxa Centaurea rossiana (Asteraceae), Cerinthe tristis subsp. smithiae (Boraginaceae) and Vincetoxicum croaticum (Asclepiadaceae). The upper belt, only reached by occasional salt spray, comprises a xeric echinate cushion community with taxa such as Aethionema thomasianum, Centaurea rupestris subsp. ceratophylla, Genista michelii, Satureja karstiana and the endemic or near endemic Edraianthus graminifolius subsp. caricinus (Campanulaceae).

Adriatic Karstic Coastal Rock Fields

These occur sporadically along the entire eastern coast of the Adriatic on flat calcareous coastlands and adjacent skerry islands. In the northeast, such as the Senj archipelago, the dominant vegetation comprises a kind of semi-woody phrygana up to 70 cm in height. The characteristic species include Artemisia alba, Asphodelus aestivus, Camphorosma monspeliaca, Colchicum kochii, Helichrysum italicum, Teucrium capitatum and the endemic or near endemic Centaurea hutteri (Asteraceae), Dianthus ciliatus (Caryophyllaceae) and Festuca lapidosa (Poaceae). However, on some of the offshore skerries where seabird ’guana’ has accumulated a nitrohalophytic grassland has developed with endemic taxa such as Carduus nutans subsp. micropterus (Asteraceae) and Euphorbia eufragifera (Euphorbiaceae). Further south in Dalmatia, a summer-deciduous scrub up to 2 m tall dominates karstic rock fields. Artemisia arborescens and Obione graeca dominated the canopy, together with various other species such as the endemic Convolvulus tartonaira (Convolvulaceae), while the under story is dominated by endemics like Centaurea fridericii (Asteraceae), Muscari speciosum (Liliaceae) and Ornithogalum visianicum (Liliaceae). Moving even further south to the Efafiti archipelago near Dubrovnik the vegetation includes a summer-deciduous pulvinate thorn scrub of Calycotome villosa and Erica manipuliflora. Other species here include Coronilla valentina and the endemic Crocus dalmaticus (Iridaceae).

Adriatic Coastal Forests

In the upper most coastal zones, rich sub Mediterranean forests have developed dominated by endemic taxa. These include pine forests dominated by the endemic Pinus nigra subsp. croatica (Pinaceae). Other trees include Acer opalus and Quercus dalechampii, but the dendroflora can include up to 56 species of trees and shrubs. The field layer includes endemic or near endemic taxa such as Centaurea diversicolor, Hieracium vratnikense (Asteraceae) and Viola vilaensis (Violaceae). On the cliff tops and uppermost shelves sub-mediterranean fir-forests predominate. These are characterized by the endemic Abies pardei (Pinaceae), while other common dendroflora include Acer carpinifolia and Ostrya carpinifolia, but with 62 different species of trees and shrubs these represent the richest forests in Europe. Among the many endemic or near endemic taxa are shrubs such as Lonicera alschingeri (Caprifoliaceae), Petteria alschingeri (Caesalpiniaceae), Sorbus baldaccii (Rosaceae) and the herbaceous species Aconitum adriaticum (Ranunculaceae).

References

Forenbacher, S. 2001. Velebit Range – Treasure of Croatian Flora. Croatian Medical Journal, 42: 111-112.

Horvat, I, Glavac, V & Ellenberg, H. 1974. Vegetation of Southeast Europe. Gustav Fischer Verlag. Stuttgart.

Lovric, A. Z. 1997. Dry coastal ecosystems of Croatia and Yugoslavia. In: Ecosystems of the World 2C  Dry Coastal Ecosystems  - Polar Regions and Europe. Ed. Eddy van der Marel. Elsevier.

Milovic, M. 2002. The flora of Sibenik and its surroundings. Natura Croatica, 11: 171-223.

Rac, M. & Lovric, A. Z. 2002. Benthic and xeric vegetation of remote islands Susac and Kopisce and of the adjacent seafloors in southern Adriatic. Periodicum Biologorum, 104: 139-147.