engleski

Significance of ornithochory in the succession of the mediterranean evergreen vegetation

Significant for the tropic and subtropic forests in respect to their diaspore dissemination is that in them the forms with fruits disseminated by animals (zoochorically) prevail, and in such dissemination an important role is played by birds (ornithochory). In the Mediterranean evergreen forests the species with the zoochorically disseminated fruits dominate, too. A few species only, such as the evergreen species of the genus Quercus as well as the species of the genera Pinus and Cupressus, have a special form of zoochory. The largest number of other species develops the succulent fruits rich with sugar or oil and is disseminated endozoochorically (by ornithochory). The advantage of ornithochory is that seeds may be disseminated by the birds at very large distances. The above fact is of crucial importance for the succession of the evergreen forest vegetation throughout the Mediteranean, because by leaving the pasture and rocky lands to natural processes of overgrowing with forest vegetation elements the following genera predominate as the pioneer species Pistacia, Juniperus, Phillyrea, Olea, Rhamnus, Myrtus, Arbutus, Laurus, Lonicera, Rosa, Rubus, Ephedra, Asparagus Ruscus, Smilax, Rubia, Arum and others. The species of these genera are propagated by means of birds eating their succulent fruits and thus disseminating their seeds at considerable distances. They are dominant in the floristical composition of progressive succession stages, such as in our country Pistacio-Juniperetum phoeniceae, Oleo-Pistacietum lentisci, Oleo-Euphorbietum dendroidis, Oleo-Juniperetum phoeniceae, and in the other parts of the Mediterranean Calycomoto-Myrtetum, Myrto-Pistacietum lentisci, Prasio-Oleetum, Clematido-Myrtetum, Aro-Phillyreetum rodriguesii, Juniperetum lyciae and others, with regard to both the quality and the quantity. In our Croatian littoral an instructive example can be seen that precisely owing to the birds the formerly bare large Kornati islands are becoming green successfully in the last decades.

ornithochory; mediterranean evergreen vegetation; succession

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