Acta Botanica Croatica, Vol. 43 No. 1, 1984.
Conference paper
A New View of the Plant Cover and Phytogeographical Zonation of Istria
Ivan Šugar
; Hrvatska
Abstract
In the course of floristic and phytosociological investigations in Istria we established several new plant communities of both thermophilous and mesophilic characteristics within a rather wide area, especially in the middle parts of Istria. This fact required a phytogeographic zonation of this province different from the one existing until now. Consequently, we have separated particular areas which used to be connected to the single zones of the Mediterranean region and have included them into the Eurosibiric-Northamerican region where we have isolated two zones:
a) the paramediterranean zone with significant associations Seslerio- -Fragetum, Querco-Carpinetum submediterraneum, Seslerio-Quercetum petraeae and Lathyro-Quercetum petraeae, for wich the presence of certain numbers of thermophilous species is notable, as for instance Sesleria autumnalis, Cornus mas, Asparagus tenufiolius and others;
b) the illyric zone characterised by two types of beech forests of continental regions, namely: Fagetum subalpinum (only on Vojak, the highest peak of Učka mountain) and Fagetum montanum (valleys and karst holes of Planik and Lisina only).
Two new thermophilous but extrazonal associations — Molinio-Quercetum pubescentis and Potentillo albae-Quercetum pubescentis — have been included in the paramediterranean zone too.
In relation to the earlier standpoint about three phytogeographical zones in Istria, after the latest investigations in that area we have separated the following zones:
1. Mediterranean region: a) eumediterranean, b) submediterranean,
c) epimediterranean zones;
2. Eurosibiric-Northamerican region: a) paramediterranean, b) illyric zones.
Analyses of the elements of evergreen forests and shrubs in Istria have shown that this type of vegetation is much more expanded than it was considered until now.
It has been established that the Mediterranean vegetation penetrates the inland parts of Istria along the valley of the rivers Mirna and Raša and Limska draga (a cove) much more deeply and more to the north on the east and the west coasts than it was considered so far, and that there is a greater number of relict habitats on the slopes of Učka and Ćićarija — from Plomin to Buzet and the thermal springs of Sv. Stjepan up the river Mirna.
Finally, along the west coast of Istria, as well as along the east coast, continuous north boundary of evergreen oak forests and shrubs, a good representation has been established of some elements from the alliances
Quercion ilicis and Cisto-Ericion. Consequently, we have separated a new subassociation, Querco-Carpinetum orientalis cistetosum salviifolii and on the basis of this we propose a transitional phytogeographical zone between the eumediterranean and the submediterranean zones.
Keywords
Hrčak ID:
158972
URI
Publication date:
31.12.1984.
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