Ecological and floristic characteristics of beech and fir forests on the basic eruptives in ophiolite zone in Bosnia

Abstract

UDK 581.5:630*1(497.6)

Beech and fir forests on basic eruptive, gabbro and diabas soils of the ophiolite zone in Bosnia are specific in their ecological similitude, especially in edaphic conditions and floristic structure. In comparison to beech and fir forests of other substrataes, the specificity of these forests is also evident, in their sinsystematical location. In order to determine the above characteristics of the forests within the researched area (map), we have chosen 22 quadratic experimental plots with surfaces between 400 to 900 m² (16 plots on gabbro soils and 6 plots on diabas). Phytocoenological monitoring was conducted on the above mentioned experimental plots during two vegetation periods (using the Braun-Blanquet method of phytocoenological measuring) as well as pedological recording and laboratory analysis of soil samples. The data obtained through phytocoenological monitoring served as the main indicator of floristic characterization of the researched forests.

Testing revealed a great complexity and variability of soil found on these rocks. The following types of soil are present: eutric brown soil, brunipodzol, luvisol (as well as pseudogley) and ranker. The analysis of these soils showed that the largest differences between the types were in humus quantity and type. When it came to soil reaction, the analysis demonstrated that the soils were acid or extremly acid, with the exception of ranker which has low acidity or shows neutral reaction.

The analysis of floristic structure showed that the former is influenced by edaphic conditions, i.e. humus conditions, hence the strong correlation between the two. Essential floristic differences were noted between beech and fir forests found on eutric brown soil and ranker on gabbro and diabas, which are characterized by mull humus, unlike beech and fir forests of brunipodzol and luvisol which are typified by the presence of mor and semi-mor humus.The former are neutrophil phytocenoses, while the latter are acidophilic in character.

On the basis of the defined floristic characteristics of beech and fir phytocenoses in basic eruptive ophiolite zone in Bosnia, it was determined that they fall under different sinsystematical categories. With the exception of calciphilic shrubs, neutrophil beecand fir forests on eutric brown soli and ranker on gabbro and diabas do not differ significantly from the beech and fir forests found on limestone and dolomite. Both are extremely rich in their floristic character, and both are characterized by the same plant species. Furthermore, neutrophil species (Table 1) with dominant growth during spring are dominant in these forests.

The presence of Aremonia agrimonoides /L./ DC in both neutrophil and acidophil beech and fir forests on gabbro and diabas (Tables 1 and 5), as well as on other soils that form over different rocks(carbonate and siliceous rocks), implies the inadequate term Aremonio – Fagion (Horv. 1938) TÖREK ET AL. 1989, which refers to the beech and fir forests (with spruce) respectively.

Taking into consideration the above mentioned facts, we can say that, sinsystematically, neutophil beech and fir forests on gabbro and diabas (present in the above described edaphic conditions) may be regarded as separate subassociation of neutrophil beech and fir forests.

On the other hand, acidophilic beech and fir forests on brunipodzol, luvisol and pseudogley soils on gabbro and diabas are diametrically different in comparison to neutrophil forests (Table 5). They have a significantly smaller number of plant species, are dominated by acidophil floristic elements, a complete absence of typical neutrophytes, as well as hardly evident spring growth. According to the above characteristics, it is possible to say that these forests are identical to acidophil beech and fir forests on various acidic silicate roks, which belong to alliance Luzulo-Fagion (Lohm. et Tx. 1954).