Classification and phytogeographical differentiation of broad‐leaved ravine forests in southeastern Europe

Abstract

Question: How do broad‐leaved ravine forests in SE Europe differentiate phytogeographically? Do they differ from analogous European forests? What is their distribution pattern? Location: southeastern Europe, Apennine‐Balkan province. Methods: The initial data set of 2189 relevés was stratified geographically and phytosociologically; 614 relevés remaining after stratification were classified with aTWINSPAN and cluster analysis, wich resulted in four clusters and eight subclusters. Average Pignatti indicator values for releves of each subcluster were subjected to PCA to show ecological relationships among the clusters. The spectra of geoelements and sociological species groups of individual subclusters were calculated to show phytogeographical and sociological relationships between them. The diagnostic species combination was calculated by a fidelity measure (φ‐coefficient) and presented in a synoptic table. Results: Broad‐leaved ravine forests in southeastern Europe form a separate group within the European broad‐leaved ravine forests. They are well differentiated by the species with a southeast European distribution, as well as by many other species that reflect their different ecological affinities. Conclusions: The phytosociological and phytogeographical relationships between the Apennines and the Balkan peninsula that have already been recognized for other vegetation types have been confirmed for broad‐leaved ravine forests. According to the numerical analysis, two suballiances of broad‐leaved ravine forests in southeastern Europe are proposed, both belonging to the alliance Tilio‐Acerion. an amphi‐Adriatic xerothermo‐philous suballiance Ostryo‐Tilienion platyphylli suball. nova and a mesophilous suballiance Lamio orvalae‐Acerenion suball. nova, the latter appearing only on the Balkan Peninsula.

Acer-Fraxinus dominated woods of the Italian peninsula: a floristic and phytogeographical analysis

“…In the European context, this study confirms the results of the paper by Košir et al [42] and demonstrates that Alpine, south-east European, and Apennine groups are autonomous. This strong differentiation is attributable to the endemic species groups being better conserved in these azonal coenoses, with a "buffered" flora with respect to other more closely interconnected woodlands, to the limited effect of the human disturbance, which can be seen in the station characteristics and finally to the species from zonal woods in contact with maple-ash woods, which differ in function of different biogeographical regions.…”

“…This also emerges from the studies of several Balkan authors [76,77] and in particular from [78], who propose the attribution of Apennine and Dinaric Alpine maple-ash woods to the alliance Fraxino-Acerion Fukarek 1969, including two new suballiances distinguished on a floristic-ecological basis. In a later paper, Košir et al [42] state that classification into the independent alliance proposed by Fukarek [43] is not a suitable solution, as they did not succeed in confirming it by numerical analyses. Their numerical analyses show that xerothermophilous and mesophilous broad-leaved ravine forests in different phytogeographic regions are more similar than xerothermophilous and mesophilous forests in a single region.…”

“…Their numerical analyses show that xerothermophilous and mesophilous broad-leaved ravine forests in different phytogeographic regions are more similar than xerothermophilous and mesophilous forests in a single region. Thus, Košir et al [42] base their classification on ecologically as well as geographically differential groups. Stressing the importance of the dominant trees, they propose classifying the Apennine coenoses, together with some Balkan ones (of the southern Balkan to Illyrian area), into a new suballiance of Tilio-Acerion, named Ostryo carpinifoliae-Tilienion platyphylli.…”

“…Can these differences be used to identify phytogeographical gradients? (iii) Does the differentiation of the Acer-Fraxinus woodlands in the Apennines reflect their attribution to a single suballiance (Ostryo-Tilienion platyphylli) together with some Balkan coenoses, as reported by Košir et al [42]?…”

“…The new alliance Lauro nobilis-Tilion platyphylli Biondi, Casavecchia and Biscotti 2008, recently described by Biondi et al [41] for the Tilia and Acer woods in the southern Apennines, could also be considered as a geographic vicariant of Tilio-Acerion. In fact, according to Košir et al [42] and Biondi et al [41] the southern limit of the Tilio-Acerion suballiance in the Apennine, represented by the association Aro lucani-Aceretum lobelii, is the Matese Massif (Campania, Molise). In this paper, we address the following questions regarding maple-ash coenoses ascribed to Tilio-Acerion, using a large dataset and various numerical methods: (i) Which types of Italian peninsular Acer-Fraxinus community can be distinguished from a phytosociological viewpoint, based on a large (114 relevés) data set?…”