Šumarski list, Vol. 142 No. 3-4, 2018.
Izvorni znanstveni članak
https://doi.org/10.31298/sl.142.3-4.1
Phytocoenological analysis of grey alder (Alnus incana /L./ Moench supsp. incana) forest in Croatia
Joso Vukelić
; Šumarski fakultet Sveučilišta u Zagrebu
Dario Baričević
orcid.org/0000-0001-5708-9382
; Šumarski fakultet Sveučilišta u Zagrebu
Igor Poljak
; Šumarski fakultet Sveučilišta u Zagrebu
Mario Vrček
; Priroda d.d., Petrijanec
Irena Šapić
; Šumarski fakultet Sveučilišta u Zagrebu
Sažetak
This paper provides a comprehensive survey of the results of phytocoenological research of Alnus incana (L.) Moench subsp. incana stands in Croatia. Here, the grey alder appears in two biogeographic regions with contrasting climates (Figure 1): the continental region, along the course of the Drava river; and the mountainous Alpine-Dinaric region in Gorski kotar, along the course of the Kupa river and its tributaries. In the continental region of Croatia, the grey alder occurs mainly in riparian and floodplain forests along the main watercourse of the river Drava, where it forms smaller and isolated stands. These stands are included within the association Equiseto hyemali-Alnetum incanae Moor 1958 (Figure 3). Stands from the north-western Dinarides are defined within the association Lamio orvalae-Alnetum incanae Dakskobler 2010 var geogr. Helleborus dumetorum Vukelić et al. 2012 (Figure 4, Figure 5).
Our main objectives were: (1) to present the results of recent studies of the association Equiseto hyemali-Alnetum incanae; (2) to compare them with the results of the studies from early second half of the 20th century (Trinajstić 1964, 1973); and (3) to compare them with the phytocoenological characteristics of grey alder forests from the Dinaric area of Croatia.
The research was conducted on the basis of 11 new phytocoenological relevés and 37 from previous studies, according to the principles of the standard Central European Phytocoenological School (Braun-Blanquet 1964). Plant nomenclature was coordinated with the Flora Croatica Database (Nikolić 2015), and the mosses with Atherton et al. (2010). A part of the syntaxa was described in accordance with ICPN (Weber et al. 2000), and another part follows a multidimensional classification of vegetational
units (Matuszkiewicz and Matuszkiewicz 1981). The sociological species affiliation was determined according to Vukelić (2012). The analysis of the floral composition of the association Equiseto hyemali-Alnetum incanae (=Alnetum incanae Lüdi 1921) from north-western Croatia demonstrates a high degree of floral similarity with colline stands of the same association presented in the forest vegetation of Austria (Willner and Grabherr 2007). As grey alder stands in Podravina grow on lower altitudes, they lack or have considerably less of the following species: Fraxinus excelsior, Lonicera xylosteum, Cardus perssonata, Picea abies, Anemone ranunculoides, Salvia glutinosa and others. On the other hand, some species in them have certain differential significance, namely: Ulmus laevis, U. minor, Quercus robur, Fraxinus angustifolia, Populus alba, Valeriana dioica and others. Table 1 shows 11 new relevés of grey alder-scouring rush stands. Due to major anthropogenic interventions, grey alder-scouring rush forests have seen considerable regressive changes in the distribution and floral composition, hence just like the species Equisetum hyemale, they should be considered an endangered type of habitat. A large part of the original forests and shrubbery has been cleared over the last 50 years due to the construction of two accumulation lakes and other melioration and infrastructural needs. Meliorations have greatly impacted the hydrological regime of the entire area, which resulted in alterations in the habitat, and eventually in the disappearance of areas that used to be covered by grey alder forests. In order to determine the changes in the floral composition of grey alder-scouring rush stands, we compared our phytocoenological relevés with those from 1964 (Trinajstić 1964). Table 2 specifies 35 species that indicate changes in the habitat and composition of the association. The table clearly demonstrates that the number of hygrophytes has been reduced, and the share of mesophilic species and species from less wet habitats considerably increased (column 2, table 2), especially from the order Fagetalia and class Querco-Fagetea Br.-Bl. et Vlieger 1937.
The association Equiseto hyemali-Alnetum incanae has been compared with the stands from Gorski kotar, i.e. with the association Lamio orvalae-Alnetum incanae, where it was found that they differ significantly both from the ecological and from the floral point of view (Figure 2). Floral differences of the said forest communities result primarily from the climate and orographic factors of biogeographic regions, and the share of species from zonal forests in whose belts they grow. Table 3 specifies 76 differentiating species: seven for the association Equiseto hyemali-Alnetum incanae and 69 for the association Lamio orvalae-Alnetum incanae. The criterion employed to single them out was that they grow in only one association with at least 20% of relevés, or that the difference between the level of representation in associations is in excess of 35%. The largest number of differentiating species are mesophytes from the alliances Aremonio-Fagion /Ht. 1938/ Borhidi in Törek et al. 1989, Tilio-Acerion Klika 1955, Erythronio-Carpinion (Ht. 1938) Marinček in Wallnöfer et al. 1993 and the order Fagetalia (33 species in total). The large number and frequency of those differentiating species is the reason for clear independence and identity of the association Lamio orvalae-Alnetum incanae compared to other European grey alder forests (Vukelić et al. 2017). The most important differentiating species of the association Equiseto hyemali-Alnetum incanae is Prunus padus. With regard to syntaxonomy, the analyzed associations Equiseto hyemali-Alnetum incanae and Lamio orvalae-Alnetum incanae belong to the suballiance Alnenion glutinoso-incanae Oberd. 1953, alliance Alnion incanae Pawl. in Pawl. et al. 1928, of the order Fagetalia sylvaticae Pawl. in Pawl. et al. 1928 and class Querco-Fagetea Br.-Bl. et Vlieger 1937.
Ključne riječi
<i>Alnus incana; Lamio orvalae-Alnetum incanae; Equiseto hyemali-Alnetum incanae; </i>floral composition; Croatia
Hrčak ID:
199391
URI
Datum izdavanja:
30.4.2018.
Posjeta: 1.781 *