Herb layer dynamics of primeval fir-beech forests in central Slovakia

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1 Ujházy, K.; Križová, E.; Vančo, M.; Freňáková, E.; Ondruš, M., 2005: Herb layer dynamics of primeval fir-beech forests in central Slovakia. In: Commarmot, B.; Hamor, F. D. (eds): Natural Forests in the Temperate Zone of Europe Values and Utilisation. Conference October 2003, Mukachevo, Ukraine. Proceedings. Birmensdorf, Swiss Federal Research Institute WSL; Rakhiv, Carpathian Biosphere Reserve Herb layer dynamics of primeval fir-beech forests in central Slovakia Karol Ujházy, Eva Križová, Michal Vančo, Elena Freňáková and Miroslav Ondruš Department of Phytology, Faculty of Forestry, Technical University in Zvolen, T. G. Masaryka 24, Zvolen, Slovakia; Abstract Badínsky prales and Dobročský prales primeval forests are the oldest nature reserves in Slovakia, established in Our current research in these primeval forests is aimed at the study of herb species dynamics during the cyclic changes of fir-beech stands. We established 28 plots in different development stages of three communities, sampled frequency data of the herb layer and measured the structure of the tree layer. Indirect gradient analysis (DCA) showed separated clusters corresponding to different syntaxonomical units. Thus, herb species dynamics during cyclic changes were community-specific, reflecting differences between habitats. We found relatively low species turnover during particular cycle in comparison to commercial forests. Development stages were differentiated more by changing abundance or dominance of herb species. Generally, frequency values of most of herb species (closely correlated with the total herb cover) increased similarly as the number of trees and their estimated cover in the lowest layer (0 130 cm) the traits representing natural regeneration. On the other hand, they decreased with increasing sum of tree heights, as well as with the number of trees and the cover of the main and/or understorey tree layer. However, in several herb species, relationships deviating from this general rule were found. Especially the density of understorey trees seems to be an important factor, limiting herb layer development more than shading of main storey trees. Keywords: primeval forests, Eu-Fagenion, herb layer, cyclic changes, development stages, nature reserve, Western Carpathians 1 Introduction The Badínsky prales and Dobročský prales primeval forests belong to the oldest nature reserves in Slovakia. At the time of their foundation in 1913 they were considered to be the best preserved sites of primeval firbeech forests in Slovakia. Since then, the ecosystems of these two reserves have been strictly protected and maintained without direct human impact. Both reserves now offer good opportunity to study spatial and temporal dynamics of fir-beech forest ecosystems in Western Carpathians. Changes of vertical and horizontal structure of a local tree stands have been already described very well. The first research plots were founded in Dobročský prales in 1948 (Leibundgut 1959) to study structure, development stages, production abilities and natural regeneration. Silvicultural research was conduced by Kusák (1960), Priesol (1966), Korpeľ (1967, 1989) and Saniga (1999a). Structural characteristics and changes in Badínsky prales were studied on permanent plots also by Korpeľ et al. (1991) and Saniga (1999b). Results from these localities were used within well known descriptions of primeval forests life cycles and development stages of Leibundgut (1978) and Korpeľ (1995). On the other hand, the dynamics of whole phytocoenoses or whole ecosystems has not been described and explained sufficiently till now. Randušková (1964) started to study changes of forest types of Dobročský prales in course of stand development on parallel plots. She compared occurrence of typological units according to six development phases (originally distinguished by Leibundgut) and found different phytocoenose

2 types combinations in different development phases. She also noted surprisingly high abundance of spruce in some parts of the reserve, which was not consistent with the herb layer and rejuvenation species composition. Her results were published together with dendrometrical characteristics by Priesol and Randuška (1967). Unfortunately, the research was not continued and, at present, it is not possible to identify the plots. The main aim of our work was to contribute to the knowledge of herb layer development during the life cycle of West Carpathian fir-beech forests. We want to describe the changes of species composition within development stages, find the relations between herb layer changes and tree stand dynamics and to compare development cycles of different community types. We intended to describe a variability of plant community within forest type as a unit of potential natural vegetation, following ideas of A. Zlatník, who defined a forest type as a complex of natural developmental biocoenose stages as well as changed stages within the same permanent site conditions (Zlatník 1976). He described system of Western Carpathian groups of forest types according to species composition of optimum natural stand stages. He cannot describe all development stages of numerous forest types, but he emphasized that the complete knowledge of particular types is possible only by means of long term observations of a representative network of permanent plots (Zlatník 1961). Although numerous plots were established in Slovak beech forests, their temporal herb layer variability has not been studied sufficiently; species composition of development stages of particular forest types has not been described yet. The lack of information on this variability still causes problems in practical applications of forest typology in Slovakia. 2 Material and methods Dobročský prales (48º 41 N, 19º 40 E) and Badínsky prales (48º 41 N, 19º 03 E) are located in central Slovakia, central Western Carpathians. Both nature reserves are occupied mainly by fir-beech forests on cambisol soil types. Badínsky prales (30.03 ha) is situated in Slovenské Stredohorie Mts. in the 4 th beech altitudinal vegetation zone (according to Zlatník 1959 classification), at m a. s. l., on the volcanic andesite bedrock, with optimal conditions for beech (Fagus sylvatica) which reaches maximal height of about 45 m. Dobročský prales (49.9 ha of core area, ha whole area of reserve) in Veporské vrchy Mts. is on granite bedrock, climatically shifted to the 5 th fir-beech altitudinal vegetation zone in m a. s. l., with a natural occurrence of spruce (Picea abies) and optimal conditions for fir (Abies alba). Fir reaches the height of 58 m and above ground biomass of 51.3 m 3 (Randuška, Priesol 1967). According to the Slovak typological classification system (Hančinský 1972), fir-beech forest communities of Badínsky prales belong mainly to groups of forest types Fagetum typicum and Fagetum pauper (Križová 2000), whereas communities of Dobročský prales are classified as Abieto-Fagetum and partly as Fageto-Aceretum. According to Zürich-Montpellier school, herb-rich communities of Badínsky prales are close to Asperulo-Fagetum Sougnez et Thill 1959 association, nudal types are classified as Dentario bulbiferae-fagetum Zlatník Both communities are similarly formed by beech stands with regular admixture of fir. Herb-rich fir-beech stands of Dobročský prales belong to the Dentario enneaphylli-fagetum salvietosum glutinosae Oberdorfer ex W. et. A. Matuszkiewicz ex Guzikova et Kornaś They are dominated by beech and fir, with a regular admixture of sycamore (Acer pseudoplatanus), rarely also with spruce (Picea abies), elm (Ulmus glabra), ash (Fraxinus excelsior) and maple (Acer platanoides). In each reserve, 14 square or rectangular plots, 400 m 2 in size have been established (in Badínsky prales in 2001 and in Dobročský prales in 2002). Plots were placed with the aim to cover different stages of tree stand development after Korpeľ et al. (1991). Series of plots were set up in surroundings of optimum stages (with well-developed herb layer) with similar site conditions. Number of plots in one series (from three to ten) and number of series were limited by heterogeneity of site conditions, size of reserves and, mainly in Badínsky prales, by lack of optimum stages. Overall we have established one series with three plots in Fagetum pauper (Fp), three series with eleven plots in Fagetum typicum (Ft) and series 14 plots in Abieto-Fagetum (AF). Five additional relevés from notfixed plot (nr ) from Badínsky prales and two fixed plots (nr. 3, 4) from Figure 1. Sample plots with 200 squares on belt transects

3 buffer zone of this reserve were used for some analyses. The plots were stabilised in corners by wooden poles. Following data were recorded on each plot: - abundance and dominance of all vascular plant species using Zlatník s estimating scale (Zlatník 1976) - vertical structure by estimating woody species cover in each of seven layers: 1 over-storey; 2 main storey; 3 under-storey (higher than 1/2 of main storey); 4 from 1.3 m to 1/2 of main storey; 5 1a from 0.2 to 1.3 m; 5 1b < 0.2 m; 5 2 juvenile trees - frequencies of herb layer species (including woody species) recorded on two-hundred 0.25 m 2 square subplots located along systematically placed belt transects within the plot (Fig. 1) - absolute abundance of tree species (separately according to vertical layers) counted on each transect - diameter and height of all trees with diameter at breast height (dbh) > 7 cm The classification of development stages follows Korpeľ (et al. 1991) with English equivalents (growing, optimum, decaying stage) according to Neuert (et al. 2001). Names of typological units are used according to Hančinský (1972). Plant species nomenclature follows Marhold, Hindák (1998). Rubus hirtus was determined as a broad species R. hirtus Waldst. et Kit. (Dostál, Červenka 1991). Species of Dryopteris carthusiana agg. were not determined, however, in most cases it should be Dryopteris dilatata. The relevés were stored and processed using the TURBOVEG programme package (Hennekens 1996a) and MEGATAB programme (Hennekens 1996b). Similarity of all relevés (from both localities) was analysed by TWINSPAN divisive classification method (Hill 1979). Further analyses were based mainly on herb species frequencies. CANOCO programme (ter Braak & Šmilauer 1998) was used for indirect gradient analysis (Detrended Correspondence Analysis DCA) and for testing the tree stand characteristics in relation with herb layer variability by Monte Carlo permutation test. Statistica 6.0 software was used for correlation analysis using Spearman rank correlation coefficient. 3 Results Samples were taken in three vegetation units with quite similar species composition of herb layer. 28 out of 57 herb species were found in both reserves. Only 19 of these common species occurred at more than 50 % of plots in one reserve (Actaea spicata, Athyrium filix-femina, Dentaria bulbifera, Dryopteris dilatata, Dryopteris filix-mas, Galeobdolon luteum, Galium odoratum, Geranium robertianum, Impatiens nolitangere, Mercurialis perenis, Oxalis acetosella, Paris quadrifolia, Prenanthes purpurea, Rubus idaeus, Salvia glutinosa, Sanicula europaea, Senecio ovatus, Urtica dioica, Viola reichenbachiana). All dominants (in a single plot) belong to the most frequent species. Differentiating species between the two reserves were generally both less frequent and dominant, with the exception of Rubus hirtus in Badínsky prales, Dentaria enneaphyllos, Gymnocarpium dryopteris and Stellaria nemorum in Dobročský prales. The first division of TWINSPAN classification strictly separated the two localities (Fig. 2), which is clearly the consequence of the numerous differentiating species and down-weighting of cover values of the relevé nr.: locality: herb layer cover (%): development stage: typological unit: vegetation stage: trophic series: Dobročský prales Badínsky prales dec opt dec dec dec opt gro gro gro dec opt opt dec opt opt "gro" dec opt gro gro opt dec gro opt opt gro opt gro gro dec gro gro opt "opt" gro AF AF AF AF* AF* AF AF* AF AF Ftil FAc Ft Ft Ft Ft Fp Ft Ft Fp Ft Fp Fp AF AF* AF AF AF FrAc Ft Ft Ft Ft Ft Fp Ft B B B B(/C) B(/C) B B(/C) B B B/C B/C B B B B B B B B B B B C Figure 2. TWINSPAN classification of phytosociological relevés from all sample plots based on transformed cover values of herb layer species. Abbreviations: opt = optimum, dec = decaying, gro = growing stage, B = mesotrophic, B/C = heminitrophitic, C = nitrophytic

4 most frequent and dominant species. The second division approximately separated herb rich stages and stages with low herb layer cover (independent of the community type). Three relevés from heminitrophilous and nitrophilous communities of Badínsky prales (Fagetum tiliosum, Fageto-Aceretum and Fraxineto- Aceretum) were allocated to the cluster of mesotrophic communities (Fagetum typicum) with well-developed herb layer. Development stages of Fagetum typicum with low herb cover were, on the other hand, allocated to the cluster of the nudum type (Fagetum pauper). Herb-rich relevés of the decaying stages of mesotrophic Abieto-Fagetum type were clustered together with relevés from heminitrophillous type (Abieto-Fagetum* Fig. 2, 3) in Dobročský prales. The application of indirect gradient analysis (DCA) to frequency data (Fig. 3; each plot was represented by sampled species frequencies; rare species with presence on less than three plots were omitted) yielded better results (from the point of view of vegetation dynamics). Plots were ordered into clusters according to the community type (vegetation unit). With exception of plot 11 from the Dobročský prales, plots of different communities were not mixed together and vegetation dynamics could thus be analysed for each community separately. Figure 3. Ordination of sample plots according to herb species frequencies (DCA). B plots from Badínsky, D Dobročský prales. 3.1 Herb species dynamics during Abieto-Fagetum development cycle In this paper, we are focusing on the best documented series of Abieto-Fagetum from Dobročský prales. Plots 1 11D were considered. Tabular synthesis (Table 1) shows that with exception of Galeopsis sp. occuring only in decaying stage, there are no distinctive species for each stage. However, there seem to be few species which can be used for negative floristic differentiation of the growing stage (Senecio germanicus, Galeopsis sp., Circaea alpina). According to these results, species change their frequency but most of them are present during the whole cycle. Increasing frequency values can be used for estimating the species optimum and each stage can be characterised by species that reach their ecological optimum in this given stage. Two ferns Gymnocarpium dryopteris and Dryopteris dilatata have optimum in growing stage. Two other species which can grow on thick raw-humus layer or directly on dead wood (Oxalis acetosella, Dryopteris dilatata) are also frequent in the growing stage. However, their highest frequency values were recorded in the decaying stage. Viola reichenbachiana is the only species with a distinct optimum in the optimum stage. Another group of species (Galium odoratum, Galeobdolon luteum, Stellaria nemorum, Salvia glutinosa) has high (the highest) frequencies in both the optimum and the decaying stage. The group of nitrophytic species has increasing values through the whole cycle from the growing through the optimum to the decaying stage. The last group of taxa with rare records in the growing and the optimum stage (Urtica dioica, Senecio sp., Rubus idaeus, Galeopsis sp.) is characterised by tall-growing plants and is associated with humus decomposition in decaying stage. DCA indirect gradient analysis (Fig. 4, 5) provided the differentiation of species to the three groups corresponding to three stages of development cycle. Sample plots as well as species are arranged to the circular pattern according to the first two axes of ordinal space. This spatial pattern should have also temporal character, if we expect that position of sample plots will rotate counter-clockwise in the future

5 Table 1. Tabular species frequencies differentiation of Abieto-Fagetum development stages. Frequencies higher than average are bolded. Less frequent species without distinct dynamic pattern were not included (Asarum europaeum, Dentaria eneaphylos, Paris quadrifolia, Polygonatum verticillatum, Veronica montana, Chrysosplenium alternifolium, Stachys sylvatica). 6d 11d 5d 4d 9d 1d 8d 7d 2d 3d developm ent stage grow ing optim um decaying he rb la y er c over (% ) c anopy (% ) tree lay er c over (% ) - 1, , , Gym nocarpium dryopteris Dryopteris carthusiana agg Oxalis acetosella A th yriu m filix-fem in a D entaria b ulb ifera Dryopteris filix-m as Anem one nem orosa P renanthes purpurea Viola reichenb achiana Mycelis muralis Sanicula europaea Galium odoratum Galeobdolon luteum Stellaria nem orum Salvia glutinosa A c taea s picata G eranium rob ertianum Im patiens noli-tangere M erc urialis perennis Rub us idaeus Urtica dioica S enecio ovatus S enecio germ anicus Circaea alpina Galeopsis sp. 2 5 Figure 5. DCA differentiation of species according to stages: triangle = growing, circle = optimum, cross = decaying. Figure 4. DCA ordination of sample plots following circular character of Abieto-Fagetum development

6 3.2 Relationships between herb species frequencies and tree layers traits We used Monte Carlo permutation test to study changes of herb species frequencies according to several measured or estimated stand variables. The variables that best explained the variance of herb species frequencies are: abundance in 5 1a tree layer 10.1 % (of total variance explained); cover of th tree layer 9.7 %; abundance of beech in 5 1a 8.9 %; sum of tree heights 7.4 %; abundance in 5 1 tree layer 7.3 %; cover of 4 th layer 7.2 %. Table 2. Significant (bold) correlations of optimum stage species frequencies with tree layers traits and total herb layer cover. Den bul Gal odo Vio rei San eur Sal glu Ste nem total herbs cover tree mainstorey cover mainstorey abundancy understorey abundancy juvenile trees abundancy Table 3. Significant (bold) correlations of decaying and growing stage species with tree layers traits, total herb layer cover and sum of all species frequencies on plot. Mer per Urt dio Sen ova Imp nol total herbs cover cover a cover b cover a abundancy sum of frequencies sum of tree heights Ger rob Gal lut Asa eur Act spi Dry fil Partial correlations of individual species with tree layer traits using Spearman rank correlation coefficient allowed us to distinguish two groups of herb species with different responses to the traits (Table 2 and 3). Optimum stage species seems to be adapted to medium-shady conditions in hall mature stands with a closed canopy. Dense understorey (3+4) characteristic for the growing stage probably suppressed some herb species, especially Dentaria bulbifera and Galium odoratum. On the contrary, decaying stage species such as Urtica dioica, Impatiens nolitangere or Geranium robertianum (connected with a higher light and subsequently also nutrient supply) were recorded with the highest frequencies when canopy was open (low cover and abundance of mainstorey and understorey trees negatively indicated by decreasing sum of trees heights of 1 3 layers) and regeneration was in progress (positive correlations with abundance and the cover of trees < 1.3 m). Dryopteris filix-mas and Oxalis acetosella, the two of growing stage species have similar correlation pattern as decaying species. Although they have higher frequencies in growing stage than other species, their frequency values are highest in decaying stage, too. Oxa ace 3.3 Interspecific correlations Interspecific relations could play an important role, at least in the later optimum and in the decaying stage with high herb layer cover, since competition might gain importance in these stages. We found a group of strongly positively correlated species (Geranium robertianum, Galeobdolon luteum, Impatiens noli-tangere, Mercurialis perennis, Galium odoratum; Table 4). However, correlation of their frequencies can most likely be explained by similar reactions to changing ecological conditions. frequency (%) Geranium robertianum Impatiens noli-tangere Salvia glutinosa R 2 = 0,72 R 2 = 0,62 R 2 = 0, frequency of Galium odoratum (%) Figure 6. Exponential regression of frequencies of Galium odoratum and three nitrophytic species. Galium odoratum and Galeobdolon luteum (the second and third most frequent species of local beech forest with Oxalis acetosella being the most frequent) are typical for optimum stage. They are grouped with three nitrophytic species whose frequency increases more rapidly in the decaying stage. Differences in the development of frequencies of these closely correlated species to changing light and nutrient levels from the growing to the decaying stage are expressed by the regression on Figure 6. The only significant negative correlation (weak negative power regression) was observed between species Dryopteris dilatata and Stellaria nemorum, but Stellaria nemorum is not a very frequent species of those communities

7 Table 4. Matrix of Spearman rank correlations of herb species frequencies from all plots of Dobročský prales. Significant correlations (on p<0.05) are indicated in bold. Ger rob Gal lut Imp nol Mer per Gal odo Sal glu Oxa ace Ste nem Dry fil Rub ida Ath fil Vio rei San eur Den bul Dry dil Geranium robertianum Galeobdolon luteum Impatiens noli-tangere Mercurialis perennis Galium odoratum Salvia glutinosa Oxalis acetosella Stellaria nemorum Dryopteris filix-mas Rubus idaeus Athyrium filix-femina Viola reichenbachiana Sanicula europaea Dentaria bulbifera Dryopteris dilatata Discussion The processes studied in both primeval forests can be considered as fluctuations in a broad sense according to Miles (1979), or as an internal community dynamics (van der Maarel 1996), when vegetation keeps the same overall appearance. Changes in herb layer are influenced by beech and fir population dynamics, their mortality and regeneration. Whole process can be interpreted as gap or patch dynamics (depending on size of canopy gaps). Especially in Dobročský prales we met small-scale horizontal pattern of development stages given by the death of one or couple of old canopy trees. Regeneration of beech is quite rapid in this small openings with the width most frequently not more than 20 m. This characteristic feature can explain surprisingly low species turnover during the development cycle we noted only five taxa to grow only in decaying stage (Chrysosplenium alternifolium, Galeopsis sp., Festuca altissima, Fragaria vesca, Pulmonaria obscura the latter three were recorded only within complete relevés; all of them were rare species). Seven of decaying stage species were missing on growing stage. Lot of other so called clearcut flora species were not found on any plot, however, we tried to find the most opened stages. FAJMONOVÁ (1986), who studied clearcut plant communities on sites of fir-beech forests on crystalic bedrock of four mountain ranges within inner Western Carpathians, recorded these diagnostic species of Epilobietea angustifolii class: Rubus idaeus, Epilobium angustifolium, Senecio germanicus (the highest constancy), Senecio ovatus, Omalotheca sylvatica, Fragaria vesca, Eupatorium cannabinum (lower constancy). RANDUŠKA et al. (1985) and KRIŽOVÁ (1991) compared herb layer species composition of mature stands and clearcuts of the Abieto-Fagetum group of forest types on 9 pairs of plots in the Nízke Tatry and Kremnické vrchy Mts. (Central Slovakia). On clearcuts they found species in addition to mature stands with closed canopy. Among them, there were some ruderal species (as Tussilago farfara, Cirsium spec. div.), several heliophilous species of oak forests (Hypericum perforatum, Steris viscaria) and a number of a typical clearcut species not recorded in the reserve (Chamaerion angustifolium, Digitalis grandiflora, Eupatorium cannabinum, Fragaria vesca). Chamaerion angustifolium and Rubus idaeus were always present on clearings of beech forests in Romanian Carpathians (RESMERITA 1982). Rubus idaeus is the most characteristic species in the gaps of the Dobročský prales reserve, but Chamaerion angustifolium is missing. Also Senecio nemorensis agg. does not play important role here in comparison with well-known situation in clearcuts or opened canopy stands of managed fir-beech forests. According to RANDUŠKA et al. (1985) and KRIŽOVÁ (1991), it belongs among the most frequent dominants of clearcuts (along with Rubus idaeus, Urtica dioica, Galium odoratum, Stachys sylvatica, Oxalis acetosella, Geranium robertianum and Rubus hirtus). Unfortunately, there are no comparable works dealing with herb layer changes within development cycle of primeval forests communities from Western Carpathians. From the Central European region, we can compare our results with long-term studies from some forest reserves of Czech Republic. VRŠKA et al. (2002) studied changes of Dentario enneaphyli-fagetum after 21 years on exactly recovered permanent plots. On most of plots of comparable community type (6D1) in the Žákova hora Mt. reserve (Českomoravská vrchovina uplands), they observed decreased total herb cover due to the developing complex tree stand structure and hence a greater shade. Decreased cover degree showed Rubus idaeus, Urtica dioica, Mercurialis

8 perennis, Senecio nemorensis, Galium odoratum, Galeobdolon luteum, Oxalis acetosella and Viola reichenbachiana. Only Dentaria bulbifera and Dryopteris carthusiana had slightly increased covers. These results are consistent with our findings, when the above mentioned increasing species belong to growing stage species (Fig. 5, Table 1) tolerating a high tree density and the decreasing species we classified as optimum and decaying stage species negatively correlating with the sum of tree heights the trait reflecting mainly a high number of understorey trees (Table 3). Mercurialis perennis, Galium odoratum, Galeobdolon luteum and Oxalis acetosella also belong to the group of species with the most close reaction to the stand changes (Table 4) in the Dobročský prales. VRŠKA et al. (2002) explain the changes mainly by changing light conditions. Probably this is the most important factor, however, our results show also two other important features. Negative reaction of most of species to increasing beech stand density can be explained also by increasing root competition. SLAVÍKOVÁ (1986) presented an example, when cut across of beech roots enabled development of herb layer under the same light conditions of Fagetum nudum community. Other feature is live strategy and life form. The most rapid development showed polychoric and autochoric terophytes Geranium robertianum and Impatiens nolitangere (cf. JURKO 1990), followed by species with vegetative reproduction ability (Galium odoratum, Galeobdolon luteum and others). On the other hand, long living perennial ferns survived without a big change of abundance through the whole cycle (Table 1). RESMERITA (1982) ranked Athyrium filix-femina, Dryopteris filix-mas and Dryopteris carthusiana to the same group of shade tolerant species which can also survive long time on completely opened clearcuts. We were interested also on whole community changes and variability. Although species turnover is relatively low, the composition undergoes considerable changes during the development cycle of the studied communities. The comparison of three different cycles by means of frequency values ordination (Fig. 3) shows that these changes do not exceed community type. Within this cyclic process, ordination seems to be a more efficient method to classify the stages than classification methods such as TWINSPAN (Fig. 2), whose results reflects more floristic differences than developmental trends. This result is important for the application in syntaxonomic classification systems used in Slovakia, which do not consider variability between development stages enough. We can see (Table 1), that communities of development stages are differentiated more by dominance os species than by other species occurence. Thus, especially when dominance is considered to be important classification criterion, some development stages of the same community can be classified separately or together with stages of the other community (Fig. 2) Units of the Slovak typological school are differentiated both by the presence and the cover of diagnostic species. Thus, at the same site of Abieto-Fagetum, the floristic composition can vary in the range of two or three groups of forest types. In particular, herb layer with the dominance of nitrophytic species, such as Geranium robertianum and Impatiens noli-tangere (cf. Križová, Nič 1997), in the decaying stage of Abieto- Fagetum would be improperly classified as Fageto-Aceretum. Even if we speak about a broad association as Dentario enneaphylli-fagetum from Fagion alliance of the floristic-based classification system of Zürich-Montpelliér school, its decaying stage in Dobročský prales with increasing dominance of nitrophytes seems to be closer to the heminitrophilous Mercuriali-Fraxinetum association (sensu Husová in Moravec et al. 2000) from Tilio-Acerion alliance. Consequently, the incorrect estimation of development stage can lead to the improper classification results. In the case of forest typology, it can have negative consequences in forest management practice, such as plantations of less suitable tree species. 5 Conclusions Some common features of herb layer changes during natural fir-beech primeval forests development were found: - In both reserves studied in Central Slovakia, frequencies of most of the herb species had the tightest associations with the total herb cover (estimated on a whole plot), number of individual trees in the lowest (5 th ) layer (0 130 cm) and estimated 5 th layer tree cover (whole plot). The decline of frequencies was explained by the increasing values of summed tree heights (dbh > 7 cm), a number of individuals and the cover of particular tree layers (mainstorey and understorey). - Temporal development of plant populations as well as their relationships with tree layer traits are nonlinear; we can find groups of species with similar reaction to the changes of tree stand

9 - There is a relatively high frequency of ferns (Dryopteris carthusiana agg., D. filix-mas, Athyrium filixfemina) and Dentaria bulbifera in dense and shady growing stages and rapid frequency increase of nitrophytic (Geranium robertianum) or so called clear cut species (Rubus idaeus) in opened gaps of decaying stage. - There is a low species turnover during the development cycle of fir-beech primeval forest in comparison to managed forests with clear-cut stages. - The highest vascular plant diversity of fir-beech primeval forests is in the beginning of decay stage and in the phase of beech regeneration. However, behaviour of particular species and trees/herbs relations differ between the two localities and community types as well. In Badínsky prales, the 4 th layer (from 1.3 m to half of main storey height) featured the strongest negative influence on the herb layer species frequencies, whereas in Dobročský prales, it was the 3 th layer (understorey). In best described series of Abieto-Fagetum in Dobročský prales very clear gradient from oligotrophic, mesotrophic to eutrophic and nitrophytic species between the growing and decaying stage was observed. Similar gradient was not so obvious in different conditions of Badínsky prales. Dentaria bulbifera was not significantly positively related to any other species but in Badínsky prales it showed significant (p < 0.05) negative correlation with some of them (Impatiens noli-tangere, Galium odoratum and Dryopteris filix-mas). We distinguished groups of species with similar reactions to tree stand structure changes and with tight positive correlations between their frequency values as well, but they partly differ between two localities (Galeobdolon luteum, Geranium robertianum, Impatiens noli-tangere and Galium odoratum in Dobročský prales; Galium odoratum, Geranium robertianum and Oxalis acetosella in Badínsky prales). In conclusion, we scan say that different herb species dynamics were related to different community types, reflecting differences in habitats and available species pool of particular phytogeographical region, as shown by indirect gradient analysis of the same herb frequencies data set. DCA results showed separated clusters of the above-mentioned community types. Ordering of plots according to the development dynamics could be recognized only within particular clusters. The variability of species composition within the development cycle does not seem to exceed limits of community type, although it markedly exceeds static perception of community represented only by single phytosociological relevé of mature forest stand. 6 References Dostál, J.; Červenka, M., 1991: Veľký kľúč na určovanie vyšších rastlín 1. SPN, Bratislava, 775 pp. Fajmonová, E., 1986: K fytocenológii trávnatých rúbaniskových spoločenstiev v niektorých oblastiach Slovenska. Biológia (Bratislava) 41(1): Hančinský, L., 1972: Lesné typy Slovenska, Príroda, Bratislava, 307pp. Hennekens, S. M., 1996a: TURBO(VEG). Sofware package for input, processing, and presentation of phytosociological data (User's guide). IBN-DLO, Wageningen et University of Lancaster, Lancaster, 52 pp. Hennekens, S. M., 1996b: MEGATAB a visual editor for phytosociological tables (version 1.0). Gielsen & Geurts, Ulft, 10 pp. Hill, M. O., 1979: TWINSPAN. A Fortran program for arranging multivariate data in an ordered two-way table by classification of the individuals and attributes. Cornell Univ., Ithaca, 52 pp. Jurko, A, 1990: Ekologické a socioekonomické hodnotenie vegetácie. Príroda, Bratislava, 195 pp. Korpeľ, Š., 1967: Dobročskýprales jeho štruktúra, vývoj a produkčné pomery. Sborník ČSOP, Bratislava, p Korpeľ, Š., 1989: Pralesy Slovenska. Veda, Bratislava, 329 pp. Korpeľ, Š.; Peňáz, J; Saniga, M.; Tesař, V., 1991: Pestovanie lesa. Príroda, Bratislava, p Korpeľ, Š., 1995: Die Urwälder der Westkarpaten. Fischer Verlag, Sttuttgart-Jena-New York, 310 pp. Križová, E., 2000: Lesné spoločenstvá NPR Badínsky prales. Chránené územia Slovenska, 46: Križová, E.; Nič, J., 1997: Fytocenológia a lesnícka typológia Návody na cvičenia. TU vo Zvolene, Zvolen, 106 pp. Kusák, A., 1960: Výskum pralesovitej rezervácie Dobroč. Záverečná správa VÚLH, Zvolen, 159 pp. Leibundgut, M., 1959: Über Zweck und Metodik der Struktur und Zuwachsanalyse von Urwäldern. Schweiz. Zeitschr. F. Forstwesen 120(3): Leibundgut, M., 1978: Über die Dynamik europaischer Urwälder. Allg. Forstzeitshrift 24: Marhold, K.; Hindák F. eds., 1998: Zoznam nižších a vyšších rastlín Slovenska. Veda, Bratislava, 687 pp. Miles, J., 1979: Vegetation dynamics. Chapman and Hall, London, 80 pp. Moravec, J.; Husová, M.; Chytrý, M.; Neuhäuslová, Z., 2000: Přehled vegetace ČR Svazek 2 Hygrofilní, mezofilní a xerofilní opadavé lesy. Academia, Praha, 319 pp

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