1	Long-term dynamics of plant communities in subalpine and alpine zone of the Eastern Krkonoše Mts. (Giant Mts.) Karel Matějka IDS – Praha www.infodatasys.cz
2	Abstract Main aim of the study (prepared within the project No. 2B06012, www.infodatasys.cz/biodivkrsu) is evaluation of long-term changes in plant communities (prevailing grasslands) in the Eastern Krkonoše Mts. Permanent plots were sampled repeatedly during the period 1977-2008 (102 relevés). Total 34 plots were established in 1977 (Úpské rašeliniště peatland and Kaple-locality) and 1990 (Modrý důl valley and Studniční Mt.) in grasslands (dominant species Avenella flexuosa, Nardus stricta and Calamagrostis villosa), dwarf shrub communities (with Vaccinium myrtillus and V. uliginosum) and dwarf pine (Pinus mugo) stands. Altitudes vary between 1225 and 1503 m a.s.l. Prevailing part of communities was classified in association Carici bigelowii-Nardetum strictae (Zlatník 1928) Jeník 1961. These grasslands were used as pastures in the history. Diversity of single i-th relevé can be quantified by Shannon-Wiener's index (Hi) as a measure of α-diversity. In case of repeated sampling, summary or average sample over all relevés shows diversity within whole (temporal) gradient - similar index is Htot. Change of community structure over whole period (temporal β-diversity) can be calculated as dH=Htot-avg(Hi) in absolute value or relatively as dH/Htot. Total 57 species in herb and shrub layers were recorded in all relevés. Herb layers of the communities prevail poor in both species richness (S = 4 to 23) and total diversity (H = 0.67 to 3.90). Minor species changes were observed in a high portion of plots: dH was observed in the interval 0.03 - 0.37, dH/Htot varies between 1 and 17 %. All plots were classified (Ward's hierarchical method with square of Euclidean distance) according to average (over all relevés) cover of species in the herb layer. First classification group (0) represents typical grasslands of the association Carici bigelowii-Nardetum strictae in altitudes 1350-1503 m a.s.l. Communities are without dwarf pine, Avenella flexuosa covers more than 40 % of the plot, Hieracium alpinum is present, maximal number of species per sample is 13. Species structure shows minimal changes (dH ≤ 0.18; dH/Htot ≤ 9.2 %). The second main classification group (1) is more variable. Species as Vaccinium myrtillus, Calamagrostis villosa, Avenella flexuosa or Nardus stricta are dominant or subdominant. Subalpine tall forbs can be present. Herb layer of communities is often more diverse, particularly below 1300 m a.s.l., where number of species was between 10 and 23, H = 2.17 - 3.90. Maximal changes in composition of herb layer (4 plots, altitudes 1345 -1456, dH > 0.20, dH/Htot >8 %) was found in communities with speeding Vaccinium myrtillus or V. myrtillus with Calamagrostis villosa, under dense stand of Pinus mugo (decreasing diversity was manifested in all these cases) or in wet meadow where cover of formerly dominant Deschampsia cespitosa decreased and it is replaced with Molinia coerulea (both species richness and diversity increased). Communities overgrown by dwarf pine show similar species structure of herb layer as grasslands in respective site conditions. It points to origin of such stands in pastures without woods or with low cover of woods. Grasslands and similar communities in the investigated subalpine and alpine region of the Giant Mts. are highly stable in the species structure during the period of last 16-29 years regardless of regular pasture was excluded and changes in the man-influenced disturbances (paths near to some plots were closed).
3	Hierarchical levels of biodiversity and ecosystem processes Landscape (variability of ecosystem within a landscape segment) Ecosystem (species set within an ecosystem) Population (including genetic diversity of selected population)
4	Aim of the study Evaluation of long-term changes in plant communities (prevailing grasslands) in the Eastern Krkonoše Mts. was performed. Permanent plots were sampled repeatedly during the period 1977-2008 (102 relevés). Total 34 plots were established in 1977 (Úpské rašeliniště peatland and Kaple-locality) and 1990 (Modrý důl valley and Studniční Mt.) in grasslands. Altitudes vary between 1225 and 1503 m a.s.l. Dominant species: Avenella flexuosa, Nardus stricta, Calamagrostis villosa, Vaccinium myrtillus, V. uliginosum and Pinus mugo.
5	Plot localization
6	Methods Plant coenological relevés: DBreleve – database of relevés which is suitable for all data on species composition of any communities (plants, insect, fungi, ...) Accompanying software (TWINSPAN, CANOCO, PC-ORD, Statistica ...)
7	Methods of numerical analyse β-diversity along temporal gradient
8	Methods of numerical analyse Shifts in the ordination space
9	Numerical classification of average relevé – E₁ (Ward‘s method, Euclidean distance, y-axis - logarithm of dissimilarity)
10	Differentiation of the community groups: altitude
11	Differentiation of the community groups: species diversity
12	Differentiation of the community groups: species change (dynamics)
13	DCA ordination – species position
14	Average species diversity
15	Community dynamics - dH
16	Correlation analyse
17	Altitude and community diversity
18	Altitude and community dynamics
19	Plot M8N Year 1990 2008 E₂ Pinus mugo Turra 90 95 E₁ Calamagrostis villosa 48 57 Dryopteris dilatata 15 1 Trientalis europaea 15 1 Homogyne alpina 3 1 Avenella flexuosa 8 Vaccinium myrtillus 8 Maianthemum bifolium 1 Year 1990 2008 E₁ Vaccinium myrtillus 51 41 Calamagrostis villosa 10 11 Avenella flexuosa 5 11 Pinus mugo 2 11 Veratrum album lobelianum 8 1 Homogyne alpina 2 1 Picea abies 2 1 Potentilla erecta 8 0.1 Vaccinium vitis-idaea 8 0.1 Vaccinium uliginosum 7 Anthoxanthum alpinum 1 Calluna vulgaris 1 Juncus effusus 1 Melampyrum pratense 1 Molinia caerulea 1 Bistorta major 0.1 Carex nigra 0.1 Trientalis europaea 0.1
20	Plot S3L Year 1990 1995 2006 E₁ Deschampsia cespitosa 71 23 16 Calamagrostis villosa 7 15 9 Avenella flexuosa 4 23 33 Nardus stricta 6 12 9 Bistorta major 3 2 2 Homogyne alpina 0.2 4 Molinia caerulea 9 16 Anthoxanthum alpinum 3 1 Solidago virgaurea minuta 2 1 Carex bigelowii 1 1 Vaccinium myrtillus 9 Silene vulgaris 0.1
21	Conclusions Communities in lower altitudes have higher species diversity and richness. Highest dynamics (temporal variance) is founded in subalpine zone (often overgrown by Pinus mugo) or in wet biotopes.
22	Conclusions Relative stability of species composition in communities of higher altitudes is probably common feature of these communities. Similar situation is known from high montane Norway spruce forests. Main limiting factor pressing down diversity is light deficiency.
23	Project Management of biodiversity in the areas of Krkonoše Mts. (Giant Mts.) and Šumava Mts. (Bohemian Forest Mts.) 2006 - 2011 Supplied by Ministry of education of Czech Rep. & IDS