Introduction

The Krkonose Mts. (a mountain range in the northern part of the Czech Republic, the highest peak 1602 m) reach above the timberline and hence harbour natural treeless vegetation (alpine meadows above timberline and in avalanche tracks). In addition to that, there are numerous larger and smaller grassland areas below the timberline that are due to systematic felling in the area. (These meadows are 300-400 years old.) The flora of these man-made grasslands contains also numerous species that descended from natural treeless habitats above the timberline, such as glacial cirques (e.g. Hypochaeris uniflora, Viola lutea ssp. sudetica, Anthoxanthum alpinum, Potentilla aurea etc.).

A view of several grassland sites surrounded by forests (the altitude of the peak, Snezka, is 1602 m; it is the highest peak of the Krkonose range)

Traditionally these grasslands have been used for cattle-keeping. The species composition of the grasslands has thus been maintained by human activity, particularly primarily by mowing (once or twice a year, depending on productivity of the site) and irregular manuring. However, these meadows have been in steady decline after the WW II when most of the German population had been forced to leave and new settlers came into the area; these new settlers not always had good knowledge or motivation to maintain earlier agricultural practices. This process of decline was particularly speeded up following intensification of agriculture in 70ies and 80ies. Since mountain grasslands are largely not suitable for high-input agriculture, they shared the fate of other low-productivity grasslands elsewhere, and a major share of them have been abandoned by now; the abandonments results in developing coarser grain in vegetation structure (i.e. reducing richness at the fine scale), in dominance of some competitive species (particularly Polygonum bistorta, sometimes also Holcus mollis, Calamagrostis villosa or Hypericum maculatum).

Study sites

The intensive research is carried out at two major study sites (species lists are here):

• the Severka study site (also referred to as the species-poor site) is located in a mountain grassland in the Krkonose Mts., ca. 3 km NW of Pec pod Snezkou, latitude 50^o 41' 42'' N, longitude 15^o 42' 25'' E, altitude approx. 1100 m. The site has a harsh climate; mean temperature in the warmest month (July) was 13.6^o C (1988), 13.7^o C (1989) at the nearby climatic station (Pec pod Snezkou, ca. 900 m a.s.l.). There is a long winter with thick snow cover, which lasts generally from November till the end of April. There are only five principal species at the site: Anthoxanthum alpinum, Deschampsia flexuosa, Festuca rubra, Nardus stricta and Polygonum bistorta. Though the system is species poor at the large scale, the species are coexisting at the very fine scale; the species density is 2-4 species/10 cm2 and 6-10 species/2500 cm2. In the Braun-Blanquet classification of the Krkonose grasslands (Krahulec 1990) the studied grassland is classified as Sileno-Nardetum (Nardo-Agrostion, Nardetalia), subassociation pleurozietosum. Most of the research carried out here terminated in 2001. Also  recording of the permanent plots S1 to S4 finished that year.
  
  Here are two photographs from a grassland very similar (both in floristic composition and overall structure) to the Severka site (but taken elsewhere)
  
  

Nardus stricta, Festuca rubra, Anthoxanthum spp., Campanula spp., Hieracium lachenalii, Polygonum bistorta

An idealized view of the grassland at the Severka site (drawn by Sylvie Pechackova)

• the Jana study site (also referred to as the species-rich site): Janovy boudy, 3.75 km ESE of Pec pod Snezkou, latitude 50⁰ 41' 28'' N, longitude 15o 47' 35'' E, altitude 880 m. This is a species-rich locality, with ca. 4- 7 species per 10 cm² and 25-30 species per 2500 cm). The locality has a milder climate with a longer growing season (ca. 7-8 months) than the Severka locality. Also soils are richer in magnesium and calcium and have a lower C/N ratio in the species-rich locality. In the Braun-Blanquet classification of the Krkonose grasslands (Krahulec 1990) the studied grassland is classified as Sileno-Nardetum (Nardo-Agrostion, Nardetalia), subassociation silenetosum. Except for Euphrasia rostkoviana at the species-rich locality there are only perennial species at both localities.

An overall view of the Jana site in early summer

A meadow at the Jana site in June with Geranium sylvaticum, Ranunculus acris, Rumex acetosa, Alchemilla spp., Anthoxanthum odoratum, (and many other plants) in flower

Management at the sites

The plots have been managed by clipping that simulated mowing. No other management has been done at the Severka site (except for manuring - see below). At the Jana site, the whole grassland has been mown by the owner some 5-20 (depending on the year) days after the recording/clipping done by us; therefore the plants that resprouted after the clipping (there was some regrowth, but usually not much) were thus mown for the second time.

Two plots at each site (S1, S3, J1, J2) have been regularly manured every four years in September (in 1985, 1989, 1993, 1997, 2001). Local source manure (cow manure at Severka, horse manure at Jana) was used. This amounted to adding (approximately) the following amount of nutrients (g/m²): Total N = 17, NO₃-N = 0.2, NH₄-N˙=˙3.8, PO₄-P = 2.4.

The remaining four plots were manured only once, in 1997.

Data collection methods

We recorded fine-scale dynamics using permanent plots of 50 x 50 cm with grid of cells of 3.3 cm x 3.3 cm. The recording is done using a wooden frame with steel wires to make the grid; the frame is positioned using large nails that are permanently marking the site (see in the corners of the frame - outside). These nails fit into thin long aluminum tubes in the soil. Repeated positionings of the frame do not differ by more than 0.5 cm; however, there may be some cumulative movements of the nails over the years.

The data have been recorded by the number of people; it was impossible to assure that always the same people did the recordings. While we did cross-checkings, there still may be some inconsistency in the way how different people interpreted the plants. Most of the recordings were done (arranged alphabetically) by Stanislav Brezina, Martina Fabsicova, Vera Hadincova, Tomas Herben, Marcela Kovarova, Frantisek Krahulec, Sylvie Pechackova, Hana Skalova, Karla Vincenecova and Radka Wildova.

Overview of the data currently available/being recorded for the fine-scale dynamics

 

Severka, four 50 x 50 permanent plots of 15x15 cells	1984-2001
Jana, four 50 x 50 permanent plots of 15x15 cells	1985-present

Data set

The long-term fine-scale permanent plot recording at the both sites has produced an essentially uninterrupted (exceptions see below) data series of 18 (Severka) and 19 (Jana) years of 50 cm x 50 cm plots with shoot counts recorded at the level 3.3 cm x 3.3 cm; sterile and flowering shoots are listed separately. In particular, the data contain information on spatio-temporal dynamics at the module level of all species of coexisting clonal plants in one community at a fine scale.

An example of the data structure is here. It contains an Excel sheet containing two years of one plot at the Severka site (S1) and at the Jana site (J1).

A visual rendering (done by Ulf Dieckmann of IIASA) of the plot S1 (Severka site) over 8 year interval (1987, 1989, 1991, 1993, 1995) is here. Each row is one recording; each column is one species (Deschampsia flexuosa, Festuca rubra, Nardus stricta and Anthoxanthum alpinum). The plot is 0.5x0.5 m; small squares correspond to 3.3 x 3.3 squares of the field recording. The rainbow spectrum in the small squares indicates ramet numbers of these species counted in each grid cell. Note the change in local density of species over time, while the overall density changes only little.

Additional data available

• climatic data from the nearby station starting from 1996 (analysis of biomass/density - climate relationship is just being done)
• data on biomass sorted into species in each plot
• root distribution below the Severka plots in blocks of identical size as used for the aboveground recording. After the plots have been abandoned, we dug the whole plots out and divided the below-ground into blocks 3.3x3.3 cm. There is a slight difficulty: while the blocks were collected and separated, roots were never washed out and the whole thing is stored in the freezer (once we have resources to do it ...)

Then there is 'context' information from many other experiments done at the site: removal and implant experiments, genet structure of dominant grasses, root and rhizome distribution, management experiments, demographic data on some species etc. (see publications below)

Irregularities and problems in the data set

General problems with the recording technique

Although the recording technique is rather well reproducible, there is one important reason for variation:

• If there is a clump of modules of a species at the line separating two cells (a common situation), the assignment of these modules to cells may vary from one recording to the other. Even a very small shift of the frame may change have an important effect for clumped species like Nardus stricta.

Specific

As any data set that has been collected over rather a long time and by different people, this data set contains irregularities and missing data. These are mainly due to the following: (i) recording practices changed over time to some extent, (ii) people doing the recording learned to identify tiny bits of plants better over time, (iii) we erroneously recorded a wrong plot once, (iv) start of the recording was not completely synchronous. These facts account for the following:

• at the Jana site, some rare species (particularly grasses) might have slipped attention in the early years of recording (when we had difficulties to identify all sterile shoots). This may concern Briza media, Trisetum flavescens and perhaps some other species as well
• at the Jana site, one recording of the plot J4 is missing (in 1989)
• at the Severka site in 1985 and 1986, only estimation instead of counting was done in some cells with very high module numbers. This concerns mainly Nardus stricta and Deschampsia flexuosa.
• at the Severka site, recording of one plot (S3) started one year later (1985) than recording of the other plots
• Biomass data from 1985 are missing

Management maintenance

• There are successional trends, particularly at the Severka plots, with increase of Nardus and decrease of Deschampsia. While this may have many reasons, we assume that it may be due to the (very regular) clipping (that has been done perhaps at slightly shorter height that usual mowing would be done).
• The fertilized plots are definitely richer and some species show cycles following manuring. For logistic reasons the fertilized plots had to be established at richer part of the meadow anyway, and therefore the differences cannot be interpreted as the result of our fertilization.

Some analyses already done on the data

• spatial and temporal autocorrelations of species (Herben et al. 1990, 1993, 1994, 1995): both species-rich and species-poor, but limited to 1984-1996
• cross-correlation of species (Herben et al. 1997): only species-poor, 1984-1996
• correlations of species changes (Herben et al. 1995): only species-poor, 1984-1995
• correlation of plot-level data with climate (Herben et al. 1997): only species-poor, 1984-1994
• regression estimation of species-specific competition coefficients (Law et al. 1997): only species-poor, 1984-1995
• NB. Except for simple autocorrelation analyses (Herben et al. 1993), no detailed analysis of the data from the species-rich site was published. An extensive autocorrelation and cross-correlation analyses have been done, but are still unpublished.

Publications (if no pdf is provided here, we will be happy to send you reprints. Just please send an e-mail)

Directly based on the data set

• Dieckmann U., Herben T. & Law R. (1999): Spatio-temporal processes in ecological communities. CWI Quartely 12: 213-238. Abstract
• Herben T., Krahulec F., Hadincova V., Pechackova S. & Kovarova M. (1997): Fine-scale spatio-temporal patterns in a mountain grassland: do species replace each other in a regular fashion? Journal of Vegetation Science 8: 217-224. Abstract pdf
• Law R., Herben T. & Dieckmann U. (1997): Non manipulative estimates of competition coefficients in a montane grassland community. Journal of Ecology 85: 505-517. Abstract pdf
• Herben T. (1996): Permanent plots as tools for plant community ecology. Journal of Vegetation Science 7: 195-202. Abstract
• Herben T., During H.J. & Krahulec F. (1995): Spatiotemporal dynamics in mountain grasslands: species autocorrelations in space and time. Folia Geobotanica and Phytotaxonomica 30: 185-196. Abstract pdf
• Herben T., Krahulec F., Hadincova V. & Pechackova S. (1995): Climatic variability and grassland community composition over 10 years: separating effects on module biomass and number of modules. Functional Ecology 9: 767-773. Abstract
• Herben T., Krahulec F., Hadincova V. & Pechackova S. (1994): Is a grassland community composed of coexisting species with low and high spatial mobility? Folia Geobotanica and Phytotaxonomica 29: 459-468. Abstract pdf
• Herben T., Krahulec F., Hadincova V. & Kovarova M. (1993): Small-scale spatial dynamics of plant species in a grassland community over six years. Journal of Vegetation Science 4: 171-178. Abstract pdf
• Herben T., Krahulec F., Hadincova V. & Skalova H. (1993): Small-scale variability as a mechanism for large scale stability in mountain grasslands. Journal of Vegetation Science 4: 163-170. Abstract
• Herben T., Krahulec F., Kovarova M. & Hadincova V. (1990): Fine scale dynamics in a mountain grassland. In: Krahulec F., Agnew A.D.Q., Agnew S. & Willems J.H. (eds.) Spatial processes in plants communities,. SPB Publishers, The Hague, pp. 173-184. Abstract

Some related publications

• Herben T., Krahulec F, Hadincová V., Pecháčková S., Wildová R. (2003). Year-to-year variation in plant competition in a mountain grassland. J. Ecol. 91: 103-113. Abstract pdf (publisher's notice here).
• Herben T., Suzuki J. (2001). A simulation study of the effects of architectural constraints and resource translocation on population structure and competition in clonal plants. Evolutionary Ecology 15: 403-423 Abstract pdf (Copyright Kluwer Academic Publishers)
• Herben T., Hara T., Hadincova V., Krahulec F., Pechackova S., Skalova H. & Suzuki J. (2001): Neighborhood effects and genetic structure in a clonal grass: The role of the spatial structure of the environment. Plant Species Biology 16: 1-11. Abstract
• Herben T., Krahulec F., Hadincova V. & Pechackova S. (2001): Clone-specific response of Festuca rubra to natural variation in biomass and species composition of neighbours. Oikos 95: 43-52. Abstract
• Herben T., During H.J. & Law R. 2000. Spatio-temporal patterns in grassland communities. In: Dieckmann U., Law R. & Metz J.H.J. (eds.) The geometry of ecological interactions: simplifying spatial complexity, Cambridge University Press, pp. 48-64. pdf
• Pechackova S., During H.J., Rydlova V. & Herben T. (1999): Species-specific spatial pattern of below-ground plant parts in a montane grassland community. Journal of Ecology 87: 569-582. Abstract
• Skalova H., Krahulec F., During H.J., Hadincova V., Pechackova S. & Herben T. (1999): Grassland canopy composition and spatial heterogeneity in the light quality. Plant Ecology 143: 129-139. Abstract
• Suzuki J., Herben T., Krahulec F. & Hara T. (1999): Size and spatial pattern of Festuca rubra genets in a mountain grassland: its relevance to genet establishment and dynamics. Journal of Ecology 87: 942-954. Abstract
• Herben T., Krahulec F., Hadincova V. & Pechackova S. (1997): Fine-scale species interactions of clonal plants in a mountain grassland: a removal experiment. Oikos 78: 299-310. Abstract
• Skalova H., Pechackova S., Suzuki J., Herben T., Hara T., Hadincova V. & Krahulec F. (1997): Within population genetic differentiation in traits affecting clonal growth: Festuca rubra in a mountain grassland. Journal of Evolutionary Biology 10: 383-406. Abstract
• Pechackova S. & Krahulec F. (1995): Efficient nitrogen economy: key to the success of Polygonum bistorta in an abandoned mountain meadow. Folia Geobotanica and Phytotaxonomica 30: 211-222. Abstract
• Herben T., Krahulec F., Hadincova V., Kovarova M. & Skalova H. (1993): Tiller demography of Festuca rubra in a mountain grassland: seasonal development, life span, and flowering. Preslia 65: 341-353. Abstract
• Skalova H. & Krahulec F. (1992): The response of three Festuca rubra clones to changes in light quality and plant density. Functional Ecology 6: 282-290. Abstract
• Herben T. & Krahulec F. (1990): Competitive hierarchies, reversals of rank order and the de Wit approach: are they compatible? Oikos 58: 254-256.

Further publications can be found at our Krkonose page and at the page of Tomas Herben