Fine-scale grassland permanent plots

 

Study sites
Data collection methods
Data set
Publications

 

 

Are you interested in analysing this data set yourself?

 

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):

 

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

 

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.


Number of modules (shoots for grasses, leaves for larger herbs, rosettes for small rosette herbs) of each species rooting in each cell have been counted every year. Flowering shoots are counted separately. Plots are recorded yearly in ca. mid June (Jana site) and mid July (Severka site); after the recording the plots are clipped and the clippings are sorted into species. (Biomass data at the plot level are also available.)

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

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:

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:

Management maintenance

Some analyses already done on the data

 

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

Some related publications

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