Regeneration patterns in a central European dry heathland: effects of burning, sod-cutting and cutting
Published source details
Sedláková I. & Chytrý M. (1999) Regeneration patterns in a central European dry heathland: effects of burning, sod-cutting and cutting. Plant Ecology (formerly Vegetatio 1948-1996), 143, 77-87.
Published source details Sedláková I. & Chytrý M. (1999) Regeneration patterns in a central European dry heathland: effects of burning, sod-cutting and cutting. Plant Ecology (formerly Vegetatio 1948-1996), 143, 77-87.
Vegetation development in dry heathlands was studied over 6-years following experimental burning, sod-cutting and cutting at a site in the southern Czech Republic (Podyji National Park). Prior to this, the heather Calluna vulgaris-dominated heathlands here were composed of uneven-aged stands and had been unmanaged for several decades. The aim of the study was testing the applicability of Western European maritime management systems to nature conservation of this inland continental European area.
Study area: The study was undertaken in the Podyji National Park near the town of Znojmo (48º49'N, 16º01'E), southern Czech Republic. The area was extensively sheep grazing for several centuries but since the end of the 19th century, grazing declined dramatically as it became uneconomical. Several accidental fires of limited extent occurred in the last decade. Prior to these management trials, the heathland had patchy Calluna stands, most in the mature phase but some patches in degenerate phase.
Sampling and treatments: Data were sampled in eight permanent plots with the following treatments:
i) Burning - three 4 x 4m plots were established in mid-April 1992, and most above-ground plant material was burnt. Parts of branches of Calluna and hairy greenweed Genista pilosa, located in the soil surface or buried in the litter, and a proportion of perennating organs of grasses and forbs were not destroyed. Fire intensity depended on Calluna cover (i.e. on the amount of woody fuel).
ii) Sod-cutting - two 4 x 4 m plots were established in mid-April 1992. Vegetation, litter and topsoil (exposing the underlying mineral soil) were removed.
iii) Cutting - two, 3 x 4 m plots were established in July 1992. All vascular plants were clipped to 3-5 cm above the ground. Creeping branches of Calluna and Genista, mosses and lichens were left.
iv) Control - three 3 x 4 m, control plots (no treatment) were established in July 1992; two in dense heathland and one in open heathland. However, only one control plot (in dense heath) could be subsequently relocated.
Each plots was divided into a 25 x 25 cm grid, and shoot presence, and data on the dominant species (i.e. those with cover >50%) of vascular plants, bryophytes and lichens were recorded for each grid square, and Calluna seedlings were counted. The original vegetation of burnt plots was sampled in mid-April 1992, prior to treatment. Burnt and sod-cut plots were sampled in July 1992, when original vegetation of cut plots was sampled just prior to cutting. Repeat sampling in all plots was undertaken in the summers of 1993-1997. An influence of adjacent vegetation was evident on the edges of some plots in the later years, thus marginal grid squares were not considered in the analysis except for the control.
Responses to burning: Burning of the densely vegetated heathland plot (which contained a large amount of woody fuel) resulted in medium fire-intensity that burnt most moss mats, lichen, and litter, and exposed patches of mineral soil. This facilitated Calluna regeneration by seed (with seedlings first appearing in the third year), in addition to vegetative regrowth mostly by resprouting from stem bases (also apparent for G.pilosa) which steadily increased over time. Early successional vegetation e.g. sheep's sorrel Rumex acetosella dominated in the second year. A species-rich heathland with higher abundance of graminoids, mosses and lichens than in the original vegetation was formed during years 4-6.
In the two burnt open heathland plots (originally patchy heather with forbs and graminoids) fires were of lower intensity. Hypnum cupressiforme moss mats and associated lichens and litter were only reduced patchily, and the mineral soil was hardly exposed. Almost all Calluna regenerated by resprouting and regrowth was slower. In one plot there was a slight decline in Calluna until the fourth year, followed by a slight increase; a similar pattern was observed in lichens. Grasses, in particular sheep's fescue Festuca ovina and a bent-grass, Agrostis coarctata, dominated in this plot. After six years a species-rich open heathland with graminoids, forbs, mosses and lichens had developed.
Responses to sod-cutting: Heath recovery after sod-cutting to mineral soil depended on whether or not Calluna seed germination occurred. With germination, the community developed towards Calluna-dominated heath; without it towards grassland. Early succession on the initially bare ground started with a few surviving species via vegetative regeneration, e.g., G.pilosa, burnet saxifrage Pimpinella saxifrage, perforate St. John's-wort Hypericum perforatum and
pasque flower Pulsatilla grandis (Syn: P.vulgaris grandis) the rapid spread of R.acetosella and then colonization by grasses, mosses and a few Cladonia lichens.
Responses to cutting: Cutting promoted a marked increase in grass cover (mainly wavy hair-grass Deschampsia flexuosa, F.ovina and A.coarctata) in open areas created by the removal of the shrub canopy, followed by slow Calluna recovery.
These experiments suggest that of the three management techniques trialled, burning is perhaps the most appropriate in the study area.
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