Znaleziono wyników: 3

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: subalpine grassland

Sortuj według:

Ogranicz wyniki do:

Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik

Regeneration of Nardus stricta subalpine grasslands in the Giant Mountains [Krkonose]

100%

Hejcman M., Nezerkova P., Pavlu V., Gaisler J., Lokvenc T., Pavlu L.

Acta Societatis Botanicorum Poloniae

2005

tom 74

nr 3

The origin of Nardus stricta dominated subalpine grassland (Nardo-Caricion rigidae alliance) is a frequently discussed topic in the Giant Mountains (Karkonosze in the Czech Republic). Many researchers considered them, as secondary stands arisen after Pinus mugo removal and by consequent oligotrophization of original plant communities, caused by long-term rough grazing and hay making activities without manuring. On the contrary, they are recognized as natural due to inability of generative reproduction of N. stricta and the very slow vegetative spread there. The aim of this study was to find proofs for generative reproduction of mat grass in subalpine conditions of the Giant Mountains. We identified a Pinus mugo nursery with arable land abandoned in 1956 and compared its vegetation with that of the surrounding area. Dense and homogenous sward dominated by N. stricta developed during the succession on the old arable land for 48 years, and it is an indisputable proof of generative reproduction of N. stricta there. Synthesizing historical facts on human activities in the past and the results of our contemporary vegetation analysis, we conclude that the Nardo-Caricion rigidae grassland was capable to spread relatively quickly, when agricultural activities above the upper timber line were introduced.

Farmer decision making and its effect on subalpine grassland succession in the Giant Mts., Czech Republic

84%

Hejcman M., Pavlu V., Hejcmanova P., Gaisler J., Hakl J., Rauch O.

Acta Societatis Botanicorum Poloniae

2006

tom 75

nr 2

165-174

Nitrogen deposition is generally considered as a main reason for many recent plant expansions, but management changes are often not taken into account. Understanding the effects of agriculture management in the past can be decisive in the explanation of plant expansions at present. In order to understand the spread of Molinia caerulea and Calamagrostis villosa into Nardus stricta dominated subalpine grassland in the Giant Mts. (Krkonoše, Karkonosze), we undertook an experiment to explain farmer decision making and we discussed its effect on grassland succession. We measured mowing productivity, yields, biomass quality and nutrient removal in N. stricta, M. caerulea, and C. villosa dominated swards. With regard to defoliation management performed on the subalpine grasslands for at least 500 years and cancelled after the Second World War, we found the following results and conclusions. 1. Mowing productivity, yield and forage quality were lowest in the N. stricta sward, therefore farmers preferred to harvest C. villosa and M. caerulea stands if they had the possibility to select a sward for mowing. 2. Removal of all nutrients was the lowest in the N. stricta sward. With respect to these facts, the competitive advantage of N. stricta is obvious under long-term scything without fertilization. Consequently, the recent increase of defoliation sensitive species M. caerulea and C. villosa above the timber line must be evaluated with respect to both: termination of agricultural activities and recent nitrogen deposition.

Carbohydrate reserve changes in below-ground biomass of subalpine grasslands as a result of different snow conditions [Hruby Jesenik Mts., Czech Republic]

84%

Zeidler M., Banas M., Duchoslav M.

Polish Journal of Ecology

2008

tom 56

nr 1

Carbohydrate concentration changes in below-ground biomass of subalpine tall grasslands with Calamagrostis villosa (Chaix) J.F. Gmelin were monitored during one year on the slope of Petrovy kameny Mt. (Hruby Jesenik Mts., Czech Republic). Stands of the community with natural snow conditions were compared with stands on a ski piste. Soil temperature development and snow melting times were also observed in the territory concerned. The difference was stated between mean annual temperature on control stands (4.21oC) and ski piste (3.95oC) in the upper 5 cm of soil. At the average, snow melted on the ski piste two weeks later than that on the natural stands. The natural stands and the stands on the ski piste differ significantly from each other in terms of development of carbohydrate accumulation in the below-ground biomass. Consumption of reserve carbohydrates by the plants at both the ski piste and in the natural stands was nearly similar during the winter. At the beginning of the growing season (July), significant difference in carbohydrate concentration in below-ground organs between stands on the ski piste and natural stands was observed. It was caused by late melting of the snow cover and subsequent delay of the phenologic development and assimilation of the vegetation in the ski piste. Later in season (August, October), the differences in carbohydrate concentration between stands at the ski piste and natural stands disappeared. The mean annual amount of carbohydrates in the upper (0–5cm) and lower (5–10 cm) soil horizons in natural stands and ski piste stands do not differ fundamentally, except for the significant difference in July. The results obtained are discussed in view of abiotic environmental conditions, the plant physiology and strategy of the dominant species.

Ograniczanie wyników

2 Acta Societatis Botanicorum Poloniae

1 Polish Journal of Ecology

2 Gaisler J.

2 Hejcman M.

2 Pavlu V.

1 Banas M.

1 Duchoslav M.

1 Hakl J.

1 Hejcmanova P.

1 Lokvenc T.

1 Nezerkova P.

1 Pavlu L.

1 Rauch O.

1 Zeidler M.

1 2008

1 2006

1 2005

Wyniki wyszukiwania

Regeneration of Nardus stricta subalpine grasslands in the Giant Mountains [Krkonose]

Farmer decision making and its effect on subalpine grassland succession in the Giant Mts., Czech Republic

Carbohydrate reserve changes in below-ground biomass of subalpine grasslands as a result of different snow conditions [Hruby Jesenik Mts., Czech Republic]