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Effects of Increased Precipitation and Nitrogen Deposition on Methane Uptake of Alpine Meadow in Qinghai-Tibet Plateau : in situ Experiments

Guo Xiaowei, Dail Licong, Zhang Fawei, Li Yikang, Lin Li, Li Qian, Dawen Qian, Fan Bo, Ke Xun, Cao Guangmin, Zhou Huakun, Du Yangong

Polish Journal of Ecology

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2020

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Vol. 68, nr 2

109--120

EN

The methane (CH4) fluxes in grasslands are sensitive to changes in precipitation and soil nitrogen concentrations, which was poorly understood, especially on the Tibetan Plateau. Therefore, an experiment was conducted from May 2012 to October 2013, by using the static chamber technique and gas chromatography method. We set up five treatments: an increased 2 g m-2 NH4NO3 treatment (2gN); an increased 4 g m-2 NH4NO3 treatment (4gN); and treatment with precipitation increased by 20% (Pre), and added 2 g m-2 NH4NO3 and precipitation (20%) treatment (N+Pre), and a control treatment (CK). The five treatments showed decreasing CH4 uptake rates in the following order: CK (71.66 ± 6.6 µg m-2 h-1) > N+Pre (58.57 ± 3.7 µg m-2 h-1) > Pre (52.66 ± 2.3 µg m-2 h-1) > 2gN (47.63 ± 3.1 µg m-2 h-1) > 4gN (39.12 ± 3.3 µg m-2 h-1). The 2gN and 4gN treatment resulted in 33.5% and 45.4% lower CH4 uptake than the CK treatment, respectively. The path analysis indicated that the above-ground biomass and litter fall were the most important factor promoting and limiting the CH4 uptake rate of alpine meadow, respectively.

2

The impact of cattle and sheep grazing on grassland in Vel'ká Fatra National Park

Jendrisakova S., Kovacikova Z., Vargova V., Michalec M.

Journal of Water and Land Development

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2011

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no. 15

83-90

EN

The Vel'ká Fatra National Park (declared on 1 April 2002) is extending on an area of 40,371 ha and was established to protect well-preserved ecosystems. The Vel'ká Fatra (Greater Fatra) with the highest peak Ostredok (1592 m altitude) is a typical mountain territory and ranks among the highest mountain ranges in Slovakia. Grassland areas above the forest line ("hole" in Slovak) and highland relief are typical for Vel'ká Fatra where forests cover is 85% of the area. Large areas of grassland located on gently modelled ridges resulted from deforestation many centuries ago. The alpine meadows which are rich in rare plant communities cover the area of 2000 ha. In the past, these grasslands were used by cutting and grazing. Nowadays, the meadows are not mowed at all. The reasons are low numbers of ruminants in nearby farms, high cost and poor access roads that are eroded very much. Grazing with young cattle has been banned and consequently tall grasses expanded, swards thinned as well as avalanche risk increased. Currently, it is allowed to graze young cattle again, but farmers do not exploit this option very much. About 200 heifers and 2,500 sheep graze there, but only at the lowest areas of the mountains and for short periods of time. The grassland is dominated by Deschampsia caespitosa (L.) P. Beauv. and also by very rapidly expanding Calamagrostis epigejos (L.) Roth, Brachypodium pinnatum (L.) P. Beauv. and Cirsium arvense (L.) Scop. indicating a prolonged period of abandonment.

PL

Park Narodowy Vel'ká Fatra ustanowiony 1 kwietnia 2002 r. dla ochrony dobrze zachowanych ekosystemów zajmuje powierzchnię 40 371 ha. Vel'ká Fatra (Większa Fatra) z najwyższym szczytem Ostredok (1592 m n.p.m.) jest typowym obszarem górskim i zalicza się do najwyższych grzbietów górskich Słowacji. Charakterystyczne dla parku są ekosystemy trawiaste położone powyżej linii lasów ("hole" w języku słowackim), porastających 85% obszaru i wysokogórskie ukształtowanie terenu. Rozległe obszary trawiaste, usytuowane na łagodnie uformowanych grzbietach, są wynikiem wylesiania, które miało miejsce wiele wieków temu. Alpejskie łąki, bogate w zespoły rzadkich roślin, pokrywają powierzchnię 2000 ha. W przeszłości były wykorzystywane jako użytki zielone. Obecnie łąki nie są koszone. Powodem jest niewielka liczba przeżuwaczy w okolicznych gospodarstwach, wysoki koszt i uciążliwy transport na silnie zerodowanych drogach. Zakazano wypasu młodego bydła. W konsekwencji rozwinęły się zespoły wysokich traw, ruń została przerzedzona i zwiększyło się ryzyko lawinowe. Obecnie zezwala się ponownie na wypas młodego bydła, ale rolnicy nie korzystają powszechnie z tej możliwości. Wypasa się tam jedynie 200 jałówek i 2500 owiec jedynie w najniżej położonych terenach górskich przez krótki okres. Zespoły trawiaste są zdominowane przez Deschampsia caespitosa (L.) P. Beauv. i przez bardzo ekspansywne Calamagrostis epigejos (L.) Roth, Brachypodium pinnatum (L.) P. Beauv. and Cirsium arvense (L.) Scop., co wskazuje na wydłużony okres zaniechania użytkowania.

3

The effect of habitat on methane emission from an alpine wetland

Chen H., Wu N., Gao Y., Yao S., Wang Y., Tian J., Sun G., Yuan X.

Polish Journal of Ecology

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2009

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Vol. 57, nr 2

377-381

EN

Alpine wetland is a source for methane (CH[4]), an important greenhouse gas, but little is known about how this habitat influences the emission. To understand this wetland habitats were selected at the altitude of 3430 m a.s.l. (in National Wetland Nature Reserve of Zoige, Quingle - Tibetan Plateau) and the methane flux was measured with static chambers in three different sites, including hollows with Carex muliensis Hand - Mazz. and Eleocharis valleculosa Ohwi f. setosa (Ohwi) Kitagawa., grass hummocks composed of Kobresia tibetica Maxim, Cremanthodium pleurocaule R. D. Good, Potentilla bifurca L. and Pedicularis sp. We have found that in alpine wetland these habitats significantly affect CH[4] emissions in the onset (April, 2006) and peak (August, 2005) stages of growing season. Hollows covered with Carex muliensis and Eleocharis valleculosa had higher values of emission than grass hummocks built by several grass species. Slight difference of CH[4] emission was found between two kinds of hollows with Carex muliensis and Eleocharis valleculosa. These results were consistent with the change of water table, which was found best correlated with CH4 emissions (r[^2] = 0.43, P <0.01) in the peak stage of growing season. Directly measured shoot biomass and plant heights were best related to CH[4] emissions (r[^2] = 0.59, P <0.01). However, in the onset stage of growing season, variation of CH[4] emission may not be simply ascribed to changes in water table and vegetation structure.

4

Invasion of Descurainia sophia (L.) (Crucuferae) in alpine meadow is enhanced by ground disturbance made by Myospalax fontanierii (Milne-Edwards)

Li W., Zhang Y., Wang Y.

Polish Journal of Ecology

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2009

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Vol. 57, nr 2

389-393

EN

Because of cold weather and extremely harsh environment, there is few exotic species in Qinghai-Tibetan Plateau. Plateau zokor (Myospalax fontanierii), dominant borrowing small mammal, plays a role as .ecosystem engineer. in alpine meadow ecosystem. We measured and compared the dispersion area, branches, height and number of branches of flixweed tansymustard (Descurainia sophia) on the area disturbed by zokor mounds and in the undisturbed alpine meadow. Flixweed tansymustard is cool-season annual or biennial typical farmland weed in China, and is not found in alpine meadow before. The results indicated that zokor mounds significantly increased the dispersion area, number of individuals in each dispersion area, height and number of branches of flixweed tansymustard on the area disturbed by zokor mounds compared to those in undisturbed alpine meadow. These results suggest that ecosystem engineering by native species of rodent could promote the invasions of alien plant species in alpine meadow ecosystem, leading to higher abundances of invaders.