Herbivore exclusion stabilizes alpine grassland biomass production across spatial scales.

There is growing evidence that land-use management practices such as livestock grazing can strongly impact the local diversity, functioning, and stability of grassland communities. However, whether these impacts depend on environmental condition and propagate to larger spatial scales remains unclear. Using an 8-year grassland exclosure experiment conducted at nine sites in the Tibetan Plateau covering a large precipitation gradient, we found that herbivore exclusion increased the temporal stability of alpine grassland biomass production at both the local and larger (site) spatial scales.

Geo-Distribution Patterns of Soil Fungal Community of in Tibet.

can be used as a pioneer species for the restoration of degraded grasslands and as a high-quality forage for local yak and sheep in alpine regions. The geographical distribution pattern of soil fungal community can modify that of . A field survey along 32 sampling sites was conducted to explore the geo-distribution patterns of soil fungal community of in Tibet.

Asymmetrical warming of growing/non-growing season increases soil respiration during growing season in an alpine meadow.

Soil respiration (R) is an important carbon flux in the global carbon cycle, and understanding the influence of global warming on R is critical for precise prediction future climate change. Actually, global warming is expected to be seasonally asymmetric, however, it is still unclear on the response of R to asymmetrical warming of growing/non-growing season in alpine regions. In this study, an experiment with asymmetrical warming of growing/non-growing season (including three treatments, CK: control; GLNG: warming magnitude of growing season lower than non-growing season; GHNG: warming magnitude of growing season higher than non-growing season) was performed in an alpine meadow of the Northern Tibet since June 2015.

Effects of experimental warming and increased precipitation on soil respiration in an alpine meadow in the Northern Tibetan Plateau.

Uncertainty on the response of soil respiration (R) to warming and increased precipitation on the Tibetan Plateau can limit our ability to predict how alpine ecosystems will respond to future climate change. Based on a warming (control, low- and high-level) and increased precipitation (control, low- and high-level) experiment, the response of R to experimental warming and increased precipitation was examined in an alpine meadow in the Northern Tibetan Plateau from 2014 to 2017. The low-level warming increased soil temperature (T) by 1.

Response of soil respiration to experimental warming in a highland barley of the Tibet.

Highland barley is an important dominant crop in the Tibet and the croplands of the Tibet are experiencing obvious climatic warming. However, information about how soil respiration will respond to climatic warming in the highland barley system is still lacking. A field warming experiment using infrared heaters with two warming magnitudes was conducted in a highland barley system of the Tibet in May 2014.

Nutrient Enrichment Mediates the Relationships of Soil Microbial Respiration with Climatic Factors in an Alpine Meadow.

Quantifying the effects of nutrient additions on soil microbial respiration (R m) and its contribution to soil respiration (R s) are of great importance for accurate assessment ecosystem carbon (C) flux. Nitrogen (N) addition either alone (coded as LN and HN) or in combination with phosphorus (P) (coded as LN + P and HN + P) were manipulated in a semiarid alpine meadow on the Tibetan Plateau since 2008. Either LN or HN did not affect R m, while LN + P enhanced R m during peak growing periods, but HN + P did not affect R m.

Spatial and climatic patterns of the relative abundance of poisonous vs. non-poisonous plants across the Northern Tibetan Plateau.

It is the most serious challenge to promote degraded grassland recovery currently facing the developing Tibetan Autonomous Region. We conducted field surveys of 75 grazing sites between 2009 and 2012 across the Northern Tibetan Plateau and described the spatial and climatic patterns of the occurrence of poisonous plants. Our results showed lower ratios of species richness (SprRatio), coverage (CovRatio), and biomass (BioRatio) of non-poisonous vs.

Response of soil C and N, dissolved organic C and N, and inorganic N to short-term experimental warming in an Alpine meadow on the Tibetan Plateau.

Although alpine meadows of Tibet are expected to be strongly affected by climatic warming, it remains unclear how soil organic C (SOC), total N (TN), ammonium N (NH4 (+)-N) , nitrate N (NO3 (+)-N), and dissolved organic C (DOC) and N (DON) respond to warming. This study aims to investigate the responses of these C and N pools to short-term experimental warming in an alpine meadow of Tibet. A warming experiment using open top chambers was conducted in an alpine meadow at three elevations (i.

Response of soil respiration to grazing in an alpine meadow at three elevations in tibet.

Alpine meadows are one major type of pastureland on the Tibetan Plateau. However, few studies have evaluated the response of soil respiration (R(s)) to grazing along an elevation gradient in an alpine meadow on the Tibetan Plateau. Here three fenced enclosures were established in an alpine meadow at three elevations (i.

[Soil N/P ratio distribution characteristics of alpine grassland ecosystem in Qinghai-Tibet Plateau].

The distribution characteristics of soil N/P ratio in alpine grassland ecosystem of Qinghai-Tibet Plateau were surveyed by field investigation and laboratory analysis. Horizontally, soil N/ P ratio was generally higher in west and lower in east in a manner of staggered patch distribution, with higher N/P ratios mainly centralized in the hinterland of northern part of Tibet Plateau and in the lake basin area of the northern foot of Himalayas. Significant differences in soil N/P ratio were observed among grassland types and natural transects.

Responses of ecosystem CO 2 fluxes to short-term experimental warming and nitrogen enrichment in an Alpine meadow, northern Tibet Plateau.

Over the past decades, the Tibetan Plateau has experienced pronounced warming, yet the extent to which warming will affect alpine ecosystems depends on how warming interacts with other influential global change factors, such as nitrogen (N) deposition. A long-term warming and N manipulation experiment was established to investigate the interactive effects of warming and N deposition on alpine meadow. Open-top chambers were used to simulate warming.

Changes in individual plant traits and biomass allocation in alpine meadow with elevation variation on the Qinghai-Tibetan Plateau.

Plant traits and individual plant biomass allocation of 57 perennial herbaceous species, belonging to three common functional groups (forbs, grasses and sedges) at subalpine (3700 m ASL), alpine (4300 m ASL) and subnival (≥5000 m ASL) sites were examined to test the hypothesis that at high altitudes, plants reduce the proportion of aboveground parts and allocate more biomass to belowground parts, especially storage organs, as altitude increases, so as to geminate and resist environmental stress. However, results indicate that some divergence in biomass allocation exists among organs. With increasing altitude, the mean fractions of total biomass allocated to aboveground parts decreased.

[Rainffall interception model of forest canopy: a preliminary study].

Canopy interception is an important hydrological process in forest ecosystem, and its modelling is of significance to understand and estimate the rainfall interception by the canopy. In this paper, a canopy rainfall interception model was established by dividing a rain incident into a set of short period, calculating the rainfall distribution intercepted by the canopy, and educing the process of the rain incident. This model considered the effects of the dryness of canopy and trunk on the evaporation from wet canopy and trunk during one rain incident, and introduced two factors, leaf area index (LAI) and surface area of trunk per unit area of ground (SAI), when computing the evaporation.

[Evapotranspiration of natural Quercus litaotungensis and Tilia paucicostata secondary stands in Liupan Mountains of Ningxia].

With heat dissipation probe technique and combined with microlysimeter and hydrological methods, this paper studied the evapotranspiration of secondary Quercus liaotungensis and Tilia paucicostata stands, and its relationship to forest structure from August to September 2004. The results indicated that the stem sap flux density (SFD) of Quercus liaotungensis and Tilia paucicostata changed regularly from day to night in later growth season. In relatively still period (nighttime), the SFD kept low values continuously, usually below 0.

[Clonal growth of stoloniferous herb Potentilla anserina on degraded and non-degraded alpine meadow soil].

The clonal growth of Potentilla anserina on degraded and non-degraded Kobresia humilis meadow soil was studied by a transplanting experiment in the field. No significant differences in numbers of stolons, height, and leave size per mother ramet were observed between the two soils, but the numbers of leaves per mother ramet, length and width of stolon, and spacer length were significantly different. There were more leaves per mother ramet, longer stolon and spacer, and wider stolon on degraded soil, where available nutrient was poor than in non-degraded soil.

[Analysis of formation causes of grassland degradation in Maduo County in the source region of Yellow River].

Natural and artificial factors of grassland degradation in Maduo County in source region of Yellow River were analyzed in this paper. The results showed that overgrazing was the major reason for grassland degradation. Compared with historical average, annual temperature and precipitation in Maduo had an obvious rise since the end of 1980s.