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Wu G.-L.,Plateau State University | Wu G.-L.,CAS Institute of Soil and Water Conservation | Tian F.-P.,Lanzhou Institute of Animal and Veterinary Pharmaceutics science CAAS | Ren G.-H.,Lanzhou University | Liu Z.-H.,Maqu Alpine Grassland Workstation
Polish Journal of Ecology | Year: 2011

Seed mass is a critical lifehistory character in seed evolutionary ecology. Plant species can present responses in seed mass to environment stresses. We tested the hypotheses that seed mass was positively correlated with altitude within species. We selected four congeneric Saussurea species as study objects, and collected their seeds along altitudinal gradients (2100-4200 m a.s.l.) in the alpine area of the Qinghai-Tibetan Plateau, China. Results showed that mean seed mass of the four species were significantly affected by altitude (P <0.001). There was a general trend of an increase in seed weight with altitude among the populations of the four species. In addition, mean seed mass of four species were not significantly different, but all presented a bigger coefficients of variation within species along altitude gradients. Our results indicate selection pressure within species, with larger seeds occurring at higher altitudes. Source


Wu G.-L.,Plateau State University | Wu G.-L.,Shaanxi University of Science and Technology | Wu G.-L.,CAS Institute of Soil and Water Conservation | Liu Z.-H.,Maqu Alpine Grassland Workstation | And 5 more authors.
Plant and Soil | Year: 2010

Disturbance and management approaches can contribute significantly to restoration of degraded grassland ecosystems. This study has examined the re-establishment of artificial grassland to renew extremely degraded black-soils in an alpine area of the Qinghai-Tibetan Plateau, in China. We evaluated this method for which grassland ecosystem responses to this restoration approach are needed. Here, we evaluated the response of aboveground plant communities and belowground soil nutrient and soil carbon storage to the establishment of artificial grassland in grasslands on black-soils in the eastern Qinghai-Tibetan Plateau. Three grasslands sites were selected: a degraded grassland on an original black-soil, and 3- and 6-year-old Elymus nutans artificial grasslands. Artificial grassland establishment significantly improved aboveground biomass, but also significantly decreased species richness, diversity and evenness for black-soil-type degraded grassland. Artificial grassland establishment resulted in significantly improved soil total nitrogen and phosphorus, and decreased soil organic matter, available nitrogen, and phosphorus, especially in the depth of 20-30 cm soil layer. Although artificial grassland establishment significantly improved soil organic carbon in the topsoil (0-10 cm), it decreased at depths of 10-20 and 20-30 cm. Six-year artificial grassland significantly increased soil carbon storage compared with black-soil-type degraded grasslands. Accordingly, artificial grassland can be used as effective restoration and rehabilitation approach to improve productivity and regulate community and soil properties in black-soil-type degraded grasslands. Our results suggest that ecosystem functions such as production of aboveground biomass, the provision of soil surface cover, and nutrient accumulation may be provided by artificial grassland. However, more time is needed for plant diversity and soil carbon storage functions to recover fully from degradation. © 2010 Springer Science+Business Media B.V. Source


Wu G.-L.,CAS Institute of Soil and Water Conservation | Wu G.-L.,Shaanxi University of Science and Technology | Liu Z.-H.,Maqu Alpine Grassland Workstation | Zhang L.,CAS Institute of Soil and Water Conservation | And 3 more authors.
Plant and Soil | Year: 2010

Overgrazing significantly affects alpine meadows in ways similar to grasslands in other areas. Fencing to exclude grazers is one of the main management practices used to protect alpine meadows. However, it is not known if fencing can improve soil properties and soil organic carbon storage by restraining grazing in alpine meadows. We studied the long-term (nine-year) effects of fencing on soil properties, soil organic carbon and nitrogen storage compared with continued grazing in an alpine swamp meadow of the Qinghai-Tibetan Plateau, NW China. Our results showed that fencing significantly improved vegetation cover and aboveground biomass. There were significant effects of fencing on pH value, soil bulk density, and soil moisture. Long-term fencing favored the increase of soil total nitrogen, soil organic matter, soil organic carbon, soil microbial biomass carbon and soil carbon storage compared with grazed meadows. Our study suggests that long-term fencing to prevent disturbance could greatly affect soil organic carbon and nitrogen storage with regard to grazed meadows. Therefore, it is apparent from this study that fencing is an effective restoration approach of with regard to the soil's storage ability for carbon and nitrogen in alpine meadow of the Qinghai-Tibetan Plateau. © 2010 Springer Science+Business Media B.V. Source


Wu G.-L.,Northwest University, China | Wu G.-L.,Chinese Academy of Sciences | Hu T.-M.,Northwest University, China | Liu Z.-H.,Maqu Alpine Grassland Workstation
Polish Journal of Ecology | Year: 2010

Ligularia virgaurea (Maxim.) is a typical naturally-occurring native noxious weed, widely distributed in alpine grasslands of the Tibetan Plateau, China. Three field sampling plots (30 m ' 50 m) dominated by L. virgaurea were selected to study its population colonization mode and the relationship between sexual- and clonal- recruitment in alpine meadow of the Qinghai- Tibetan Plateau, NW China. Field investigations were conducted on its soil seed bank, seed rain and the individuals of new recruitment (seedlings and ramets) to study its sexual and asexual recruitment. And, 46 individuals which produced the seeds were selected randomly to study their relationship between seed production and ramet production. Results showed that there were more ramets (26.23 ramets m-2) and less seedlings (6.70 seedlings m-2) and a mean value of seed rain was close to 8.04 seeds m-2, but the soil seed bank for this species was not found in study sites. Significantly negative correlations (r = - 0.416, P <0.001) between seed number per individual and ramet number per adult individual were found for L. vrigaurea in studied alpine grasslands. Our results revealed that clonal reproduction was the main population colonization mode. In addition, there was a significantly negative relationship between seed production and ramets for this species. Source


Xiao-Peng L.,Northwest University, China | Xin-Gang L.,Northwest University, China | Quan-Min D.,Qinghai Academy of Animal and Veterinary science | Zhen-Heng L.,Maqu Alpine Grassland Workstation
African Journal of Biotechnology | Year: 2011

To help understand the effects of grazing on seed germination characteristics of Vicia angustifolia L., we conducted a laboratory germination experiment of V. angustifolia L., which is a main companion species of Leguminosae family in alpine grassland of the Qinghai-Tibetan Plateau, using Yak and Tibetan sheep rumen juices along three seed size categories. Results show that Yak and Tibetan sheep rumen juices significantly restrained germination of seeds for three size categories, decreased seed germination percentage, germination index and prolonged first and mean germination times. Meanwhile, the medium-size seeds presented the maximum geminated percentage, and the larger seeds germinated better than the smaller seeds. Additionally, there were significant interaction effects between rumen juice and seed size on seed germination of V. angustifolia. Our results suggest that grazing pressure of animal feed present have significant negatively effects on seed germination for V. angustifolia with different seed size in alpine area of the Qinghai-Tibetan Plateau. © 2011 Academic Journals. Source

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