Fusun Shi

Agricultural heritage in disintegration: Trends of agropastoral transhumance on the southeast Tibetan Plateau

This paper examines agropastoral transhumance in 12 sampled villages on the southeast Tibetan Plateau. By analysing trends in this indigenous livelihood system and examining causes and potential consequences, we conclude that Tibetan agropastoral transhumance is a fragile system extremely vulnerable to external impacts. Within the context of Chinas rapid development and globalisation, this agricultural heritage is changing rapidly, as is most saliently reflected in herd size and structure, movement patterns, relative economic importance of pastoral activities and the relations between pastoralism and crop cultivation. Immediate causes of changes are local changes in livestock management objectives, land uses and labour availability, which are driven by more fundamental changes of environmental, political, socioeconomic, technological and cultural profiles, from local to global scales. Changes in local livelihood systems can have multifaceted and profound political, socioeconomic, cultural and ecological consequences, in both constructive and destructive terms. Policy-makers and/or project designers must have a holistic perspective so as to integrate multiple objectives of promoting sustainable socioeconomic development, preserving biological and cultural diversities and maintaining the environmentally stable balance of human society, animal population and ecosystem that has existed in the area for centuries.

Different growth and physiological responses to experimental warming of two dominant plant species Elymus nutans and Potentilla anserina in an alpine meadow of the eastern Tibetan Plateau

The effects of experimental warming on the growth and physiology of grass Elymus nutans and forb Potentilla anserina were studied by using open-top chambers (OTCs) in an alpine meadow of the eastern Tibetan Plateau. The warming treatment increased mean air and soil surface temperatures by 1.53°C and 0.50°C, respectively, but it reduced soil relative water content in the surface layer. Experimental warming enhanced the growth and gas exchange of E. nutans, while it reduced those of P. anserina. Experimental warming resulted in an increased efficiency of photosystem II (PSII) in E. nutans, while decreasing it in P. anserina; significantly stimulated non-photochemical quenching, antioxidative enzymes and non-enzymes in both species; and significantly reduced malondialdehyde content in E. nutans, while promoting it in P. anserina. The results of this study indicated that the two species showed different growth responses to experimental warming and their different physiological performances further indicated that experimental warming alleviated the negative effect of low temperature on the growth and development of E. nutans, but limited the competitive ability of P. anserina in the study region.

Detecting One-Hundred-Year Environmental Changes in Western China Using Seven-Year Repeat Photography

Due to its diverse, wondrous plants and unique topography, Western China has drawn great attention from explorers and naturalists from the Western World. Among them, Ernest Henry Wilson (1876 –1930), known as ‘Chinese’ Wilson, travelled to Western China five times from 1899 to 1918. He took more than 1,000 photos during his travels. These valuable photos illustrated the natural and social environment of Western China a century ago. Since 1997, we had collected E.H. Wilsons old pictures, and then since 2004, along the expedition route of E.H. Wilson, we took 7 years to repeat photographing 250 of these old pictures. Comparing Wilsons photos with ours, we found an obvious warming trend over the 100 years, not only in specific areas but throughout the entire Western China. Such warming trend manifested in phenology changes, community shifts and melting snow in alpine mountains. In this study, we also noted remarkable vegetation changes. Out of 62 picture pairs were related to vegetation change, 39 indicated vegetation has changed to the better condition, 17 for degraded vegetation and six for no obvious change. Also in these photos at a century interval, we found not only rapid urbanization in Western China, but also the disappearance of traditional cultures. Through such comparisons, we should not only be amazed about the significant environmental changes through time in Western China, but also consider its implications for protecting environment while meeting the economic development beyond such changes.

Uptake and recovery of soil nitrogen by bryophytes and vascular plants in an alpine meadow

Due to their particular physiology and life history traits, bryophytes are critical in regulating biogeochemical cycles and functions in alpine ecosystem. Hence, it is crucial to investigate their nutrient utilization strategies in comparison with vascular plants and understand their responses to the variation of growing season caused by climate change. Firstly, this study testified whether or not bryophytes can absorb nitrogen (N) directly from soil through spiking three chemical forms of 15N stable isotope tracer. Secondly, with stronger ability of carbohydrates assimilation and photosynthesis, it is supposed that N utilization efficiency of vascular plants is significantly higher than that of bryophytes. However, the recovery of soil N by bryophytes can still compete with vascular plants due to their greater phytomass. Thirdly, resource acquisition may be varied from the change of growing season, during which N pulse can be manipulated with 15N tracer addition at different time. Both of bryophytes and vascular plants contain more N in a longer growing season, and prefer inorganic over organic N. Bryophytes assimilate more NH4+ than NO3- and amino acid, which can be indicated from the greater shoot excess 15N of bryophytes. However, vascular plants prefer to absorb NO3- for their developed root systems and vascular tissue. Concerning the uptake of three forms N by bryophytes, there is significant difference between two manipulated lengths of growing season. Furthermore, the capacity of bryophytes to tolerate N-pollution may be lower than currently appreciated, which indicates the effect of climate change on asynchronous variation of soil N pools with plant requirements.

Allometric Partitioning Theory Versus Optimal Partitioning Theory: The Adjustment of Biomass Allocation and Internal C-N Balance to Shading and Nitrogen Addition in Fritillaria unibracteata (Liliaceae)

ABSTRACT Fritillaria unibracteata is a classic perennial alpine herb. In this study, we examined its responses to shading (SH) and nitrogen addition (NA), as well as its correlation with internal C-N balance to detect how it adjusted to the changes of habitat conditions. Randomized block experiment was carried out in the field in Chuanbeimu Research Station in Songpan County, Sichuan Province, China (32°09′54″N, 103°38′36″E, altitude 3300 m a.s.l.). Two growing seasons after NA and SH, Fritillaria unibracteatas total plant biomass decreased significantly, with the proportion of biomass allocated to aboveground significantly increased. In addition, in this study, under both SH and NA treatments, Fritillaria unibracteata increased its biomass allocation to above-ground, which consisted with optimal partitioning theory. Moreover, Fritillaria unibracteatas biomass allocation was significantly correlated with its internal C-N status, regardless of nitrogen and light condition. We conclude that Fritillaria unibracteata optimizes its biomass allocation between root and shoot by adjusting its internal C-N balance, which would not be changed by the specialized resource storage organ-bulb.

Biomass and Morphology Responses of Fritillaria unibracteata to Shading and Warming

Fritillaria unibracteata Hsiao and Hsia (Liliaceae) (F. unibracteata) is a perennial and protected species distributed in the meadow or under the shrub at the eastern Tibetan Plateau. To understand how F. unibracteata response to changing environment, OTC (open top chamber) and PSN (Polypropylene shading nets) were used to simulate warming and shading effects. Two years later, dry biomass of each organ (leaf, stem, bulb and root), leaf length (LL), leaf area (LA) and special leaf area (SLA) were measured individually to determine F. unibracteata responses to environmental change. The results showed that: (1) total biomass (TB), leaf biomass (LB) and root biomass (RB) increased significantly under warming treatment (P<0.05), but no significant change under shading; (2) LB/RB was decreased under warming, while both LB/RB and AB/BeB showed no significant responses to shading; (3) leaf morphological characteristics responded significantly to warming and shading; leaf length (LL) significantly increased under both shading and warming treatments (P<0.05); leaf area (LA) increased significantly under warming treatment; special leaf area (SLA) increased significantly under shading treatment. Based on the results above, we get conclusions as below: (1) F. unibracteata responded to warming and shading effects differently; (2) For perennial alpine plants such as F. unibracteata, morphological traits may be more sensitive to environment variations than other traits.