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Pak. J. Bot., 47(6): 2127-2134, 2015. |
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Updated: 02-01-16 | ||||
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SEEDLING RECRUITMENT OF FORB SPECIES UNDER EXPERIMENTAL MICROHABITATS IN ALPINE GRASSLAND
TIAN FU-PING1,3, LIU YU2, WU GAO-LIN2,3* AND SHI SHANG-LI1*
1College of Grassland Science, Gansu Agricultural University, Lanzhou, Gansu 730070, China 2State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences / Northwest A&F University, Yangling, Shaanxi 712100, China 3Lanzhou Institute of Husbandry and Pharmaceutical Sciences of Chinese Academy of Agricultural Sciences, The Lanzhou Scientific Observation and Experiment Field Station of Ministry of Agriculture for Ecological System in the Loess Plateau Area, Lanzhou, Gansu 730050 China *Corresponding author’s e-mail: shishl@gsau.edu.cn; gaolinwu@gmail.com
Abstract: Which factors limit plant seedling recruitment in alpine meadow of the Qinghai-Tibetan Plateau (QTP), China? This study examined the relative influence of seed mass and microsites (resulted from grazing disturbance) on field seedling emergence and survival of nineteen alpine herbaceous species with a range of traits in QTP. Seed mass had significant effects on seedling emergence and survival eliminating influence of light and nutrient variances among these species. The larger-seed species had more advantageous than the smaller-seed species in seedling survival, but it was disadvatage for seedling emergence, especially under high nutrient availability and low light intensity conditions. Light had obvious effects on seedling survival, but less effects on seedling emergence for these species. Moreover, nutrient and light treatments altered the regression relationships of seed mass and seedling emergence and survival and the order of significances was L25>L50>L100>L10>L4. These results suggested that seed mass may restrict seedling recruitment processes, however, light and nutrient availability all have significant effects on seedling emergence and survival for these alpine species. Moderate light intensity was propitious to seedling emergence and survival in alpine grassland. This suggests that ecological factors in alpine grassland provide a stochastic influence on different seed-mass species. These trends may help to explain why many small-seeded species of Asteraceae and Gramineae tend to be more abundant in disturbed habitats.
Key words: Alpine meadow, Light, Nutrient, Seed mass, Seedling emergence.
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