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| 1 | Soil Microbial Population Dynamics along a Chronosequence of Moist Evergreen Broad-leaved Forest Succession in Southwestern China显示文摘Little is known about whether soil microbial population dynamics are correlated with forest succession.To test the hypotheses that(1) soil microbial composition changes over successional stages,and(2) soil microbial diversity is positively correlated with plant species diversity,we determined the soil microbial populations,community composition,and microflora diversity in evergreen broad-leaved forests along a chronosequence of vegetation succession from 5 to 300 years in southwestern China.The soil microbial community was mainly composed of bacteria(87.1-98.7% of the total microorganisms and 10 genera identified),fungi(0.3-4.0%,7 genera),and actinomycetes(2.1-9.1%,8 species and 1 genus).There were significant differences in soil microbial populations among different successional stages and within the four seasons.The seasonal variations of the soil microbial community may be associated with the seasonal changes in environmental conditions.The changes in soil microbial diversity(Shannon-Wiener index) with successional time followed one-humped,convex curves peaked at-100 years since restoration,which is identical with the trends of the aboveground plant diversity.Higher plant diversity resulting in enhanced nutrient flow and root exudation may contribute to positive relationships between the soil microbial diversity and plant diversity.Hence,decreases in soil microbial diversity in the late-successional stages appear to be related to the net loss in species richness that occurs after 100 years since restoration.Our findings confirm the intermediate disturbance hypothesis that suggests diversity peaks at midsuccessional stages. | ZHU Wanze CAI Xiaohu LIU Xingliang WANG Jinxi CHENG Song ZHANG Xiuyan LI Dengyu LI Maihe | 2010 | Journal of Mountain Science2010，7，4： | 8 |
| 2 | Annual Time-series Analyses of Total Gaseous Mercury Measurement and its Impact Factors on the Gongga Mountains in the Southeastern Fringe of the Qinghai-Tibetan Plateau显示文摘Long-term monitoring programs for measurement of atmospheric mercury concentrations are presently recognized as powerful tools for local,regional and global studies of atmospheric long-range transport processes,and they could also provide valuable information about the impact of emission controls on the global budget of atmospheric mercury,their observance and an insight into the global mercury cycle. China is believed to be an increasing atmospheric mercury emission source. However,only a few measurements of mercury,to our knowledge,have been done in ambient air over China. The highly-time resolved atmospheric mercury concen-trations have been measured at Moxi Base Station (102°72′E 29°92′N,1640 m asl) of the Gongga Alpine Ecosystem Observation and Experiment Station of Chinese Academy of Sciences (CAS) from May 2005 to June 2006 by using a set of Automatic Atmospheric Mercury Speciation Analyzers (Tekran 2537A). Measurements were carried out with a time resolution of every 15 minutes. The overall average total gaseous mercury (TGM) covering the measurement periods was 4±1.38 ng·m-3 (N=57310),which is higher than the global background level of approximately 1.5~2.0 ng·m-3. The measurements in all seasons showed a similar diurnal change pattern with a high concentration during daytime relative to nighttime and maximum concentration near solar noon and minimum concentration immediately before sunrise. The presence of diurnal TGM peaks during spring and summer was found earlier than that during autumn and winter. When divided seasonally,it was found that the concentrations of TGM were highest in winter with 6.13 ± 1.78 ng·m-3 and lowest in summer with 3.17 ± 0.67 ng·m-3. There were no significant differences in TGM among wind sectors during each season. Whereas Hg generally exhibited significant correlations with the parameters,such as temperature,saturated vapor pressure,precipitation,ultraviolet radiation (UV) and atmospheric pressure at the whole measurement stage,and the correlations varied seasonally. Our results suggest that the local or regional abundant geothermal activities,such as thermal spring,anthropogenic source processes and changes in meteorological conditions,regulate and affect Hg behavior in the study area. | ZHU Wanze FU Xuewu FENG Xinbin Julia Y. Lu | 2008 | Journal of Mountain Science2008，5，1： | 4 |
| 3 | Stem CO_(2) efflux of Abies fabri in subalpine forests in the Gongga Mountains,Eastern Tibetan Plateau显示文摘Aims Despite the importance of stem cO_(2)efflux(Es)in ecosystem carbon cycling and energy balance,little is known about temporal variation in the temperature coefficient(Q10)and sapwood nitrogen concen-trations([N])and their intrinsic links with Es.The objectives of this study were:(i)to examine the response of Es to temperature in a subalpine region and(ii)to explore the influence of stem diameter and[N]on Es.Also,we will test the hypothesis that(i)Es in trees has thermal acclimation and(ii)Es will be well correlated with diameter at breast height(DBH)and[N].Methods Here,a horizontally oriented soil chamber technique was applied to measure Es of Abies fabri in two subalpine forest stands in Southwestern china from May to December 2014.We also exam-ined the variability in Es,Q10 and[N]in trees and monitored the relationship between temperature,[N],DBH and Es.Important Findings During the measurement period,Es showed an apparent seasonal trend,following the change in air temperature,increasing from May and peaking in July,then continuously decreasing until December.The mean Es for the growing and dormant seasons were 1.45 and 0.25μmol·m^(−2)·s^(−1),respectively,and Es in the mature forest was sig-nificantly higher than in the immature forest.The area-based Es was positively correlated with DBH and sapwood width(SW),while volume-based Es showed negative relationship with DBH and SW.Across the five diameter classes,69.8-89.0%of the variation in Es could be explained by air temperature.The temperature sensitiv-ity(Q10)of Es ranged from 2.98 to 5.61 during the measurement period,with a higher Q10 appearing in the growing season than in the dormant season.There was a significant linear relationship(P<0.01)between[N]and Es(expressed based on two different units).Additionally,exponential models of Es against[N]and air temperature were applied to estimate Es. | Guang Zhao Gangcai Liu Wanze Zhu Jixia Zhao Xuemei Wang Yaoyao Wang Min Jia | 2017 | Journal of Plant Ecology2017，10，6： | 1 |
| 4 | Suitable Size of Nature Reserves in Tibet,P.R.China Based on Endangerment Degree of Species显示文摘In a view of natural conditions of establishing nature reserve,an index system was prepared for quantitative assessment on status of endangered species,and thus degree of endangered species in Tibet was evaluated.Taking a sub-ecozone as basic unit,top 5 animals and 1 plant with high E as well as the number of species in each unit were enumerated;and the degree of land utilization was figured out.Afterward,we selected 6 coefficients,assigned weight,and framed formula to reckon proportion of nature reserve,thus an area of nature reserve in each sub-ecozone was obtained.In 5 schemes of weight assignment,a scheme with medium area of nature reserve was selected.All sub-ecozones were classified into 4 grades prior conservation,1 was in grade A,2 in grade B,2 in grade C,and 11 in grade D.Total planned area was approximately 365 135 km2,about 48 834 km2 smaller than the actual area of 413 969 km2,ratio of nature reserve in Tibet diminishes from 34.4% to 30.38%.Based on 3 factors of human disturbance,ratio of buffer-experimental zone in proposed nature reserve was calculated.It was demonstrated that existing size of nature reserves is excessive on the whole,and their distribution is not reasonable entirely.The size of nature reserves in 3 sub-ecozones of northern Changtang should decrease,and decrement of area is apportioned among other 13 sub-ecozones which should increase nature reserve.Heterogeneity of regional distribution of rare species in Tibet is quite obvious,so proposed area distribution of nature reserves is more scattered than the existing. | DONG Ke LIU Shuzhen ZHONG Xianghao ZHU Wanze | 2012 | Chinese Forestry Science and Technology2012，11，Z1： | 0 |
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