Yong Shen

China Academy of Chinese Medical Sciences, Peping, Beijing, China

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Publications (6)11.53 Total impact

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    ABSTRACT: We evaluated the degree to which relative growth rate (RGR) of saplings and large trees is related to seven functional traits that describe physiological behavior and soil environmental factors related to topography and fertility for 57 subtropical tree species in Dinghushan, China. The mean values of functional traits and soil environmental factors for each species that were related to RGR varied with ontogenetic stage. Sapling RGR showed greater relationships with functional traits than large-tree RGR, whereas large-tree RGR was more associated with soil environment than was sapling RGR. The strongest single predictors of RGR were wood density for saplings and slope aspect for large trees. The stepwise regression model for large trees accounted for a larger proportion of variability (R (2) = 0.95) in RGR than the model for saplings (R (2) = 0.55). Functional diversity analysis revealed that the process of habitat filtering likely contributes to the substantial changes in regulation of RGR as communities transition from saplings to large trees.
    Full-text · Article · Jun 2014 · Oecologia
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    ABSTRACT: Ecologists have been monitoring community dynamics with the purpose of understanding the rates and causes of community change. However, there is a lack of monitoring of community dynamics from the perspective of phylogeny. We attempted to understand temporal phylogenetic turnover in a 50 ha tropical forest (Barro Colorado Island, BCI) and a 20 ha subtropical forest (Dinghushan in southern China, DHS). To obtain temporal phylogenetic turnover under random conditions, two null models were used. The first shuffled names of species that are widely used in community phylogenetic analyses. The second simulated demographic processes with careful consideration on the variation in dispersal ability among species and the variations in mortality both among species and among size classes. With the two models, we tested the relationships between temporal phylogenetic turnover and phylogenetic similarity at different spatial scales in the two forests. Results were more consistent with previous findings using the second null model suggesting that the second null model is more appropriate for our purposes. With the second null model, a significantly positive relationship was detected between phylogenetic turnover and phylogenetic similarity in BCI at a 10 m×10 m scale, potentially indicating phylogenetic density dependence. This relationship in DHS was significantly negative at three of five spatial scales. This could indicate abiotic filtering processes for community assembly. Using variation partitioning, we found phylogenetic similarity contributed to variation in temporal phylogenetic turnover in the DHS plot but not in BCI plot. The mechanisms for community assembly in BCI and DHS vary from phylogenetic perspective. Only the second null model detected this difference indicating the importance of choosing a proper null model.
    Full-text · Article · Apr 2014 · PLoS ONE
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    ABSTRACT: Tree survival is a critical driver of stand dynamics, influencing forest structure and composition. Many local-scale drivers (tree size, abiotic and biotic factors) have been proposed as being important in explaining patterns of tree survival, but their contributions are still unknown. We examined the relative importance of these local drivers on tree survival using generalized linear mixed models in an old-growth sub-tropical forest in south China at three levels (community, guild, and species). Among the variables tested, tree size was typically the most important driver of tree survival, followed by abiotic and then biotic variables. Tree size has a strongly positive effect on tree survival for small trees (10–30 cm dbh) and shade-tolerant tree species. Of the abiotic factors tested, elevation tended to be more important in affecting tree survival than other topographic variables. Abiotic factors generally influenced survival of species with relatively high abundances, for individuals in smaller size classes and for mid-tolerant species. Among biotic factors, we found that the mortality of tree species was not driven by density- and frequency-dependent effects in this sub-tropical forest, as indicated by the results of both total basal area of neighbors and the proportion of conspecific neighbors in our study. We conclude that the relative importance of variables driving patterns of tree survival varied greatly among tree size classes, species guilds, shade tolerance, density, and abundance classes in this sub-tropical forest. These results also provide critical information for future studies of forest dynamics and offer insight into forest management in this region.
    No preview · Article · Jan 2014 · Ecological Research
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    ABSTRACT: Structure and demographics in many tropical forests is changing, but the causes of these changes remain unclear. We studied 5 y (2005–2010) of species turnover, recruitment, mortality and population change data from a 20-ha subtropical forest plot in Dinghushan, China, to identify trends in forest change, and to test whether tree mortality is associated with intraspecific or interspecific competition. We found the Dinghushan forest to be more dynamic than one temperate and two tropical forests in a comparison of large, long-term forest dynamics plots. Within Dinghushan, size-class distributions were bell-shaped only for the three most dominant species and reverse J-shaped for other species. Bell-shaped population distributions can indicate a population in decline, but our data suggest that these large and long-lived species are not in decline because the pattern is driven by increasing probabilities of transition to larger size class with increasing size and fast growth in saplings. Spatially aggregated tree species distributions were common for surviving and dead individuals. Competitive associations were more frequently intraspecific than interspecific. The competition that induced tree mortality was more associated with intraspecific than interspecific interactions. Intraspecific competitive exclusion and density-dependence appear to play important roles in tree mortality in this subtropical forest.
    Full-text · Dataset · Mar 2013
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    ABSTRACT: Structure and demographics in many tropical forests is changing, but the causes of these changes remain unclear. We studied 5 y (2005-2010) of species turnover, recruitment, mortality and population change data from a 20-ha subtropical forest plot in Dinghushan, China, to identify trends in forest change, and to test whether tree mortality is associated with intraspecific or interspecific competition. We found the Dinghushan forest to be more dynamic than one temperate and two tropical forests in a comparison of large, long-term forest dynamics plots. Within Dinghushan, size-class distributions were bell-shaped only for the three most dominant species and reverse J-shaped for other species. Bell-shaped population distributions can indicate a population in decline, but our data suggest that these large and long-lived species are not in decline because the pattern is driven by increasing probabilities of transition to larger size class with increasing size and fast growth in saplings. Spatially aggregated tree species distributions were common for surviving and dead individuals. Competitive associations were more frequently intraspecific than interspecific. The competition that induced tree mortality was more associated with intraspecific than interspecific interactions. Intraspecific competitive exclusion and density-dependence appear to play important roles in tree mortality in this subtropical forest.
    Full-text · Article · Feb 2013 · Journal of Tropical Ecology
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    Yue Bin · Guojun Lin · Buhang Li · Linfang Wu · Yong Shen · Wanhui Ye
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    ABSTRACT: Seedling recruitment can be influenced by seed dispersal, conspecific density dependence, and environmental factors. These forces are variant in space. In this study, seedling recruitment was investigated by the inverse modeling method. The inverse modeling framework here was made up of two components: a conspecific effect and a declining function. Power functions (P) and constant conspecific (C) effects were tried. Two types of declining functions were tried: isotropic (I) and anisotropic (A). Thus, the combination of conspecific effect and declining function generated four candidate models: PI, PA, CI, CA. These four models were used to study the seedling recruitment of 13 species in a 20ha forest plot in subtropical China. It was found that PI, PA, CI, CA are the best models for two, three, five, and three species, respectively. Negative exponents in P were found in three species, which may indicate negative density-dependent mortality. Among those species that supported an anisotropic component, all moderately shade-tolerant and shade-tolerant species except Calophyllum membranaceum had higher possibilities of successful recruitment if their altitudes were relatively low, consistent with their ecological niches. The shade intolerant species, Castanopsis fissa produces seeds weighing 6–250 times more than other species. Yet, its seedling recruitment was more successful at higher altitudes, which again was consistent with its ecological niche. Our research indicated that it is necessary to take anisotropic forces into account when investigating seed dispersal and seedling recruitment in regions with complex topography, and that the niche-based processes and density-dependent mortality at least play some part in constructing the seedling distribution pattern. KeywordsConspecific effect–Inverse modeling–Density dependence–Forest dynamic plot–Niche
    Preview · Article · Mar 2012 · European Journal of Forest Research

Publication Stats

8 Citations
11.53 Total Impact Points

Institutions

  • 2014
    • China Academy of Chinese Medical Sciences
      Peping, Beijing, China
  • 2013
    • University of California, Riverside
      • Department of Botany and Plant Sciences
      Riverside, California, United States
  • 2012-2013
    • Chinese Academy of Sciences
      • Beijing Botanical Garden
      Peping, Beijing, China