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Both S.,Martin Luther University of Halle Wittenberg | Fang T.,Gutianshan National Nature Reserve | Bohnke M.,Martin Luther University of Halle Wittenberg | Bruelheide H.,Martin Luther University of Halle Wittenberg | And 5 more authors.
Journal of Vegetation Science | Year: 2011

Question: Knowledge of the interaction between understorey herb and overstorey tree layer diversity is mostly restricted to temperate forests. How do tree layer diversity and environmental variables affect herb layer attributes in subtropical forests and do these relationships change in the course of succession? Do abundance and diversity of woody saplings within the herb layer shift during succession? Location: Subtropical broad-leaved forests in southeast China (29°8′18″-29°17′29″N, 118°2′14″118°11′12″E). Methods: A full inventory of the herb layer including all plants below 1-m height was done in 27 plots (10 × 10m) from five successional stages (<20, <40, <60, <80 and ≥80 yr). We quantified the contribution of different life forms (herbaceous, woody and climber species) to herb layer diversity and productivity and analysed effects of environmental variables and tree layer diversity on these attributes. Results: Herb layer composition followed a successional gradient, as revealed by non-metric multidimensional scaling (NMDS), but diversity was not correlated to the successional gradient. There was no correlation of diversity across layers. Herb layer productivity was neither affected by tree layer diversity nor by herb layer diversity. Although abundance of woody species in the herb layer decreased significantly during succession, woody species contributed extraordinarily to herb layer species diversity in all successional stages. All environmental factors considered had little impact on herb layer attributes. Conclusions: The subtropical forest investigated displays an immense richness of woody species in the herb layer while herbaceous species are less prominent. Species composition of the herb layer shows a clear successional pattern, however, the presence or absence of certain species appears to be random. © 2011 International Association for Vegetation Science.

Nadrowski K.,University of Leipzig | Pietsch K.,University of Leipzig | Baruffol M.,University of Zurich | Both S.,Martin Luther University of Halle Wittenberg | And 16 more authors.
PLoS ONE | Year: 2014

Future climates are likely to include extreme events, which in turn have great impacts on ecological systems. In this study, we investigated possible effects that could mitigate stem breakage caused by a rare and extreme ice storm in a Chinese subtropical forest across a gradient of forest diversity. We used Bayesian modeling to correct stem breakage for tree size and variance components analysis to quantify the influence of taxon, leaf and wood functional traits, and stand level properties on the probability of stem breakage. We show that the taxon explained four times more variance in individual stem breakage than did stand level properties; trees with higher specific leaf area (SLA) were less susceptible to breakage. However, a large part of the variation at the taxon scale remained unexplained, implying that unmeasured or undefined traits could be used to predict damage caused by ice storms. When aggregated at the plot level, functional diversity and wood density increased after the ice storm. We suggest that for the adaption of forest management to climate change, much can still be learned from looking at functional traits at the taxon level. © 2014 Nadrowski et al.

Bruelheide H.,Martin Luther University of Halle Wittenberg | Bohnke M.,Martin Luther University of Halle Wittenberg | Both S.,Martin Luther University of Halle Wittenberg | Fang T.,Gutianshan National Nature Reserve | And 38 more authors.
Ecological Monographs | Year: 2011

Subtropical broad-leaved forests in southeastern China support a high diversity of woody plants. Using a comparative study design with 30×30 m plots (n1/427) from five successional stages (<20, <40, <60, <80,≤80 yr), we investigated how the gradient in species composition reflects underlying processes of community assembly. In particular, we tested whether species richness of adult trees and shrubs decreased or increased and assessed to which degree this pattern was caused by negative density dependence or continuous immigration over time. Furthermore, we tested whether rare species were increasingly enriched and the species composition of adult trees and shrubs became more similar to species composition of seedlings during the course of succession. We counted the individuals of all adult species and shrubs >1 m in height in each plot and counted all woody recruits (bank of all seedlings ≤1 m in height) in each central 10×10 m quadrant of each plot. In addition, we measured a number of environmental variables (elevation, slope, aspect, soil moisture, pH, C, N, and C/N ratio) and biotic structural variables (height and cover of layers). Adult species richness varied from 25 to 69 species per plot, and in total 148 woody species from 46 families were recorded. There was a clear successional gradient in species composition as revealed by nonmetric multidimensional scaling (NMDS), but only a poor differentiation of different successional stages with respect to particular species. Adult richness per 100 individuals (rarefaction method) increased with successional stage. None of the measured abiotic variables were significantly correlated with adult species richness. We found no evidence that rare species were responsible for the increasing adult species richness, as richness of rare species among both adults and recruits was independent of the successional stage. Furthermore, the similarity between established adults and recruits did not increase with successional stage. There was a constant number of recruit species and also of exclusive recruit species, i.e., those that had not been present as adult individuals, across all successional stages, suggesting a continuous random immigration over time. © 2011 by the Ecological Society of America.

Yang X.,Martin Luther University of Halle Wittenberg | Yang X.,CAS Kunming Institute of Botany | Bauhus J.,Albert Ludwigs University of Freiburg | Both S.,Martin Luther University of Halle Wittenberg | And 13 more authors.
European Journal of Forest Research | Year: 2013

Experimental forest plantations to study biodiversity-ecosystem functioning (BEF) relationships have recently been established in different regions of the world, but subtropical biomes have not been covered so far. Here, we report about the initial survivorship of 26 tree species in the first such experiment in subtropical China. In the context of the joint Sino-German-Swiss Research Unit "BEF-China," 271 experimental forest plots were established using 24 naturally occurring tree species and two native commercial conifers. Based on the survival inventories carried out in November 2009 and June 2010, the overall survival rate was 87 % after the first 14 months. Generalized mixed-effects models showed that survival rates of seedlings were significantly affected by species richness, the species' leaf habit (deciduous or evergreen), species identity, planting date, and altitude. In the first survey, seedling establishment success decreased with increasing richness levels, a tendency that disappeared in the second survey after replanting. Though evergreen species performed less well than deciduous species with establishment rates of 84 versus 93 % in the second survey, their planting success exceeded the general expectation for subtropical broad-leaved evergreen species. These results have important implications for establishing mixed-species plantations for diversity conservation and improvement of ecosystem functioning in the Chinese subtropics and elsewhere. Additional costs associated with mixed-species plantations as compared to conventional plantations also demonstrate the potential of upscaling BEF experiments to large-scale afforestation projects. © 2013 Springer-Verlag Berlin Heidelberg.

Bohnke M.,Martin Luther University of Halle Wittenberg | Kreissig N.,Martin Luther University of Halle Wittenberg | Krober W.,Martin Luther University of Halle Wittenberg | Fang T.,Gutianshan National Nature Reserve | Bruelheide H.,Martin Luther University of Halle Wittenberg
Trees - Structure and Function | Year: 2012

Concerning forest communities, not much is known about the relationship between wood traits and environmental conditions. Using a succession series, we analyzed which wood anatomical traits were correlated with successional stage and asked which traits and which environmental factors were particularly important for the trait-environment relationship. An extensive dataset of 11 groups of wood traits was generated for 93 woody species that occurred in 27 permanent plots in a secondary subtropical secondary broadleaved forest in Zhejiang Province (SE-China) and subjected to Fourth Corner Analyses, using different permutation models. We encountered a strong relationship of wood porosity, visibility of growth rings and vessel arrangement to the successional gradient. Compared to biotic community characteristics such as density of plants, abiotic environmental variables such as soil characteristics, aspect and inclination of the plots showed only marginal correlations to wood anatomical traits. Furthermore, the link between environment and species composition of the forest communities was found to be more important in explaining the trait-environment relationship than between the communities and species wood traits. In addition, our results support the idea that most of the species in the subtropical forest might be functionally equivalent. © 2011 Springer-Verlag.

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