Knowledge about the biogeographic affinities of the world's tropical forests helps to better understand regional differences in forest structure, diversity, composition, and dynamics. Such understanding will enable anticipation of... more
Knowledge about the biogeographic affinities of the world's tropical forests helps to better understand regional differences in forest structure, diversity, composition, and dynamics. Such understanding will enable anticipation of region-specific responses to global environmental change. Modern phylogenies, in combination with broad coverage of species inventory data, now allow for global biogeographic analyses that take species evolutionary distance into account. Here we present a classification of the world's tropical forests based on their phylogenetic similarity. We identify five principal floristic regions and their floristic relationships: (i) Indo-Pacific, (ii) Subtropical, (iii) African, (iv) American, and (v) Dry forests. Our results do not support the traditional neo- versus paleotropical forest division but instead separate the combined American and African forests from their Indo-Pacific counterparts. We also find indications for the existence of a global dry for...
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Abstract Cities have become the main abodes for people, and landscape plants with their notable influence on quality of life, are important components of the urban ecosystem. The need to explore the climatic suitability and sustainability... more
Abstract Cities have become the main abodes for people, and landscape plants with their notable influence on quality of life, are important components of the urban ecosystem. The need to explore the climatic suitability and sustainability of landscape plants is especially relevant due to globalization and climate change. Nevertheless, this research area is constrained by the limited understanding of the biogeographical origin of landscape plants. We have compiled data on species lists, taxonomic information, and geographical and climatic origins for woody landscape plants in 36 major cities across China. We used climatic niche breadth (CNB) and climatic mismatched ratio (CMR) to assess the climatic suitability and sustainability of landscape plants. We found that 412 alien species had several hotspots of origin, mainly tropical regions in the Americas, Asia, and Australia. The 1258 domestic species mainly originated from temperate southern China. Tropical species had a conspicuous geographical clustering in coastal cities of southern China, while the temperate species were abundant in all cities. The CNBs of domestic species were wider than those of alien species, and arid cities with harsher environmental stresses (mainly due to the limited precipitation) registered higher CMRs. In terms of sustainability, the response of landscape plants to climate change varied across climate zones, being influenced by a rich presence of temperate species. Overall, our findings emphasized that landscape plant selections should not only pay attention to the existing landscape needs, but also consider the climatic sustainability of landscape plant species to climate change, especially for long lifespan woody plants.
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Background and aim Global warming is expected to have large impacts on high alpine and Arctic ecosystems in future. Here we report the effects of 18 years of experimental warming on two contrasting high alpine plant communities in... more
Background and aim Global warming is expected to have large impacts on high alpine and Arctic ecosystems in future. Here we report the effects of 18 years of experimental warming on two contrasting high alpine plant communities in subarctic Sweden.Methods Using open-top chambers (OTCs), we analysed the effects of long-term passive experimental warming on two high alpine plant communities, a species- and nutrient-poor heath and a more nutrient- and species-rich mesic meadow. We determined the impact on species composition, species diversity (at the level of rare, frequent and dominant species in each community), and phylogenetic and functional diversity.Key results Long-term warming drove differentiation in the species composition in both heath and meadow vegetation, with the warmed plots having distinctly different species composition in 2013 compared with 1995. In addition, variability in species composition increased in the meadow, while it decreased in the heath. The long-term wa...
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Research Interests: Plant Ecology, Climate Change, Plant Biology, Biology, Ecology, and 15 moreGlobal Environmental Change, Lichenology, Global Change Biology, Medicine, Arctic Climate, Climate Change Impacts, Global Warming, Environment and climate change, Lichen, Alpine Ecology, Lichens, Flora and Vegetation, Alpine Ecosystems, Ecosystem, and Alpine and Arctic Research
Niche-based and neutrality-based theories are two major classes of theories explaining the assembly mechanisms of local communities. Both theories have been frequently used to explain species diversity and composition in local communities... more
Niche-based and neutrality-based theories are two major classes of theories explaining the assembly mechanisms of local communities. Both theories have been frequently used to explain species diversity and composition in local communities but their relative importance remains unclear. Here, we analyzed 57 assemblages of angiosperm trees in 0.1-ha forest plots across China to examine the effects of environmental heterogeneity (relevant to niche-based processes) and spatial contingency (relevant to neutrality-based processes) on phylogenetic structure of angiosperm tree assemblages distributed across a wide range of environment and space. Phylogenetic structure was quantified with six phylogenetic metrics (i.e., phylogenetic diversity, mean pairwise distance, mean nearest taxon distance, and the standardized effect sizes of these three metrics), which emphasize on different depths of evolutionary histories and account for different degrees of species richness effects. Our results show...
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Biological invasion is a serious threat to biodiversity and ecosystem function in nature reserves. However, the knowledge of the spatial patterns and underlying mechanisms of plant invasions in nature reserves is still limited. Based on a... more
Biological invasion is a serious threat to biodiversity and ecosystem function in nature reserves. However, the knowledge of the spatial patterns and underlying mechanisms of plant invasions in nature reserves is still limited. Based on a recent dataset on both invasive and native plants in 67 nature reserves of China, we used correlation, regression, and variation partitioning methods to statistically assess the relative roles of the “human activity,” “biotic acceptance,” and “environmental heterogeneity” hypotheses in explaining the geographic pattern of plant invasion. A total of 235 invasive plant species were compiled from 67 nature reserves. The high explanatory power of the human activity variables supported the human activity hypothesis. The biotic acceptance hypothesis was weakly supported since no significant correlations between climatic variables and invasion levels were found when the effects of the other factors were controlled. The environmental heterogeneity hypothes...
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Understanding the drivers of geographic variation in species richness is one of the fundamental goals in ecology and biogeography. Fish is the key element in freshwater ecosystem and the focus of fishery production and biological... more
Understanding the drivers of geographic variation in species richness is one of the fundamental goals in ecology and biogeography. Fish is the key element in freshwater ecosystem and the focus of fishery production and biological conservation. Chinese freshwater fish fauna is rich and largely endemic due to variable geography and climate. By compiling the published data on fish richness for 86 nature reserves, and taking environmental predictors into consideration, we aimed to test latitudinal and longitudinal gradients in fish richness and the relative roles of energy availability, physiological tolerance, climatic seasonality and habitat heterogeneity hypotheses in explaining geographic fish richness pattern. Fish richness in China's nature reserves decreases with latitude and showed a hump-shaped relationship with longitude. Latitudinal fish richness is mainly shaped by mean temperature of the coldest month. Mean elevation and associated changes in temperature lead to longitu...
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1.Bryophytes in the Arctic and Alpine regions are important in terms of biodiversity, cover and biomass. However, climate change and widespread shrubification of alpine and arctic tundra is predicted to increase in the future, with... more
1.Bryophytes in the Arctic and Alpine regions are important in terms of biodiversity, cover and biomass. However, climate change and widespread shrubification of alpine and arctic tundra is predicted to increase in the future, with potentially large impacts on bryophyte communities. 2.We studies the impact of 18 years of experimental warming with open top chambers (OTCs) on bryophyte cover, richness and diversity in an alpine mesic meadow and a heath plant community in Northern Sweden. In addition we investigated the relationship between deciduous shrubs and bryophytes.3.Cover and richness of bryophytes both declined due to long-term warming, while diversity did not show any significant responses. After 18 years, bryophyte cover had decreased by 71% and 26 in the heath and meadow, while richness declined by 39% and 26%, respectively. 4.Synthesis. Decline in total bryophyte cover in both communities in response to long-term warming was driven by a general decline in many species, wit...
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Species assemblage in a local community is determined by the interplay of evolutionary and ecological processes. The Tropical Niche Conservatism hypothesis proposes mechanisms underlying patterns of biodiversity in biological communities... more
Species assemblage in a local community is determined by the interplay of evolutionary and ecological processes. The Tropical Niche Conservatism hypothesis proposes mechanisms underlying patterns of biodiversity in biological communities along environmental gradients. This hypothesis predicts that, among other things, clades in areas with warm or wet environments are, on average, older than those in areas with cold or dry environments. Focusing on angiosperm trees in forests, this study tested the age-related prediction of the Tropical Niche Conservatism hypothesis. We related the mean family age of angiosperm trees in 57 local forests from across China with 23 current and paleo-environmental variables, which included all major temperature- and precipitation-related variables. Our study shows that the mean family age of angiosperm trees in local forests was positively correlated with temperature and precipitation. This finding is consistent with the age-related prediction of the Tropical Niche Conservatism hypothesis. Approximately 85% of the variance in the mean family age of angiosperm trees was explained by temperature-related variables, and 81% of the variance in the mean family age of angiosperm trees was explained by precipitation-related variables. Climatic conditions at the Last Glacial Maximum did not explain additional variation in mean family age after accounting for current environmental conditions.
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Based on the analysis of characteristics of forest light environmental heterogeneity, this paper reviewed the research advance in the response of forest seedlings to light environmental heterogeneity from the aspects of photosynthesis,... more
Based on the analysis of characteristics of forest light environmental heterogeneity, this paper reviewed the research advance in the response of forest seedlings to light environmental heterogeneity from the aspects of photosynthesis, thermal dissipation, biomass accumulation and distribution, morphological traits, germination, and population dynamics, and discussed the ecological significance of different responses of seedling regeneration to light environmental heterogeneity in forest biodiversity maintenance, forest succession, and revegetation. Some suggestions for future research in this field were put forward.
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Background/Question/Methods Forests are recognized as the most important carbon pool of terrestrial ecosystems. How to estimate the carbon capacity of forests is an important research issue for ecologists. Some authors used old-growth... more
Background/Question/Methods Forests are recognized as the most important carbon pool of terrestrial ecosystems. How to estimate the carbon capacity of forests is an important research issue for ecologists. Some authors used old-growth forests with stand age > 300 years to estimate the upper bounds of carbon storage. Unfortunately, few old-growth forests remain; the upper bounds of forest biomass across climatic gradients are not well understood. We assume that aboveground biomass (AGB) of forest is controlled by the combined effect of the amount and ratio of resources (water and energy). Since forests differ in stand age (SA), the amounts of received resources are the products of annual energy and water input and stand age. If we can build a model with water, energy and SA, and set SA to be 300 years, then, we can predict the upper bounds of AGB (UBAGB) across climatic gradient. To this end, we collected 1018 forest plots with the data on coordinates, AGB, and SA in Eastern China...
Winter wheat (Triticum aestivum L. cv. Jingdong 8) was exposed to short-term high ozone treatment after anthesis and then was either well irrigated with soil water content (SWC) of 80–85 % (O3+W) or drought treated (SWC 35–40 %, O3+D).... more
Winter wheat (Triticum aestivum L. cv. Jingdong 8) was exposed to short-term high ozone treatment after anthesis and then was either well irrigated with soil water content (SWC) of 80–85 % (O3+W) or drought treated (SWC 35–40 %, O3+D). Short-term ozone exposure significantly decreased irradiance-saturated net photosynthetic rate (P N) of winter wheat. Under good SWC, P N of the
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ABSTRACT In order to study the responses of winter wheat cultivars released in different years to short-term high O3 exposure, an old cultivar (‘Nongda 311’, released in 1960s) and a modern one (‘Yannong 19’, released in 1990s) were... more
ABSTRACT In order to study the responses of winter wheat cultivars released in different years to short-term high O3 exposure, an old cultivar (‘Nongda 311’, released in 1960s) and a modern one (‘Yannong 19’, released in 1990s) were treated with an O3 exposure (145 ± 12 mm3 m−3, 4 h d−1 for 3 d) shortly after anthesis stage (> 50 % main stems blossomed). During the O3 exposure, light-saturated photosynthetic rate (P N) and stomatal conductance (g s) of both cultivars decreased considerably. Elevated O3 did not decrease dark-adapted maximum photochemical efficiency, but induced significant reduction in actual photochemical efficiency and thereby considerably increase in non-photochemical quenching. P N, g s of the modern cultivar ‘Yannong 19’ decreased more than the older one ‘Nongda 311’, indicating the former exhibited higher sensitivity to O3 than the latter. After O3 exposure, P N, g s and chlorophyll (Chl) content in flag leaf decreased more quickly than control, indicating induction of faster premature leaf senescence. As a result, the short-term O3 exposure caused substantial yield loss, with larger reduction in ‘Yannong 19’ (−19.2 %) than in ‘Nongda 311’ (−8.4 %). Our results indicated that high O3 exposure at grain filling stage would have greater negative impacts on the high yielding modern cultivar relative to the old one with lower yield.
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ABSTRACT Various mechanistic theories of community assembly have been proposed ranging from niche-based theory to neutral theory. Analyses of beta diversity in a phylogenetic context could provide an excellent opportunity for testing many... more
ABSTRACT Various mechanistic theories of community assembly have been proposed ranging from niche-based theory to neutral theory. Analyses of beta diversity in a phylogenetic context could provide an excellent opportunity for testing many of these hypotheses. We analyzed the patterns of phylogenetic beta diversity in tropical tree communities in Panama to test several community assembly hypotheses. In particular, the degree to which the phylogenetic dissimilarity between communities can be explained by geographical or environmental distance can yield support for stochastic or deterministic assembly processes, respectively. Therefore, we examined: (i) the existence of distance decay of phylogenetic similarity among communities and its degree of departure from that expected under a null model; and (ii) the relative importance of geographical versus environmental distance in predicting the phylogenetic dissimilarity of communities. We found evidence that the similarity in the phylogenetic composition of communities decayed with geographical distance and environmental gradients. Null model evidence showed that beta diversity in the study system was phylogenetically non-random. Our results highlighted not only the role of local ecological mechanisms, including environmental filtering and competitive exclusion, but also biogeographical processes such as speciation, dispersal limitation, and niche evolution in structuring phylogenetic turnover. These results also highlight the importance of niche conservatism in structuring species diversity patterns.