Both abiotic conditions and management influence the success of forest restoration.Despite growing interest and practical effort in restoring degraded forest landscapes,understanding of how disparate factors,such as t...Both abiotic conditions and management influence the success of forest restoration.Despite growing interest and practical effort in restoring degraded forest landscapes,understanding of how disparate factors,such as terrain,soil conditions,climate and silvicultural treatments,directly or collectively control species performance and shape community recovery remains limited.In this study,we assessed how topography and management intervention affect seedling survival and growth in the early stages of restoration.To do so,we established seven experimental plots,each measuring 20 m×20 m(400 m2)subdivided into 48 subplots,in coarse,anthropogenic grassland on a mid-elevation mountain slope in Hong Kong,and planted a total of 3975 native tree seedlings belonging to 12 tree species within them.To characterise topography,we modelled the elevation,slope,convexity and aspect of each subplot.Two types of tree guard(enclosed blue plastic sleeve and open yellow mesh),two types of fertiliser(organic and inorganic)and cardboard weeding mats were used to assess the impact of management interventions on the establishment of the seedlings.Survivorship,height and basal diameter were measured at 1,2 and 4 years after planting.We used generalised linear models to examine the effect of these factors and their interactions on seedling survival,and we applied linear models and hierarchical partitioning to explore their relative importance in determining the relative growth rate(RGR)of each species.The most parsimonious models were selected using the Akaike Information Criterion.Survivorship was 98.1%,95.2%and 86.4%across all plots in the first,second and fourth year,respectively.On average,topographic and management variables explained 1.48–3.34%of total variation in RGR,respectively,for all species.The models revealed that type of tree guard,aspect and elevation were the most important factors explaining RGR and survival.Results of hierarchical partitioning by species and growth period showed that the key determinants of performance vary by species and shift over the course of early seedling establishment,emphasising the importance of both spatial and temporal scales in the restoration of degraded tropical forests.Our findings support the use of enclosed tree guards and fertiliser to improve survivorship and growth across a range of broadleaved Asiatic species.All potential limiting factors pertaining to both site factors and management,as well as their interactions,should be considered in restoration planning to maximise restoration success.展开更多
Aims Deserts are one of the ecosystems most sensitive to global climate change.However,there are few studies examining how changing abiotic and biotic factors under climate change will affect plant species diversity i...Aims Deserts are one of the ecosystems most sensitive to global climate change.However,there are few studies examining how changing abiotic and biotic factors under climate change will affect plant species diversity in the temperate deserts of Asia.This study aimed to:(i)characterize species distributions and diversity patterns in an Asian temperate desert;and(ii)to quantify the effects of spatial and environment variables on plant species diversity.Methods We surveyed 61 sites to examine the relationship between plant species diversity and several spatial/environmental variables in the Gurbantunggut Desert.Spatial and environmental variables were used to predict plant species diversity in separate multiple regression and ordination models.Variation in species responses to spatial and environmental conditions was partitioned by combining these variables in a redundancy analysis(RDA)and by creating multivariate regression trees(MRT).Important Findings We found 92 plant species across the 61 sites.Elevation and geographic location were the dominant environmental factors underlying variation in site species richness.A RDA indicated that 93%of the variance in the species–environment relationships was explained by altitude,latitude,longitude,precipitation and slope position.Precipitation and topographic heterogeneity,through their effects on water availability,were more important than soil chemistry in determining the distribution of species.MRT analyses categorized communities into four groups based on latitude,soil pH and elevation,explaining 42.3%of the standardized species variance.Soil pH strongly influenced community composition within homogeneous geographic areas.Our findings suggest that precipitation and topographic heterogeneity,rather than edaphic heterogeneity,are more closely correlated to the number of species and their distributions in the temperate desert.展开更多
Aims Several studies have shown that plant height changes along environmen-tal gradients.However,altitudinal patterns of plant height across species are still unclear,especially in regions sensitive to climate change....Aims Several studies have shown that plant height changes along environmen-tal gradients.However,altitudinal patterns of plant height across species are still unclear,especially in regions sensitive to climate change.As canopy height decreases dramatically near the tree line in alpine areas,we hypothesize that plant height across all species also decreases with increasing altitude,and distinct thresholds exist along this gradient.Methods Using a large dataset of maximum plant height and elevation range(400 to 6000 m a.s.l.)of 4295 angiosperms from the regional flora of the Tibetan Plateau,we regressed plant height for every 100 m belt against elevation to explore the relationships.To identify the approximate boundaries where dramatic changes in plant height occurs for herbaceous plants,shrubs,trees,woody plants and all angiosperms,we used piecewise linear regression.Phylogenetically independent contrast was used to test the potential evolutionary influences on altitudinal patterns at the family level.Important Findings Results showed that for herbaceous plants,shrubs,trees,woody plants and all angiosperms,plant height decreases significantly as altitude increases.In addition,we found that altitude,a proxy for many environmental factors,had obvious thresholds(breakpoints)dictating patterns of plant height.The results of phylogenetically independent contrast also emphasized the importance of evolution-ary history in determining the altitudinal patterns of plant height for some growth forms.Our results highlight the relative intense filter-ing effect of environmental factors in shaping patterns of functional traits and how this could vary for different ranges of environmental variables.展开更多
Aims Exploring flowering patterns and detecting processes are essential when probing into the nature of reproductive traits during the life history and the interactions among different evolutionary clades.such pattern...Aims Exploring flowering patterns and detecting processes are essential when probing into the nature of reproductive traits during the life history and the interactions among different evolutionary clades.such patterns are believed to be influenced by many factors,but quantifying these impacts at the community-level remains poorly understood.Methods We investigated the flowering patterns based on long-term her-barium records in a given area from subtropical forest regions in southern China.We obtained 5258 herbarium voucher specimens collected from the Dinghushan National Nature reserve(DNNr)belonging to 166 families,943 genera and 2059 species and exam-ined the month when each species was flowering during the period 1920-2007.Important Findings The results showed that plants flowered sequentially almost through-out the whole year,showing the characteristics of subtropical evergreen broad-leaved forests.Flowering spectrums of the entire flora and the four life forms exhibited a clear unimodality that is probably typical of subtropical forest communities.Flowering pat-terns of the DNNr were positively correlated with mean rainfall,mean air temperature and mean sunshine duration.median flowering dates of the 38 large species-rich families ranged from early april to late august;25 families exhibited significant unimodal distribution patterns,whereas the remaining families were unclear or bimodal.median flowering dates of the 10 most species-rich genera ranged from middle may to later July.While the results are consist-ent with climatic factors playing a general role in flowering patterns,median flowering dates varied significantly among species-rich families and genera,suggesting that phylogenies could provide spe-cific constraints in subtropical forests.展开更多
基金The financial support of CLP Holdings Limited is acknowledged for supporting KFBG's ongoing applied forest restoration research.
文摘Both abiotic conditions and management influence the success of forest restoration.Despite growing interest and practical effort in restoring degraded forest landscapes,understanding of how disparate factors,such as terrain,soil conditions,climate and silvicultural treatments,directly or collectively control species performance and shape community recovery remains limited.In this study,we assessed how topography and management intervention affect seedling survival and growth in the early stages of restoration.To do so,we established seven experimental plots,each measuring 20 m×20 m(400 m2)subdivided into 48 subplots,in coarse,anthropogenic grassland on a mid-elevation mountain slope in Hong Kong,and planted a total of 3975 native tree seedlings belonging to 12 tree species within them.To characterise topography,we modelled the elevation,slope,convexity and aspect of each subplot.Two types of tree guard(enclosed blue plastic sleeve and open yellow mesh),two types of fertiliser(organic and inorganic)and cardboard weeding mats were used to assess the impact of management interventions on the establishment of the seedlings.Survivorship,height and basal diameter were measured at 1,2 and 4 years after planting.We used generalised linear models to examine the effect of these factors and their interactions on seedling survival,and we applied linear models and hierarchical partitioning to explore their relative importance in determining the relative growth rate(RGR)of each species.The most parsimonious models were selected using the Akaike Information Criterion.Survivorship was 98.1%,95.2%and 86.4%across all plots in the first,second and fourth year,respectively.On average,topographic and management variables explained 1.48–3.34%of total variation in RGR,respectively,for all species.The models revealed that type of tree guard,aspect and elevation were the most important factors explaining RGR and survival.Results of hierarchical partitioning by species and growth period showed that the key determinants of performance vary by species and shift over the course of early seedling establishment,emphasising the importance of both spatial and temporal scales in the restoration of degraded tropical forests.Our findings support the use of enclosed tree guards and fertiliser to improve survivorship and growth across a range of broadleaved Asiatic species.All potential limiting factors pertaining to both site factors and management,as well as their interactions,should be considered in restoration planning to maximise restoration success.
基金Natural Science Foundation of ChinaXinjiang(U1130304)the National Science Foundation of China(41061004 and 31260099).
文摘Aims Deserts are one of the ecosystems most sensitive to global climate change.However,there are few studies examining how changing abiotic and biotic factors under climate change will affect plant species diversity in the temperate deserts of Asia.This study aimed to:(i)characterize species distributions and diversity patterns in an Asian temperate desert;and(ii)to quantify the effects of spatial and environment variables on plant species diversity.Methods We surveyed 61 sites to examine the relationship between plant species diversity and several spatial/environmental variables in the Gurbantunggut Desert.Spatial and environmental variables were used to predict plant species diversity in separate multiple regression and ordination models.Variation in species responses to spatial and environmental conditions was partitioned by combining these variables in a redundancy analysis(RDA)and by creating multivariate regression trees(MRT).Important Findings We found 92 plant species across the 61 sites.Elevation and geographic location were the dominant environmental factors underlying variation in site species richness.A RDA indicated that 93%of the variance in the species–environment relationships was explained by altitude,latitude,longitude,precipitation and slope position.Precipitation and topographic heterogeneity,through their effects on water availability,were more important than soil chemistry in determining the distribution of species.MRT analyses categorized communities into four groups based on latitude,soil pH and elevation,explaining 42.3%of the standardized species variance.Soil pH strongly influenced community composition within homogeneous geographic areas.Our findings suggest that precipitation and topographic heterogeneity,rather than edaphic heterogeneity,are more closely correlated to the number of species and their distributions in the temperate desert.
文摘Aims Several studies have shown that plant height changes along environmen-tal gradients.However,altitudinal patterns of plant height across species are still unclear,especially in regions sensitive to climate change.As canopy height decreases dramatically near the tree line in alpine areas,we hypothesize that plant height across all species also decreases with increasing altitude,and distinct thresholds exist along this gradient.Methods Using a large dataset of maximum plant height and elevation range(400 to 6000 m a.s.l.)of 4295 angiosperms from the regional flora of the Tibetan Plateau,we regressed plant height for every 100 m belt against elevation to explore the relationships.To identify the approximate boundaries where dramatic changes in plant height occurs for herbaceous plants,shrubs,trees,woody plants and all angiosperms,we used piecewise linear regression.Phylogenetically independent contrast was used to test the potential evolutionary influences on altitudinal patterns at the family level.Important Findings Results showed that for herbaceous plants,shrubs,trees,woody plants and all angiosperms,plant height decreases significantly as altitude increases.In addition,we found that altitude,a proxy for many environmental factors,had obvious thresholds(breakpoints)dictating patterns of plant height.The results of phylogenetically independent contrast also emphasized the importance of evolution-ary history in determining the altitudinal patterns of plant height for some growth forms.Our results highlight the relative intense filter-ing effect of environmental factors in shaping patterns of functional traits and how this could vary for different ranges of environmental variables.
基金NSF-China(31200471)Special Fund for Forest Scientific Research in the Public Welfare(20140430105)+3 种基金Ministry of Finance of China(RITFYWZX201208)China Scholarship Council(201303270006)CFERN&GENE Award Funds on Ecological Paper to N.C.P.Ministry of Science and Technology of China(2005DKA21401,2013FY111200)to D.X.Z.
文摘Aims Exploring flowering patterns and detecting processes are essential when probing into the nature of reproductive traits during the life history and the interactions among different evolutionary clades.such patterns are believed to be influenced by many factors,but quantifying these impacts at the community-level remains poorly understood.Methods We investigated the flowering patterns based on long-term her-barium records in a given area from subtropical forest regions in southern China.We obtained 5258 herbarium voucher specimens collected from the Dinghushan National Nature reserve(DNNr)belonging to 166 families,943 genera and 2059 species and exam-ined the month when each species was flowering during the period 1920-2007.Important Findings The results showed that plants flowered sequentially almost through-out the whole year,showing the characteristics of subtropical evergreen broad-leaved forests.Flowering spectrums of the entire flora and the four life forms exhibited a clear unimodality that is probably typical of subtropical forest communities.Flowering pat-terns of the DNNr were positively correlated with mean rainfall,mean air temperature and mean sunshine duration.median flowering dates of the 38 large species-rich families ranged from early april to late august;25 families exhibited significant unimodal distribution patterns,whereas the remaining families were unclear or bimodal.median flowering dates of the 10 most species-rich genera ranged from middle may to later July.While the results are consist-ent with climatic factors playing a general role in flowering patterns,median flowering dates varied significantly among species-rich families and genera,suggesting that phylogenies could provide spe-cific constraints in subtropical forests.
