To further study the fungal community in heavy metal contaminated ecosystems,soil samples were collected from an abandoned chromium(Cr)factory,and fungal community was analyzed by Illumina sequencing of Internal Trans...To further study the fungal community in heavy metal contaminated ecosystems,soil samples were collected from an abandoned chromium(Cr)factory,and fungal community was analyzed by Illumina sequencing of Internal Transcribed Spacer(ITS)amplicons.The results showed that Cr contamination changed the composition and structure of soil fungal community,but didn’t change the diversity.Fungus showed various responses to Cr contamination.LEfSe analysis revealed that the biomarker changed a lot in the Cr-contaminated samples in comparison with that in the control samples.The changes in fungal community may be caused by the direct toxic effects on fungi by high concentration of Cr and the significant change in soil properties resulting from Cr contamination.Among all the Cr fractions,organic matter-bound Cr and exchangeable Cr showed significant effects on the fungal community and organic matter also showed a significant effect on soil fungal community.展开更多
Background:Rapid climate changes lead to an increase in forest disturbance,which in turn lead to growing concerns for biodiversity.While saproxylic beetles are relevant indicators for studying different aspects of bio...Background:Rapid climate changes lead to an increase in forest disturbance,which in turn lead to growing concerns for biodiversity.While saproxylic beetles are relevant indicators for studying different aspects of biodiversity,most are smaller than 2 mm and difficult to sample.This,together with a high number of species and trophic roles,make their study remarkably challenging,time-consuming,and expensive.The Landsat mission provides data since 1984 and represents a powerful tool in this scenario.While we believe that remote sensing data cannot replace on-site sampling and analysis,in this study we aim to prove that the Landsat Time Series(TS)may support the identification of insects’hotspots and consequently guide the selection of areas where to concentrate field analysis.Methods:With this aim,we constructed a Landsat-derived NDVI TS(1984–2020)and we summarised the NDVI trend over time by calculating eight Temporal Metrics(TMs)among which four resulted particularly successful in predicting the amount of saproxylic insects:(i)the slope of the regression line obtained by linear interpolating the NDVI values over time;(ii)the Root Mean Square Error(RMSE)between the regression line and the NDVI TS;(iii)the median,and the(iv)minimum values of the NDVI TS.The study area consists of four monitoring sectors in a Mediterranean-managed beech forest located in the Apennines(Molise,Italy),where 60 window flight traps for flying beetles were installed.First,the saproxylic beetle's biodiversities of monitoring sectors were quantified in terms of species richness and alpha-diversity.Second,the capability of TMs in predicting the richness of saproxylic beetles family and trophic categories was assessed in terms of Pearson's product-moment correlation.Results:The alpha diversity and species richness analysis indicate dissimilarities across the four monitored sectors(Shannon and Simpson's index ranging between 0.67 to 2.31 and 0.69 to 0.88,respectively),with Landsat TS resulting in effective predictors for estimating saproxylic beetle richness.The strongest correlation was reached between the Monotomidae family and the RMSE temporal metric(R=0.66).The mean absolute correlation(r)between the NDVI TMs and the saproxylic community was 0.46 for Monotomidae,0.31 for Cerambycidae,and 0.25 for Curculionidae.Conclusions:Our results suggest that Landsat TS has important implications for studying saproxylic beetle distribution and,by helping the selection of monitoring areas,increasing the amount of information acquired while decreasing the effort required for field analysis.展开更多
Biodiversity conservation has long been a subject of extreme interest to community ecologists,with a particular focus on exploring the underlying causes of species diversity based on niche and neutral theories.This st...Biodiversity conservation has long been a subject of extreme interest to community ecologists,with a particular focus on exploring the underlying causes of species diversity based on niche and neutral theories.This study aims to identify the potential determinants of species diversity in a deciduous broad-leaved forest in the transitional region from subtropical to temperate climate in China.We collected woody plant data and environmental variables in a fully mapped 25-ha permanent forest plot,partitioned the beta-diversity into local contributions(LCBD)and species contributions(SCBD),and then applied multivariate linear regression analysis to test the effects of biotic and abiotic factors on alpha-diversity,LCBD,and SCBD.We used variation partitioning in combination with environmental variables and spatial distance to determine the contribution of environment-related variations versus spatial variations.Our results showed that the indices of alpha-diversity(i.e.,species abundance and richness)were positively correlated with soil available phosphorus(P)and negatively with slope.For the betadiversity,environment and space together explained nearly half of the variations in community composition.Approximately 60%of the variation of LCBD in the understory layer,40%in the substory layer,and 29%in the canopy layer were jointly explained by topographic,soil and biological variables,with biotic factors playing a dominant role in determining the beta-diversity.Species abundance accounted for a large proportion of the variations in SCBD in each vertical stratum,and niche position(NP)was the ecological trait that significantly affected the variations in SCBD in the substory and canopy layers.Our findings help to gain better understanding on how species diversity in forest ecosystem responds to environmental conditions and how it is influenced by biotic factors and ecological traits of species.展开更多
Alpine wetlands are hotspots of carbon(C)storage and methane emission,and they could be key contributors to global warming.In recent years,rapid warming has lowered the water table in alpine wetlands on the Tibetan Pl...Alpine wetlands are hotspots of carbon(C)storage and methane emission,and they could be key contributors to global warming.In recent years,rapid warming has lowered the water table in alpine wetlands on the Tibetan Plateau,concurrent with intensified nitrogen(N)deposition via anthropogenic activities.We carried out a field experiment to investigate the ecological impacts of these two factors on soil bacterial and functional communities,which are essential drivers of greenhouse gas emissions.Nitrogen amendment alone decreased the phylogenetic alpha-diversity of bacterial communities which could be offset by lowered water table.In contrast,microbial functional alpha-diversity,revealed by a high-throughput microarray,remained unchanged.Both bacterial and functional beta-diversity responded to lowered water table,but only bacterial community responded to N amendment.The alpha-Proteobacteria,beta-Proteobacteria,and Bacteroidetes were the major responsive bacterial lineages,and C degradation,methanogenesis,alkaline shock,and phosphorus oxidation were the major responsive functional processes.Partitioning analysis revealed that N amendment changed bacterial community structure mainly via species loss processes but did not affect bacterial functional communities,with soil pH and ammonium as the key factors influencing changes in bacterial community structure.Conversely,lowered water table altered bacterial and functional communities through species substitution processes linked to soil pH and soil moisture.According to our results,the response mechanisms of microbial communities to lowered water table and N amendment are fundamentally different in alpine wetlands.展开更多
Aims The effects of traditional land use by mobile livestock keepers on biodiversity in forest steppe ecotones are insufficiently studied.Epiphytes are an important part of forest plant diversity.Here we analyze diffe...Aims The effects of traditional land use by mobile livestock keepers on biodiversity in forest steppe ecotones are insufficiently studied.Epiphytes are an important part of forest plant diversity.Here we analyze differences in the diversity and composition of the epiphytic lichen vegetation between the edge and the interior of Siberian larch forests in the Khangai Mountains,western Mongolia,which are highly subdivided into patches.We asked whether the epiphytic lichen vegetation at the forest edge differs significantly from that in the interior,whether the edge is inhabited by more nitrophilous species than the interior and whether the density of nomad camps around the forest affects epiphytic lichen diversity.Methods Cover percentages of epiphytic lichen species were recorded from 20 trees per plot on 6 plots in the interior and 6 plots at the edge of Larix sibirica forests.The position of nomad summer camps was surveyed using Global Positioning System.Data were analyzed with pairwise significance tests,analysis of similarities,nonmetric multidimensional scaling and canonical correspondence analysis.Important Findings The composition of the epiphytic lichen vegetation clearly differed between the two habitats,with more species being more frequent at the edge than in the interior.However,there was no difference in species richness(α-diversity).The epiphyte vegetation at the edge was more uniform and characterized by lower variation of tree-levelα-diversity and lowerβ-diversity than in the interior.At the edge,only nitrophytic lichens were dominant,whereas in the interior,nitrophytes and acidophytes were among the dominant species.This pattern is probably attributable to the spatial heterogeneity of the intensity of forest grazing and was shown to be influenced by the density of nomad summer camps in the vicinity of the forests.Tree-levelα-diversity increased with stem diameter,but high-diameter trees were rare.The results suggest that the present level of forest patchiness and the effect of forest grazing increases the diversity of epiphytic lichens on the landscape level,while logging of highdiameter trees reduces lichen diversity.展开更多
基金Project(51504298)supported by the National Natural Science Foundation of ChinaProject(2016JJ3146)supported by the Natural Science Foundation of Hunan Province,China+1 种基金Project(1053320171098)supported by the Fundamental Research Funds for the Central Universities of ChinaProject supported by the Postdoctoral Research Funding Plan in Central South University,China
文摘To further study the fungal community in heavy metal contaminated ecosystems,soil samples were collected from an abandoned chromium(Cr)factory,and fungal community was analyzed by Illumina sequencing of Internal Transcribed Spacer(ITS)amplicons.The results showed that Cr contamination changed the composition and structure of soil fungal community,but didn’t change the diversity.Fungus showed various responses to Cr contamination.LEfSe analysis revealed that the biomarker changed a lot in the Cr-contaminated samples in comparison with that in the control samples.The changes in fungal community may be caused by the direct toxic effects on fungi by high concentration of Cr and the significant change in soil properties resulting from Cr contamination.Among all the Cr fractions,organic matter-bound Cr and exchangeable Cr showed significant effects on the fungal community and organic matter also showed a significant effect on soil fungal community.
文摘Background:Rapid climate changes lead to an increase in forest disturbance,which in turn lead to growing concerns for biodiversity.While saproxylic beetles are relevant indicators for studying different aspects of biodiversity,most are smaller than 2 mm and difficult to sample.This,together with a high number of species and trophic roles,make their study remarkably challenging,time-consuming,and expensive.The Landsat mission provides data since 1984 and represents a powerful tool in this scenario.While we believe that remote sensing data cannot replace on-site sampling and analysis,in this study we aim to prove that the Landsat Time Series(TS)may support the identification of insects’hotspots and consequently guide the selection of areas where to concentrate field analysis.Methods:With this aim,we constructed a Landsat-derived NDVI TS(1984–2020)and we summarised the NDVI trend over time by calculating eight Temporal Metrics(TMs)among which four resulted particularly successful in predicting the amount of saproxylic insects:(i)the slope of the regression line obtained by linear interpolating the NDVI values over time;(ii)the Root Mean Square Error(RMSE)between the regression line and the NDVI TS;(iii)the median,and the(iv)minimum values of the NDVI TS.The study area consists of four monitoring sectors in a Mediterranean-managed beech forest located in the Apennines(Molise,Italy),where 60 window flight traps for flying beetles were installed.First,the saproxylic beetle's biodiversities of monitoring sectors were quantified in terms of species richness and alpha-diversity.Second,the capability of TMs in predicting the richness of saproxylic beetles family and trophic categories was assessed in terms of Pearson's product-moment correlation.Results:The alpha diversity and species richness analysis indicate dissimilarities across the four monitored sectors(Shannon and Simpson's index ranging between 0.67 to 2.31 and 0.69 to 0.88,respectively),with Landsat TS resulting in effective predictors for estimating saproxylic beetle richness.The strongest correlation was reached between the Monotomidae family and the RMSE temporal metric(R=0.66).The mean absolute correlation(r)between the NDVI TMs and the saproxylic community was 0.46 for Monotomidae,0.31 for Cerambycidae,and 0.25 for Curculionidae.Conclusions:Our results suggest that Landsat TS has important implications for studying saproxylic beetle distribution and,by helping the selection of monitoring areas,increasing the amount of information acquired while decreasing the effort required for field analysis.
基金supported by the National Natural Science Foundation of China(Nos.31971491,31770517)the Meituan Qingshan Special Commonweal Fund of China Environmental Protection Foundation(CEPFQS202169-20)。
文摘Biodiversity conservation has long been a subject of extreme interest to community ecologists,with a particular focus on exploring the underlying causes of species diversity based on niche and neutral theories.This study aims to identify the potential determinants of species diversity in a deciduous broad-leaved forest in the transitional region from subtropical to temperate climate in China.We collected woody plant data and environmental variables in a fully mapped 25-ha permanent forest plot,partitioned the beta-diversity into local contributions(LCBD)and species contributions(SCBD),and then applied multivariate linear regression analysis to test the effects of biotic and abiotic factors on alpha-diversity,LCBD,and SCBD.We used variation partitioning in combination with environmental variables and spatial distance to determine the contribution of environment-related variations versus spatial variations.Our results showed that the indices of alpha-diversity(i.e.,species abundance and richness)were positively correlated with soil available phosphorus(P)and negatively with slope.For the betadiversity,environment and space together explained nearly half of the variations in community composition.Approximately 60%of the variation of LCBD in the understory layer,40%in the substory layer,and 29%in the canopy layer were jointly explained by topographic,soil and biological variables,with biotic factors playing a dominant role in determining the beta-diversity.Species abundance accounted for a large proportion of the variations in SCBD in each vertical stratum,and niche position(NP)was the ecological trait that significantly affected the variations in SCBD in the substory and canopy layers.Our findings help to gain better understanding on how species diversity in forest ecosystem responds to environmental conditions and how it is influenced by biotic factors and ecological traits of species.
文摘Alpine wetlands are hotspots of carbon(C)storage and methane emission,and they could be key contributors to global warming.In recent years,rapid warming has lowered the water table in alpine wetlands on the Tibetan Plateau,concurrent with intensified nitrogen(N)deposition via anthropogenic activities.We carried out a field experiment to investigate the ecological impacts of these two factors on soil bacterial and functional communities,which are essential drivers of greenhouse gas emissions.Nitrogen amendment alone decreased the phylogenetic alpha-diversity of bacterial communities which could be offset by lowered water table.In contrast,microbial functional alpha-diversity,revealed by a high-throughput microarray,remained unchanged.Both bacterial and functional beta-diversity responded to lowered water table,but only bacterial community responded to N amendment.The alpha-Proteobacteria,beta-Proteobacteria,and Bacteroidetes were the major responsive bacterial lineages,and C degradation,methanogenesis,alkaline shock,and phosphorus oxidation were the major responsive functional processes.Partitioning analysis revealed that N amendment changed bacterial community structure mainly via species loss processes but did not affect bacterial functional communities,with soil pH and ammonium as the key factors influencing changes in bacterial community structure.Conversely,lowered water table altered bacterial and functional communities through species substitution processes linked to soil pH and soil moisture.According to our results,the response mechanisms of microbial communities to lowered water table and N amendment are fundamentally different in alpine wetlands.
基金Volkswagen Foundation to M.H,Ch.Dulamsuren and Ch.Leuschner for the project‘Forest regeneration and biodiversity at the forest steppe border of the Altai and Khangai Mountains under contrasting developments of livestock numbers in Kazakhstan and Mongolia’.
文摘Aims The effects of traditional land use by mobile livestock keepers on biodiversity in forest steppe ecotones are insufficiently studied.Epiphytes are an important part of forest plant diversity.Here we analyze differences in the diversity and composition of the epiphytic lichen vegetation between the edge and the interior of Siberian larch forests in the Khangai Mountains,western Mongolia,which are highly subdivided into patches.We asked whether the epiphytic lichen vegetation at the forest edge differs significantly from that in the interior,whether the edge is inhabited by more nitrophilous species than the interior and whether the density of nomad camps around the forest affects epiphytic lichen diversity.Methods Cover percentages of epiphytic lichen species were recorded from 20 trees per plot on 6 plots in the interior and 6 plots at the edge of Larix sibirica forests.The position of nomad summer camps was surveyed using Global Positioning System.Data were analyzed with pairwise significance tests,analysis of similarities,nonmetric multidimensional scaling and canonical correspondence analysis.Important Findings The composition of the epiphytic lichen vegetation clearly differed between the two habitats,with more species being more frequent at the edge than in the interior.However,there was no difference in species richness(α-diversity).The epiphyte vegetation at the edge was more uniform and characterized by lower variation of tree-levelα-diversity and lowerβ-diversity than in the interior.At the edge,only nitrophytic lichens were dominant,whereas in the interior,nitrophytes and acidophytes were among the dominant species.This pattern is probably attributable to the spatial heterogeneity of the intensity of forest grazing and was shown to be influenced by the density of nomad summer camps in the vicinity of the forests.Tree-levelα-diversity increased with stem diameter,but high-diameter trees were rare.The results suggest that the present level of forest patchiness and the effect of forest grazing increases the diversity of epiphytic lichens on the landscape level,while logging of highdiameter trees reduces lichen diversity.
