The species-area relationship （SAR） is one of the most fundamental concepts in community ecology and is helpful for biodiversity conservation. However, few studies have systematically addressed this topic for differ...The species-area relationship （SAR） is one of the most fundamental concepts in community ecology and is helpful for biodiversity conservation. However, few studies have systematically addressed this topic for different alpine grassland types on the Tibetan Plateau, China. We explored whether the plant composition of different functional groups affects the manner in which species richness inereases with increasing area at scales ≤ 1.0 m^2. We also compared species richness （S） within and across forbs, legumes, sedges and grasses, with sampling subplot area （A） increasing from 0.0625 m^2 to 1.0 m^2 between alpine meadow and steppe communities. We applied a logarithmic function （S = b0 ＋ b1 ln A） to determine the slope and intercept of SAR curves within and across functional groups. The results showed that the logarithmic relationship holds true between species richness and sampling area at these small scales. Both the intercept and slope of the logarithmic forbs-area curves are significantly higher than those for the three other functional groups （P 〈 0.05）. Forb accounts for about 91.9 % of the variation in the intercept and 75.0% of the variation in the slope of the SAR curve when all functional groups＇ data were pooled together. Our results indicated that the different SAR patterns should be linked with species dispersal capabilities, environmental filtering, and life form composition within alpine grassland communities. Further studies on the relationship between species diversity and ecosystem functions should specify the differential responses of different functional groups to variations in climate and anthropogenic disturbances.展开更多
Dew has been recognized for its ecological significance and has also been identified as an additional source of water in arid zones. We used factorial control experiment, under dew presence in the field, to explore ph...Dew has been recognized for its ecological significance and has also been identified as an additional source of water in arid zones. We used factorial control experiment, under dew presence in the field, to explore photosynthetic performance, water status and growth response of desert annual herbage. Bassia dasyphylla seedlings were grown in contrasting dew treatments （dew-absent and dew-present） and different watering regimes （normal and deficient）. The effects of dew on the water status and photosynthetic performance of Bassia dasyphylla grown in a desert area of the Hexi Corridor in Northwestern China, were evaluated. The results indicated the pres- ence of dew significantly increased relative water content （RWC） of shoots and total biomass of plants in both water regimes, and enhanced the diurnal shoot water potential and stomatal conductance in the early morning, as well as photosynthetic rate, which reached its maximum only in the water-stressed regime. The presence of dew increased aboveground growth of plants and photosynthate accumulation in leaves, but decreased the root-to-shoot ratio in both water regimes. Dew may have an important role in improving plant water status and ameliorating the adverse effects of plants exposed to prolonged drought.展开更多
A plethora of studies investigating the origin and evolution of diverse mountain taxa has assumed a causal link between geological processes （orogenesis） and a biological response （diversification）. Yet, a substan...A plethora of studies investigating the origin and evolution of diverse mountain taxa has assumed a causal link between geological processes （orogenesis） and a biological response （diversification）. Yet, a substantial delay （up to 30 Myr） between the start of orogenesis and diversification is often observed. Evolutionary biologists should therefore identify alternative drivers of diversification and maintenance of biodiversity in mountain systems. Using phylogenetic, biogeographic, and diversification rate analyses, we could identify two independent processes that most likely explain the diversity of the widespread genus Allium in the Qinghai-Tibet Plateau （QTP） region： （1） While the QTP-related taxa of the subgenus Melanocrommyum diversified in situ, （2） QTP-related taxa of other subgenera migrated into the QTP from multiple source areas. Furthermore, shifts in diversification rates within Allium could not be attributed spatially and temporally to the uplift history of the QTP region. Instead, global cooling and climate oscillations in the Quaternary were major contributors to increased speciation rates in three clades of AUium. Our study therefore adds to the growing evidence supporting the ＂mountain-geo-biodiversity hypothesis＂, which highlights the role of climate oscillations for the diversification of mountain organisms.展开更多
Dissolved organic matter(DOM)occupies a huge and uncharted molecular space.Given its properties,DOM can be presented as a promising biotechnological resource.However,research into bioactivities of DOM is still in earl...Dissolved organic matter(DOM)occupies a huge and uncharted molecular space.Given its properties,DOM can be presented as a promising biotechnological resource.However,research into bioactivities of DOM is still in early stages.In this study,the biotechnological potential of terrestrial and marine DOM,its molecular composition and their relationships are investigated.Samples were screened for their in vitro antibacterial,antifungal,anticancer and antioxidant activities.Antibacterial activity was detected against Staphylococcus aureus in almost all DOM samples,with freshwater DOM showing the lowest IC50 values.Most samples also inhibited Staphylococcus epidermidis,and four DOM extracts showed up to fourfold higher potency than the reference drug.Antifungal activity was limited to only porewater DOM towards human dermatophyte Trichophyton rubrum.No significant in vitro anticancer activity was observed.Low antioxidant potential was exerted.The molecular characterization by FT-ICR MS allowed a broad compositional overview.Three main distinguished groups have been identified by PCoA analyses.Antibacterial activities are related to high aromaticity content and highly-unsaturated molecular formulae(O-poor).Antifungal effect is correlated with highly-unsaturated molecular formulae(O-rich).Antioxidant activity is positively related to the presence of double bonds and polyphenols.This study evidenced for the first time antibacterial and antifungal activity in DOM with potential applications in cosmeceutical,pharmaceutical and aquaculture industry.The lack of cytotoxicity and the almost unlimited presence of this organic material may open new avenues in future marine bioprospect-ing efforts.展开更多
In nature,plant communities are affected simultaneously by a variety of functionally dissimilar organisms both above and below the ground.However,there is a gap of knowledge on interactive effects of functionally diss...In nature,plant communities are affected simultaneously by a variety of functionally dissimilar organisms both above and below the ground.However,there is a gap of knowledge on interactive effects of functionally dissimilar organisms on plant communities that is needed to be filled to better understand and predict the general impact of biotic factors on plant communities.Methods We conducted a full-factorial mesocosm study to investigate the individual and combined impacts of above-and belowground functionally dissimilar organisms on a grassland plant community.We studied the effects of aboveground herbivores(Helix aspersa,Gastropoda),arbuscular mycorrhizal fungi(AMF;Glomus spp.,Glomeromycota)and endogeic earthworms(Aporrectodea spp.,Lumbricidae)on the diversity,structure and productivity of an experimental grassland plant community and each other.Important Findings Aboveground herbivory by snails decreased,AMF increased and earthworms had no effects on the diversity of the grassland plant community,while their combined effects were additive.The biomass of the plant community was negatively affected by snails and AMF,while no effects of earthworms or interaction effects were found.The plant species were differently affected by snails and AMF.No effects of the above-and belowground organisms on each other’s performance were detected.Since the effects of the functionally dissimilar organisms on the grassland plant community were mainly independent,the results indicate that their combined effects may be predicted by knowing the individual effects,at least under the conditions used in the present mesocosm study.展开更多
Aims The aim of our research was to understand small-scale effects of topography and soil fertility on tree growth in a forest biodiversity and ecosystem functioning(BEF)experiment in subtropical SE China.Methods Geom...Aims The aim of our research was to understand small-scale effects of topography and soil fertility on tree growth in a forest biodiversity and ecosystem functioning(BEF)experiment in subtropical SE China.Methods Geomorphometric terrain analyses were carried out at a spatial resolution of 5×5 m.Soil samples of different depth increments and data on tree height were collected from a total of 566 plots(667 m2 each).The soils were analyzed for carbon(soil organic carbon[SOC]),nitrogen,acidity,cation exchange capacity(CEC),exchangeable cations and base saturation as soil fertility attributes.All plots were classified into geomorphological units.Analyses of variance and linear regressions were applied to all terrain,soil fertility and tree growth attributes.Important Findings In general,young and shallow soils and relatively small differences in stable soil properties suggest that soil erosion has truncated the soils to a large extent over the whole area of the experiment.This explains the concurrently increasing CEC and SOC stocks downslope,in hollows and in valleys.However,colluvial,carbon-rich sediments are missing widely due to the convexity of the footslopes caused by uplift and removal of eroded sediments by adjacent waterways.The results showed that soil fertility is mainly influenced by topography.Monte-Carlo flow accumulation(MCCA),curvature,slope and aspect significantly affected soil fertility.Furthermore,soil fertility was affected by the different geomorphological positions on the experimental sites with ridge and spur positions showing lower exchangeable base cation contents,especially potassium(K),due to leaching.This geomorphological effect of soil fertility is most pronounced in the topsoil and decreases when considering the subsoil down to 50 cm depth.Few soil fertility attributes affect tree height after 1-2 years of growth,among which C stocks proved to be most important while pH_(KCl)and CEC only played minor roles.Nevertheless,soil acidity and a high proportion of Al on the exchange complex affected tree height even after only 1-2 years growth.Hence,our study showed that forest nutrition is coupled to a recycling of litter nutrients,and does not only depend on subsequent supply of nutrients from the mineral soil.Besides soil fertility,topography affected tree height.We found that especially MCCA as indicator of water availability affected tree growth at small-scale,as well as aspect.Overall,our synthesis on the interrelation between fertility,topography and tree growth in a subtropical forest ecosystem in SE China showed that topographic heterogeneity lead to ecological gradients across geomorphological positions.In this respect,small-scale soil-plant interactions in a young forest can serve as a driver for the future development of vegetation and biodiversity control on soil fertility.In addition,it shows that terrain attributes should be accounted for in ecological research.展开更多
Mesopelagic fish(meso-fish)are central species within the Southern Ocean(SO).However,their ecosystem role and adaptive capacity to climate change are rarely integrated into protected areas assessments.This is a pity g...Mesopelagic fish(meso-fish)are central species within the Southern Ocean(SO).However,their ecosystem role and adaptive capacity to climate change are rarely integrated into protected areas assessments.This is a pity given their importance as crucial prey and predators in food webs,coupled with the impacts of climate change.Here,we estimate the habitat distribution of nine meso-fish using an ensemble model approach(MAXENT,random forest,and boosted regression tree).Four climate model simulations were used to project their distribution under two representative concentration pathways(RCP4.5 and RCP8.5)for short-term(2006–2055)and long-term(2050–2099)periods.In addition,we assess the ecological representativeness of protected areas under climate change scenarios using meso-fish as indicator species.Our models show that all species shift poleward in the future.Lanternfishes(family Myctophidae)are predicted to migrate poleward more than other families(Paralepididae,Nototheniidae,Bathylagidae,and Gonostomatidae).In comparison,lanternfishes were projected to increase habitat area in the eastern SO but lose area in the western SO;the opposite was projected for species in other families.Important areas(IAs)of meso-fish are mainly distributed near the Antarctic Peninsula and East Antarctica.Negotiated protected area cover 23% of IAs at present and 38%of IAs in the future(RCP8.5,long-term future).Many IAs of meso-fish still need to be included in protected areas,such as the Prydz Bay and the seas around the Antarctic Peninsula.Our results provide a framework for evaluating protected areas incorporating climate change adaptation strategies for protected areas management.展开更多
Aims Studies that investigate the space-filling heterogeneity of biological struc-tures in plant communities remain scarce.The main objective of this study was to evaluate the relationship between newly developed phot...Aims Studies that investigate the space-filling heterogeneity of biological struc-tures in plant communities remain scarce.The main objective of this study was to evaluate the relationship between newly developed photo-graphic measures of structural heterogeneity in digital images and plant species composition in the context of a long-term grassland experiment.Methods We tested a close-range photographic protocol using measures of structural heterogeneity in gray-tone images,namely mean infor-mation gain(MIG)and spatial anisotropy,to assess differences in the compositional(species richness)and functional characteristics(plant height and flowering)of 78 managed grassland communities.We also implemented a random placement model of community assembly to explore the links between our measures of structural complexity and the geometric pattern of plant communities.Important Findings MIG and spatial anisotropy correlated with the growth and species richness of grassland communities.Simulations showed that struc-tural heterogeneity in gray-tone digital images is a function of the size distribution and orientation pattern of plant modules.This easy,fast and non-destructive methodological approach could eventually serve to monitor the diversity and integrity of various ecosystems at different resolutions across space and time.展开更多
Background Krill(Euphausia superba)and salps(Salpa thompsoni)are key macrozooplankton grazers in the Southern Ocean ecosystem.However,due to differing habitat requirements,both species previously exhibited little spat...Background Krill(Euphausia superba)and salps(Salpa thompsoni)are key macrozooplankton grazers in the Southern Ocean ecosystem.However,due to differing habitat requirements,both species previously exhibited little spatial overlap.With ongoing climate change-induced seawater temperature increase and regional sea ice loss,salps can now extend their spatial distribution into historically krill-dominated areas and increase rapidly due to asexual reproduction when environmental conditions are favorable.Understanding the potential effects on krill is crucial,since krill is a species of exceptional trophic significance in the Southern Ocean food web.Negative impacts on krill could trigger cascading effects on its predators and prey.To address this question,we combined two individual-based models on salps and krill,which describe the whole life cycle of salp individuals and the dynamic energy budget of individual krill.The resulting new model PEKRIS(PErformance of KRIll vs.Salps)simulates a krill population for 100 years under varying chlorophyll-a concentrations in the presence or absence of salps.Results All of the investigated krill population properties(abundance,mean length,and yearly egg production)were significantly impacted by the presence of salps.On the other hand,salp density was not impacted if krill were present.The medians of krill population properties deviated during variable maximum chlorophyll-a density per year when salps were introduced by−99.9%(−234 individuals per 1000 m3)for krill density,−100%(−22,062 eggs per 1000 m3)for krill eggs and−0.9%(−0.3 mm)for mean length of krill.Conclusions If both species compete for the same food resource in a closed space,salps seem to inhibit krill populations.Further simulation studies should investigate whether this effect prevails if different phytoplankton sizes and consumption preferences of krill are implemented.Furthermore,direct predation of the two species or consumption of krill fecal pellets by salps could change the impact size of the food competition.展开更多
Background The impact of changing land-use patterns and associated anthropogenic threats on scale-dependent habitat use of semi-aquatic mustelids in scent-marking and social behaviour can provide important insights in...Background The impact of changing land-use patterns and associated anthropogenic threats on scale-dependent habitat use of semi-aquatic mustelids in scent-marking and social behaviour can provide important insights into the habitat ecology of smooth-coated otters(Lutrogale perspicillata).Methods We sampled 180 stream segments(100–400 m)as spatial replicates of 601-km2 sites to record indirect evidence(i.e.spraints and mass latrine sites)and group sizes of smooth-coated otters along the Tungabhadra Otter Conservation Reserve(TOCR)during the dry season.To quantify habitat,we recorded stream characteristics,riparian vegetation,and anthropogenic disturbances at the local scale,and hydro-environmental characteristics and land uses at the landscape scale.Using Markovian-chain detection and occupancy models,we assessed the multi-scale habitat use of otters in their selection of suitable areas for scent-marking based on repeated presence-absence data on spraint/latrine locations along the TOCR.We further used linear regression techniques to explore relationships between the number of individuals in smooth-coated otter group and hydro-environmental characteristics,spraint/latrine encounter rate,anthropogenic pressure,land cover,topography,and vegetation.Results At the local scale,the probability of spraint deposition and group size decreased with anthropogenic disturbance while the probability of spraint detections decreased with grass cover.At the landscape scale,the probability of otter site use for spraint deposition and group sizes increased in southeast flowing streams.Spraint deposition increased with the proportion of sugarcane fields,whereas in contrast,group size decreased with proportion of sugarcane fields.Conclusions Our findings highlight the first empirical evidence on multi-scale habitat use of a southern Indian population of smooth-coated otters in an inland freshwater ecosystem surrounded by the scrub jungle–agriculture matrix.We suggest that habitat models built from analytical approaches that account for correlated detections can avoid biased predictions when estimating occupancy and detection probability of semi-aquatic or riparian mammal communities with linear distributions.Our findings indicate that human activity can impose constraints on the choice of sites used for spraint deposition and preliminary patterns in otter groups.The study provides some crucial evidence on the need to maintain areas with minimal human interference for sustainability of freshwater reserves.展开更多
The author wants to highlight the important role of mes-opelagic fish in the conservation of marine living resources.Therefore,in order to further clarify and focus research point on the conservation of marine living ...The author wants to highlight the important role of mes-opelagic fish in the conservation of marine living resources.Therefore,in order to further clarify and focus research point on the conservation of marine living resources,the authors replaced the MPA with the protected areas,and slightly modified several other vague places.In these corrections,most of them are the replacement of the terms.展开更多
基金supported by the Chinese Academy of Sciences (Grant Nos.XDB03030401,KZCXZ-XB3-08)the State Scholarship Fund of the China Scholarship Council (Grant No.201400260118)the International Postdoctoral Exchange Fellowship Program 2014 by the Office of China Postdoctoral Council (Grant No.20140041)
文摘The species-area relationship （SAR） is one of the most fundamental concepts in community ecology and is helpful for biodiversity conservation. However, few studies have systematically addressed this topic for different alpine grassland types on the Tibetan Plateau, China. We explored whether the plant composition of different functional groups affects the manner in which species richness inereases with increasing area at scales ≤ 1.0 m^2. We also compared species richness （S） within and across forbs, legumes, sedges and grasses, with sampling subplot area （A） increasing from 0.0625 m^2 to 1.0 m^2 between alpine meadow and steppe communities. We applied a logarithmic function （S = b0 ＋ b1 ln A） to determine the slope and intercept of SAR curves within and across functional groups. The results showed that the logarithmic relationship holds true between species richness and sampling area at these small scales. Both the intercept and slope of the logarithmic forbs-area curves are significantly higher than those for the three other functional groups （P 〈 0.05）. Forb accounts for about 91.9 % of the variation in the intercept and 75.0% of the variation in the slope of the SAR curve when all functional groups＇ data were pooled together. Our results indicated that the different SAR patterns should be linked with species dispersal capabilities, environmental filtering, and life form composition within alpine grassland communities. Further studies on the relationship between species diversity and ecosystem functions should specify the differential responses of different functional groups to variations in climate and anthropogenic disturbances.
基金financially supported by the National Natural Sciences Foundation of China (30771767 and 40601016)
文摘Dew has been recognized for its ecological significance and has also been identified as an additional source of water in arid zones. We used factorial control experiment, under dew presence in the field, to explore photosynthetic performance, water status and growth response of desert annual herbage. Bassia dasyphylla seedlings were grown in contrasting dew treatments （dew-absent and dew-present） and different watering regimes （normal and deficient）. The effects of dew on the water status and photosynthetic performance of Bassia dasyphylla grown in a desert area of the Hexi Corridor in Northwestern China, were evaluated. The results indicated the pres- ence of dew significantly increased relative water content （RWC） of shoots and total biomass of plants in both water regimes, and enhanced the diurnal shoot water potential and stomatal conductance in the early morning, as well as photosynthetic rate, which reached its maximum only in the water-stressed regime. The presence of dew increased aboveground growth of plants and photosynthate accumulation in leaves, but decreased the root-to-shoot ratio in both water regimes. Dew may have an important role in improving plant water status and ameliorating the adverse effects of plants exposed to prolonged drought.
基金the German Research Foundation for funding of staff (project no. MU 2934/2-1)the support of the German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig funded by the German Research Foundation (FZT 118) for funding of lab expenses
文摘A plethora of studies investigating the origin and evolution of diverse mountain taxa has assumed a causal link between geological processes （orogenesis） and a biological response （diversification）. Yet, a substantial delay （up to 30 Myr） between the start of orogenesis and diversification is often observed. Evolutionary biologists should therefore identify alternative drivers of diversification and maintenance of biodiversity in mountain systems. Using phylogenetic, biogeographic, and diversification rate analyses, we could identify two independent processes that most likely explain the diversity of the widespread genus Allium in the Qinghai-Tibet Plateau （QTP） region： （1） While the QTP-related taxa of the subgenus Melanocrommyum diversified in situ, （2） QTP-related taxa of other subgenera migrated into the QTP from multiple source areas. Furthermore, shifts in diversification rates within Allium could not be attributed spatially and temporally to the uplift history of the QTP region. Instead, global cooling and climate oscillations in the Quaternary were major contributors to increased speciation rates in three clades of AUium. Our study therefore adds to the growing evidence supporting the ＂mountain-geo-biodiversity hypothesis＂, which highlights the role of climate oscillations for the diversification of mountain organisms.
基金Marie Skłodowska-Curie individual Fellowship,H2020-MSCA-IF-2016749586,Teresa S.Catalá,Carl von Ossietzky Universität Oldenburg.
文摘Dissolved organic matter(DOM)occupies a huge and uncharted molecular space.Given its properties,DOM can be presented as a promising biotechnological resource.However,research into bioactivities of DOM is still in early stages.In this study,the biotechnological potential of terrestrial and marine DOM,its molecular composition and their relationships are investigated.Samples were screened for their in vitro antibacterial,antifungal,anticancer and antioxidant activities.Antibacterial activity was detected against Staphylococcus aureus in almost all DOM samples,with freshwater DOM showing the lowest IC50 values.Most samples also inhibited Staphylococcus epidermidis,and four DOM extracts showed up to fourfold higher potency than the reference drug.Antifungal activity was limited to only porewater DOM towards human dermatophyte Trichophyton rubrum.No significant in vitro anticancer activity was observed.Low antioxidant potential was exerted.The molecular characterization by FT-ICR MS allowed a broad compositional overview.Three main distinguished groups have been identified by PCoA analyses.Antibacterial activities are related to high aromaticity content and highly-unsaturated molecular formulae(O-poor).Antifungal effect is correlated with highly-unsaturated molecular formulae(O-rich).Antioxidant activity is positively related to the presence of double bonds and polyphenols.This study evidenced for the first time antibacterial and antifungal activity in DOM with potential applications in cosmeceutical,pharmaceutical and aquaculture industry.The lack of cytotoxicity and the almost unlimited presence of this organic material may open new avenues in future marine bioprospect-ing efforts.
文摘In nature,plant communities are affected simultaneously by a variety of functionally dissimilar organisms both above and below the ground.However,there is a gap of knowledge on interactive effects of functionally dissimilar organisms on plant communities that is needed to be filled to better understand and predict the general impact of biotic factors on plant communities.Methods We conducted a full-factorial mesocosm study to investigate the individual and combined impacts of above-and belowground functionally dissimilar organisms on a grassland plant community.We studied the effects of aboveground herbivores(Helix aspersa,Gastropoda),arbuscular mycorrhizal fungi(AMF;Glomus spp.,Glomeromycota)and endogeic earthworms(Aporrectodea spp.,Lumbricidae)on the diversity,structure and productivity of an experimental grassland plant community and each other.Important Findings Aboveground herbivory by snails decreased,AMF increased and earthworms had no effects on the diversity of the grassland plant community,while their combined effects were additive.The biomass of the plant community was negatively affected by snails and AMF,while no effects of earthworms or interaction effects were found.The plant species were differently affected by snails and AMF.No effects of the above-and belowground organisms on each other’s performance were detected.Since the effects of the functionally dissimilar organisms on the grassland plant community were mainly independent,the results indicate that their combined effects may be predicted by knowing the individual effects,at least under the conditions used in the present mesocosm study.
基金funded by the German Research Foundation(DFG FOR 891/1,2 and 3)funds from the National Natural Science Foundation of China(NSFC 30710103907,30930005,31170457 and 31210103910)+2 种基金the Swiss National Science Foundation(SNSF)financed by the Sino-German Centre for Research Promotion in Beijing(GZ 524,592,698,699 and 785)the University of Tübingen,Germany(PROMOS).
文摘Aims The aim of our research was to understand small-scale effects of topography and soil fertility on tree growth in a forest biodiversity and ecosystem functioning(BEF)experiment in subtropical SE China.Methods Geomorphometric terrain analyses were carried out at a spatial resolution of 5×5 m.Soil samples of different depth increments and data on tree height were collected from a total of 566 plots(667 m2 each).The soils were analyzed for carbon(soil organic carbon[SOC]),nitrogen,acidity,cation exchange capacity(CEC),exchangeable cations and base saturation as soil fertility attributes.All plots were classified into geomorphological units.Analyses of variance and linear regressions were applied to all terrain,soil fertility and tree growth attributes.Important Findings In general,young and shallow soils and relatively small differences in stable soil properties suggest that soil erosion has truncated the soils to a large extent over the whole area of the experiment.This explains the concurrently increasing CEC and SOC stocks downslope,in hollows and in valleys.However,colluvial,carbon-rich sediments are missing widely due to the convexity of the footslopes caused by uplift and removal of eroded sediments by adjacent waterways.The results showed that soil fertility is mainly influenced by topography.Monte-Carlo flow accumulation(MCCA),curvature,slope and aspect significantly affected soil fertility.Furthermore,soil fertility was affected by the different geomorphological positions on the experimental sites with ridge and spur positions showing lower exchangeable base cation contents,especially potassium(K),due to leaching.This geomorphological effect of soil fertility is most pronounced in the topsoil and decreases when considering the subsoil down to 50 cm depth.Few soil fertility attributes affect tree height after 1-2 years of growth,among which C stocks proved to be most important while pH_(KCl)and CEC only played minor roles.Nevertheless,soil acidity and a high proportion of Al on the exchange complex affected tree height even after only 1-2 years growth.Hence,our study showed that forest nutrition is coupled to a recycling of litter nutrients,and does not only depend on subsequent supply of nutrients from the mineral soil.Besides soil fertility,topography affected tree height.We found that especially MCCA as indicator of water availability affected tree growth at small-scale,as well as aspect.Overall,our synthesis on the interrelation between fertility,topography and tree growth in a subtropical forest ecosystem in SE China showed that topographic heterogeneity lead to ecological gradients across geomorphological positions.In this respect,small-scale soil-plant interactions in a young forest can serve as a driver for the future development of vegetation and biodiversity control on soil fertility.In addition,it shows that terrain attributes should be accounted for in ecological research.
基金supported by the research project“Impact and Response of Antarctic Seas to Climate Change”(IRASCC2020-2022-No.01-02-05C)from the Chinese Arctic and Antarctic Administration,Ministry of Natural Resources of the People’s Republic of China.
文摘Mesopelagic fish(meso-fish)are central species within the Southern Ocean(SO).However,their ecosystem role and adaptive capacity to climate change are rarely integrated into protected areas assessments.This is a pity given their importance as crucial prey and predators in food webs,coupled with the impacts of climate change.Here,we estimate the habitat distribution of nine meso-fish using an ensemble model approach(MAXENT,random forest,and boosted regression tree).Four climate model simulations were used to project their distribution under two representative concentration pathways(RCP4.5 and RCP8.5)for short-term(2006–2055)and long-term(2050–2099)periods.In addition,we assess the ecological representativeness of protected areas under climate change scenarios using meso-fish as indicator species.Our models show that all species shift poleward in the future.Lanternfishes(family Myctophidae)are predicted to migrate poleward more than other families(Paralepididae,Nototheniidae,Bathylagidae,and Gonostomatidae).In comparison,lanternfishes were projected to increase habitat area in the eastern SO but lose area in the western SO;the opposite was projected for species in other families.Important areas(IAs)of meso-fish are mainly distributed near the Antarctic Peninsula and East Antarctica.Negotiated protected area cover 23% of IAs at present and 38%of IAs in the future(RCP8.5,long-term future).Many IAs of meso-fish still need to be included in protected areas,such as the Prydz Bay and the seas around the Antarctic Peninsula.Our results provide a framework for evaluating protected areas incorporating climate change adaptation strategies for protected areas management.
基金German Research Foundation(FOR 456)Natural Sciences and Engineering Research Council of Canada(R.P.).
文摘Aims Studies that investigate the space-filling heterogeneity of biological struc-tures in plant communities remain scarce.The main objective of this study was to evaluate the relationship between newly developed photo-graphic measures of structural heterogeneity in digital images and plant species composition in the context of a long-term grassland experiment.Methods We tested a close-range photographic protocol using measures of structural heterogeneity in gray-tone images,namely mean infor-mation gain(MIG)and spatial anisotropy,to assess differences in the compositional(species richness)and functional characteristics(plant height and flowering)of 78 managed grassland communities.We also implemented a random placement model of community assembly to explore the links between our measures of structural complexity and the geometric pattern of plant communities.Important Findings MIG and spatial anisotropy correlated with the growth and species richness of grassland communities.Simulations showed that struc-tural heterogeneity in gray-tone digital images is a function of the size distribution and orientation pattern of plant modules.This easy,fast and non-destructive methodological approach could eventually serve to monitor the diversity and integrity of various ecosystems at different resolutions across space and time.
基金Open Access funding enabled and organized by Projekt DEALThis work was supported by the Federal Ministry of Education and Research of Germany(BMBF,Grant number 03F0828B).
文摘Background Krill(Euphausia superba)and salps(Salpa thompsoni)are key macrozooplankton grazers in the Southern Ocean ecosystem.However,due to differing habitat requirements,both species previously exhibited little spatial overlap.With ongoing climate change-induced seawater temperature increase and regional sea ice loss,salps can now extend their spatial distribution into historically krill-dominated areas and increase rapidly due to asexual reproduction when environmental conditions are favorable.Understanding the potential effects on krill is crucial,since krill is a species of exceptional trophic significance in the Southern Ocean food web.Negative impacts on krill could trigger cascading effects on its predators and prey.To address this question,we combined two individual-based models on salps and krill,which describe the whole life cycle of salp individuals and the dynamic energy budget of individual krill.The resulting new model PEKRIS(PErformance of KRIll vs.Salps)simulates a krill population for 100 years under varying chlorophyll-a concentrations in the presence or absence of salps.Results All of the investigated krill population properties(abundance,mean length,and yearly egg production)were significantly impacted by the presence of salps.On the other hand,salp density was not impacted if krill were present.The medians of krill population properties deviated during variable maximum chlorophyll-a density per year when salps were introduced by−99.9%(−234 individuals per 1000 m3)for krill density,−100%(−22,062 eggs per 1000 m3)for krill eggs and−0.9%(−0.3 mm)for mean length of krill.Conclusions If both species compete for the same food resource in a closed space,salps seem to inhibit krill populations.Further simulation studies should investigate whether this effect prevails if different phytoplankton sizes and consumption preferences of krill are implemented.Furthermore,direct predation of the two species or consumption of krill fecal pellets by salps could change the impact size of the food competition.
基金the Science and Engineering Research Board(SERB),Govt.of India,under the“Start-up Research Grant”(Grant Id:SRG/2019/000995)for providing financial support to the fourth author during manuscript preparation
文摘Background The impact of changing land-use patterns and associated anthropogenic threats on scale-dependent habitat use of semi-aquatic mustelids in scent-marking and social behaviour can provide important insights into the habitat ecology of smooth-coated otters(Lutrogale perspicillata).Methods We sampled 180 stream segments(100–400 m)as spatial replicates of 601-km2 sites to record indirect evidence(i.e.spraints and mass latrine sites)and group sizes of smooth-coated otters along the Tungabhadra Otter Conservation Reserve(TOCR)during the dry season.To quantify habitat,we recorded stream characteristics,riparian vegetation,and anthropogenic disturbances at the local scale,and hydro-environmental characteristics and land uses at the landscape scale.Using Markovian-chain detection and occupancy models,we assessed the multi-scale habitat use of otters in their selection of suitable areas for scent-marking based on repeated presence-absence data on spraint/latrine locations along the TOCR.We further used linear regression techniques to explore relationships between the number of individuals in smooth-coated otter group and hydro-environmental characteristics,spraint/latrine encounter rate,anthropogenic pressure,land cover,topography,and vegetation.Results At the local scale,the probability of spraint deposition and group size decreased with anthropogenic disturbance while the probability of spraint detections decreased with grass cover.At the landscape scale,the probability of otter site use for spraint deposition and group sizes increased in southeast flowing streams.Spraint deposition increased with the proportion of sugarcane fields,whereas in contrast,group size decreased with proportion of sugarcane fields.Conclusions Our findings highlight the first empirical evidence on multi-scale habitat use of a southern Indian population of smooth-coated otters in an inland freshwater ecosystem surrounded by the scrub jungle–agriculture matrix.We suggest that habitat models built from analytical approaches that account for correlated detections can avoid biased predictions when estimating occupancy and detection probability of semi-aquatic or riparian mammal communities with linear distributions.Our findings indicate that human activity can impose constraints on the choice of sites used for spraint deposition and preliminary patterns in otter groups.The study provides some crucial evidence on the need to maintain areas with minimal human interference for sustainability of freshwater reserves.
文摘The author wants to highlight the important role of mes-opelagic fish in the conservation of marine living resources.Therefore,in order to further clarify and focus research point on the conservation of marine living resources,the authors replaced the MPA with the protected areas,and slightly modified several other vague places.In these corrections,most of them are the replacement of the terms.
