Aims We investigate the effect of position within a size-structured population on the reproductive allocation(RA)and flowering probability of individual plants of Sinapis arvensis.We also assess the effects of plant s...Aims We investigate the effect of position within a size-structured population on the reproductive allocation(RA)and flowering probability of individual plants of Sinapis arvensis.We also assess the effects of plant size and changing level of CO_(2) on both responses.Methods Sinapis arvensis L.,(field mustard),an annual agricultural weed,was grown in monoculture at six densities under ambient and elevated CO_(2) in a study with 84 stands.Individual aboveground biomass and reproductive biomass were measured.Varying density produced a wide range of mean plant sizes across stands and size hierarchies within stands.Many(;40%)individuals had zero reproductive biomass.Employing a novel modelling approach,we analysed the joint effects of position in stand size hierarchy,plant size and CO_(2) on RA and flowering probability of individuals.Important Findings We found a strong effect of position within the size hierarchy of individuals in a population:for an individual of a given size,greater size relative to neighbours substantially increased RA and flowering probability at a single harvest time.There was no other effect of plant size on RA.We found a positive effect of elevated CO_(2) on RA regardless of position within the size hierarchy.These observed patterns could impact doubly on the reproductive biomass(R)of small individuals.First,because RA is not affected by size,smaller plants will have smaller R than larger plants;and second,for smaller plants lower down in a population size hierarchy,their RA and hence R will be further reduced.These results suggest that size relative to neighbours may be independent of and more important than direct abiotic effects in determining RA.Further studies are required to evaluate how these observed patterns generalize to other populations in non-experimental conditions.展开更多
Background:Agricultural yields have increased continuously over the last few decades.However,a focus solely on production can harm the environment.Diversification of agriculture has been suggested to increase producti...Background:Agricultural yields have increased continuously over the last few decades.However,a focus solely on production can harm the environment.Diversification of agriculture has been suggested to increase production and sustainability.Biodiversity experiments showed positive effects on ecosystems and productivity.However,application of these results to intensively managed grasslands has been questioned due to differences in plant species and management regimes.Research on whether diversity can benefit multifunctionality,that is,an integrated index of multiple ecosystem functions,under intensive management,is still scarce.Methods:To address this,we manipulated plant species richness from one to six species spanning three functional groups(legumes,herbs,and grasses)in intensively managed multispecies grassland leys and examined seven ecosystem functions.Results:We found that multifunctionality increased with functional group and species richness.Legume+herb mixtures showed high multifunctionality,while grass monocultures and mixtures with high proportions of grasses had low multifunctionality.Different plant species and plant communities drove different ecosystem functions.Legumes and herbs improved productivity and water availability,while grasses enhanced invasion resistance.These results indicate that multifunctionality and individual ecosystem functions can be promoted through targeted combinations of plants with complementary ecological traits.Conclusions:Plant diversity can improve multifunctionality also under intensive management,potentially benefitting agroeconomics and sustainability.展开更多
文摘Aims We investigate the effect of position within a size-structured population on the reproductive allocation(RA)and flowering probability of individual plants of Sinapis arvensis.We also assess the effects of plant size and changing level of CO_(2) on both responses.Methods Sinapis arvensis L.,(field mustard),an annual agricultural weed,was grown in monoculture at six densities under ambient and elevated CO_(2) in a study with 84 stands.Individual aboveground biomass and reproductive biomass were measured.Varying density produced a wide range of mean plant sizes across stands and size hierarchies within stands.Many(;40%)individuals had zero reproductive biomass.Employing a novel modelling approach,we analysed the joint effects of position in stand size hierarchy,plant size and CO_(2) on RA and flowering probability of individuals.Important Findings We found a strong effect of position within the size hierarchy of individuals in a population:for an individual of a given size,greater size relative to neighbours substantially increased RA and flowering probability at a single harvest time.There was no other effect of plant size on RA.We found a positive effect of elevated CO_(2) on RA regardless of position within the size hierarchy.These observed patterns could impact doubly on the reproductive biomass(R)of small individuals.First,because RA is not affected by size,smaller plants will have smaller R than larger plants;and second,for smaller plants lower down in a population size hierarchy,their RA and hence R will be further reduced.These results suggest that size relative to neighbours may be independent of and more important than direct abiotic effects in determining RA.Further studies are required to evaluate how these observed patterns generalize to other populations in non-experimental conditions.
基金Science Foundation Ireland Frontiers for the Future program,Grant/Award Number:19/FFP/6888Deutsche Forschungsgemeinschaft,Grant/Award Numbers:GSC 81,ME5474/1-1,WE3081/39-1。
文摘Background:Agricultural yields have increased continuously over the last few decades.However,a focus solely on production can harm the environment.Diversification of agriculture has been suggested to increase production and sustainability.Biodiversity experiments showed positive effects on ecosystems and productivity.However,application of these results to intensively managed grasslands has been questioned due to differences in plant species and management regimes.Research on whether diversity can benefit multifunctionality,that is,an integrated index of multiple ecosystem functions,under intensive management,is still scarce.Methods:To address this,we manipulated plant species richness from one to six species spanning three functional groups(legumes,herbs,and grasses)in intensively managed multispecies grassland leys and examined seven ecosystem functions.Results:We found that multifunctionality increased with functional group and species richness.Legume+herb mixtures showed high multifunctionality,while grass monocultures and mixtures with high proportions of grasses had low multifunctionality.Different plant species and plant communities drove different ecosystem functions.Legumes and herbs improved productivity and water availability,while grasses enhanced invasion resistance.These results indicate that multifunctionality and individual ecosystem functions can be promoted through targeted combinations of plants with complementary ecological traits.Conclusions:Plant diversity can improve multifunctionality also under intensive management,potentially benefitting agroeconomics and sustainability.
