Since the 1950s of the last century, the exotic plant, Eupatorium adenophorum, has spread rapidly across southwest China, damaging native ecosystems and causing great economic losses. We examined the pH, N, P, K, and ...Since the 1950s of the last century, the exotic plant, Eupatorium adenophorum, has spread rapidly across southwest China, damaging native ecosystems and causing great economic losses. We examined the pH, N, P, K, and organic matter concentrations, and the bacterial community character (by Biolog EcoPlateTM) in soils from sites heavily and lightly invaded by this exotic species. Also, soil from the lightly invaded site was treated with a water extract of E. adenophorum roots to examine the effect of the plant on soil properties. We grew three plant species, one native and two exotic, in pot experiment using soil from heavily invaded site to examine the effects of the soil on these plants growth. The soil analysis demonstrated that the pH, organic matter, total N, total P and total K in soils from the heavily invaded site were only slightly different from those of the lightly invaded site, but concentrations of NH4+, NO?3 and available P and K in the heavily invaded site were greater than those in the lightly invaded site. The catabolic activity of soil bacterial community in the heavily invaded site was different from that in the lightly invaded site. The catabolic activity of bac- terial community in soils treated by the water extract of E. adenophorum roots changed and became similar to that in soils from the heavily invaded site. The pot experiment showed that the exotic plants growth in heavily invaded soil were not different from in lightly invaded soil; however, the native plant biomass decreased dramatically when grown in soil from the heavily invaded site as compared to soil from the lightly invaded site; and the same phenomenon was found when any potential allelopathic effects by E. adeno- phorum were eliminated by added activated carbon to those soils. Difference in soil nutrient availability and allelopathy could not explain this phenomenon of the native plant in the soils from the heavily and lightly invaded sites. Changes ob- served in the soil bacterial community were obviously related to native plant growth in those tow soils. Those results sug- gest that changing soil microbial community may be an im- portant part of E. adenophorum invasion process. Since the soil microbial community serves as bridge in connection of exotic and natural plants, the exotic plant could inhibit the natural plant growth and reproduction by changing the soil microbial community in invaded site.展开更多
Land-use and plant invasion influence biodiversity.Understanding the effects of land-use types and invasive plants on the ecosystem is crucial for better management and the development of strategic plans for increasin...Land-use and plant invasion influence biodiversity.Understanding the effects of land-use types and invasive plants on the ecosystem is crucial for better management and the development of strategic plans for increasing biodiversity in Jeju Island,Korea,a designated Biosphere Reserve by the United Nations Education,Scientific,and Cultural Organization.The effect of the most dominant invasive exotic species,Hypochaeris radicata,on the four land-use types of Jeju Island was investigated.Plant composition,soil characteristics,and plant diversity among four land-use types(cropland,green space,neglected land,and residential)were compared.Among the land-use types,croplands had the most diverse plant composition and the highest richness in exotic and native plant species.Croplands,such as tangerine orchards,which are widely distributed throughout Jeju Island,showed the highest plant diversity because of medium intensity disturbance caused by weed removal.The relative cover of H.radicata did not differ between land-use types.However,H.radicata invasion was negatively related with plant species richness,making this invasive species a threat to the biodiversity of native herbs present in land-use areas.H.radicata adapts to areas with a broad range of soil properties and a variety of land-use types.Therefore,it is crucial to monitor land-use types and patterns of plant invasion to guide the implementation of consistent management and conservation strategies for maintaining ecosystem integrity of the transformed habitat in Jeju Island.展开更多
Globalization of social and economic activities has led to the large-scale redistribution of plant species.It is still unclear how the traits aid the successful invasion of alien species.Here,we downloaded global plan...Globalization of social and economic activities has led to the large-scale redistribution of plant species.It is still unclear how the traits aid the successful invasion of alien species.Here,we downloaded global plant trait data from the TRY-Plant Trait Database and classified alien species in China into four groups:high,medium,need attention and harmless according to their distribution and degree of harm to local plant communities based on existed studies.The relationship between plant functional traits and invasion level was clarified,and we established a prediction model based on plant functional traits and taxonomy.The results showed that species with smaller seeds,smaller individuals,lower special leaf area and longer seed bank longevity(SL)are more likely to be an invasive species after introduction to foreign ecosystems.In summary,exotic species with longer SL and lower seed dry mass are more likely to be invasive in China.We also trained two predictive models to check if we can predict a species’invasion.Combining the two models together,statistically,we could predict if a species is invasive from its traits and taxonomy with a 91.84%accuracy.This model could help local governments,managers and stakeholders to evaluate shall we introduce some plant species in China.展开更多
The intentional introduction of exotic species can increase the level of local biodiversity,enrich people’s material lives,and bring significant social and economic benefits that are also the symbols of human progres...The intentional introduction of exotic species can increase the level of local biodiversity,enrich people’s material lives,and bring significant social and economic benefits that are also the symbols of human progress.However,along with the frequent intercourse among countries and regions,the frequency of uncontrolled crossregional migration of species is increased and there is a lack of scientific management strategy for the intentional introduction of exotic species.Exotic species invasion,which is behind habitat fragmentation,has become the second largest threatening factor to the maintenance of the global-scale level of biological diversity.Exotic species invasion can destroy the structure of an ecosystem,disturb the economic life of a society,and do harm to human health.In this paper,the authors review some of the ecological explanations for issues such as“what causes or mechanisms have led to the successful invasion of exotic species”,including the“ideal weeds characteristics”,“biodiversity resistance hypothesis”,“enemies release hypothesis”,“evolution of increased competitive ability hypothesis”,“niche opportunity hypothesis”,and“novel weapon hypothesis”.The authors also analyze and evaluate the background and theoretical basis of the hypotheses,providing explanations for some phenomena,as well as the deficiencies of these explanations.展开更多
The control of exotic and invasive species in areas undergoing recovery is a challenge for ecological restoration and this problem may be even greater in urbanized areas. This study evaluated the seed bank and seed ra...The control of exotic and invasive species in areas undergoing recovery is a challenge for ecological restoration and this problem may be even greater in urbanized areas. This study evaluated the seed bank and seed rain of a 5-year-old riparian forest located at the metropolitan region of Belo Horizonte in southeast Brazil, and verified changes over time in the abundance and species richness and whether planted species already were providing propagules to the site. At the forest, fifteen parcels of 100 m<sup>2</sup> were distributed randomly and soil samples were collected thrice (October 2011, March 2012 and July 2012) to evaluate the seed bank. Seed traps were installed in nine parcels to collect propagules over 1 year. Propagules were segregated and germinate at greenhouse. Species richness and abundance were estimated, and variance and similarity were quantified. In total, 86 species were recorded in the seed banks, 41.9% natives and 33.7% exotics, with the predominance of herbs (87.2%) and only 7% of trees. Species classified as weeds amounted to 52.3%. In the seed rain 642 seedlings germinated but they belonged to only 10 species, half of them were exotics. Regarding life forms, half of the species were arboreal and dominated the samples, highlighting the exotic species Melia azedarach. The species richness of the seed bank did not differ by season, unlike the seed rain which varied significantly by month. Seed bank and seed rain species had a very low floristic similarity with the list of planted species, suggesting that few planted trees had dispersed or were stocking propagules. Many non-planted species were recorded, mostly exotics and/or invasive that were probably derived from the surrounding urban matrix. These might interrupt the successional dynamics of the restoration forest and compromise the restoration process in the medium and long-terms. Our results highlight: (1) the importance of monitoring areas undergoing restoration; (2) that restoration methods and management actions directed to control exotic and invasive species are particularly important for sites in urban regions; and (3) the relevance of conserving forest fragments as sources of propagules for nearby areas.展开更多
Artificially introduced cordgrass, Spartina alterniflora, rapidly colonized the intertidal flats of the Jiangsu coast, eastern China. The epibenthos on an intertidal flat invaded by S. alterniflorawere studied, to ide...Artificially introduced cordgrass, Spartina alterniflora, rapidly colonized the intertidal flats of the Jiangsu coast, eastern China. The epibenthos on an intertidal flat invaded by S. alterniflorawere studied, to identify how local epibenthos species react to an altered environment. Epibenthic samples and surficial sediment samples were collected along a shore-normal profile in 50 quadrats at ten stations across the Spartina salt marsh; and five control quadrats for a station located on the barren sandy-mud flat. The grain size param- eters of the surficial sediments show that S. alterniflora altered the grain size gradient along the profile of the intertidal zone by trapping fine-grained sediments. Spartina alterniflora could inhabit lower elevation- s than indigenous salt marsh vegetation, thus creating larger areas of finer surficial sediments, which was suitable for not only native epibenthic species but also species which do not exist on the barren sandy-mud flat. Correlation analyses show that the epibenthos were sensitive to sediment grain size and type, on the invaded S. alterniflora salt marsh. Further, there was an interspecific relationship affecting the distribution of epibenthos. The results show that epibenthos preferred ecological niches, within the Spartina salt marsh, even in the same sampling station.展开更多
Exotic plant invasions may alter ecosystem carbon processes, especially when native plants are displaced by plants of a different functional group. Forb invasions into grasslands are common, yet little is known about ...Exotic plant invasions may alter ecosystem carbon processes, especially when native plants are displaced by plants of a different functional group. Forb invasions into grasslands are common, yet little is known about how they impact carbon cycling. We conducted a field study over 2 years from April 2010 to March 2012 in China to examine changes in soil respiration （Rsoil） following invasion of exotic perennial forb species （Alternanthera philoxeroides or Solidago canadensis） into an annual grassland dominated by a native annual graminoid （Eragrostis pilosa）. Measurements of Rsoil were taken once a week in stands of the native annual graminoid or one of the forb species using static chamber-gas chromatograph method. Aboveground litterfall of each of the three focal species was collected biweekly and litter decomposition rates were measured in a 6-month litterbag experiment. The monthly average and annual cumulative Rsoil increased following invasion by either forb species. The increases in cumulative Rsoil were smaller with invasion of Solidago （36%） than Alternanthera （65%）. Both invasive forbs were associated with higher litter quantity and quality （e.g., C：N ratio） than the native annum graminoid. Compared to the native annual graminoid, the invasive forbs Altevnanthera （155%） and Solidago （361%） produced larger amounts of more rapidly decomposing litter, with the litter decay constant k being 3.8, 2.0 and 1.0 for Alternanthera, Solidago and Eragrostis, respectively. Functional groups of the invasive plants and the native plants they replaced appear to be useful predictors of directions of changes in Rsoil, but the magnitude of changes in Rsoil seems to be sensitive to variations in invader functional traits.展开更多
Public urban greenery greatly contributes to the residential and tourist value of cities in the Gulf Region,but due to the hyper-arid climatic conditions,the cost of irrigation and plant maintenance is very high.Exist...Public urban greenery greatly contributes to the residential and tourist value of cities in the Gulf Region,but due to the hyper-arid climatic conditions,the cost of irrigation and plant maintenance is very high.Existing strategies to reduce the monetary and ecological costs involve the cultivation of native xerophytic plantations,and/or the use of soil improvers to increase water-and nutrient-holding capacity of the sandy soils.Various soil improvers based on mineral,organic,or synthetic materials have entered the United Arab Emirates(UAE)market in recent years,but there is considerable uncertainty about how they should best be used in combination with ornamental plant stands involving xerophytic native plants.The present study investigated the effect of soil amendment and deep pipe irrigation on perennial ornamental plant stands involving native plants(Tephrosia appolinea(Gel.)Link in combination with Aerva javanica(Burm.f.)Juss.ex Schult.)and native-exotic plants(T.appolinea in combination with Ruelia simplex C.Wright)either or not topsoil and subsoil amendment with bentonite and hydrophobic sand under the irrigation water supply of less than 50%of reference evapotranspiration(ET0).After one year of cultivation,T.appolinea and A.javanica(native vs.native)produced high biomass and exhibited high water use efficiency(WUE)as compared with T.appolinea and R.simplex(native vs.exotic)combination given that no significant differences were found under the soil amendment treatments.All stands thrived under irrigation water supply far below what is usually supplied to exotic ornamental stands in public parks of the Al Ain City,the UAE.However,subsoil amendment in combination with deep pipe irrigation reduced the occurrence of weeds and increased the overall plant rooting depth.Our results suggest that subsoil amendment and irrigation up to 60-80 cm depth can potentially control ephemeral weed infestation,which is a great challenge in various plant production systems of the Gulf Region.The results of the present study suggest that the impact of soil amendment on the WUE of exotic plants is marginal and might not be economically justified.Replacing exotic with native ornamental plant species seems to have a far greater water-saving potential than the amendment of the soil,while weeds can be suppressed in the absence of topsoil moisture.展开更多
Galinsona parviflora(Asteraceae)is a wide-spread annual weed that is invasive,colonizing new ground where it is able to persist.We studied the bio-mass structure of the G.parviflora population at the module level by u...Galinsona parviflora(Asteraceae)is a wide-spread annual weed that is invasive,colonizing new ground where it is able to persist.We studied the bio-mass structure of the G.parviflora population at the module level by using the methods of field plot invest-igation and weighing at 10 sample plots.Modular bio-mass was calculated and used for analysis of relation-ships between various modules.The results show that there was a positive correlation between plant height and modular biomass,between stem biomass and root biomass,stem biomass and capitulum biomass,above-ground biomass and underground biomass,and lastly,stem biomass and leaf biomass.The preferred model which measured all the relationships was a power function model with absolute coefficients(R2)ranging from 0.6303 to 0.9782.展开更多
Aims Changes in soil microbial communities after occupation by invasive alien plants can represent legacy effects of invasion that may limit recolonization and establishment of native plant species in soils previously...Aims Changes in soil microbial communities after occupation by invasive alien plants can represent legacy effects of invasion that may limit recolonization and establishment of native plant species in soils previously occupied by the invader.In this study,for three sites in southern Germany,we investigated whether invasion by giant goldenrod(Solidago gigantea)leads to changes in soil biota that result in reduced growth of native plants compared with neighbouring uninvaded soils.Methods We grew four native plant species as a community and treated those plants with soil solutions from invaded or uninvaded soils that were sterilized,or live,with live solutions containing different fractions of the soil biota using a decreasing sieve mesh-size approach.We measured aboveground biomass of the plants in the communities after a 10-week growth period.Main FindingsAcross all three sites and regardless of invasion,communities treated with<20μm soil biota or sterilized soil solutions had significantly greater biomass than communities treated with the complete soil biota solution.This indicates that soil biota>20μm are more pathogenic to the native plants than smaller organisms in these soils.Across all three sites,there was only a non-significant tendency for the native community biomass to differ among soil solution types,depending on whether or not the soil was invaded.Only one site showed significant differences in community biomass among soil solution types,depending on whether or not the soil was invaded;community biomass was significantly lower when treated with the complete soil biota solution than with soil biota<20μm or sterilized soil solutions,but only for the invaded soil.Our findings suggest that efforts to restore native communities on soils previously invaded by Solidago gigantea are unlikely to be hindered by changes in soil microbial community composition as a result of previous invasion.展开更多
Invasive plants are a major threat to biodiversity and may adversely affect food security.Clonal integration enables the sharing of resources between connected ramets and can enhance plant performance in many invasive...Invasive plants are a major threat to biodiversity and may adversely affect food security.Clonal integration enables the sharing of resources between connected ramets and can enhance plant performance in many invasive species.However,few studies have examined the role of clonal integration when weeds are exposed to plant growth regulators(PGRs).PGRs are used extensively in agriculture and may affect nearby weeds through soil leaching,erosion and runoff.Our aim was to investigate the effects of clonal integration on growth in a noxious weed,Alternanthera philoxeroides(alligator weed),in response to two PGRs frequently used in agriculture,gibberellins(GAs)and paclobutrazol(PAC).Ramets of A.philoxeroides were propagated in the greenhouse,and treated with PGRs.PGRs were applied to the older ramets(i.e.‘basal’part),with half of the plants having the stems between the apical(younger)and basal parts left connected,while the remaining plants had the stems between the two parts severed.Following the growing period,plants were measured for growth traits.We found that GA and PAC had contrasting effects on plant growth.GA significantly promoted above-ground growth of the apical ramets via clonal integration.Alternatively,PAC inhibited above-ground growth in the basal and apical parts,and enhanced below-ground growth of the basal and apical ramets through clonal integration.Our results highlight how clonal integration can promote growth in A.philoxeroides following the application of PGRs,which is likely an important mechanism for this species to invade new environments.展开更多
Solidago canadensis,a perennial Compositae plant originating from North America,was introduced into China as a horticultural plant in 1935.Under natural condi-tions,S.canadensis allocates large amounts of energy to se...Solidago canadensis,a perennial Compositae plant originating from North America,was introduced into China as a horticultural plant in 1935.Under natural condi-tions,S.canadensis allocates large amounts of energy to sexual reproduction and produces many seeds,which reflects an r-strategy with high seed number and small seed size.In addition,naturalized populations have a great capacity to grow clonally with underground stems.S.canadensis has become an invasive weed in eastern China,and has caused serious damages to agricultural production and ecosystems in several provinces in China.In order to understand the reproductive characteristics of S.canadensis and effectively control its spread,we examined soil conditions,seed charac-teristics,seed germination and the capacity for asexual reproduction in different plant parts.We investigated the population dispersion of S.canadensis in fixed sites for three years,and analyzed the seasonal dynamics of the morphological parameters of the underground parts and the caloric values of different organs of S.canadensis.We also compared differences in the root systems of S.canadensis and composite exotic weeds.The following results were obtained:1)Under natural conditions,the germination season of S.canadensis lasts from March to October,with a peak from April to May.Vegetative growth and asexual reproduction are especially vigorous during summer due to high temperatures and soil drought stress.On the other hand,the rainy season proves suitable for seed germination.Most S.canadensis flower between September and January,and fruit in late October.A mature plant can produce about 20000 seeds.The mean weight of 1000 seeds ranges from 0.045 g to 0.050 g,and the mean seed moisture content ranges from 60%to 80%.The light-winged seeds disperse readily by air,water,vehicles,human activity or through livestock.2)S.canadensis seeds have a wide tolerance for different values of pH,salinity and soil moisture.The mean percent germination of seeds is 30%under suitable conditions.The results of seed germination under various environmental stresses and investigation of soil conditions indicate that well-aerated,slightly acidic soils with low salinity are suitable for the growth of S.canadensis.Additionally,S.canadensis has a high tolerance for contamination by heavy metal elements including Zn,Cu and Pb,but has low accumulation coefficients for these elements.3)S.canadensis reproduces asexually via underground rhizomes and nodes on the stem base to recruit new individuals,and in plants that experience mechanical damage,this repro-ductive strategy is used to produce clonal shoots.The capacity for asexual reproduction among different plant parts rank as follows:underground parts>stem-base(20 cm)>stem-base(30 cm)>stem-base(45 cm)>stem.Further,with increasing mechanical damage,the quantity of shoots produced by the plant decreases.4)The morphological parameters of the root system of S.canadensis including length,surface area,volume,and average diameter are greater than for composite exotic weeds.These parameters indicate that S.canadensis has the physiological potential to widely invade China.5)The aboveground growth rate and most of the underground morphological parameters vary remarkably among the seasons,with a peak normally occurring in September.In August,a fraction of the energy in leaves and stems is allocated underground to increase fine root growth and water uptake during hot weather.Additionally,the seasonal dynamics of the underground morphological parameters and the caloric values of different organs of S.canadensis enhance its reproductive ability.Based on the results above,we conclude that S.canadensis has great invasive potential in China.We suggest that urgent measures should be taken to control its further spread,and to minimize its impact on local plant diversity.展开更多
Global changes such as atmospheric CO_(2)enrichment often facilitate exotic plant invasions and alter soil arbuscular mycorrhizal fungi(AMF)community.However,it is still unclear whether the effects of CO_(2)enrichment...Global changes such as atmospheric CO_(2)enrichment often facilitate exotic plant invasions and alter soil arbuscular mycorrhizal fungi(AMF)community.However,it is still unclear whether the effects of CO_(2)enrichment on exotic plant invasions are associated with its effects on root-AMF symbiosis of invasive and native plants.To address this issue,the annual invasive plant Xanthium strumarium and two phylogenetically related annual natives were compared under ambient and elevated CO_(2)concentrations for three consecutive years.Atmospheric CO_(2)enrichment increased AMF colonization rates for the species only in few cases,and the invader did not benefit more from CO_(2)enrichment in terms of AMF colonization.Under ambient CO_(2)concentration,however,the invader had a higher AMF colonization rate than the natives in the first year of the study,which disappeared in the second and third year of the study due to the increase of AMF colonization rates in the natives but not in the invader.The influences of species,CO_(2)concentrations and planting year on AMF colonization were associated with their effects on both soil nutrient and AMF community,and the former may be more important as it also influenced the latter.Our results indicate that the invader could more quickly form symbiosis with soil AMF,contributing to adaptation and occupation of new habitats,and that it is necessary to consider the roles of AMF and the effects of time when determining the effects of global changes such as atmospheric CO_(2)enrichment on exotic plant invasions.展开更多
Introduction:Here,we compare the arbuscular mycorrhizal fungal(AMF)community composition in soils from the root zone of the exotic invasive species Prosopis juliflora(EXO soils)and soils from the root zone of the nati...Introduction:Here,we compare the arbuscular mycorrhizal fungal(AMF)community composition in soils from the root zone of the exotic invasive species Prosopis juliflora(EXO soils)and soils from the root zone of the native species Mimosa tenuiflora(NAT soils)from five locations in the Brazilian tropical seasonal dry forest,Paraíba,Brazil,using morphological analyses.Results:AMF community composition in EXO and NAT soils were dissimilar.Available phosphorus,diversity index,spore abundance,and species richness were the main factors differing between the EXO and NAT soils.In general,the most dominant order present in the soils were Glomerales(44.8%)and Gigasporales(41.4%).The most abundant AMF genus in all studied soils was Funneliformis.Conclusions:Differences in AMF community composition were associated with(1)differences in the dominant plant species(P.juliflora vs.M.tenuiflora)and(2)changes in soil chemical factors(soil,pH,total organic carbon,total nitrogen,and available P)in EXO soils.These results contribute to a deeper view of the AMF communities in exotic soils and open new perspectives for ecological processes involving AMF species and exotic plant species in the Brazilian tropical seasonal dry forest.展开更多
基金the Major Project of Knowledge Innovation of the Chinese Academy of Sciences(KSCX1-SW-13-0X-0X).
文摘Since the 1950s of the last century, the exotic plant, Eupatorium adenophorum, has spread rapidly across southwest China, damaging native ecosystems and causing great economic losses. We examined the pH, N, P, K, and organic matter concentrations, and the bacterial community character (by Biolog EcoPlateTM) in soils from sites heavily and lightly invaded by this exotic species. Also, soil from the lightly invaded site was treated with a water extract of E. adenophorum roots to examine the effect of the plant on soil properties. We grew three plant species, one native and two exotic, in pot experiment using soil from heavily invaded site to examine the effects of the soil on these plants growth. The soil analysis demonstrated that the pH, organic matter, total N, total P and total K in soils from the heavily invaded site were only slightly different from those of the lightly invaded site, but concentrations of NH4+, NO?3 and available P and K in the heavily invaded site were greater than those in the lightly invaded site. The catabolic activity of soil bacterial community in the heavily invaded site was different from that in the lightly invaded site. The catabolic activity of bac- terial community in soils treated by the water extract of E. adenophorum roots changed and became similar to that in soils from the heavily invaded site. The pot experiment showed that the exotic plants growth in heavily invaded soil were not different from in lightly invaded soil; however, the native plant biomass decreased dramatically when grown in soil from the heavily invaded site as compared to soil from the lightly invaded site; and the same phenomenon was found when any potential allelopathic effects by E. adeno- phorum were eliminated by added activated carbon to those soils. Difference in soil nutrient availability and allelopathy could not explain this phenomenon of the native plant in the soils from the heavily and lightly invaded sites. Changes ob- served in the soil bacterial community were obviously related to native plant growth in those tow soils. Those results sug- gest that changing soil microbial community may be an im- portant part of E. adenophorum invasion process. Since the soil microbial community serves as bridge in connection of exotic and natural plants, the exotic plant could inhibit the natural plant growth and reproduction by changing the soil microbial community in invaded site.
基金This research is supported by National Research Foundation of Korea(No:2019R1I1A2A03061067).
文摘Land-use and plant invasion influence biodiversity.Understanding the effects of land-use types and invasive plants on the ecosystem is crucial for better management and the development of strategic plans for increasing biodiversity in Jeju Island,Korea,a designated Biosphere Reserve by the United Nations Education,Scientific,and Cultural Organization.The effect of the most dominant invasive exotic species,Hypochaeris radicata,on the four land-use types of Jeju Island was investigated.Plant composition,soil characteristics,and plant diversity among four land-use types(cropland,green space,neglected land,and residential)were compared.Among the land-use types,croplands had the most diverse plant composition and the highest richness in exotic and native plant species.Croplands,such as tangerine orchards,which are widely distributed throughout Jeju Island,showed the highest plant diversity because of medium intensity disturbance caused by weed removal.The relative cover of H.radicata did not differ between land-use types.However,H.radicata invasion was negatively related with plant species richness,making this invasive species a threat to the biodiversity of native herbs present in land-use areas.H.radicata adapts to areas with a broad range of soil properties and a variety of land-use types.Therefore,it is crucial to monitor land-use types and patterns of plant invasion to guide the implementation of consistent management and conservation strategies for maintaining ecosystem integrity of the transformed habitat in Jeju Island.
基金supported by National Forestry and Grassland Administration Emergency Leading the Charge with Open Competition Project(202302)the Fundamental Research Funds for the Central University(BLX202250).
文摘Globalization of social and economic activities has led to the large-scale redistribution of plant species.It is still unclear how the traits aid the successful invasion of alien species.Here,we downloaded global plant trait data from the TRY-Plant Trait Database and classified alien species in China into four groups:high,medium,need attention and harmless according to their distribution and degree of harm to local plant communities based on existed studies.The relationship between plant functional traits and invasion level was clarified,and we established a prediction model based on plant functional traits and taxonomy.The results showed that species with smaller seeds,smaller individuals,lower special leaf area and longer seed bank longevity(SL)are more likely to be an invasive species after introduction to foreign ecosystems.In summary,exotic species with longer SL and lower seed dry mass are more likely to be invasive in China.We also trained two predictive models to check if we can predict a species’invasion.Combining the two models together,statistically,we could predict if a species is invasive from its traits and taxonomy with a 91.84%accuracy.This model could help local governments,managers and stakeholders to evaluate shall we introduce some plant species in China.
基金supported by the National Natural Science Foundation of China(Grant No.30770334).
文摘The intentional introduction of exotic species can increase the level of local biodiversity,enrich people’s material lives,and bring significant social and economic benefits that are also the symbols of human progress.However,along with the frequent intercourse among countries and regions,the frequency of uncontrolled crossregional migration of species is increased and there is a lack of scientific management strategy for the intentional introduction of exotic species.Exotic species invasion,which is behind habitat fragmentation,has become the second largest threatening factor to the maintenance of the global-scale level of biological diversity.Exotic species invasion can destroy the structure of an ecosystem,disturb the economic life of a society,and do harm to human health.In this paper,the authors review some of the ecological explanations for issues such as“what causes or mechanisms have led to the successful invasion of exotic species”,including the“ideal weeds characteristics”,“biodiversity resistance hypothesis”,“enemies release hypothesis”,“evolution of increased competitive ability hypothesis”,“niche opportunity hypothesis”,and“novel weapon hypothesis”.The authors also analyze and evaluate the background and theoretical basis of the hypotheses,providing explanations for some phenomena,as well as the deficiencies of these explanations.
基金supported by Coordination for the Improvement of Higher Educational Personnel(CAPES)
文摘The control of exotic and invasive species in areas undergoing recovery is a challenge for ecological restoration and this problem may be even greater in urbanized areas. This study evaluated the seed bank and seed rain of a 5-year-old riparian forest located at the metropolitan region of Belo Horizonte in southeast Brazil, and verified changes over time in the abundance and species richness and whether planted species already were providing propagules to the site. At the forest, fifteen parcels of 100 m<sup>2</sup> were distributed randomly and soil samples were collected thrice (October 2011, March 2012 and July 2012) to evaluate the seed bank. Seed traps were installed in nine parcels to collect propagules over 1 year. Propagules were segregated and germinate at greenhouse. Species richness and abundance were estimated, and variance and similarity were quantified. In total, 86 species were recorded in the seed banks, 41.9% natives and 33.7% exotics, with the predominance of herbs (87.2%) and only 7% of trees. Species classified as weeds amounted to 52.3%. In the seed rain 642 seedlings germinated but they belonged to only 10 species, half of them were exotics. Regarding life forms, half of the species were arboreal and dominated the samples, highlighting the exotic species Melia azedarach. The species richness of the seed bank did not differ by season, unlike the seed rain which varied significantly by month. Seed bank and seed rain species had a very low floristic similarity with the list of planted species, suggesting that few planted trees had dispersed or were stocking propagules. Many non-planted species were recorded, mostly exotics and/or invasive that were probably derived from the surrounding urban matrix. These might interrupt the successional dynamics of the restoration forest and compromise the restoration process in the medium and long-terms. Our results highlight: (1) the importance of monitoring areas undergoing restoration; (2) that restoration methods and management actions directed to control exotic and invasive species are particularly important for sites in urban regions; and (3) the relevance of conserving forest fragments as sources of propagules for nearby areas.
基金the National Natural Science Foundation of China under contract No. 40476041the State Oceanic Administration of China under contract No. 2010418006
文摘Artificially introduced cordgrass, Spartina alterniflora, rapidly colonized the intertidal flats of the Jiangsu coast, eastern China. The epibenthos on an intertidal flat invaded by S. alterniflorawere studied, to identify how local epibenthos species react to an altered environment. Epibenthic samples and surficial sediment samples were collected along a shore-normal profile in 50 quadrats at ten stations across the Spartina salt marsh; and five control quadrats for a station located on the barren sandy-mud flat. The grain size param- eters of the surficial sediments show that S. alterniflora altered the grain size gradient along the profile of the intertidal zone by trapping fine-grained sediments. Spartina alterniflora could inhabit lower elevation- s than indigenous salt marsh vegetation, thus creating larger areas of finer surficial sediments, which was suitable for not only native epibenthic species but also species which do not exist on the barren sandy-mud flat. Correlation analyses show that the epibenthos were sensitive to sediment grain size and type, on the invaded S. alterniflora salt marsh. Further, there was an interspecific relationship affecting the distribution of epibenthos. The results show that epibenthos preferred ecological niches, within the Spartina salt marsh, even in the same sampling station.
基金supported by the National Natural Science Foundation of China (No.41225003)the Scientific Research Foundation of Jiangxi Agricultral University, China (No.09005172)+2 种基金the Program of Introducing Talents of Discipline to Nanjing Agricultural University, the China Ministry of Education (111 Project) (No.B12009)US National Science Foundation (No.DEB0820560)the Priority Academic Program Development of Jiangsu Higher Education Institutions, China
文摘Exotic plant invasions may alter ecosystem carbon processes, especially when native plants are displaced by plants of a different functional group. Forb invasions into grasslands are common, yet little is known about how they impact carbon cycling. We conducted a field study over 2 years from April 2010 to March 2012 in China to examine changes in soil respiration （Rsoil） following invasion of exotic perennial forb species （Alternanthera philoxeroides or Solidago canadensis） into an annual grassland dominated by a native annual graminoid （Eragrostis pilosa）. Measurements of Rsoil were taken once a week in stands of the native annual graminoid or one of the forb species using static chamber-gas chromatograph method. Aboveground litterfall of each of the three focal species was collected biweekly and litter decomposition rates were measured in a 6-month litterbag experiment. The monthly average and annual cumulative Rsoil increased following invasion by either forb species. The increases in cumulative Rsoil were smaller with invasion of Solidago （36%） than Alternanthera （65%）. Both invasive forbs were associated with higher litter quantity and quality （e.g., C：N ratio） than the native annum graminoid. Compared to the native annual graminoid, the invasive forbs Altevnanthera （155%） and Solidago （361%） produced larger amounts of more rapidly decomposing litter, with the litter decay constant k being 3.8, 2.0 and 1.0 for Alternanthera, Solidago and Eragrostis, respectively. Functional groups of the invasive plants and the native plants they replaced appear to be useful predictors of directions of changes in Rsoil, but the magnitude of changes in Rsoil seems to be sensitive to variations in invader functional traits.
基金partly funded by the Al Ain MunicipalityNational Water and Energy Center, United Arab Emirates University。
文摘Public urban greenery greatly contributes to the residential and tourist value of cities in the Gulf Region,but due to the hyper-arid climatic conditions,the cost of irrigation and plant maintenance is very high.Existing strategies to reduce the monetary and ecological costs involve the cultivation of native xerophytic plantations,and/or the use of soil improvers to increase water-and nutrient-holding capacity of the sandy soils.Various soil improvers based on mineral,organic,or synthetic materials have entered the United Arab Emirates(UAE)market in recent years,but there is considerable uncertainty about how they should best be used in combination with ornamental plant stands involving xerophytic native plants.The present study investigated the effect of soil amendment and deep pipe irrigation on perennial ornamental plant stands involving native plants(Tephrosia appolinea(Gel.)Link in combination with Aerva javanica(Burm.f.)Juss.ex Schult.)and native-exotic plants(T.appolinea in combination with Ruelia simplex C.Wright)either or not topsoil and subsoil amendment with bentonite and hydrophobic sand under the irrigation water supply of less than 50%of reference evapotranspiration(ET0).After one year of cultivation,T.appolinea and A.javanica(native vs.native)produced high biomass and exhibited high water use efficiency(WUE)as compared with T.appolinea and R.simplex(native vs.exotic)combination given that no significant differences were found under the soil amendment treatments.All stands thrived under irrigation water supply far below what is usually supplied to exotic ornamental stands in public parks of the Al Ain City,the UAE.However,subsoil amendment in combination with deep pipe irrigation reduced the occurrence of weeds and increased the overall plant rooting depth.Our results suggest that subsoil amendment and irrigation up to 60-80 cm depth can potentially control ephemeral weed infestation,which is a great challenge in various plant production systems of the Gulf Region.The results of the present study suggest that the impact of soil amendment on the WUE of exotic plants is marginal and might not be economically justified.Replacing exotic with native ornamental plant species seems to have a far greater water-saving potential than the amendment of the soil,while weeds can be suppressed in the absence of topsoil moisture.
基金The research was funded by Liaoning Province Science and Technology Plan Project(No.2004214001)Liaoning Province Education Department Science and Technology Research Project(No.2005275)。
文摘Galinsona parviflora(Asteraceae)is a wide-spread annual weed that is invasive,colonizing new ground where it is able to persist.We studied the bio-mass structure of the G.parviflora population at the module level by using the methods of field plot invest-igation and weighing at 10 sample plots.Modular bio-mass was calculated and used for analysis of relation-ships between various modules.The results show that there was a positive correlation between plant height and modular biomass,between stem biomass and root biomass,stem biomass and capitulum biomass,above-ground biomass and underground biomass,and lastly,stem biomass and leaf biomass.The preferred model which measured all the relationships was a power function model with absolute coefficients(R2)ranging from 0.6303 to 0.9782.
基金funding from the Deutsche Forschungsgemeinschaft(AZ DA 1502/1-1).
文摘Aims Changes in soil microbial communities after occupation by invasive alien plants can represent legacy effects of invasion that may limit recolonization and establishment of native plant species in soils previously occupied by the invader.In this study,for three sites in southern Germany,we investigated whether invasion by giant goldenrod(Solidago gigantea)leads to changes in soil biota that result in reduced growth of native plants compared with neighbouring uninvaded soils.Methods We grew four native plant species as a community and treated those plants with soil solutions from invaded or uninvaded soils that were sterilized,or live,with live solutions containing different fractions of the soil biota using a decreasing sieve mesh-size approach.We measured aboveground biomass of the plants in the communities after a 10-week growth period.Main FindingsAcross all three sites and regardless of invasion,communities treated with<20μm soil biota or sterilized soil solutions had significantly greater biomass than communities treated with the complete soil biota solution.This indicates that soil biota>20μm are more pathogenic to the native plants than smaller organisms in these soils.Across all three sites,there was only a non-significant tendency for the native community biomass to differ among soil solution types,depending on whether or not the soil was invaded.Only one site showed significant differences in community biomass among soil solution types,depending on whether or not the soil was invaded;community biomass was significantly lower when treated with the complete soil biota solution than with soil biota<20μm or sterilized soil solutions,but only for the invaded soil.Our findings suggest that efforts to restore native communities on soils previously invaded by Solidago gigantea are unlikely to be hindered by changes in soil microbial community composition as a result of previous invasion.
基金supported by National Natural Science Foundation of China(32171509,32071905,32071521,32001087)the Natural Science Foundation of Jiangsu(BK20211321)+2 种基金Jiangsu Planned Projects for Postdoctoral Research Funds(2021K160B)Jiangsu University Research Foundation(20JDG055)Part of the funding for this research was supported by Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘Invasive plants are a major threat to biodiversity and may adversely affect food security.Clonal integration enables the sharing of resources between connected ramets and can enhance plant performance in many invasive species.However,few studies have examined the role of clonal integration when weeds are exposed to plant growth regulators(PGRs).PGRs are used extensively in agriculture and may affect nearby weeds through soil leaching,erosion and runoff.Our aim was to investigate the effects of clonal integration on growth in a noxious weed,Alternanthera philoxeroides(alligator weed),in response to two PGRs frequently used in agriculture,gibberellins(GAs)and paclobutrazol(PAC).Ramets of A.philoxeroides were propagated in the greenhouse,and treated with PGRs.PGRs were applied to the older ramets(i.e.‘basal’part),with half of the plants having the stems between the apical(younger)and basal parts left connected,while the remaining plants had the stems between the two parts severed.Following the growing period,plants were measured for growth traits.We found that GA and PAC had contrasting effects on plant growth.GA significantly promoted above-ground growth of the apical ramets via clonal integration.Alternatively,PAC inhibited above-ground growth in the basal and apical parts,and enhanced below-ground growth of the basal and apical ramets through clonal integration.Our results highlight how clonal integration can promote growth in A.philoxeroides following the application of PGRs,which is likely an important mechanism for this species to invade new environments.
基金This work was supported by the Science and Technology Development Foundation of Shanghai High School(No.04DB17,06ZZ20)the Natural Science Foundation of Zhejiang Province(No.Y505018).
文摘Solidago canadensis,a perennial Compositae plant originating from North America,was introduced into China as a horticultural plant in 1935.Under natural condi-tions,S.canadensis allocates large amounts of energy to sexual reproduction and produces many seeds,which reflects an r-strategy with high seed number and small seed size.In addition,naturalized populations have a great capacity to grow clonally with underground stems.S.canadensis has become an invasive weed in eastern China,and has caused serious damages to agricultural production and ecosystems in several provinces in China.In order to understand the reproductive characteristics of S.canadensis and effectively control its spread,we examined soil conditions,seed charac-teristics,seed germination and the capacity for asexual reproduction in different plant parts.We investigated the population dispersion of S.canadensis in fixed sites for three years,and analyzed the seasonal dynamics of the morphological parameters of the underground parts and the caloric values of different organs of S.canadensis.We also compared differences in the root systems of S.canadensis and composite exotic weeds.The following results were obtained:1)Under natural conditions,the germination season of S.canadensis lasts from March to October,with a peak from April to May.Vegetative growth and asexual reproduction are especially vigorous during summer due to high temperatures and soil drought stress.On the other hand,the rainy season proves suitable for seed germination.Most S.canadensis flower between September and January,and fruit in late October.A mature plant can produce about 20000 seeds.The mean weight of 1000 seeds ranges from 0.045 g to 0.050 g,and the mean seed moisture content ranges from 60%to 80%.The light-winged seeds disperse readily by air,water,vehicles,human activity or through livestock.2)S.canadensis seeds have a wide tolerance for different values of pH,salinity and soil moisture.The mean percent germination of seeds is 30%under suitable conditions.The results of seed germination under various environmental stresses and investigation of soil conditions indicate that well-aerated,slightly acidic soils with low salinity are suitable for the growth of S.canadensis.Additionally,S.canadensis has a high tolerance for contamination by heavy metal elements including Zn,Cu and Pb,but has low accumulation coefficients for these elements.3)S.canadensis reproduces asexually via underground rhizomes and nodes on the stem base to recruit new individuals,and in plants that experience mechanical damage,this repro-ductive strategy is used to produce clonal shoots.The capacity for asexual reproduction among different plant parts rank as follows:underground parts>stem-base(20 cm)>stem-base(30 cm)>stem-base(45 cm)>stem.Further,with increasing mechanical damage,the quantity of shoots produced by the plant decreases.4)The morphological parameters of the root system of S.canadensis including length,surface area,volume,and average diameter are greater than for composite exotic weeds.These parameters indicate that S.canadensis has the physiological potential to widely invade China.5)The aboveground growth rate and most of the underground morphological parameters vary remarkably among the seasons,with a peak normally occurring in September.In August,a fraction of the energy in leaves and stems is allocated underground to increase fine root growth and water uptake during hot weather.Additionally,the seasonal dynamics of the underground morphological parameters and the caloric values of different organs of S.canadensis enhance its reproductive ability.Based on the results above,we conclude that S.canadensis has great invasive potential in China.We suggest that urgent measures should be taken to control its further spread,and to minimize its impact on local plant diversity.
基金supported by the National Natural Science Foundation of China(31971557,31670545 and 31470575)the National Key R&D Program of China(2017YFC1200101).
文摘Global changes such as atmospheric CO_(2)enrichment often facilitate exotic plant invasions and alter soil arbuscular mycorrhizal fungi(AMF)community.However,it is still unclear whether the effects of CO_(2)enrichment on exotic plant invasions are associated with its effects on root-AMF symbiosis of invasive and native plants.To address this issue,the annual invasive plant Xanthium strumarium and two phylogenetically related annual natives were compared under ambient and elevated CO_(2)concentrations for three consecutive years.Atmospheric CO_(2)enrichment increased AMF colonization rates for the species only in few cases,and the invader did not benefit more from CO_(2)enrichment in terms of AMF colonization.Under ambient CO_(2)concentration,however,the invader had a higher AMF colonization rate than the natives in the first year of the study,which disappeared in the second and third year of the study due to the increase of AMF colonization rates in the natives but not in the invader.The influences of species,CO_(2)concentrations and planting year on AMF colonization were associated with their effects on both soil nutrient and AMF community,and the former may be more important as it also influenced the latter.Our results indicate that the invader could more quickly form symbiosis with soil AMF,contributing to adaptation and occupation of new habitats,and that it is necessary to consider the roles of AMF and the effects of time when determining the effects of global changes such as atmospheric CO_(2)enrichment on exotic plant invasions.
文摘Introduction:Here,we compare the arbuscular mycorrhizal fungal(AMF)community composition in soils from the root zone of the exotic invasive species Prosopis juliflora(EXO soils)and soils from the root zone of the native species Mimosa tenuiflora(NAT soils)from five locations in the Brazilian tropical seasonal dry forest,Paraíba,Brazil,using morphological analyses.Results:AMF community composition in EXO and NAT soils were dissimilar.Available phosphorus,diversity index,spore abundance,and species richness were the main factors differing between the EXO and NAT soils.In general,the most dominant order present in the soils were Glomerales(44.8%)and Gigasporales(41.4%).The most abundant AMF genus in all studied soils was Funneliformis.Conclusions:Differences in AMF community composition were associated with(1)differences in the dominant plant species(P.juliflora vs.M.tenuiflora)and(2)changes in soil chemical factors(soil,pH,total organic carbon,total nitrogen,and available P)in EXO soils.These results contribute to a deeper view of the AMF communities in exotic soils and open new perspectives for ecological processes involving AMF species and exotic plant species in the Brazilian tropical seasonal dry forest.
