Biological invasion is triggered by human development activities such as the construction and expansion of road networks.Road verges serve as important habitats and corridors for the distribution of invasive alien pla...Biological invasion is triggered by human development activities such as the construction and expansion of road networks.Road verges serve as important habitats and corridors for the distribution of invasive alien plant species(IAPS)between geographically distant habitats.However,the trajectory of plant invasion and the data regarding the impact of roads on IAPS distribution are relatively poor in Nepal.Here,we surveyed two road types(main roads and feeder road)in the Middle Mountain region of central Nepal in order to investigate how different road types are driving the dispersal of IAPS along road verges and the adjacent natural habitats.Systematic sampling was conducted at ca 2.5 km intervals along the roads.At each sampling site,paired plots(25 m×4 m)were sampled:one adjacent to and along the road,and another 20 m away and parallel to it in the interior habitat.Our results revealed that the main road verges had a higher cover(33%)and a larger number of IAPS(14 species)than the feeder road(25%;10 species).The IAPS cover and richness were significantly higher along verges than in the adjacent interior habitats for both road types,indicating that roads are contributing as corridors for the dispersal of IAPS in the Middle Mountain areas of central Nepal.Further,elevation,tree canopy,and disturbances(grazing/mowing/trampling)were found to be the key factors that determine spatial distribution of IAPS along road verges.We emphasize that regular monitoring of vegetation along the road verges can help with the early detection and control of potential IAPS in the region before they become problematic.展开更多
Invasive species have profound negative impacts on native ranges.Unraveling the mechanisms employed by invasive plant species is crucial to controlling invasions.One important approach that invasive plants use to outc...Invasive species have profound negative impacts on native ranges.Unraveling the mechanisms employed by invasive plant species is crucial to controlling invasions.One important approach that invasive plants use to outcompete native plants is to disrupt mutualistic interactions between native roots and mycorrhizal fungi.However,it remains unclear how differences in the competitive ability of invasive plants affect native plant associations with mycorrhizae.Here,we examined how a native plant,Xanthium strumarium,responds to invasive plants that differed in competitive abilities(i.e.,as represented by aboveground plant biomass)by measuring changes in root nitrogen concentration(root nutrient acquisition)and mycorrhizal colonization rate.We found that both root nitrogen concentration and mycorrhizal colonization rate in the native plant were reduced by invasive plants.The change in mycorrhizal colonization rate of the native plant was negatively correlated with both aboveground plant biomass of the invasive plants and the change in aboveground plant biomass of the native plant in monocultures relative to mixed plantings.In contrast,the change in root nitrogen concentration of the native plant was positively correlated with aboveground plant biomass of the invasive plants and the change in aboveground plant biomass of the native plant.When we compared the changes in mycorrhizal colonization rate and root nitrogen concentration in the native plant grown in monocultures with those of native plants grown with invasive plants,we observed a significant tradeoff.Our study shows that invasive plants can suppress native plants by reducing root nutrient acquisition rather than by disrupting symbiotic mycorrhizal associations,a novel finding likely attributable to a low dependence of the native plant on mycorrhizal fungi.展开更多
This paper examines the hypothesis that non-native plant invasions are related to fluctuating resource availability as proposed by Davis et al. (2000). I measured relative functional responses of both invasive and n...This paper examines the hypothesis that non-native plant invasions are related to fluctuating resource availability as proposed by Davis et al. (2000). I measured relative functional responses of both invasive and native plants to changed resource availability due to nutrient enrichment and rainfall, and to increased disturbance. Data are presented from studies in two contrasting ecosystems. First is a series of glasshouse and field experiments on the invader Hieracium lepidulum and associated invasive and native species in subalpine temperate New Zealand. Second is a field study of invasive and native plant responses to altered disturbance regimes and rainfall from tropical savannas of north eastern Australia. Invaders responded differently from native species to changes in resource availability in both subalpine and tropical studies. However, invaders differed among themselves showing that different species exploit different functional niches to invade their respective habitats. These findings contribute to the contention that the fluctuating resource hypothesis does not provide a universal explanation for plant invasions. The diverse functional responses to increased resource availability among invaders in this and previous studies suggest that the cause of invasion depends on unique combinations of habitat and functional attributes of invaders and native assemblages. Such findings imply that universal predictions of what will happen under climate change scenarios across the globe will be difficult to make.展开更多
Background: Natural resources within and around urban landscapes are under increasing pressure from ongoing urbanisation, and management efforts aimed at ensuring the sustainable provision of ecosystem services(ES) ar...Background: Natural resources within and around urban landscapes are under increasing pressure from ongoing urbanisation, and management efforts aimed at ensuring the sustainable provision of ecosystem services(ES) are an important response. Given the limited resources available for assessing urban ES in many cities, practical approaches for integrating ES in decision-making process are needed.Methods: We apply remote sensing techniques(integrating LiDAR data with high-resolution multispectral imagery)and combined these with supplementary spatial data to develop a replicable approach for assessing the role of urban vegetation(including invasive alien plants) in providing ES and ecosystem disservices(EDS). We identify areas denoting potential management trade-offs based on the spatial distribution of ES and EDS using a local-scale case study in the city of Cape Town, South Africa. Situated within a global biodiversity hotspot, Cape Town must contend with widespread invasions of alien plants(especially trees and shrubs) along with complex socio-political challenges. This represents a useful system to examine the challenges in managing ES and EDS in the context of urban plant invasions.Results: Areas of high ES provision(for example carbon sequestration, shade and visual amenity) are characterized by the presence of large trees. However, many of these areas also result in numerous EDS due to invasions of alien trees and shrubs – particularly along rivers, in wetlands and along the urban edge where tall alien trees have established and spread into the natural vegetation(for example increased water consumption, increased fire risk and reduced soil quality). This suggests significant trade-offs regarding the management of species and the ES and EDS they provide.Conclusions: The approach applied here can be used to provide recommendations and to guide city planners and managers to fine-tune management interventions at local scales to maximise the provision of ES.展开更多
Terrestrial invasive plant species continue to wreak havoc on a global economic and ecological scale. With the advent of climate change and pending future catastrophes, the spread of resilient invasive plants will onl...Terrestrial invasive plant species continue to wreak havoc on a global economic and ecological scale. With the advent of climate change and pending future catastrophes, the spread of resilient invasive plants will only increase exponentially. Here, the search continues for a better understanding of the below-ground microbially driven mechanisms involved in plant invasion where other above-ground mechanisms have been exhausted. Microbes govern the world around us and interact with every living and non-living facet of the world. To reinforce the important underpinnings of the role of microorganisms in plant invasion, a systematic review of recently published articles was undertaken. Using the ScienceDirect database, five (5) search queries were used to generate 1221 research articles. After a two-step reduction was made based on relevance of the articles, a final total of 59 articles were retrieved. An additional 18 relevant articles were also assessed through the PubMed database for analysis to account for other invasive plants. Thirty-seven (37) invasive species were investigated where soil physiochemical and microbial community structure changes were most prevalent (32% & 39% respectively) while enhanced mutualism, allelopathy and pathogen accumulation were reported less (16%, 10% & 3% respectively). In all invasive species assessed, the impact on plant invasion and inability of the native plants to compete was due to specific microbial associations of the invasive plant or disruption of the soil microbial community. This microbial community shift coincided with changes in physiochemical properties of the soil and the subsequent negative soil feedback for native plants. There is still an expanding potential for the use of biocontrol agents to aid restoration once the underpinnings of biotic resistance and enemy release are understood in a microbial and physiochemical context. The active and functional microbial community structure of the invasive plant rhizosphere and adjacent soil in its native and non-native region can offer a better inference of how they can be controlled using novel-below ground biocontrol methods.展开更多
Suppression of roots and/or their symbiotic microorganisms,such as mycorrhizal fungi and rhizobia,is an effective way for alien plants to outcompete native plants.However,little is known about how invasive and native ...Suppression of roots and/or their symbiotic microorganisms,such as mycorrhizal fungi and rhizobia,is an effective way for alien plants to outcompete native plants.However,little is known about how invasive and native plants interact with the quantity and activity of nutrient-acquisition agents.Here a pot experiment was conducted with monoculture and mixed plantings of an invasive plant,Xanthium strumarium,and a common native legume,Glycine max.We measured traits related to root and nodule quantity and activity and mycorrhizal colonization.Compared to the monoculture,fine root quantity(biomass,surface area)and activity(root nitrogen(N)concentration,acid phosphatase activity)of G.max decreased in mixed plantings;nodule quantity(biomass)decreased by 45%,while nodule activity in Nfixing via rhizobium increased by 106%;mycorrhizal colonization was unaffected.Contribution of N fixation to leaf N content in G.max increased in the mixed plantings,and this increase was attributed to a decrease in the rhizosphere soil N of G.max in the mixed plantings.Increased root quantity and activity,along with a higher mycorrhizal association was observed in X.strumarium in the mixed compared to monoculture.Together,the invasive plant did not directly scavenge N from nodule-fixed N,but rather depleted the rhizosphere soil N of the legume,thereby stimulating the activity of N-fixation and increasing the dependence of the native legume on this N source.The quantity-activity framework holds promise for future studies on how native legumes respond to alien plant invasions.展开更多
Aims Alien plant invasion has become a major global environmental issue,causing severe economic and ecological damages.Severe invasions have been reported in some regions of China.However,most studies have been conduc...Aims Alien plant invasion has become a major global environmental issue,causing severe economic and ecological damages.Severe invasions have been reported in some regions of China.However,most studies have been conducted at local and provincial levels,and the overall degree of invasion in natural forests across China remains unclear.Here,we explored the biogeographic patterns and their environmental and socioeconomic controls of the invaded alien woody plants in natural forests across the country.Methods We compiled the data of 3573 natural forest plots across the China's Mainland and mapped spatial distribution of alien woody plant invasion.We also used logistic regression models to identify the key socioeconomic and environmental factors that were associated with the observed invasion patterns.Important Findings We found that only 271 plots among 3573 natural forest plots were invaded by alien woody plants,accounting for 7.58%of all plots.Among all 2825 woody plant species across all plots surveyed,only 5 alien species(0.177%)were found.Both human activities and climate factors were related to the observed invasion patterns.Since China’s natural forests are mostly located in remote mountainous areas with limited human disturbance,alien woody plant invasions are less than those reported in North America and Europe.However,with the development of transportation and increased economic activities in mountainous areas,more invasions by alien plants may be expected in the future.Therefore,proactive management and policy making are desired to prevent or slow down the invasion processes.展开更多
To reduce the harms of plant invasion,the risk assessment for biological invasion of exotic species( including intentionally introduced species and accidentally introduced species) is particularly important. Through...To reduce the harms of plant invasion,the risk assessment for biological invasion of exotic species( including intentionally introduced species and accidentally introduced species) is particularly important. Through data review,investigation research and expert consultation,risk assessment system and standard for exotic species invasion in Zhengzhou region was established. Risk of Praxelis clematidea was assessed,in order to provide a reference for possible biological invasion of exotic plants in Zhengzhou.展开更多
Recent trends in globalization,human mobility surge and global trade aggravated the expansion of alien species introduction leading to invasion by alien plants compounded by climate change.The ability to predict the s...Recent trends in globalization,human mobility surge and global trade aggravated the expansion of alien species introduction leading to invasion by alien plants compounded by climate change.The ability to predict the spread of invasive species within the context of climate change holds significance for accurately identifying vulnerable regions and formulating strategies to contain their wide proliferation and invasion.Anthropogenic activities and recent climate change scenarios increased the risk of Chromolaena odorata invasion and habitat expansion in Mizoram.To forecast its current distribution and habitat suitability amidst climatic alterations in Mizoram,a MaxEnt-driven habitat suitability model was deployed using the default parameters.The resultant model exhibited that the current spatial range of C.odorata occupies 15.37%of geographical areas deemed suitable for varying degrees of invasion.Projections for 2050 and 2070 anticipated an expansion of suitable habitats up to 34.37%of the geographical area of Mizoram,specifically under RCP 2.6 in 2070 in comparison with its present distribution.Currently,the distributional range of C.odorata in Mizoram spans from lower(450 m)to mid elevational ranges up to 1700 meters,with limited presence at higher altitudes.However,the habitat suitability model extrapolates that climate changes will elevate the invasion risk posed by C.odorata across Mizoram,particularly in the North-Western and Central regions.The projection of further territorial expansion and an upward shift in altitudinal range in the future underscores the urgency of instating robust management measures to pre-empt the impact of C.odorata invasion.This study recommends the imperative nature of effective C.odorata management,particularly during the initial stages of invasion.展开更多
Current plant diversity can influence exotic plant invasion,but it is unclear whether there is a legacy effect of plant diversity on exotic plant invasion.As plant diversity can affect soil microbial communities and p...Current plant diversity can influence exotic plant invasion,but it is unclear whether there is a legacy effect of plant diversity on exotic plant invasion.As plant diversity can affect soil microbial communities and physio-chemical properties,which may cascade to impact subsequent exotic plant growth,we hypothesize that the soil legacy effect of plant diversity can influence exotic plant invasion.We conducted a plant–soil feedback experiment.In the conditioning phase,we trained soils by monocultures of 12 plant species from three functional groups(4 grasses,3 legumes and 5 forbs)and mixtures of 8 randomly selected species with all three functional groups from this 12-species pool.In the test phase,we grew the invasive plant Bidens pilosa with a co-occurring native grass(Arthraxon hispidus),with a co-occurring native forb(Pterocypsela indica)or with both in each type of the conditioned soils.The performance of B.pilosa relative to its native competitors varied depending on the functional type of both conditioning plant species in the conditioning phase and competing plant species in the test phase.Diversity of the conditioning plants did not influence the growth difference between B.pilosa and its native competitors.However,increasing diversity of the competing plant species reduced the performance of B.pilosa relative to its native competitors.Our results suggest that current plant diversity can reduce exotic plant invasion through increasing growth inequality between invasive and native plants,but the soil legacy effect of plant diversity may have little impact on exotic plant invasion.展开更多
For a long time,forestry primarily had industrial goals.Volume of wood production was the main criterion of forestry efficacy,and thus rapid-growing arboreal species were cultivated in natural forests.More recently,na...For a long time,forestry primarily had industrial goals.Volume of wood production was the main criterion of forestry efficacy,and thus rapid-growing arboreal species were cultivated in natural forests.More recently,nature protection has become one of forestry's goals.Unfortunately,some introduced,rapid-growing species became aggressive components of natural ecological systems during the interim.In this paper,we first describe a method that we developed to categorize aggressiveness of invasive arboreal plants in natural forest ecosystems of Kazakhstan.We then apply this new scheme to monitoring data of invasive arboreal plants to provide an insight into the invasion potential of different species in the fruit forests of Southeast Kazakhstan.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
[Objectives]The paper was to investigate the garden greenbelt in 30 sample plots such as parks,roads,communities,etc.in Shijiazhuang City.[Methods]The species,abundance and frequency of weeds in the greenbelt of publi...[Objectives]The paper was to investigate the garden greenbelt in 30 sample plots such as parks,roads,communities,etc.in Shijiazhuang City.[Methods]The species,abundance and frequency of weeds in the greenbelt of public gardens were recorded through point-line-surface investigation,and typical plants were sampled.[Results]There were 56 species of alien invasive plants in garden greenbelts of Shijiazhuang City,belonging to 44 genera and 20 families.In terms of life form,herbaceous plants were absolutely dominant,accounting for 92.8%of the total.The most alien invasive plants were native to America,accounting for 66.1%of the total.In terms of introduction path,the plants introduced artificially and unintentionally accounted for almost half.The species and quantity of alien invasive plants were related to the size of greenbelt area,the length of the build time of the surveyed plot,the composition structure of greenbelt and the level of green management and protection.There was larger distribution of alien invasive plants in the sample plots with large greenbelt area,long build time,herbaceous-dominated greenbelt and low level of green management and protection.Among the 56 alien invasive plants,3 plants were toxic.From the perspective of invasiveness,the alien invasive plants in the garden greenbelt of Shijiazhuang City could be divided into 5 levels:invasive alien species of malignant consequences,invasive alien species of severe consequences,invasive alien species of partial consequences,invasive alien species of average consequences,and invasive alien species to be observed.[Conclusions]This study will provide a reference for the prevention and control of alien plant invasion,and lay a foundation for the prevention and control of existing invasive plants.展开更多
[Objectives]The paper was to investigate and assess the species,distribution and hazard status of invasive alien plants on the campus of Tongren University.[Methods]A survey was conducted using line survey method,and ...[Objectives]The paper was to investigate and assess the species,distribution and hazard status of invasive alien plants on the campus of Tongren University.[Methods]A survey was conducted using line survey method,and the risk assessment index system of invasive alien plants was established by analytic hierarchy process(AHP).[Results]There were 11 species of invasive alien plants on the campus of Tongren University,belonging to 8 genera and 5 families.There were 6 species of invasive alien plants belonging to Asteraceae,accounting for 54.55%of the total.In terms of the origin of invasive plants,most of them were native to North America and Europe,accounting for 27.27%of the total.In terms of harmful level,there were no high-risk invasive plants on the campus of Tongren University,but Alternanthera philoxeroides had the highest score and was the most harmful.[Conclusions]The present situation of alien plant invasion on the campus of Tongren University is closely related to the ecological environment of the campus.It is suggested to strengthen the management of campus plants,focus on the prevention and control of A.philoxeroides,and carry out regular investigation of invasive alien plants on campus to ensure the ecological safety of the campus.展开更多
Bidens pilosa is recognized as one of the major invasive plants in China.Its invasion has been associated with significant losses in agriculture,forestry,husbandry,and biodiversity.Soil ecosystems play an important ro...Bidens pilosa is recognized as one of the major invasive plants in China.Its invasion has been associated with significant losses in agriculture,forestry,husbandry,and biodiversity.Soil ecosystems play an important role in alien plant invasion.Microorganisms within the soil act as intermediaries between plants and soil ecological functions,playing a role in regulating soil enzyme activities and nutrient dynamics.Understanding the interactions between invasive plants,soil microorganisms,and soil ecological processes is vital for managing and mitigating the impacts of invasive species on the environment.In this study,we conducted a systematic analysis focusing on B.pilosa and Setaria viridis,a common native companion plant in the invaded area.To simulate the invasion process of B.pilosa,we constructed homogeneous plots consisting of B.pilosa and S.viridis grown separately as monocultures,as well as in mixtures.The rhizosphere and bulk soils were collected from the alien plant B.pilosa and the native plant S.viridis.In order to focus on the soil ecological functional mechanisms that contribute to the successful invasion of B.pilosa,we analyzed the effects of B.pilosa on the composition of soil microbial communities and soil ecological functions.The results showed that the biomass of B.pilosa increased by 27.51% and that of S.viridis was significantly reduced by 66.56%.The organic matter contents in the bulk and rhizosphere soils of B.pilosa were approximately 1.30 times those in the native plant soils.The TN and NO_(3)^(-)contents in the rhizosphere soil of B.pilosa were 1.30 to 2.71 times those in the native plant soils.The activities of acid phosphatase,alkaline phosphatase,and urease in the rhizosphere soil of B.pilosa were 1.98-2.25 times higher than in the native plant soils.Using high-throughput sequencing of the16S rRNA gene,we found that B.pilosa altered the composition of the soil microbial community.Specifically,many genera in Actinobacteria and Proteobacteria were enriched in B.pilosa soils.Further correlation analyses verified that these genera had significantly positive relationships with soil nutrients and enzyme activities.Plant biomass,soil p H,and the contents of organic matter,TN,NO_(3)^(-),TP,AP,TK,and AK were the main factors affecting soil microbial communities.This study showed that the invasion of B.pilosa led to significant alterations in the composition of the soil microbial communities.These changes were closely linked to modifications in plant traits as well as soil physical and chemical properties.Some microbial species related to C,N and P cycling were enriched in the soil invaded by B.pilosa.These findings provide additional support for the hypothesis of soil-microbe feedback in the successful invasion of alien plants.They also offer insights into the ecological mechanism by which soil microbes contribute to the successful invasion of B.pilosa.Overall,our research contributes to a better understanding of the complex interactions between invasive plants,soil microbial communities,and ecosystem dynamics.展开更多
Guangdong has become a major"window" for invasive plants, and the largest zone, where cross-border and intercontinental migration frequencies reach the peak. The invasive plants in Guangdong are dominated by Mikania...Guangdong has become a major"window" for invasive plants, and the largest zone, where cross-border and intercontinental migration frequencies reach the peak. The invasive plants in Guangdong are dominated by Mikania micrantha, Eichhornia crassipes, Alternanthera philoxeroides, Eupatorium odoratum, and Wedelia trilobata. It is an important way for treating the invasive plants by exploring the prevention methods and making ful use of the characteristics of the invasive plants, and it is of great significance to prevent and utilize alien species in a scientific and effective way in order to control the invasive plants with minimal cost.展开更多
[Objective] The aim was to conduct investigation and risk assessment of the alien invasive plants in riparian zone of Dongjiang River.[Method] The field survey was carried out by the combination methods of sampling pl...[Objective] The aim was to conduct investigation and risk assessment of the alien invasive plants in riparian zone of Dongjiang River.[Method] The field survey was carried out by the combination methods of sampling plots investigation and route survey,and the whole Dongjiang River was covered.52 sampling points were set in the main streams,and 87 sampling points in tributaries streams,624 quadrats were set in total;multi-index comprehensive evaluation method was adopted for the risk assessment with 6 first-level indexes and 25 second-level indexes.[Result] Through the investigation on the riparian zone of Dongjiang River for 2 years,51 species of alien invasive plants were found,belonging to 17 families and 38 genera.The risk level assessment results of these 51 species showed that 18 species,such as Ageratum conyzoides,belonged to high-level risk with over 60 points;26 species,such as Chenopodium ambrosioides,were between 30 and 60 points which belonged to middle-level risk;7 species,such as Paspalum dilatatum,with less than 30 points belonged to low-level risk.[Conclusion] Basic data on the protection,water environmental management and functional zoning of riparian zone of Dongjiang River were provided.展开更多
Plant invasion alters the fundamental structure and function of native ecosystems by affecting the biogeochemical pools and fluxes of materials and energy. Native(Suaeda salsa) and invasive(Spartina alterniflora) salt...Plant invasion alters the fundamental structure and function of native ecosystems by affecting the biogeochemical pools and fluxes of materials and energy. Native(Suaeda salsa) and invasive(Spartina alterniflora) salt marshes were selected to study the effects of Spartina alterniflora invasion on soil organic carbon(SOC) contents and stocks in the Yellow River Delta. Results showed that the SOC contents(g/kg) and stocks(kg/m^2) were significantly increased(P < 0.05) after Spartina alterniflora invasion of seven years, especially for the surface soil layer(0–20 cm). The SOC contents exhibited an even distribution along the soil profiles in native salt marshes, while the SOC contents were gradually decreased with depth after Spartina alterniflora invasion of seven years. The natural ln response ratios(Ln RR) were applied to identify the effects of short-term Spartina alterniflora invasion on the SOC stocks. We also found that Spartina alterniflora invasion might cause soil organic carbon losses in a short-term phase(2–4 years in this study) due to the negative Ln RR values, especially for 20–60 cm depth. And the SOCD in surface layer(0–20 cm) do not increase linearly with the invasive age. Spearman correlation analysis revealed that silt + clay content was exponentially related with SOC in surface layer(Adjusted R^2 = 0.43, P < 0.001), suggesting that soil texture could play a key role in SOC sequestration of coastal salt marshes.展开更多
[Objective]This study was to reveal the essence of mechanism about how the alien invasive plants spread.[Method]Species niche and material/energy flow were used as basic research indicators to analyze the intrinsic me...[Objective]This study was to reveal the essence of mechanism about how the alien invasive plants spread.[Method]Species niche and material/energy flow were used as basic research indicators to analyze the intrinsic mechanism of alien plants invasion.[Result]Most of the invasive plants have not been explicitly defined and their effective control methods not brought forward.[Conclusion]Overrun of alien invasive plants depends on whether the niche of a species could be continuously met at spatial level.Based on this we put forward corresponding control measures,proposed an assumption to establish a cylinder-network model and discussed the definition of alien invasive plants.展开更多
Plant invasions could significantly alter arbuscular mycorrhizal(AM) fungal communities, but the effect may vary with plant species and local environments. Identifying changes in the AM fungal community due to plant i...Plant invasions could significantly alter arbuscular mycorrhizal(AM) fungal communities, but the effect may vary with plant species and local environments. Identifying changes in the AM fungal community due to plant invasion could improve our understanding of the invasion processes. Here, we examined the AM fungal community composition both in roots and rhizosphere soils of the invasive plant Cenchrus incertus and the dominant native plant Setaria viridis in a typical steppe in Inner Mongolia by using terminal restriction fragment length polymorphism analyses(T-RFLP). The results showed that AM fungal abundance in the rhizosphere soils of C. incertus was significantly lower than that of S. viridis. The AM fungal community composition in the rhizosphere soils of the two plant species also largely differed. In general, AM fungal community structures in roots corresponded very well to that in rhizosphere soils for both plant species. The dominant AM fungal type both in invasive and native plants was T-RFLP 524 bp, which represents Glomus sp.(Virtual taxa 109 and 287). Three specific T-RF types(280,190 and 141bp) were significantly more abundant in C. incertus, representing three clusters in Glomus which also named as VT(virtual taxa) 287, 64 and 214, Rhizophagus intraradices(VT 113) and Diversispora sp.(VT 60). While the specific T-RF types,189 and 279 bp, for S. viridis, only existed in Glomus cluster 1(VT 156), were significantly less abundant in C. incertus. These results indicated that AM fungi might play an important role in the invasion process of C. incertus, which still remains to be further investigated.展开更多
文摘Biological invasion is triggered by human development activities such as the construction and expansion of road networks.Road verges serve as important habitats and corridors for the distribution of invasive alien plant species(IAPS)between geographically distant habitats.However,the trajectory of plant invasion and the data regarding the impact of roads on IAPS distribution are relatively poor in Nepal.Here,we surveyed two road types(main roads and feeder road)in the Middle Mountain region of central Nepal in order to investigate how different road types are driving the dispersal of IAPS along road verges and the adjacent natural habitats.Systematic sampling was conducted at ca 2.5 km intervals along the roads.At each sampling site,paired plots(25 m×4 m)were sampled:one adjacent to and along the road,and another 20 m away and parallel to it in the interior habitat.Our results revealed that the main road verges had a higher cover(33%)and a larger number of IAPS(14 species)than the feeder road(25%;10 species).The IAPS cover and richness were significantly higher along verges than in the adjacent interior habitats for both road types,indicating that roads are contributing as corridors for the dispersal of IAPS in the Middle Mountain areas of central Nepal.Further,elevation,tree canopy,and disturbances(grazing/mowing/trampling)were found to be the key factors that determine spatial distribution of IAPS along road verges.We emphasize that regular monitoring of vegetation along the road verges can help with the early detection and control of potential IAPS in the region before they become problematic.
基金supported by the National Natural Science Foundation of China(31870522,32171746 and 32171662)the Scientific Research Foundation of Henan Agricultural University(30500854),Research Funds for overseas returnee in Henan Province,China.
文摘Invasive species have profound negative impacts on native ranges.Unraveling the mechanisms employed by invasive plant species is crucial to controlling invasions.One important approach that invasive plants use to outcompete native plants is to disrupt mutualistic interactions between native roots and mycorrhizal fungi.However,it remains unclear how differences in the competitive ability of invasive plants affect native plant associations with mycorrhizae.Here,we examined how a native plant,Xanthium strumarium,responds to invasive plants that differed in competitive abilities(i.e.,as represented by aboveground plant biomass)by measuring changes in root nitrogen concentration(root nutrient acquisition)and mycorrhizal colonization rate.We found that both root nitrogen concentration and mycorrhizal colonization rate in the native plant were reduced by invasive plants.The change in mycorrhizal colonization rate of the native plant was negatively correlated with both aboveground plant biomass of the invasive plants and the change in aboveground plant biomass of the native plant in monocultures relative to mixed plantings.In contrast,the change in root nitrogen concentration of the native plant was positively correlated with aboveground plant biomass of the invasive plants and the change in aboveground plant biomass of the native plant.When we compared the changes in mycorrhizal colonization rate and root nitrogen concentration in the native plant grown in monocultures with those of native plants grown with invasive plants,we observed a significant tradeoff.Our study shows that invasive plants can suppress native plants by reducing root nutrient acquisition rather than by disrupting symbiotic mycorrhizal associations,a novel finding likely attributable to a low dependence of the native plant on mycorrhizal fungi.
文摘This paper examines the hypothesis that non-native plant invasions are related to fluctuating resource availability as proposed by Davis et al. (2000). I measured relative functional responses of both invasive and native plants to changed resource availability due to nutrient enrichment and rainfall, and to increased disturbance. Data are presented from studies in two contrasting ecosystems. First is a series of glasshouse and field experiments on the invader Hieracium lepidulum and associated invasive and native species in subalpine temperate New Zealand. Second is a field study of invasive and native plant responses to altered disturbance regimes and rainfall from tropical savannas of north eastern Australia. Invaders responded differently from native species to changes in resource availability in both subalpine and tropical studies. However, invaders differed among themselves showing that different species exploit different functional niches to invade their respective habitats. These findings contribute to the contention that the fluctuating resource hypothesis does not provide a universal explanation for plant invasions. The diverse functional responses to increased resource availability among invaders in this and previous studies suggest that the cause of invasion depends on unique combinations of habitat and functional attributes of invaders and native assemblages. Such findings imply that universal predictions of what will happen under climate change scenarios across the globe will be difficult to make.
基金Funding for this work was provided by the DST-NRF Centre of Excellence for Invasion Biology and the Working for Water Programme through their collaborative research project on “Integrated Management of invasive alien species in South Africa”the National Research Foundation,South Africa(grant85417 to DMR)
文摘Background: Natural resources within and around urban landscapes are under increasing pressure from ongoing urbanisation, and management efforts aimed at ensuring the sustainable provision of ecosystem services(ES) are an important response. Given the limited resources available for assessing urban ES in many cities, practical approaches for integrating ES in decision-making process are needed.Methods: We apply remote sensing techniques(integrating LiDAR data with high-resolution multispectral imagery)and combined these with supplementary spatial data to develop a replicable approach for assessing the role of urban vegetation(including invasive alien plants) in providing ES and ecosystem disservices(EDS). We identify areas denoting potential management trade-offs based on the spatial distribution of ES and EDS using a local-scale case study in the city of Cape Town, South Africa. Situated within a global biodiversity hotspot, Cape Town must contend with widespread invasions of alien plants(especially trees and shrubs) along with complex socio-political challenges. This represents a useful system to examine the challenges in managing ES and EDS in the context of urban plant invasions.Results: Areas of high ES provision(for example carbon sequestration, shade and visual amenity) are characterized by the presence of large trees. However, many of these areas also result in numerous EDS due to invasions of alien trees and shrubs – particularly along rivers, in wetlands and along the urban edge where tall alien trees have established and spread into the natural vegetation(for example increased water consumption, increased fire risk and reduced soil quality). This suggests significant trade-offs regarding the management of species and the ES and EDS they provide.Conclusions: The approach applied here can be used to provide recommendations and to guide city planners and managers to fine-tune management interventions at local scales to maximise the provision of ES.
文摘Terrestrial invasive plant species continue to wreak havoc on a global economic and ecological scale. With the advent of climate change and pending future catastrophes, the spread of resilient invasive plants will only increase exponentially. Here, the search continues for a better understanding of the below-ground microbially driven mechanisms involved in plant invasion where other above-ground mechanisms have been exhausted. Microbes govern the world around us and interact with every living and non-living facet of the world. To reinforce the important underpinnings of the role of microorganisms in plant invasion, a systematic review of recently published articles was undertaken. Using the ScienceDirect database, five (5) search queries were used to generate 1221 research articles. After a two-step reduction was made based on relevance of the articles, a final total of 59 articles were retrieved. An additional 18 relevant articles were also assessed through the PubMed database for analysis to account for other invasive plants. Thirty-seven (37) invasive species were investigated where soil physiochemical and microbial community structure changes were most prevalent (32% & 39% respectively) while enhanced mutualism, allelopathy and pathogen accumulation were reported less (16%, 10% & 3% respectively). In all invasive species assessed, the impact on plant invasion and inability of the native plants to compete was due to specific microbial associations of the invasive plant or disruption of the soil microbial community. This microbial community shift coincided with changes in physiochemical properties of the soil and the subsequent negative soil feedback for native plants. There is still an expanding potential for the use of biocontrol agents to aid restoration once the underpinnings of biotic resistance and enemy release are understood in a microbial and physiochemical context. The active and functional microbial community structure of the invasive plant rhizosphere and adjacent soil in its native and non-native region can offer a better inference of how they can be controlled using novel-below ground biocontrol methods.
基金funded by the National Natural Science Foundation of China (32171746,31870522,42077450,32371786)the leading talents of basic research in Henan Province+3 种基金Funding for Characteristic and Backbone Forestry Discipline Group of Henan Provincethe Scientific Research Foundation of Henan Agricultural University (30500854)Research Funds for overseas returnee in Henan Province,Chinasupported by National Key Research and Development Program of China (2019YFE0117000)。
文摘Suppression of roots and/or their symbiotic microorganisms,such as mycorrhizal fungi and rhizobia,is an effective way for alien plants to outcompete native plants.However,little is known about how invasive and native plants interact with the quantity and activity of nutrient-acquisition agents.Here a pot experiment was conducted with monoculture and mixed plantings of an invasive plant,Xanthium strumarium,and a common native legume,Glycine max.We measured traits related to root and nodule quantity and activity and mycorrhizal colonization.Compared to the monoculture,fine root quantity(biomass,surface area)and activity(root nitrogen(N)concentration,acid phosphatase activity)of G.max decreased in mixed plantings;nodule quantity(biomass)decreased by 45%,while nodule activity in Nfixing via rhizobium increased by 106%;mycorrhizal colonization was unaffected.Contribution of N fixation to leaf N content in G.max increased in the mixed plantings,and this increase was attributed to a decrease in the rhizosphere soil N of G.max in the mixed plantings.Increased root quantity and activity,along with a higher mycorrhizal association was observed in X.strumarium in the mixed compared to monoculture.Together,the invasive plant did not directly scavenge N from nodule-fixed N,but rather depleted the rhizosphere soil N of the legume,thereby stimulating the activity of N-fixation and increasing the dependence of the native legume on this N source.The quantity-activity framework holds promise for future studies on how native legumes respond to alien plant invasions.
基金This research was supported by the National Natural Science Foundation of China(31988102).
文摘Aims Alien plant invasion has become a major global environmental issue,causing severe economic and ecological damages.Severe invasions have been reported in some regions of China.However,most studies have been conducted at local and provincial levels,and the overall degree of invasion in natural forests across China remains unclear.Here,we explored the biogeographic patterns and their environmental and socioeconomic controls of the invaded alien woody plants in natural forests across the country.Methods We compiled the data of 3573 natural forest plots across the China's Mainland and mapped spatial distribution of alien woody plant invasion.We also used logistic regression models to identify the key socioeconomic and environmental factors that were associated with the observed invasion patterns.Important Findings We found that only 271 plots among 3573 natural forest plots were invaded by alien woody plants,accounting for 7.58%of all plots.Among all 2825 woody plant species across all plots surveyed,only 5 alien species(0.177%)were found.Both human activities and climate factors were related to the observed invasion patterns.Since China’s natural forests are mostly located in remote mountainous areas with limited human disturbance,alien woody plant invasions are less than those reported in North America and Europe.However,with the development of transportation and increased economic activities in mountainous areas,more invasions by alien plants may be expected in the future.Therefore,proactive management and policy making are desired to prevent or slow down the invasion processes.
基金Supported by New Century Education and Teaching Reform and Talent Cultivation Project of Local Colleges and Universities in Zhengzhou(2013,ZZJZ-A6003)
文摘To reduce the harms of plant invasion,the risk assessment for biological invasion of exotic species( including intentionally introduced species and accidentally introduced species) is particularly important. Through data review,investigation research and expert consultation,risk assessment system and standard for exotic species invasion in Zhengzhou region was established. Risk of Praxelis clematidea was assessed,in order to provide a reference for possible biological invasion of exotic plants in Zhengzhou.
基金the Ministry of Environment,Forest and Climate Change,Government of India for financial support through the National Mission on Himalaya Studies (Project NMHS2017/LG/01/475).
文摘Recent trends in globalization,human mobility surge and global trade aggravated the expansion of alien species introduction leading to invasion by alien plants compounded by climate change.The ability to predict the spread of invasive species within the context of climate change holds significance for accurately identifying vulnerable regions and formulating strategies to contain their wide proliferation and invasion.Anthropogenic activities and recent climate change scenarios increased the risk of Chromolaena odorata invasion and habitat expansion in Mizoram.To forecast its current distribution and habitat suitability amidst climatic alterations in Mizoram,a MaxEnt-driven habitat suitability model was deployed using the default parameters.The resultant model exhibited that the current spatial range of C.odorata occupies 15.37%of geographical areas deemed suitable for varying degrees of invasion.Projections for 2050 and 2070 anticipated an expansion of suitable habitats up to 34.37%of the geographical area of Mizoram,specifically under RCP 2.6 in 2070 in comparison with its present distribution.Currently,the distributional range of C.odorata in Mizoram spans from lower(450 m)to mid elevational ranges up to 1700 meters,with limited presence at higher altitudes.However,the habitat suitability model extrapolates that climate changes will elevate the invasion risk posed by C.odorata across Mizoram,particularly in the North-Western and Central regions.The projection of further territorial expansion and an upward shift in altitudinal range in the future underscores the urgency of instating robust management measures to pre-empt the impact of C.odorata invasion.This study recommends the imperative nature of effective C.odorata management,particularly during the initial stages of invasion.
基金supported by the National Natural Science Foundation of China(32001122,31761123001)Zhejiang Provincial Natural Science Foundation(LQ21C030003)the Ten Thousand Talent Program of Zhejiang Province(grant 2018R52016).
文摘Current plant diversity can influence exotic plant invasion,but it is unclear whether there is a legacy effect of plant diversity on exotic plant invasion.As plant diversity can affect soil microbial communities and physio-chemical properties,which may cascade to impact subsequent exotic plant growth,we hypothesize that the soil legacy effect of plant diversity can influence exotic plant invasion.We conducted a plant–soil feedback experiment.In the conditioning phase,we trained soils by monocultures of 12 plant species from three functional groups(4 grasses,3 legumes and 5 forbs)and mixtures of 8 randomly selected species with all three functional groups from this 12-species pool.In the test phase,we grew the invasive plant Bidens pilosa with a co-occurring native grass(Arthraxon hispidus),with a co-occurring native forb(Pterocypsela indica)or with both in each type of the conditioned soils.The performance of B.pilosa relative to its native competitors varied depending on the functional type of both conditioning plant species in the conditioning phase and competing plant species in the test phase.Diversity of the conditioning plants did not influence the growth difference between B.pilosa and its native competitors.However,increasing diversity of the competing plant species reduced the performance of B.pilosa relative to its native competitors.Our results suggest that current plant diversity can reduce exotic plant invasion through increasing growth inequality between invasive and native plants,but the soil legacy effect of plant diversity may have little impact on exotic plant invasion.
文摘For a long time,forestry primarily had industrial goals.Volume of wood production was the main criterion of forestry efficacy,and thus rapid-growing arboreal species were cultivated in natural forests.More recently,nature protection has become one of forestry's goals.Unfortunately,some introduced,rapid-growing species became aggressive components of natural ecological systems during the interim.In this paper,we first describe a method that we developed to categorize aggressiveness of invasive arboreal plants in natural forest ecosystems of Kazakhstan.We then apply this new scheme to monitoring data of invasive arboreal plants to provide an insight into the invasion potential of different species in the fruit forests of Southeast Kazakhstan.
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 Key R&D Program(2020YFF0305905-06)Science and Technology Project of Hebei Academy of Sciences(22112)Key Discipline Project of Hebei Academy of Sciences(491-0401-YBN-DDH4).
文摘[Objectives]The paper was to investigate the garden greenbelt in 30 sample plots such as parks,roads,communities,etc.in Shijiazhuang City.[Methods]The species,abundance and frequency of weeds in the greenbelt of public gardens were recorded through point-line-surface investigation,and typical plants were sampled.[Results]There were 56 species of alien invasive plants in garden greenbelts of Shijiazhuang City,belonging to 44 genera and 20 families.In terms of life form,herbaceous plants were absolutely dominant,accounting for 92.8%of the total.The most alien invasive plants were native to America,accounting for 66.1%of the total.In terms of introduction path,the plants introduced artificially and unintentionally accounted for almost half.The species and quantity of alien invasive plants were related to the size of greenbelt area,the length of the build time of the surveyed plot,the composition structure of greenbelt and the level of green management and protection.There was larger distribution of alien invasive plants in the sample plots with large greenbelt area,long build time,herbaceous-dominated greenbelt and low level of green management and protection.Among the 56 alien invasive plants,3 plants were toxic.From the perspective of invasiveness,the alien invasive plants in the garden greenbelt of Shijiazhuang City could be divided into 5 levels:invasive alien species of malignant consequences,invasive alien species of severe consequences,invasive alien species of partial consequences,invasive alien species of average consequences,and invasive alien species to be observed.[Conclusions]This study will provide a reference for the prevention and control of alien plant invasion,and lay a foundation for the prevention and control of existing invasive plants.
基金Supported by National Natural Science Foundation of China(31900271,32160086)Key Project of Guizhou Basic Research Program(QKHJC[2019]1455)Central Government Supporting Local Science and Technology Development Fund Project(QKZYD[2021]4010).
文摘[Objectives]The paper was to investigate and assess the species,distribution and hazard status of invasive alien plants on the campus of Tongren University.[Methods]A survey was conducted using line survey method,and the risk assessment index system of invasive alien plants was established by analytic hierarchy process(AHP).[Results]There were 11 species of invasive alien plants on the campus of Tongren University,belonging to 8 genera and 5 families.There were 6 species of invasive alien plants belonging to Asteraceae,accounting for 54.55%of the total.In terms of the origin of invasive plants,most of them were native to North America and Europe,accounting for 27.27%of the total.In terms of harmful level,there were no high-risk invasive plants on the campus of Tongren University,but Alternanthera philoxeroides had the highest score and was the most harmful.[Conclusions]The present situation of alien plant invasion on the campus of Tongren University is closely related to the ecological environment of the campus.It is suggested to strengthen the management of campus plants,focus on the prevention and control of A.philoxeroides,and carry out regular investigation of invasive alien plants on campus to ensure the ecological safety of the campus.
基金funded by the National Key R&D Program of China(2022YFC2601100,2021YFD1400100 and 2021YFC2600400)the National Natural Science Foundation of China(42207162)。
文摘Bidens pilosa is recognized as one of the major invasive plants in China.Its invasion has been associated with significant losses in agriculture,forestry,husbandry,and biodiversity.Soil ecosystems play an important role in alien plant invasion.Microorganisms within the soil act as intermediaries between plants and soil ecological functions,playing a role in regulating soil enzyme activities and nutrient dynamics.Understanding the interactions between invasive plants,soil microorganisms,and soil ecological processes is vital for managing and mitigating the impacts of invasive species on the environment.In this study,we conducted a systematic analysis focusing on B.pilosa and Setaria viridis,a common native companion plant in the invaded area.To simulate the invasion process of B.pilosa,we constructed homogeneous plots consisting of B.pilosa and S.viridis grown separately as monocultures,as well as in mixtures.The rhizosphere and bulk soils were collected from the alien plant B.pilosa and the native plant S.viridis.In order to focus on the soil ecological functional mechanisms that contribute to the successful invasion of B.pilosa,we analyzed the effects of B.pilosa on the composition of soil microbial communities and soil ecological functions.The results showed that the biomass of B.pilosa increased by 27.51% and that of S.viridis was significantly reduced by 66.56%.The organic matter contents in the bulk and rhizosphere soils of B.pilosa were approximately 1.30 times those in the native plant soils.The TN and NO_(3)^(-)contents in the rhizosphere soil of B.pilosa were 1.30 to 2.71 times those in the native plant soils.The activities of acid phosphatase,alkaline phosphatase,and urease in the rhizosphere soil of B.pilosa were 1.98-2.25 times higher than in the native plant soils.Using high-throughput sequencing of the16S rRNA gene,we found that B.pilosa altered the composition of the soil microbial community.Specifically,many genera in Actinobacteria and Proteobacteria were enriched in B.pilosa soils.Further correlation analyses verified that these genera had significantly positive relationships with soil nutrients and enzyme activities.Plant biomass,soil p H,and the contents of organic matter,TN,NO_(3)^(-),TP,AP,TK,and AK were the main factors affecting soil microbial communities.This study showed that the invasion of B.pilosa led to significant alterations in the composition of the soil microbial communities.These changes were closely linked to modifications in plant traits as well as soil physical and chemical properties.Some microbial species related to C,N and P cycling were enriched in the soil invaded by B.pilosa.These findings provide additional support for the hypothesis of soil-microbe feedback in the successful invasion of alien plants.They also offer insights into the ecological mechanism by which soil microbes contribute to the successful invasion of B.pilosa.Overall,our research contributes to a better understanding of the complex interactions between invasive plants,soil microbial communities,and ecosystem dynamics.
基金Guangdong Boluo Agro-technique Extension Center-South China Agricultural Univeristy Cooperation Project(7700-H13510)~~
文摘Guangdong has become a major"window" for invasive plants, and the largest zone, where cross-border and intercontinental migration frequencies reach the peak. The invasive plants in Guangdong are dominated by Mikania micrantha, Eichhornia crassipes, Alternanthera philoxeroides, Eupatorium odoratum, and Wedelia trilobata. It is an important way for treating the invasive plants by exploring the prevention methods and making ful use of the characteristics of the invasive plants, and it is of great significance to prevent and utilize alien species in a scientific and effective way in order to control the invasive plants with minimal cost.
基金Supported by National Water Pollution Control and Management Technology Major Project of ChinaEcological Function Partition Research of Level Three and Level Four in Key Watershed(2012ZX07501002)the Fundamental Work Project of Ministry ofScience and Technology (2006FY111000)~~
文摘[Objective] The aim was to conduct investigation and risk assessment of the alien invasive plants in riparian zone of Dongjiang River.[Method] The field survey was carried out by the combination methods of sampling plots investigation and route survey,and the whole Dongjiang River was covered.52 sampling points were set in the main streams,and 87 sampling points in tributaries streams,624 quadrats were set in total;multi-index comprehensive evaluation method was adopted for the risk assessment with 6 first-level indexes and 25 second-level indexes.[Result] Through the investigation on the riparian zone of Dongjiang River for 2 years,51 species of alien invasive plants were found,belonging to 17 families and 38 genera.The risk level assessment results of these 51 species showed that 18 species,such as Ageratum conyzoides,belonged to high-level risk with over 60 points;26 species,such as Chenopodium ambrosioides,were between 30 and 60 points which belonged to middle-level risk;7 species,such as Paspalum dilatatum,with less than 30 points belonged to low-level risk.[Conclusion] Basic data on the protection,water environmental management and functional zoning of riparian zone of Dongjiang River were provided.
基金Under the auspices of the National Key R&D Program of China(No.2017YFC0505906)the National Natural Science Foundation of China(No.51639001,51379012)the Interdiscipline Research Funds of Beijing Normal University
文摘Plant invasion alters the fundamental structure and function of native ecosystems by affecting the biogeochemical pools and fluxes of materials and energy. Native(Suaeda salsa) and invasive(Spartina alterniflora) salt marshes were selected to study the effects of Spartina alterniflora invasion on soil organic carbon(SOC) contents and stocks in the Yellow River Delta. Results showed that the SOC contents(g/kg) and stocks(kg/m^2) were significantly increased(P < 0.05) after Spartina alterniflora invasion of seven years, especially for the surface soil layer(0–20 cm). The SOC contents exhibited an even distribution along the soil profiles in native salt marshes, while the SOC contents were gradually decreased with depth after Spartina alterniflora invasion of seven years. The natural ln response ratios(Ln RR) were applied to identify the effects of short-term Spartina alterniflora invasion on the SOC stocks. We also found that Spartina alterniflora invasion might cause soil organic carbon losses in a short-term phase(2–4 years in this study) due to the negative Ln RR values, especially for 20–60 cm depth. And the SOCD in surface layer(0–20 cm) do not increase linearly with the invasive age. Spearman correlation analysis revealed that silt + clay content was exponentially related with SOC in surface layer(Adjusted R^2 = 0.43, P < 0.001), suggesting that soil texture could play a key role in SOC sequestration of coastal salt marshes.
基金Supported by Joint Research Fund from National Natural Science Foundation of China(NSFC)-Yunnan Province(U0933601)Students Research Fund from Southwest Forestry University(1001)~~
文摘[Objective]This study was to reveal the essence of mechanism about how the alien invasive plants spread.[Method]Species niche and material/energy flow were used as basic research indicators to analyze the intrinsic mechanism of alien plants invasion.[Result]Most of the invasive plants have not been explicitly defined and their effective control methods not brought forward.[Conclusion]Overrun of alien invasive plants depends on whether the niche of a species could be continuously met at spatial level.Based on this we put forward corresponding control measures,proposed an assumption to establish a cylinder-network model and discussed the definition of alien invasive plants.
基金Supported by National Natural Science Foundation of China(41071178,41101245)Knowledge Innovation Program of the Chinese Academy of Sciences(KZCX2-YW-BR-17)
文摘Plant invasions could significantly alter arbuscular mycorrhizal(AM) fungal communities, but the effect may vary with plant species and local environments. Identifying changes in the AM fungal community due to plant invasion could improve our understanding of the invasion processes. Here, we examined the AM fungal community composition both in roots and rhizosphere soils of the invasive plant Cenchrus incertus and the dominant native plant Setaria viridis in a typical steppe in Inner Mongolia by using terminal restriction fragment length polymorphism analyses(T-RFLP). The results showed that AM fungal abundance in the rhizosphere soils of C. incertus was significantly lower than that of S. viridis. The AM fungal community composition in the rhizosphere soils of the two plant species also largely differed. In general, AM fungal community structures in roots corresponded very well to that in rhizosphere soils for both plant species. The dominant AM fungal type both in invasive and native plants was T-RFLP 524 bp, which represents Glomus sp.(Virtual taxa 109 and 287). Three specific T-RF types(280,190 and 141bp) were significantly more abundant in C. incertus, representing three clusters in Glomus which also named as VT(virtual taxa) 287, 64 and 214, Rhizophagus intraradices(VT 113) and Diversispora sp.(VT 60). While the specific T-RF types,189 and 279 bp, for S. viridis, only existed in Glomus cluster 1(VT 156), were significantly less abundant in C. incertus. These results indicated that AM fungi might play an important role in the invasion process of C. incertus, which still remains to be further investigated.