Conservation and enhancement of old-growth forests are key in forest planning and policies.In order to do so,more knowledge is needed on how the attributes traditionally associated with old-growth forests are distribu...Conservation and enhancement of old-growth forests are key in forest planning and policies.In order to do so,more knowledge is needed on how the attributes traditionally associated with old-growth forests are distributed in space,what differences exist across distinct forest types and what natural or anthropic conditions are affecting the distribution of these old-growthness attributes.Using data from the Third Spanish National Forest Inventory(1997–2007),we calculated six indicators commonly associated with forest old-growthness for the plots in the territory of Peninsular Spain and Balearic Islands,and then combined them into an aggregated index.We then assessed their spatial distribution and the differences across five forest functional types,as well as the effects of ten climate,topographic,landscape,and anthropic variables in their distribution.Relevant geographical patterns were apparent,with climate factors,namely temperature and precipitation,playing a crucial role in the distribution of these attributes.The distribution of the indicators also varied across different forest types,while the effects of recent anthropic impacts were weaker but still relevant.Aridity seemed to be one of the main impediments for the development of old-growthness attributes,coupled with a negative impact of recent human pressure.However,these effects seemed to be mediated by other factors,specially the legacies imposed by the complex history of forest management practices,land use changes and natural disturbances that have shaped the forests of Spain.The results of this exploratory analysis highlight on one hand the importance of climate in the dynamic of forests towards old-growthness,which is relevant in a context of Climate Change,and on the other hand,the need for more insights on the history of our forests in order to understand their present and future.展开更多
The consequences of climate change continue to threaten European forests,particularly for species located at the edges of their latitudinal and altitudinal ranges.While extensively studied in Central Europe,European b...The consequences of climate change continue to threaten European forests,particularly for species located at the edges of their latitudinal and altitudinal ranges.While extensively studied in Central Europe,European beech forests require further investigation to understand how climate change will affect these ecosystems in Mediterranean areas.Proposed silvicultural options increasingly aim at sustainable management to reduce biotic and abiotic stresses and enhance these forest ecosystems'resistance and resilience mechanisms.Process-based models(PBMs)can help us to simulate such phenomena and capture early stress signals while considering the effect of different management approaches.In this study,we focus on estimating sensitivity of two state-of-the-art PBMs forest models by simulating carbon and water fluxes at the stand level to assess productivity changes and feedback resulting from different climatic forcings as well as different management regimes.We applied the 3D-CMCC-FEM and MEDFATE forest models for carbon(C)and water(H_(2)O)fluxes in two sites of the Italian peninsula,Cansiglio in the north and Mongiana in the south,under managed vs.unmanaged scenarios and under current climate and different climatic scenarios(RCP4.5 and RCP8.5).To ensure confidence in the models’results,we preliminary evaluated their performance in simulating C and H_(2)O flux in three additional beech forests of the FLUXNET network along a latitudinal gradient spanning from Denmark to central Italy.The 3D-CMCC-FEM model achieved R^(2)values of 0.83 and 0.86 with RMSEs of 2.53 and 2.05 for C and H_(2)O fluxes,respectively.MEDFATE showed R^(2)values of 0.76 and 0.69 with RMSEs of 2.54 and 3.01.At the Cansiglio site in northern Italy,both models simulated a general increase in C and H_(2)O fluxes under the RCP8.5 climate scenario compared to the current climate.Still,no benefit in managed plots compared to unmanaged ones,as the site does not have water availability limitations,and thus,competition for water is low.At the Mongiana site in southern Italy,both models predict a decrease in C and H_(2)O fluxes and sensitivity to the different climatic forcing compared to the current climate;and an increase in C and H_(2)O fluxes when considering specific management regimes compared to unmanaged scenarios.Conversely,under unmanaged scenarios plots are simulated to experience first signals of mortality prematurely due to water stress(MEDFATE)and carbon starvation(3D-CMCC-FEM)scenarios.In conclusion,while management interventions may be considered a viable solution for the conservation of beech forests under future climate conditions at moister sites like Cansiglio,in drier sites like Mongiana conservation may not lie in management interventions alone.展开更多
The primary mechanism driving plant species loss after nitrogen(N)addition has been often hypothesized to be asymmetric competition for light,resulting from increased aboveground biomass.However,it is largely unknown ...The primary mechanism driving plant species loss after nitrogen(N)addition has been often hypothesized to be asymmetric competition for light,resulting from increased aboveground biomass.However,it is largely unknown whether plants’access to soil water at different depths would affect their responses,fate,and community composition under nitrogen addition.In a semiarid grassland exposed to 8-years of N addition,we measured plant aboveground biomass and diversity under four nitrogen addition rates(0,4,10,and 16 g m2 year1),and evaluated plant use of water across the soil profile using oxygen isotope.Aboveground biomass increased significantly,but diversity and shallow soil-water content decreased,with increasing rate of nitrogen addition.The water isotopic signature for both plant and soil water at the high N rate indicated that Leymus secalinus(a perennial grass)absorbed 7%more water from the subsurface soil layer(20e100 cm)compared to Elymus dahuricus(a perennial grass)and Artemisia annua(an annual forb).L.secalinus thus had a significantly larger biomass and was more abundant than the other two species at the high N rate but did not differ significantly from the other two species under ambient and the low N rate.Species that could use water from deeper soil layers became dominant when water in the shallow layers was insufficient to meet the demands of increased aboveground plant biomass.Our study highlights the importance of water across soil depths as key driver of plant growth and dominance in grasslands under N addition.展开更多
Background:Climate change is accelerating alterations in forest species and community composition worldwide,especially following extreme events like severe droughts and windstorms.Understanding these effects on subtro...Background:Climate change is accelerating alterations in forest species and community composition worldwide,especially following extreme events like severe droughts and windstorms.Understanding these effects on subtropical forests is crucial for conservation and forest management,but it remains unclear whether the impacts are stochastic or deterministic.Methods:We analyzed a unique dataset from a 1-ha permanent plot in a subtropical monsoon broadleaf evergreen forest in China,monitored over 26 years with six surveys from 1994 to 2020.The forest has been free from anthropogenic disturbances for over 400 years.In each survey,we measured all trees with a diameter at breast height(DBH)≥1 cm,and recorded 11 plant functional traits relating to photosynthesis,wood properties,water use,and nutrient dynamics.Using this data,we calculated species and trait dispersion,assessing short-term(~5years)and long-term(26 years)trends in species and trait composition following severe droughts and windstorm events.Results:Severe droughts,and subsequent droughts,increased both species and trait dispersion,while species composition converged,and trait dispersion remained relatively stable throughout the recovery period.Windstorm events led to increased species dispersion but decreased trait dispersion.We observed a clear directional shift in both species and trait composition under these climatic stressors,with a more pronounced increase in trait dispersion compared to species dispersion.Conclusion:In the short term(~5 years),severe droughts and windstorms increased species composition divergence,while trait composition responses varied.Over 26 years,deterministic processes mainly drove community composition changes,especially for trait composition,although stochastic processes also played a role.These findings suggest enhancing forest resilience to climatic stressors by protecting adaptive species or increasing species diversity in management practices.展开更多
Climate change is expected to alter the frequency and intensity of drying-rewetting cycles,impacting water availability and consequently soil nutrient availability.However,the effects of these fluctuations on the chem...Climate change is expected to alter the frequency and intensity of drying-rewetting cycles,impacting water availability and consequently soil nutrient availability.However,the effects of these fluctuations on the chemical speciation and bioavailability of phosphorus(P)in soil remain uncertain,both in the presence of desert species and in their absence.We conducted a pot experiment involving bare soil(absence of plants)and two desert species(Alhagi sparsifolia and Calligonum mongolicum)to determine the short-term impacts of drought(no water supply),drying-rewetting 1(D-RW1,high frequency of low water inputs),and drying-rewetting 2(D-RW2,low frequency of high water inputs)on soil Hedley P pools,plant P concentration,and plant biomass accumulation.Results demonstrated that the presence of plants significantly increased soil labile P and organic P(Po)concentrations by 60%–150%and 1%–68%,respectively,compared to the absence of plants.Both D-RW1 and D-RW2 treatments significantly increased soil dissolved organic carbon concentration by 2%–35%relative to the drought treatment.Moreover,in the presence of A.sparsifolia,soil resin-extractable P and NaHCO_(3)-extractable inorganic P(Pi)concentrations in the D-RW1 treatment significantly increased by 31%and 75%,respectively,when compared to the drought treatment,with the NaHCO_(3)-and NaOH-extractable Po concentrations in the D-RW2 treatment rising by 14%and 32%,respectively.Furthermore,the D-RW2 treatment significantly increased leaf P concentration and plant biomass compared to the D-RW1 and drought treatments.Overall,compared to the drought treatment,frequent low-intensity drying-rewetting cycles enhanced soil Pi turnover,whereas infrequent high-intensity drying-rewetting cycles increased Po turnover and P bioavailability.These findings will inform better water management strategies for desertification restoration in hyper-arid desert ecosystems.展开更多
The effect of evolutionary history on wood density variation may play an important role in shaping variation in wood density,but this has largely not been tested.Using a comprehensive global dataset including 27,297 m...The effect of evolutionary history on wood density variation may play an important role in shaping variation in wood density,but this has largely not been tested.Using a comprehensive global dataset including 27,297 measurements of wood density from 2621 tree species worldwide,we test the hypothesis that the legacy of evolutionary history plays an important role in driving the variation of wood density among tree species.We assessed phylogenetic signal in different taxonomic(e.g.,angiosperms and gymnosperms)and ecological(e.g.,tropical,temperate,and boreal)groups of tree species,explored the biogeographical and phylogenetic patterns of wood density,and quantified the relative importance of current environmental factors(e.g.,climatic and soil variables)and evolutionary history(i.e.,phylogenetic relatedness among species and lineages)in driving global wood density variation.We found that wood density displayed a significant phylogenetic signal.Wood density differed among different biomes and climatic zones,with higher mean values of wood density in relatively drier regions(highest in subtropical desert).Our study revealed that at a global scale,for angiosperms and gymnosperms combined,phylogeny and species(representing the variance explained by taxonomy and not direct explained by long-term evolution process)explained 84.3%and 7.7%of total wood density variation,respectively,whereas current environment explained 2.7%of total wood density variation when phylogeny and species were taken into account.When angiosperms and gymnosperms were considered separately,the three proportions of explained variation are,respectively,84.2%,7.5%and 6.7%for angiosperms,and 45.7%,21.3%and 18.6%for gymnosperms.Our study shows that evolutionary history outpaced current environmental factors in shaping global variation in wood density.展开更多
Deciduous oaks(Quercus spp.)are distributed from subalpine to tropical regions in the northern hemi-sphere and have important roles as carbon sinks and in climate change mitigation.Determining variations in plant func...Deciduous oaks(Quercus spp.)are distributed from subalpine to tropical regions in the northern hemi-sphere and have important roles as carbon sinks and in climate change mitigation.Determining variations in plant functional traits at multiple biological levels and linking them to environmental variables across geographical ranges is important for forecasting range-shifts of broadly-distrib-uted species under climate change.We sampled leaves of five deciduous Quercus spp.covering approximately 20°of latitude(~21°N-41°N)and 20 longitude(~99°E-119°E)across China and measured 12 plant functional traits at different biological levels.The traits varied distinctively,either within each biological level or among different levels driven by climatic and edaphic variables.Traits at the organ level were significantly correlated with those at the cellular and tissue levels,while traits at the whole-plant level only correlated with those at the tissue level.The Quercus species responded to changing environments by regulating stomatal size,leaf thickness and the palisade mesophyll thickness to leaf thickness ratios with contrasting degree of effect to adjust the whole-plant functioning,i.e.,intrinsic water use efficiency(iWUE),carbon supply and nitrogen availability.The results suggest that these deciduous Quercus spp.will maintain vigour by increasing iWUE when subjected to large temperature changes and insufficient moisture,and by accu-mulating leaf non-structural carbohydrates under drought conditions.The findings provide new insights into the inher-ent variation and trait coordination of widely distributed tree species in the context of climate change.展开更多
Background: Global change is causing an increase in the incidence of natural and anthropogenic disturbances on forests, which frequently interact synergistically and promote changes in forest structure, composition an...Background: Global change is causing an increase in the incidence of natural and anthropogenic disturbances on forests, which frequently interact synergistically and promote changes in forest structure, composition and functioning. In this study we evaluate the regeneration of Pinaceae and Fagaceae species in pure and mixed stands in Mexico to determine if current regeneration patterns are indicative of changes in the relative dominance of these two tree families, as observed in other temperate regions. We also identify the environmental factors that determine the regeneration patterns of Pinaceae and Fagaceae species in these forests.Results: We use data from two consecutive surveys of the National Inventory of Forests and Soils of Mexico(INFyS),obtained in 2004–2009 and 2009–2014. Our results show that the spatial patterns of regeneration are affected by forest structure, by climate, by the type and intensity of disturbances and by land tenure. Importantly, the presence and abundance of Fagaceae regeneration is generally higher than that of Pinaceae, and tends to be favoured(relative to Pinaceae) under warmer climates and by the presence of wildfires.Conclusions: The higher regeneration of Fagaceae relative to Pinaceae under warmer and fire-prone conditions could have important impacts on the composition and functioning of Mexican temperate forests under ongoing climate change, as well as affect their resilience to future disturbances.展开更多
We examined how afforestation patterns impact carbon(C),nitrogen(N),and phosphorus(P)stoichiometry in the plant-litter-soil system.Plant leaf,branch,stem,and root,litter,and soil samples were collected from mixedspeci...We examined how afforestation patterns impact carbon(C),nitrogen(N),and phosphorus(P)stoichiometry in the plant-litter-soil system.Plant leaf,branch,stem,and root,litter,and soil samples were collected from mixedspecies plantations of Robinia pseudoacacia with Amygdalus davidiana(RPAD),R.pseudoacacia with Armeniaca sibirica(RPAS),and monocultures of R.pseudoacacia(RP),A.davidiana(AD),and A.sibirica(AS)in the Loess Hilly Region.The results showed that in mixed-species plantations,R.pseudoacacia had lower leaf N and P concentrations than in monocultures,while both A.davidiana and A.sibirica had higher leaf N and P concentrations.Soil P limited tree growth in both afforestation models.Mixing R.pseudoacacia with A.davidiana or A.sibirica reduced N-limitation during litter decomposition.Average soil total N and P concentrations were higher in RPAS than in RPAD,and both were higher than the corresponding monocultures.The average soil C:N ratio was the smallest in RPAS,while the average soil C:P ratio was larger in RPAS than in RP.A positive correlation between N and P concentrations,and between C:N and C:P ratios,was found in litter and all plant organs of mono-and mixedstands.Alternatively,for N concentration and C:N ratio,the correlations between plant(i.e.,leaf,branch,root)and litter and between plant and soil were inverse between plantation types.RPAD has an increased litter decomposition rate to release N and P,while RPAS has a faster rate of soil N mineralization.RPAD was the best plantation(mixed)to improve biogeochemical cycling,as soil nutrient restrictions,particularly for P-limitation,on trees growth were alleviated.This study thus provides insights into suitable tree selection and management by revealing C:N:P stoichiometry in the plant-litter-soil system under different afforestation patterns.展开更多
Biochar could help to stabilize soil organic （SOM） matter, thus sequestering carbon （C） into the soil. The aim of this work was to determine an easy method i） to estimate the effects of the addition of biochar an...Biochar could help to stabilize soil organic （SOM） matter, thus sequestering carbon （C） into the soil. The aim of this work was to determine an easy method i） to estimate the effects of the addition of biochar and nutrients on the organic matter （SOM） mineralization in an artificial soil, proposed by the Organization for Economic Co-operation and Development （OECD）, amended with glucose and ii） to measure the amount of labile organic matter （glucose） that can be sorbed and thus be partially protected in the same soil, amended or not amended with biochar. A factorial experiment was designed to check the effects of three single factors （biochar, nutrients, and glucose） and their interactions on whole SOM mineralization. Soil samples were inoculated with a microbial inoculum and preincubated to ensure that their biological activities were not limited by a small amount of microbial biomass, and then they were incubated in the dark at 21 ~C for 619 d. Periodical measurements of C mineralized to carbon dioxide （CO2） were carried out throughout the 619-d incubation to allow the mineralization of both active and slow organic matter pools. The amount of sorbed glucose was calculated as the difference between the total and remaining amounts of glucose added in a soil extract. Two different models, the Freundlich and Langmuir models, were selected to assess the equilibrium isotherms of glucose sorption. The CO2-C release strongly depended on the presence of nutrients only when no biochar was added to the soil. The mineralization of organic matter in the soil amended with both biochar and glucose was equal to the sum of the mineralization of the two C sources separately. Furthermore, a significant amount of glucose can be sorbed on the biochar-amended soil, suggesting the involvement of physico-chemical mechanisms in labile organic matter protection.展开更多
Aphthona whitfieldi Bryant (Coleoptera: Chrysomelidae) is a major insect pest of Jatropha curcas L. (Euphorbiacae) in Burkina Faso and other countries in West Africa. The insect pest feeds on the roots and the leaves ...Aphthona whitfieldi Bryant (Coleoptera: Chrysomelidae) is a major insect pest of Jatropha curcas L. (Euphorbiacae) in Burkina Faso and other countries in West Africa. The insect pest feeds on the roots and the leaves of the plant. When the attacks are heavy, the plant may lose all its leaves and die off. Unfortunately, little information is available on the biology of this insect pest. A study was conducted on the biology of this insect pest in the Sissili province, South Burkina Faso and resulted in the knowledge of some of the biological features of the insect pest. Aphthona whitfieldi was reared from 13th July to 22th October 2015. Larvae and pupae were collected in J. curcas plantations near Léo, the capital city of the Sissili province, and brought to the laboratory for rearing. The insects were observed daily and the dimensions and the duration of each stage were recorded. We recorded two larval stages (1<sup>st</sup> and 3<sup>rd</sup>): a pre-pupa and a pupal stage. The pupa was free and white milk-like. Both the pre-pupa and the pupal stages lasted for five days. The 1<sup>st</sup> instar larva was smaller than the third one.展开更多
Latin American cities, like those from North America and Europe, experience problems of urban sprawl. However, few studies have dedicated exclusively to this phenomenon in specific cities, and this omission is particu...Latin American cities, like those from North America and Europe, experience problems of urban sprawl. However, few studies have dedicated exclusively to this phenomenon in specific cities, and this omission is particularly noticeable regarding cities not considered among the megalopolis of the continent. The present work analyzes urban sprawl through an urban form in the Concepción Metropolitan Area, Chile, between 1990 and 2009, considering local aspects that may have played a role in the process. The main empirical results obtained from this study reveal a metropolitan area that has expanded intensely over a 20-year period, growing from 9000 hectares to more than 17,000 ha for a 96% increment in the built-up area. The new urban surfaces consolidate a central conurbation that strengthens the role of the main downtowns, with less-intense occupation towards the sub-centers but in a structure that follows the transportation infrastructure. Over the last 20 years, the distance between the shapes has grown progressively by around 2 km, increasing the size of the ellipse by more than 1000 km2. In particular the complexity of the urbanized surfaces has grown, becoming more irregular in shape and less compact as they come to occupy larger areas. So our principal findings include: an increment of nearly 100% in the urban surface, the importance of a polycentric urban structure in the process of consolidation as a support for analyzing different spatial dynamics, and the growing morphological irregularity of the territory of the sprawl.展开更多
Aphthona whitfieldi Bryant (Coleoptera: Chrysomelidae) is a major insect pest of Jatropha curcas L. in Burkina Faso. This study aimed at evaluating the effect of the insect pest populations’ density on the growth of ...Aphthona whitfieldi Bryant (Coleoptera: Chrysomelidae) is a major insect pest of Jatropha curcas L. in Burkina Faso. This study aimed at evaluating the effect of the insect pest populations’ density on the growth of the plant. To achieve this purpose, 90-day aged single plants were caged in a randomized complete block design experiment with 5 treatments and 5 replicates. The treatments consisted of increasing numbers of adults of A. whitfieldi used to infest the caged plants: T0 (0 adult = check), T1 (100 adults), T2 (200 adults), T3 (300 adults), T4 (400 adults). All caged plants were infested 21 days after transplantation and the evaluation started 14 days later one on every 2-week basis from September 18, 2014 to February 19, 2015. The growth parameters of the plant were assessed. The results showed that the intensity of damage caused by A. whitfieldi on the growth of young plants of J. curcas varied according to the treatment (i.e., according to the number of adult individuals infesting the plant at the beginning). The higher the number, the heavier the level of damage caused by the pest. So, the growth of the J. curcas plant was inversely proportional to the number of A. whitfieldi infesting individuals. There was also a positive linear correlation between the defoliation rate and the height of the seedlings. The status of this insect pest was confirmed by the results of this study.展开更多
<i>Aphthona whitfieldi</i> Bryant (Coleoptera: Chrysomelidae) is a major insect pest of <i>Jatropha curcas</i> L. (Euphorbiacae) in Burkina Faso and other countries in West Africa. The insect p...<i>Aphthona whitfieldi</i> Bryant (Coleoptera: Chrysomelidae) is a major insect pest of <i>Jatropha curcas</i> L. (Euphorbiacae) in Burkina Faso and other countries in West Africa. The insect pest feeds on the roots and the leaves of the plant. When the attacks are heavy, the plant may lose all its leaves and die off. Unfortunately, little information is available on the biology of this insect pest. A study was conducted on the biology of this insect pest in the Sissili province, South Burkina Faso and resulted in the knowledge of some of the biological features of the insect pest. <i>Aphthona whitfieldi</i> was reared from 13th July to 22th October 2015. Larvae and pupae were collected in <i>J. curcas</i> plantations near Léo, the capital city of the Sissili province, and brought to the laboratory for rearing. The insects were observed daily and the dimensions and the duration of each stage were recorded. We recorded two larval stages (1<sup>st</sup> and 3<sup>rd</sup>): a pre-pupa and a pupal stage. The pupa was free and white milk-like. Both the pre-pupa and the pupal stages lasted for five days. The 1<sup>st</sup> instar larva was smaller than the third one.展开更多
Jatropha curcas L. is a non-edible oleaginous plant of Euphorbiacea family. Its seeds provide oil for industrial use, and when grown as a biofuel, J. curcas can be used to restore degraded soil by improving their fert...Jatropha curcas L. is a non-edible oleaginous plant of Euphorbiacea family. Its seeds provide oil for industrial use, and when grown as a biofuel, J. curcas can be used to restore degraded soil by improving their fertility and by controlling water and wind erosion. The plant also reduces CO<sub>2</sub> emission by carbon sequestration. However, J. curcas is attacked by many insect pests including C. panaethiopica, a polyphagous heteroptera of the Scutelleridae family. Larvae and adults of the insect pest feed on J. curcas flowers, fruit, and seeds, thereby causing quantitative and qualitative losses. Despite the economic importance of this insect pest, there is little known about its potential natural enemies. A survey of the natural enemies of C. panaethiopica was carried out from 3rd June 2013 to 29th May 2014 on three J. curcas production sites in the South-Sudanian zone of Burkina Faso. Three Hymenopteran egg parasitoids all belonging to the Scelionidae family were found. These included Trissolcus basalis (Wollaston), Psixstriaticeps (Dodd), and Gryon sp. Several predator species belonging to the Araneae, Tarachodidae and Mantidae families were also found. The egg parasitism increased progressively between June and September 2013, reaching a peak (43%) in September 2013. The number of spiders and mantises was higher between July and August 2013. The highest numbers of natural enemies associated with the insect pest were recorded in J. curcas monoculture plantations.展开更多
The efficiency of an aqueous extract of Azadirachta indica’s seeds and deltamethrin 12.5 EC was tested for the control of Calidea panaethiopica and Aphtona whitfieldi populations, two major insect pests of Jatropha c...The efficiency of an aqueous extract of Azadirachta indica’s seeds and deltamethrin 12.5 EC was tested for the control of Calidea panaethiopica and Aphtona whitfieldi populations, two major insect pests of Jatropha curcas L. in Burkina Faso. This study was conducted in 2013 during the dry season and in 2014 during the raining season. In the laboratory, tests of toxicity by contact on paper blotter and by ingestion on organs of the plant and their repulsive effect on paper blotter were performed in vitro on the insect pests adults caught on J. curcasplantations as compared with controls. The aqueous excerpts of neem seeds were prepared at different lengths of steeping (12 h, 24 h and 48 h) and the deltamethrin 12.5 EC was diluted at different doses (4 ml, 8 ml and 16 ml/L). The results of this experiment showed the evidence of the efficiency of the doses 8 ml/L and 16 ml/L of deltamethrin 12.5 EC, and those of 24 h and 48 h for the excerpts of neem seeds. These efficient doses were evaluated in the field in 2013 and 2014. The highest decreases of C. panaethiopica (0.327) and of A. whitfieldi (0.501) populations were recorded with the 16 ml/L dose of deltamethrin in 2014 raining season. During the 2013 dry season, more insect pests were recorded (0.389 for C. panaethiopica and 0.679 for A. whitfieldi) with that dose. But these results were not significantly different from those of 8 ml/L. Regarding the A. indica extracts, the best decrease of populations in the 1st year (0.36 for C. panaethiopica and 1.278 for A. withfieldi) was recorded with the 48 h maceration. But in 2014 because of the effect of rainfalls that dose was less effective than that of 24 h maceration with 0.399 for C. panaethiopica and 1.208 for A. whitfieldi. The efficiency interval of the tested insecticides was two to three weeks in low or no rainfall conditions and one to two weeks in rainy season conditions.展开更多
Jatropha curcas L., a biofuel tree, is attacked by several insect pests, including Pempelia spp. (Lepidoptera: Pyralidae). This insect pest feeds on the stem and the leaves of the plant and can inflict severe damage t...Jatropha curcas L., a biofuel tree, is attacked by several insect pests, including Pempelia spp. (Lepidoptera: Pyralidae). This insect pest feeds on the stem and the leaves of the plant and can inflict severe damage to the shrub. This is why we studied its biology. Pempelia spp. larvae were collected in J. curcas’ plantations in the Léo, Biéha, Silly and Niabouri communes in the Sissili province of Burkina Faso, West Africa and were bred inside transparent plastic boxes. Immerged adults were separated into boxes after pairing them and were bred until their death. The female deposits its eggs in batches on the apical parts of J. curcas. Newly laid eggs are white pale. The first instar larvae are tiny and white pale or yellow. The 2<sup>nd</sup> instar larvae have a light green coloration, with longitudinal stripes. The 3<sup>rd</sup> instar larvae are lightly green with dorsal longitudinal stripes. The 4<sup>th</sup> instar larvae have a black head and a grey body. The 5<sup>th</sup> instar larvae have a blackish brown head with a dark reddish or light reddish longitudinal body. The mean duration of an instar is 8 days. The pre-pupa stadium is a period during which the larvae surround themselves with a white web developed from their saliva secretion. The pupa lives within a dark red cocoon. Pempelia spp. adults are grey. Female adults have large abdomen whereas males show a cylindrical and slender abdomen. These findings are the first of their kind reported in Burkina Faso. They are discussed in this paper.展开更多
<i>Jatropha curcas</i> L., a biofuel tree, is attacked by several insect pests, including <i>Pempelia</i> spp. (Lepidoptera: Pyralidae). This insect pest feeds on the stem and the leaves of the...<i>Jatropha curcas</i> L., a biofuel tree, is attacked by several insect pests, including <i>Pempelia</i> spp. (Lepidoptera: Pyralidae). This insect pest feeds on the stem and the leaves of the plant and can inflict severe damage to the shrub. This is why we studied its biology. <i>Pempelia</i> spp. larvae were collected in <i>J. curcas</i>’ plantations in the Léo, Biéha, Silly and Niabouri communes in the Sissili province of Burkina Faso, West Africa and were bred inside transparent plastic boxes. Immerged adults were separated into boxes after pairing them and were bred until their death. The female deposits its eggs in batches on the apical parts of <i>J. curcas</i>. Newly laid eggs are white pale. The first instar larvae are tiny and white pale or yellow. The 2<sup>nd</sup> instar larvae have a light green coloration, with longitudinal stripes. The 3<sup>rd</sup> instar larvae are lightly green with dorsal longitudinal stripes. The 4<sup>th</sup> instar larvae have a black head and a grey body. The 5<sup>th</sup> instar larvae have a blackish brown head with a dark reddish or light reddish longitudinal body. The mean duration of an instar is 8 days. The pre-pupa stadium is a period during which the larvae surround themselves with a white web developed from their saliva secretion. The pupa lives within a dark red cocoon. <i>Pempelia</i> spp. adults are grey. Female adults have large abdomen whereas males show a cylindrical and slender abdomen. These findings are the first of their kind reported in Burkina Faso. They are discussed in this paper.展开更多
<i>Jatropha curcas</i> is subject to the attacks of many insect pests, including <i>Calidea panaethiopica</i> Kirkaldy 1909 (Hemiptera: Scutelleridae) whose larvae and adults feed on flowers, f...<i>Jatropha curcas</i> is subject to the attacks of many insect pests, including <i>Calidea panaethiopica</i> Kirkaldy 1909 (Hemiptera: Scutelleridae) whose larvae and adults feed on flowers, fruit and seeds of the shrub resulting in quantitative and qualitative losses;the shrub is also attacked by <i>Aphthona whitfieldi</i> Bryan (Coleoptera: Chrysomelidae) which feeds on the leaves causing complete defoliation in severe attack. Despite their economic importance, very little is known about the alternative host plants of these insect pests. The study of the ecology of these species is a pre-requisite for the development of appropriate control methods. The identification of alternative host plants of <i>C. panaethiopica</i> and <i>A. whitfieldi</i> was conducted from June 3rd 2013 to November 30th 2014 in the Sissili province, South Burkina Faso. During that period, four <i>J. curcas</i>’ plantations of six locations in the province were prospected for alternative host plants of the two insect pests. In each plantation, observations were done across a diagonal up to 500 m away from the plantation. Fallows in the vicinity of the <i>J. curcas</i> plantations were particularly examined. Potential host plants of the two insect pests were collected and bred in the laboratory in Léo where they were used to feed the insect pests. Only <i>Jatropha gossypiifolia</i>, a cousin of <i>J. curcas</i>, was found to be a common alternative host plant of both insect pests.展开更多
Jatropha curcas is subject to the attacks of many insect pests, including Calidea panaethiopica Kirkaldy 1909 (Hemiptera: Scutelleridae) whose larvae and adults feed on flowers, fruit and seeds of the shrub resulting ...Jatropha curcas is subject to the attacks of many insect pests, including Calidea panaethiopica Kirkaldy 1909 (Hemiptera: Scutelleridae) whose larvae and adults feed on flowers, fruit and seeds of the shrub resulting in quantitative and qualitative losses;the shrub is also attacked by Aphthona whitfieldi Bryan (Coleoptera: Chrysomelidae) which feeds on the leaves causing complete defoliation in severe attack. Despite their economic importance, very little is known about the alternative host plants of these insect pests. The study of the ecology of these species is a pre-requisite for the development of appropriate control methods. The identification of alternative host plants of C. panaethiopica and A. whitfieldi was conducted from June 3rd 2013 to November 30th 2014 in the Sissili province, South Burkina Faso. During that period, four J. curcas’ plantations of six locations in the province were prospected for alternative host plants of the two insect pests. In each plantation, observations were done across a diagonal up to 500 m away from the plantation. Fallows in the vicinity of the J. curcas plantations were particularly examined. Potential host plants of the two insect pests were collected and bred in the laboratory in Léo where they were used to feed the insect pests. Only Jatropha gossypiifolia, a cousin of J. curcas, was found to be a common alternative host plant of both insect pests.展开更多
基金supported by the Spanish Ministry of Science and Innovation project GREEN-RISK(Evaluation of past changes in ecosystem services and biodiversity in forests and restoration priorities under global change impacts-PID2020-119933RB-C21)A.C.received a pre-doctoral fellowship funded by the Spanish Ministry of Science and Innovation(PRE2021-099642).
文摘Conservation and enhancement of old-growth forests are key in forest planning and policies.In order to do so,more knowledge is needed on how the attributes traditionally associated with old-growth forests are distributed in space,what differences exist across distinct forest types and what natural or anthropic conditions are affecting the distribution of these old-growthness attributes.Using data from the Third Spanish National Forest Inventory(1997–2007),we calculated six indicators commonly associated with forest old-growthness for the plots in the territory of Peninsular Spain and Balearic Islands,and then combined them into an aggregated index.We then assessed their spatial distribution and the differences across five forest functional types,as well as the effects of ten climate,topographic,landscape,and anthropic variables in their distribution.Relevant geographical patterns were apparent,with climate factors,namely temperature and precipitation,playing a crucial role in the distribution of these attributes.The distribution of the indicators also varied across different forest types,while the effects of recent anthropic impacts were weaker but still relevant.Aridity seemed to be one of the main impediments for the development of old-growthness attributes,coupled with a negative impact of recent human pressure.However,these effects seemed to be mediated by other factors,specially the legacies imposed by the complex history of forest management practices,land use changes and natural disturbances that have shaped the forests of Spain.The results of this exploratory analysis highlight on one hand the importance of climate in the dynamic of forests towards old-growthness,which is relevant in a context of Climate Change,and on the other hand,the need for more insights on the history of our forests in order to understand their present and future.
基金the Institute Research Centre for Ecological and Forestry Applications (CREAF) of Barcelona that supported the research by the Spanish “Ministerio de Ciencia e Innovacio'n”(MCIN/AEI/ 10.13039/501100011033) (grant agreement No. PID 2021-126679OBI00)partially supported by MIUR Project (PRIN 2020) between WATER and carbon cycles during droug“Unraveling interactionsht and their impact on water resources and forest and grassland ecosySTEMs in the Mediterranean climate (WATERSTEM)”(Project number: 20202WF53Z),“WAFER”at CNR (Consiglio Nazionale delle Ricerche)+3 种基金Priwitzer et al. (2014) (cod. 2020E52THS)-Research Projects of National Relevance funded by the Italian Ministry of University and Research entitled: “Multi-scale observations to predict Forest response to pollution and climate change”(MULTIFOR, project number: 2020E52THS)funding by the project OptForEU Horizon Europe research and innovation programme under grant agreement No. 101060554the project funded under the National Recovery and Resilience Plan (NRRP), Mission 4 Component 2 Investment 1.4-Call for tender No. 3138 of December 16, 2021, rectified by Decree n.3175 of December 18, 2021 of Italian Ministry of UniversityResearch funded by the European UnionationEU under award Number: Project code CN_00000033–Next Gener, Concession Decree No. 1034 of June 17, 2022 adopted by the Italian Ministry of University and Research, CUP B83C22002930006, Project title“National Biodiversity Future Centre-NBFC”
文摘The consequences of climate change continue to threaten European forests,particularly for species located at the edges of their latitudinal and altitudinal ranges.While extensively studied in Central Europe,European beech forests require further investigation to understand how climate change will affect these ecosystems in Mediterranean areas.Proposed silvicultural options increasingly aim at sustainable management to reduce biotic and abiotic stresses and enhance these forest ecosystems'resistance and resilience mechanisms.Process-based models(PBMs)can help us to simulate such phenomena and capture early stress signals while considering the effect of different management approaches.In this study,we focus on estimating sensitivity of two state-of-the-art PBMs forest models by simulating carbon and water fluxes at the stand level to assess productivity changes and feedback resulting from different climatic forcings as well as different management regimes.We applied the 3D-CMCC-FEM and MEDFATE forest models for carbon(C)and water(H_(2)O)fluxes in two sites of the Italian peninsula,Cansiglio in the north and Mongiana in the south,under managed vs.unmanaged scenarios and under current climate and different climatic scenarios(RCP4.5 and RCP8.5).To ensure confidence in the models’results,we preliminary evaluated their performance in simulating C and H_(2)O flux in three additional beech forests of the FLUXNET network along a latitudinal gradient spanning from Denmark to central Italy.The 3D-CMCC-FEM model achieved R^(2)values of 0.83 and 0.86 with RMSEs of 2.53 and 2.05 for C and H_(2)O fluxes,respectively.MEDFATE showed R^(2)values of 0.76 and 0.69 with RMSEs of 2.54 and 3.01.At the Cansiglio site in northern Italy,both models simulated a general increase in C and H_(2)O fluxes under the RCP8.5 climate scenario compared to the current climate.Still,no benefit in managed plots compared to unmanaged ones,as the site does not have water availability limitations,and thus,competition for water is low.At the Mongiana site in southern Italy,both models predict a decrease in C and H_(2)O fluxes and sensitivity to the different climatic forcing compared to the current climate;and an increase in C and H_(2)O fluxes when considering specific management regimes compared to unmanaged scenarios.Conversely,under unmanaged scenarios plots are simulated to experience first signals of mortality prematurely due to water stress(MEDFATE)and carbon starvation(3D-CMCC-FEM)scenarios.In conclusion,while management interventions may be considered a viable solution for the conservation of beech forests under future climate conditions at moister sites like Cansiglio,in drier sites like Mongiana conservation may not lie in management interventions alone.
基金supported by the Natural Science Foundation of Gansu Province(Grant Number:25JRRA749,24JRRA515,24JRRA527)the Fundamental Research Funds for the Central Universities(Grant Number:lzujbky-2022-ct01)+1 种基金JP and JS were supported by Spanish Government grants PID2020115770RB-I,PID2022-140808NB-I00,and TED2021-132627 BeI00funded by MCIN.SLC was supported by NSF award DEB-2423861.
文摘The primary mechanism driving plant species loss after nitrogen(N)addition has been often hypothesized to be asymmetric competition for light,resulting from increased aboveground biomass.However,it is largely unknown whether plants’access to soil water at different depths would affect their responses,fate,and community composition under nitrogen addition.In a semiarid grassland exposed to 8-years of N addition,we measured plant aboveground biomass and diversity under four nitrogen addition rates(0,4,10,and 16 g m2 year1),and evaluated plant use of water across the soil profile using oxygen isotope.Aboveground biomass increased significantly,but diversity and shallow soil-water content decreased,with increasing rate of nitrogen addition.The water isotopic signature for both plant and soil water at the high N rate indicated that Leymus secalinus(a perennial grass)absorbed 7%more water from the subsurface soil layer(20e100 cm)compared to Elymus dahuricus(a perennial grass)and Artemisia annua(an annual forb).L.secalinus thus had a significantly larger biomass and was more abundant than the other two species at the high N rate but did not differ significantly from the other two species under ambient and the low N rate.Species that could use water from deeper soil layers became dominant when water in the shallow layers was insufficient to meet the demands of increased aboveground plant biomass.Our study highlights the importance of water across soil depths as key driver of plant growth and dominance in grasslands under N addition.
基金supported by National Natural Science Foundation of China(Nos.42130506,42071031)the Special Technology Innovation Fund of Carbon Peak and Carbon Neutrality in Jiangsu Province(No.BK20231515)。
文摘Background:Climate change is accelerating alterations in forest species and community composition worldwide,especially following extreme events like severe droughts and windstorms.Understanding these effects on subtropical forests is crucial for conservation and forest management,but it remains unclear whether the impacts are stochastic or deterministic.Methods:We analyzed a unique dataset from a 1-ha permanent plot in a subtropical monsoon broadleaf evergreen forest in China,monitored over 26 years with six surveys from 1994 to 2020.The forest has been free from anthropogenic disturbances for over 400 years.In each survey,we measured all trees with a diameter at breast height(DBH)≥1 cm,and recorded 11 plant functional traits relating to photosynthesis,wood properties,water use,and nutrient dynamics.Using this data,we calculated species and trait dispersion,assessing short-term(~5years)and long-term(26 years)trends in species and trait composition following severe droughts and windstorm events.Results:Severe droughts,and subsequent droughts,increased both species and trait dispersion,while species composition converged,and trait dispersion remained relatively stable throughout the recovery period.Windstorm events led to increased species dispersion but decreased trait dispersion.We observed a clear directional shift in both species and trait composition under these climatic stressors,with a more pronounced increase in trait dispersion compared to species dispersion.Conclusion:In the short term(~5 years),severe droughts and windstorms increased species composition divergence,while trait composition responses varied.Over 26 years,deterministic processes mainly drove community composition changes,especially for trait composition,although stochastic processes also played a role.These findings suggest enhancing forest resilience to climatic stressors by protecting adaptive species or increasing species diversity in management practices.
基金supported by the National Natural Science Foundation of China (Nos. 42271071, 42207163,and 32250410301)the Postdoctoral Fellowship Program of China (No. GZC20232964)+5 种基金the “Tianchi Talents” Introduction Program, Xinjiang, China, the Ministry of Science and Technology, China (Nos. QN2022045005L and WGXZ2023078L)the National Key Research and Development Project of China (No. 2022YFF1302504)Josep PENUELAS and Jordi SARDANS were funded by the Spanish Government grants PID2020115770RB-I, TED2021132627 B-I00, and PID2022-140808NB-I00funded by the Ministry of Science and Innovation (MCIN) and the Agencia Espa?ola de Investigación (AEI), Spainsupported by the European Union’s Next Generation EU/PRTR program, the Fundación Ramón Areces grant CIVP20A6621Spain, and the Catalan Government grant SGR 2021–1333, Spain
文摘Climate change is expected to alter the frequency and intensity of drying-rewetting cycles,impacting water availability and consequently soil nutrient availability.However,the effects of these fluctuations on the chemical speciation and bioavailability of phosphorus(P)in soil remain uncertain,both in the presence of desert species and in their absence.We conducted a pot experiment involving bare soil(absence of plants)and two desert species(Alhagi sparsifolia and Calligonum mongolicum)to determine the short-term impacts of drought(no water supply),drying-rewetting 1(D-RW1,high frequency of low water inputs),and drying-rewetting 2(D-RW2,low frequency of high water inputs)on soil Hedley P pools,plant P concentration,and plant biomass accumulation.Results demonstrated that the presence of plants significantly increased soil labile P and organic P(Po)concentrations by 60%–150%and 1%–68%,respectively,compared to the absence of plants.Both D-RW1 and D-RW2 treatments significantly increased soil dissolved organic carbon concentration by 2%–35%relative to the drought treatment.Moreover,in the presence of A.sparsifolia,soil resin-extractable P and NaHCO_(3)-extractable inorganic P(Pi)concentrations in the D-RW1 treatment significantly increased by 31%and 75%,respectively,when compared to the drought treatment,with the NaHCO_(3)-and NaOH-extractable Po concentrations in the D-RW2 treatment rising by 14%and 32%,respectively.Furthermore,the D-RW2 treatment significantly increased leaf P concentration and plant biomass compared to the D-RW1 and drought treatments.Overall,compared to the drought treatment,frequent low-intensity drying-rewetting cycles enhanced soil Pi turnover,whereas infrequent high-intensity drying-rewetting cycles increased Po turnover and P bioavailability.These findings will inform better water management strategies for desertification restoration in hyper-arid desert ecosystems.
基金supported by the Scientific Research Project of Anhui Province(2022AH050873)the State Key Laboratory of Subtropical Silviculture(SKLSS-KF2023-08)+1 种基金the Provincial Natural Resources Fund(1908085QC140)the National Key R&D Program of China(2018YFD1000600).
文摘The effect of evolutionary history on wood density variation may play an important role in shaping variation in wood density,but this has largely not been tested.Using a comprehensive global dataset including 27,297 measurements of wood density from 2621 tree species worldwide,we test the hypothesis that the legacy of evolutionary history plays an important role in driving the variation of wood density among tree species.We assessed phylogenetic signal in different taxonomic(e.g.,angiosperms and gymnosperms)and ecological(e.g.,tropical,temperate,and boreal)groups of tree species,explored the biogeographical and phylogenetic patterns of wood density,and quantified the relative importance of current environmental factors(e.g.,climatic and soil variables)and evolutionary history(i.e.,phylogenetic relatedness among species and lineages)in driving global wood density variation.We found that wood density displayed a significant phylogenetic signal.Wood density differed among different biomes and climatic zones,with higher mean values of wood density in relatively drier regions(highest in subtropical desert).Our study revealed that at a global scale,for angiosperms and gymnosperms combined,phylogeny and species(representing the variance explained by taxonomy and not direct explained by long-term evolution process)explained 84.3%and 7.7%of total wood density variation,respectively,whereas current environment explained 2.7%of total wood density variation when phylogeny and species were taken into account.When angiosperms and gymnosperms were considered separately,the three proportions of explained variation are,respectively,84.2%,7.5%and 6.7%for angiosperms,and 45.7%,21.3%and 18.6%for gymnosperms.Our study shows that evolutionary history outpaced current environmental factors in shaping global variation in wood density.
基金supported by the Key Area Research and Development Program of Guangdong Province(2022B1111230001)theScience and Technology Foundation of Guangxi Zhuang Autonomous Region(Guike AD23026080)+1 种基金the National Natural Science Founda tion of China(No.42071065)Natural Science Foundation of US(No.2021898).
文摘Deciduous oaks(Quercus spp.)are distributed from subalpine to tropical regions in the northern hemi-sphere and have important roles as carbon sinks and in climate change mitigation.Determining variations in plant functional traits at multiple biological levels and linking them to environmental variables across geographical ranges is important for forecasting range-shifts of broadly-distrib-uted species under climate change.We sampled leaves of five deciduous Quercus spp.covering approximately 20°of latitude(~21°N-41°N)and 20 longitude(~99°E-119°E)across China and measured 12 plant functional traits at different biological levels.The traits varied distinctively,either within each biological level or among different levels driven by climatic and edaphic variables.Traits at the organ level were significantly correlated with those at the cellular and tissue levels,while traits at the whole-plant level only correlated with those at the tissue level.The Quercus species responded to changing environments by regulating stomatal size,leaf thickness and the palisade mesophyll thickness to leaf thickness ratios with contrasting degree of effect to adjust the whole-plant functioning,i.e.,intrinsic water use efficiency(iWUE),carbon supply and nitrogen availability.The results suggest that these deciduous Quercus spp.will maintain vigour by increasing iWUE when subjected to large temperature changes and insufficient moisture,and by accu-mulating leaf non-structural carbohydrates under drought conditions.The findings provide new insights into the inher-ent variation and trait coordination of widely distributed tree species in the context of climate change.
基金supported by “‘Consejo Nacional de Ciencia y Tecnología-CONACYT’“by a national research grant/scholarship(CVU 225254)to TARby the Spanish government through grant CGL2013–46808-R.JMV benefits from an ICREA Academia award
文摘Background: Global change is causing an increase in the incidence of natural and anthropogenic disturbances on forests, which frequently interact synergistically and promote changes in forest structure, composition and functioning. In this study we evaluate the regeneration of Pinaceae and Fagaceae species in pure and mixed stands in Mexico to determine if current regeneration patterns are indicative of changes in the relative dominance of these two tree families, as observed in other temperate regions. We also identify the environmental factors that determine the regeneration patterns of Pinaceae and Fagaceae species in these forests.Results: We use data from two consecutive surveys of the National Inventory of Forests and Soils of Mexico(INFyS),obtained in 2004–2009 and 2009–2014. Our results show that the spatial patterns of regeneration are affected by forest structure, by climate, by the type and intensity of disturbances and by land tenure. Importantly, the presence and abundance of Fagaceae regeneration is generally higher than that of Pinaceae, and tends to be favoured(relative to Pinaceae) under warmer climates and by the presence of wildfires.Conclusions: The higher regeneration of Fagaceae relative to Pinaceae under warmer and fire-prone conditions could have important impacts on the composition and functioning of Mexican temperate forests under ongoing climate change, as well as affect their resilience to future disturbances.
基金funded by the National Nature Science Foundation of China (No.41771556)funded by the Spanish Government Grants PID2020-115770RB-I00 and TED2021-132627B–I00+2 种基金funded by the Spanish MCIN,AEI/10.13039/501100011033the European Union NextGenerationEU/PRTR,the Catalan government grant SGR2021-1333the Fundaci on Ram on Areces grant CIVP20A6621
文摘We examined how afforestation patterns impact carbon(C),nitrogen(N),and phosphorus(P)stoichiometry in the plant-litter-soil system.Plant leaf,branch,stem,and root,litter,and soil samples were collected from mixedspecies plantations of Robinia pseudoacacia with Amygdalus davidiana(RPAD),R.pseudoacacia with Armeniaca sibirica(RPAS),and monocultures of R.pseudoacacia(RP),A.davidiana(AD),and A.sibirica(AS)in the Loess Hilly Region.The results showed that in mixed-species plantations,R.pseudoacacia had lower leaf N and P concentrations than in monocultures,while both A.davidiana and A.sibirica had higher leaf N and P concentrations.Soil P limited tree growth in both afforestation models.Mixing R.pseudoacacia with A.davidiana or A.sibirica reduced N-limitation during litter decomposition.Average soil total N and P concentrations were higher in RPAS than in RPAD,and both were higher than the corresponding monocultures.The average soil C:N ratio was the smallest in RPAS,while the average soil C:P ratio was larger in RPAS than in RP.A positive correlation between N and P concentrations,and between C:N and C:P ratios,was found in litter and all plant organs of mono-and mixedstands.Alternatively,for N concentration and C:N ratio,the correlations between plant(i.e.,leaf,branch,root)and litter and between plant and soil were inverse between plantation types.RPAD has an increased litter decomposition rate to release N and P,while RPAS has a faster rate of soil N mineralization.RPAD was the best plantation(mixed)to improve biogeochemical cycling,as soil nutrient restrictions,particularly for P-limitation,on trees growth were alleviated.This study thus provides insights into suitable tree selection and management by revealing C:N:P stoichiometry in the plant-litter-soil system under different afforestation patterns.
基金the Government of Aragon,Spainthe European Social Fund for the financial support
文摘Biochar could help to stabilize soil organic （SOM） matter, thus sequestering carbon （C） into the soil. The aim of this work was to determine an easy method i） to estimate the effects of the addition of biochar and nutrients on the organic matter （SOM） mineralization in an artificial soil, proposed by the Organization for Economic Co-operation and Development （OECD）, amended with glucose and ii） to measure the amount of labile organic matter （glucose） that can be sorbed and thus be partially protected in the same soil, amended or not amended with biochar. A factorial experiment was designed to check the effects of three single factors （biochar, nutrients, and glucose） and their interactions on whole SOM mineralization. Soil samples were inoculated with a microbial inoculum and preincubated to ensure that their biological activities were not limited by a small amount of microbial biomass, and then they were incubated in the dark at 21 ~C for 619 d. Periodical measurements of C mineralized to carbon dioxide （CO2） were carried out throughout the 619-d incubation to allow the mineralization of both active and slow organic matter pools. The amount of sorbed glucose was calculated as the difference between the total and remaining amounts of glucose added in a soil extract. Two different models, the Freundlich and Langmuir models, were selected to assess the equilibrium isotherms of glucose sorption. The CO2-C release strongly depended on the presence of nutrients only when no biochar was added to the soil. The mineralization of organic matter in the soil amended with both biochar and glucose was equal to the sum of the mineralization of the two C sources separately. Furthermore, a significant amount of glucose can be sorbed on the biochar-amended soil, suggesting the involvement of physico-chemical mechanisms in labile organic matter protection.
文摘Aphthona whitfieldi Bryant (Coleoptera: Chrysomelidae) is a major insect pest of Jatropha curcas L. (Euphorbiacae) in Burkina Faso and other countries in West Africa. The insect pest feeds on the roots and the leaves of the plant. When the attacks are heavy, the plant may lose all its leaves and die off. Unfortunately, little information is available on the biology of this insect pest. A study was conducted on the biology of this insect pest in the Sissili province, South Burkina Faso and resulted in the knowledge of some of the biological features of the insect pest. Aphthona whitfieldi was reared from 13th July to 22th October 2015. Larvae and pupae were collected in J. curcas plantations near Léo, the capital city of the Sissili province, and brought to the laboratory for rearing. The insects were observed daily and the dimensions and the duration of each stage were recorded. We recorded two larval stages (1<sup>st</sup> and 3<sup>rd</sup>): a pre-pupa and a pupal stage. The pupa was free and white milk-like. Both the pre-pupa and the pupal stages lasted for five days. The 1<sup>st</sup> instar larva was smaller than the third one.
基金sponsored by the projects FONDE-CYT No.11090163:“Valoracion del Territorio Metro-politano.Aproximaciones desde su Sostenibilidad y Eva-luacion Ambiental Estrategica”(Evaluation of the met-ropolitan territory by means of sustainable approaches and strategic environmental assessment)CONICYT/FONDAP/15110020.
文摘Latin American cities, like those from North America and Europe, experience problems of urban sprawl. However, few studies have dedicated exclusively to this phenomenon in specific cities, and this omission is particularly noticeable regarding cities not considered among the megalopolis of the continent. The present work analyzes urban sprawl through an urban form in the Concepción Metropolitan Area, Chile, between 1990 and 2009, considering local aspects that may have played a role in the process. The main empirical results obtained from this study reveal a metropolitan area that has expanded intensely over a 20-year period, growing from 9000 hectares to more than 17,000 ha for a 96% increment in the built-up area. The new urban surfaces consolidate a central conurbation that strengthens the role of the main downtowns, with less-intense occupation towards the sub-centers but in a structure that follows the transportation infrastructure. Over the last 20 years, the distance between the shapes has grown progressively by around 2 km, increasing the size of the ellipse by more than 1000 km2. In particular the complexity of the urbanized surfaces has grown, becoming more irregular in shape and less compact as they come to occupy larger areas. So our principal findings include: an increment of nearly 100% in the urban surface, the importance of a polycentric urban structure in the process of consolidation as a support for analyzing different spatial dynamics, and the growing morphological irregularity of the territory of the sprawl.
文摘Aphthona whitfieldi Bryant (Coleoptera: Chrysomelidae) is a major insect pest of Jatropha curcas L. in Burkina Faso. This study aimed at evaluating the effect of the insect pest populations’ density on the growth of the plant. To achieve this purpose, 90-day aged single plants were caged in a randomized complete block design experiment with 5 treatments and 5 replicates. The treatments consisted of increasing numbers of adults of A. whitfieldi used to infest the caged plants: T0 (0 adult = check), T1 (100 adults), T2 (200 adults), T3 (300 adults), T4 (400 adults). All caged plants were infested 21 days after transplantation and the evaluation started 14 days later one on every 2-week basis from September 18, 2014 to February 19, 2015. The growth parameters of the plant were assessed. The results showed that the intensity of damage caused by A. whitfieldi on the growth of young plants of J. curcas varied according to the treatment (i.e., according to the number of adult individuals infesting the plant at the beginning). The higher the number, the heavier the level of damage caused by the pest. So, the growth of the J. curcas plant was inversely proportional to the number of A. whitfieldi infesting individuals. There was also a positive linear correlation between the defoliation rate and the height of the seedlings. The status of this insect pest was confirmed by the results of this study.
文摘<i>Aphthona whitfieldi</i> Bryant (Coleoptera: Chrysomelidae) is a major insect pest of <i>Jatropha curcas</i> L. (Euphorbiacae) in Burkina Faso and other countries in West Africa. The insect pest feeds on the roots and the leaves of the plant. When the attacks are heavy, the plant may lose all its leaves and die off. Unfortunately, little information is available on the biology of this insect pest. A study was conducted on the biology of this insect pest in the Sissili province, South Burkina Faso and resulted in the knowledge of some of the biological features of the insect pest. <i>Aphthona whitfieldi</i> was reared from 13th July to 22th October 2015. Larvae and pupae were collected in <i>J. curcas</i> plantations near Léo, the capital city of the Sissili province, and brought to the laboratory for rearing. The insects were observed daily and the dimensions and the duration of each stage were recorded. We recorded two larval stages (1<sup>st</sup> and 3<sup>rd</sup>): a pre-pupa and a pupal stage. The pupa was free and white milk-like. Both the pre-pupa and the pupal stages lasted for five days. The 1<sup>st</sup> instar larva was smaller than the third one.
文摘Jatropha curcas L. is a non-edible oleaginous plant of Euphorbiacea family. Its seeds provide oil for industrial use, and when grown as a biofuel, J. curcas can be used to restore degraded soil by improving their fertility and by controlling water and wind erosion. The plant also reduces CO<sub>2</sub> emission by carbon sequestration. However, J. curcas is attacked by many insect pests including C. panaethiopica, a polyphagous heteroptera of the Scutelleridae family. Larvae and adults of the insect pest feed on J. curcas flowers, fruit, and seeds, thereby causing quantitative and qualitative losses. Despite the economic importance of this insect pest, there is little known about its potential natural enemies. A survey of the natural enemies of C. panaethiopica was carried out from 3rd June 2013 to 29th May 2014 on three J. curcas production sites in the South-Sudanian zone of Burkina Faso. Three Hymenopteran egg parasitoids all belonging to the Scelionidae family were found. These included Trissolcus basalis (Wollaston), Psixstriaticeps (Dodd), and Gryon sp. Several predator species belonging to the Araneae, Tarachodidae and Mantidae families were also found. The egg parasitism increased progressively between June and September 2013, reaching a peak (43%) in September 2013. The number of spiders and mantises was higher between July and August 2013. The highest numbers of natural enemies associated with the insect pest were recorded in J. curcas monoculture plantations.
文摘The efficiency of an aqueous extract of Azadirachta indica’s seeds and deltamethrin 12.5 EC was tested for the control of Calidea panaethiopica and Aphtona whitfieldi populations, two major insect pests of Jatropha curcas L. in Burkina Faso. This study was conducted in 2013 during the dry season and in 2014 during the raining season. In the laboratory, tests of toxicity by contact on paper blotter and by ingestion on organs of the plant and their repulsive effect on paper blotter were performed in vitro on the insect pests adults caught on J. curcasplantations as compared with controls. The aqueous excerpts of neem seeds were prepared at different lengths of steeping (12 h, 24 h and 48 h) and the deltamethrin 12.5 EC was diluted at different doses (4 ml, 8 ml and 16 ml/L). The results of this experiment showed the evidence of the efficiency of the doses 8 ml/L and 16 ml/L of deltamethrin 12.5 EC, and those of 24 h and 48 h for the excerpts of neem seeds. These efficient doses were evaluated in the field in 2013 and 2014. The highest decreases of C. panaethiopica (0.327) and of A. whitfieldi (0.501) populations were recorded with the 16 ml/L dose of deltamethrin in 2014 raining season. During the 2013 dry season, more insect pests were recorded (0.389 for C. panaethiopica and 0.679 for A. whitfieldi) with that dose. But these results were not significantly different from those of 8 ml/L. Regarding the A. indica extracts, the best decrease of populations in the 1st year (0.36 for C. panaethiopica and 1.278 for A. withfieldi) was recorded with the 48 h maceration. But in 2014 because of the effect of rainfalls that dose was less effective than that of 24 h maceration with 0.399 for C. panaethiopica and 1.208 for A. whitfieldi. The efficiency interval of the tested insecticides was two to three weeks in low or no rainfall conditions and one to two weeks in rainy season conditions.
文摘Jatropha curcas L., a biofuel tree, is attacked by several insect pests, including Pempelia spp. (Lepidoptera: Pyralidae). This insect pest feeds on the stem and the leaves of the plant and can inflict severe damage to the shrub. This is why we studied its biology. Pempelia spp. larvae were collected in J. curcas’ plantations in the Léo, Biéha, Silly and Niabouri communes in the Sissili province of Burkina Faso, West Africa and were bred inside transparent plastic boxes. Immerged adults were separated into boxes after pairing them and were bred until their death. The female deposits its eggs in batches on the apical parts of J. curcas. Newly laid eggs are white pale. The first instar larvae are tiny and white pale or yellow. The 2<sup>nd</sup> instar larvae have a light green coloration, with longitudinal stripes. The 3<sup>rd</sup> instar larvae are lightly green with dorsal longitudinal stripes. The 4<sup>th</sup> instar larvae have a black head and a grey body. The 5<sup>th</sup> instar larvae have a blackish brown head with a dark reddish or light reddish longitudinal body. The mean duration of an instar is 8 days. The pre-pupa stadium is a period during which the larvae surround themselves with a white web developed from their saliva secretion. The pupa lives within a dark red cocoon. Pempelia spp. adults are grey. Female adults have large abdomen whereas males show a cylindrical and slender abdomen. These findings are the first of their kind reported in Burkina Faso. They are discussed in this paper.
文摘<i>Jatropha curcas</i> L., a biofuel tree, is attacked by several insect pests, including <i>Pempelia</i> spp. (Lepidoptera: Pyralidae). This insect pest feeds on the stem and the leaves of the plant and can inflict severe damage to the shrub. This is why we studied its biology. <i>Pempelia</i> spp. larvae were collected in <i>J. curcas</i>’ plantations in the Léo, Biéha, Silly and Niabouri communes in the Sissili province of Burkina Faso, West Africa and were bred inside transparent plastic boxes. Immerged adults were separated into boxes after pairing them and were bred until their death. The female deposits its eggs in batches on the apical parts of <i>J. curcas</i>. Newly laid eggs are white pale. The first instar larvae are tiny and white pale or yellow. The 2<sup>nd</sup> instar larvae have a light green coloration, with longitudinal stripes. The 3<sup>rd</sup> instar larvae are lightly green with dorsal longitudinal stripes. The 4<sup>th</sup> instar larvae have a black head and a grey body. The 5<sup>th</sup> instar larvae have a blackish brown head with a dark reddish or light reddish longitudinal body. The mean duration of an instar is 8 days. The pre-pupa stadium is a period during which the larvae surround themselves with a white web developed from their saliva secretion. The pupa lives within a dark red cocoon. <i>Pempelia</i> spp. adults are grey. Female adults have large abdomen whereas males show a cylindrical and slender abdomen. These findings are the first of their kind reported in Burkina Faso. They are discussed in this paper.
文摘<i>Jatropha curcas</i> is subject to the attacks of many insect pests, including <i>Calidea panaethiopica</i> Kirkaldy 1909 (Hemiptera: Scutelleridae) whose larvae and adults feed on flowers, fruit and seeds of the shrub resulting in quantitative and qualitative losses;the shrub is also attacked by <i>Aphthona whitfieldi</i> Bryan (Coleoptera: Chrysomelidae) which feeds on the leaves causing complete defoliation in severe attack. Despite their economic importance, very little is known about the alternative host plants of these insect pests. The study of the ecology of these species is a pre-requisite for the development of appropriate control methods. The identification of alternative host plants of <i>C. panaethiopica</i> and <i>A. whitfieldi</i> was conducted from June 3rd 2013 to November 30th 2014 in the Sissili province, South Burkina Faso. During that period, four <i>J. curcas</i>’ plantations of six locations in the province were prospected for alternative host plants of the two insect pests. In each plantation, observations were done across a diagonal up to 500 m away from the plantation. Fallows in the vicinity of the <i>J. curcas</i> plantations were particularly examined. Potential host plants of the two insect pests were collected and bred in the laboratory in Léo where they were used to feed the insect pests. Only <i>Jatropha gossypiifolia</i>, a cousin of <i>J. curcas</i>, was found to be a common alternative host plant of both insect pests.
文摘Jatropha curcas is subject to the attacks of many insect pests, including Calidea panaethiopica Kirkaldy 1909 (Hemiptera: Scutelleridae) whose larvae and adults feed on flowers, fruit and seeds of the shrub resulting in quantitative and qualitative losses;the shrub is also attacked by Aphthona whitfieldi Bryan (Coleoptera: Chrysomelidae) which feeds on the leaves causing complete defoliation in severe attack. Despite their economic importance, very little is known about the alternative host plants of these insect pests. The study of the ecology of these species is a pre-requisite for the development of appropriate control methods. The identification of alternative host plants of C. panaethiopica and A. whitfieldi was conducted from June 3rd 2013 to November 30th 2014 in the Sissili province, South Burkina Faso. During that period, four J. curcas’ plantations of six locations in the province were prospected for alternative host plants of the two insect pests. In each plantation, observations were done across a diagonal up to 500 m away from the plantation. Fallows in the vicinity of the J. curcas plantations were particularly examined. Potential host plants of the two insect pests were collected and bred in the laboratory in Léo where they were used to feed the insect pests. Only Jatropha gossypiifolia, a cousin of J. curcas, was found to be a common alternative host plant of both insect pests.
