The present study focuses on the impacts of extreme drought and flooding situations in Amazonia, using level/discharge data from some rivers in the Amazon region as indicators of impacts. The last 10 years have featur...The present study focuses on the impacts of extreme drought and flooding situations in Amazonia, using level/discharge data from some rivers in the Amazon region as indicators of impacts. The last 10 years have featured various “once in a century” droughts and floods in the Amazon basin, which have affected human and natural systems in the region. We assess a history of such hazards based on river data, and discuss some of the observed impacts in terms of vulnerability of human and natural systems, as well as some of adaptation strategies implemented by regional and local governments to cope with them. A critical perspective of mitigation of drought and flood policies in Amazonia suggests that they have been mostly ineffective in reducing vulnerability for the majority of the population, constituting, perhaps, examples of maladaptation via the undermining of resilience.展开更多
Among the impacts of climate change,there is the intensification of phenomena such as the El Niño South-ern Oscillation(ENSO)responsible for El Niño and La Niña.However,understanding their effects on th...Among the impacts of climate change,there is the intensification of phenomena such as the El Niño South-ern Oscillation(ENSO)responsible for El Niño and La Niña.However,understanding their effects on the functional pro-cesses of forests is limited.Therefore,this study evaluated the effects of ENSO on litter stock and water holding capac-ity(WHC)in a successional forest in eastern Amazonia.Evaluations occurred in periods with the most rainfall in El Niño(2019)and least in La Niña(2021)years.Twelve permanent plots were used to sample litter.ENSO effects were evident for WHC,higher during El Niño.However,this influence was not clear for litter,as only in the rainy season effects were found.There was a positive correlation of WHC with precipitation and humidity,while litter stocks were negatively correlated with temperature and wind speed.Although the subject of this study requires long-term assessments,preliminary results suggests that,depending on the intensity of ENSO,forest functional processes can be strongly impacted and altered.The conclusion reinforces warnings by the scientific community about the impacts of climate change on the maintenance of litter stocks,decomposition and,consequently,the biogeochemical cycle and essential ecosystem services for the maintenance of Amazonia biodiversity.The need to develop long-term research to understand the effects of climatic change on litter stocks and water holding capacity is highlighted,especially in Amazonia.展开更多
High-resolution U–Pb(ID-TIMS,baddeleyite)ages are presented for mafic dykes from selected swarms in two important Amazonian regions:the Carajás Province in the east,and the Rio Apa block in the southwest–areas
The present study evaluates the performance of three numerical weather forecasting models: Global Forecast System (GFS), Brazilian Regional Atmospheric Modelling System (BRAMS) and ETA Regional Model (ETA), by means o...The present study evaluates the performance of three numerical weather forecasting models: Global Forecast System (GFS), Brazilian Regional Atmospheric Modelling System (BRAMS) and ETA Regional Model (ETA), by means of the Mean Error (ME) and the Root Mean Square Error (RMSE), during the most rainy four months period (January to April 2012) on Eastern Amazonia. The models displayed errors of superestimation and underestimation with respect to the observed precipitation, mainly over center-north of Pará and all of Amapá, where the precipitation is higher. Among the analyzed models, GFS shows the best performance, except during January and March, when the model to underestimated precipitation, possibly due to the anomalously high values recorded.展开更多
Background： Natural disturbance is a fundamental component of the functioning of tropical rainforests let to natural dynamics, with tree mortality the driving force of forest renewal. With ongoing global （i.e. land-...Background： Natural disturbance is a fundamental component of the functioning of tropical rainforests let to natural dynamics, with tree mortality the driving force of forest renewal. With ongoing global （i.e. land-use and climate） changes, tropical forests are currently facing deep and rapid modifications in disturbance regimes that may hamper their recovering capacity so that developing robust predictive model able to predict ecosystem resilience and recovery becomes of primary importance for decision-making： （i） Do regenerating forests recover faster than mature forests given the same level of disturbance？ （ii） is the local topography an important predictor of the post-disturbance forest trajectories？ （iii） Is the community functional composition, assessed with community weighted-mean functional traits, a good predictor of carbon stock recovery？ （iv） How important is the climate stress （seasonal drought and/or soil water saturation） in shaping the recovery trajectory？ Methods： Paracou is a large scale forest disturbance experiment set up in 1984 with nine 6.25 ha plots spanning on a large disturbance gradient where 15 to 60% of the initial forest ecosystem biomass were removed. More than 70,000 trees belonging to ca. 700 tree species have then been censused every 2 years up today. Using this unique dataset, we aim at deciphering the endogenous （forest structure and composition） and exogenous （local environment and climate stress） drivers of ecosystem recovery in time. To do so, we disentangle carbon recovery into demographic processes （recruitment, growth, mortality fluxes） and cohorts （recruited trees, survivors）. Results： Variations in the pre-disturbance forest structure or in local environment do not shape significantly the ecosystem recovery rates. Variations in the pre-disturbance forest composition and in the post-disturbance climate significantly change the forest recovery trajectory. Pioneer-rich forests have slower recovery rates than assemblages of late-successional species. Soil water saturation during the wet season strongly impedes ecosystem recovery but not seasonal drought. From a sensitivity analysis, we highlight the pre-disturbance forest composition and the post-disturbance climate conditions as the primary factors controlling the recovery trajectory. Conclusions＂ Highly-disturbed forests and secondary forests because they are composed of a lot of pioneer species will be less able to cope with new disturbance. In the context of increasing tree mortality due to both （i） severe droughts imputable to climate change and （ii） human-induced perturbations, tropical forest management should focus on reducing disturbances by developing Reduced Impact Logging techniques.展开更多
It is known that the Amazon region plays an important role in the global energy, hydrological cycle and carbon balance. This region has been suffering from the course of the past 40 years intense land use and land cov...It is known that the Amazon region plays an important role in the global energy, hydrological cycle and carbon balance. This region has been suffering from the course of the past 40 years intense land use and land cover changes. With this in mind, this study has examined possible associations between change in spatial and temporal rainfall variability and land cover change in the Amazon, using the PRECIS regional modelling system. It has been found that the impacts of land cover change by forest removal are more intense in the so-called “Arc of deforestation” over central and southern Amazonia. However, the relative impact of the simulated rainfall changes seems to be more important in the JJA dry season. In addition, the simulations under the deforestation scenarios also show the occurrence of extreme rainfall events as well as more frequent dry periods. Therefore, the results found show to be potentially important in the modulation of regional climate variations which have several environmental and socio-economic impacts.展开更多
The objective of this work was to evaluate the effect of different water deficiency and rehydration levels on the concentrations of osmoregulators in two plant species（Hymenaea courbaril and H. Stigonocarpa） in the ...The objective of this work was to evaluate the effect of different water deficiency and rehydration levels on the concentrations of osmoregulators in two plant species（Hymenaea courbaril and H. Stigonocarpa） in the Amazon. We adopted a 2×5×5 factorial system,referring to 2 species（H. courbaril and H. stigonocarpa）and 5 stages of hydration and rehydration. The five hydration and rehydration stages were established in:（1）Control treatment E0;（2） Plants with 13 days of stress after incubation—E13;（3） Plants with 26 days of stress E26;（4）The plants that were established after 26 days after incubation and rehydrated for two days（RD2）;（5） rehydrated for two days（RD4）. The plants that were established after 26 days after incubation and rehydrated for four days. The experiment totaled fifty young plants with five replicates.Biochemical measurements were performed at the beginning of the experiment（E0） at 13（E13） and 26（E26） days after the water stress, in which the plants were rehydrated,repeating the analyses after two（RD2） and four（RD4）days. Both species increased the sucrose concentration by18%, with a decrease of 52% in starch content. The RD4 time presented the highest mean starch concentration(0.19 mmol g-1 of the residue for H. courbaril and0.27 mmol g;of residue for H. stigonocarpa). Increased proline concentrations were recorded for controls until RD2 for both species. For glycine betaine, the highest increases in treatments E26 and RD2 were observed for the H. courbaril species. Our rehydration period was not sufficient for total recovery of pre-stress concentrations of all studied solutes.展开更多
Characterizing the diversity and structure of host–parasite communities is crucial to understandingtheir eco-evolutionary dynamics.Malaria and related haemosporidian parasites are responsible forfitness loss and mort...Characterizing the diversity and structure of host–parasite communities is crucial to understandingtheir eco-evolutionary dynamics.Malaria and related haemosporidian parasites are responsible forfitness loss and mortality in bird species worldwide.However,despite exhibiting the greatest ornithologicalbiodiversity,avian haemosporidians from Neotropical regions are quite unexplored.Here,we analyze the genetic diversity of bird haemosporidian parasites(Plasmodium andHaemoproteus)in 1,336 individuals belonging to 206 bird species to explore for differences in diversityof parasite lineages and bird species across 5 well-differentiated Peruvian ecoregions.Wedetected 70 different haemosporidian lineages infecting 74 bird species.We showed that 25 out ofthe 70 haplotypes had not been previously recorded.Moreover,we also identified 81 new host–parasite interactions representing new host records for these haemosporidian parasites.Our outcomesrevealed that the effective diversity(as well as the richness,abundance,and Shannon–Weaver index)for both birds and parasite lineages was higher in Amazon basin ecoregions.Furthermore,we also showed that ecoregions with greater diversity of bird species also had highparasite richness,hence suggesting that host community is crucial in explaining parasite richness.Generalist parasites were found in ecoregions with lower bird diversity,implying that the abundanceand richness of hosts may shape the exploitation strategy followed by haemosporidian parasites.These outcomes reveal that Neotropical region is a major reservoir of unidentified haemosporidianlineages.Further studies analyzing host distribution and specificity of these parasites inthe tropics will provide important knowledge about phylogenetic relationships,phylogeography,and patterns of evolution and distribution of haemosporidian parasites.展开更多
Understanding the ecological dynamics of weed populations in no-tillage systems is important to establish strategies for integrated weed control capable of increasing agroecosystem sustainability. This study sought to...Understanding the ecological dynamics of weed populations in no-tillage systems is important to establish strategies for integrated weed control capable of increasing agroecosystem sustainability. This study sought to evaluate the effect of succession systems on the seed bank in a no-tillage system. The effects of fifteen succession systems, composed of seven grasses, seven Leguminosae, and a fallow condition, were evaluated on the seed bank at two soil depths (0 to 10 and 10 to 20 cm). The species found in the seed bank were quantified and identified by species and family. The precision of sampling, density, dominance, the indices of diversity of Simpson and Shannon-Weiner;index of sustainability;analysis of groupings of dissimilarities;and the value of importance of each species were calculated. High weed diversity was observed;29 species were counted, including members of 12 different families. The highest expression of weeds was observed at soil depths of 0 to 10 cm. The Simpson and Shannon-Weiner coefficients indicated high diversity in both systems of succession. The index of sustainability did not indicate significant alterations in the different systems of succession. The coefficients of confenetic correlation were 0.74% and 0.82% for the 0 - 10 and the 10 - 20 cm soil depths respectively. It is concluded that there is a high diversity of weeds in the agroecosystems of Amazonia, and different cover crops promote modifications in the community and expression of the weeds’ seed bank.展开更多
Livestock is the most important economic activity in San Vicente del Caguán municipality, Caquetá department (located in Colombian Amazon region). Indeed, livestock activities have a big responsibility of Co...Livestock is the most important economic activity in San Vicente del Caguán municipality, Caquetá department (located in Colombian Amazon region). Indeed, livestock activities have a big responsibility of Colombian Amazon forest deforestation for extensive grazing lands formation, causing soil degradation processes. However, recently some cattle ranchers have changed their thoughts to a sustainable production, applying different ecological strategies. So, application of silvopastoral systems, which is a very important mode of agroforestry, consists that in the same area and time, it can interact in the ecosystem stratums different species among grasses, shrubs, and trees. On this way, the objective of this study is to determine descriptively the arboreal/arbustive component associated to livestock systems, represented according to its uses in San Vicente del Caguán, Colombia. It was made through a direct survey to 13 smallholders in this municipality. As a result, mainly, we found 58 plant species (49 arboreal and nine arbustive, corresponding to 84.48% and 15.52%, respectively). Of these, 20 species had more than one use at a time. In fact, the shade was the use most common with 29 species, corresponding to 34.94% of total species (25 arboreal and just four arbustive, corresponding to 30.12% and 4.82%, respectively). On this way, according to smallholders surveyed, we can conclude that shade provided by trees integration in silvopastoral systems is for diminishing heat stress on cattle caused by enduring climate change of tropical, thus contributing to good welfare for animals.展开更多
In this study, we used the Standard Precipitation Index (SPI) to identify and to characterize the dry extreme events in the Amazon region. The results showed that the drought of 1998 was the most intense (SPI average ...In this study, we used the Standard Precipitation Index (SPI) to identify and to characterize the dry extreme events in the Amazon region. The results showed that the drought of 1998 was the most intense (SPI average equal to -1.69) in the period from 1979 to 2014. However, some papers have characterized the years 2005 and 2010 as the two largest droughts of the century. Thus, it was also carried out a comparative study of these droughts. The results showed that the drought 1998 was more intensive and extreme than the droughts of 2005 and 2010, although droughts of 2005 and 2010 lasted longer than 1998 due to oceanic and atmospheric conditions with influencing to cause greater social and economic impacts. Furthermore, it is suggested that the impact of the 2005 and 2010 droughts is a response from the dry occurred in 1993-1994 and 1997-1998.展开更多
Scientists regularly lament that development and habitat destruction in once isolated and distant areas are promoting species extinction before species can even be known by science. In the Brazilian Amazon, the govern...Scientists regularly lament that development and habitat destruction in once isolated and distant areas are promoting species extinction before species can even be known by science. In the Brazilian Amazon, the government’s Plan for Growth Acceleration in part involves major improvements and expansion of highways. Such infrastructure has long been linked to the main causes of deforestation in this region. It is essential for scientists to assess where to target bio-diversity collections in relation to the location of road development and existing protected areas. The objective of this study was to amass all of the records of occurrence of orchid bees in digital form, in order to obtain a spatial picture of our knowledge thus far and to make recommendations about priority areas for future collections and the role of protected areas in species conservation. The collection data used for this study come from various collection efforts, and were also gathered from the literature. The collection data were then imported into a Geographic Information System, making it possible to integrate other spatial data layers such as highways, conservation units, indigenous lands and forest cover. Results show a major need for collections along the BR 163 and BR 230 highways, heavily deforested areas with few conservation units. We suggest the creation of conservation units and recommend that abandoned areas be allowed to remain fallow as a way to help save additional biodiversity in the area of influence of these two main highways.展开更多
The family farmer’s knowledge about floodplains agroecosystems dynamics is part of agrobiodiversity conservation cognitive strategies. This is because the conservation in floodplains is conditioned by the ecophysiolo...The family farmer’s knowledge about floodplains agroecosystems dynamics is part of agrobiodiversity conservation cognitive strategies. This is because the conservation in floodplains is conditioned by the ecophysiological adaptation to the period and flood gradient of the agricultural lands and by the transformations promoted in the environment by the waters pulse. The aim of this study was to understand the cognitive strategies expressed in the organized meaning of agroecosystems by local knowledge, related to the geomorphological dynamics of the Aramaçá Island, Amazonas, Brazil. In this research, the Case Study and Ethnoecology were adopted as approach, taking the systemic complexity paradigm as a theoretical framework. To do so, it was necessary to establish a dialogue with the local knowledge through multitemporal analyses of satellite images, historical series of hydrological data, as well as cartographic documents of the locality. The floodplains amphibian mark, as a living organism in permanent autopoietic process, seems to be imprinted in the family farmer’s knowledge. In order to live in the floodplains and of floodplains, it is necessary, above all, to develop a cognitive ability capable of understanding not only the rivers action on the lands, but also that of the lands on the rivers as well. Therefore, the geomorphological dynamics in the spaces managed by the family farmers impose on them, risks and uncertainties, demanding from them strategies that allow knowing and dealing with this complexity.展开更多
The ants are one of the mega diverse insets found in all terrestrial environments, and occur in great diversity, richness and abundance, acting at all trophic levels. The present study was conducted to verify the know...The ants are one of the mega diverse insets found in all terrestrial environments, and occur in great diversity, richness and abundance, acting at all trophic levels. The present study was conducted to verify the knowledge of ant fauna at Caxiuanã National forest. All available ant literature and some collection in Caxiuanã were compiled and analyzed in EXCEL program. Caxiuanã is one Brazilian Amazonia forest that has good biological conservation. A total of 197 species belonging to 52 genera of the nine subfamilies are present in Caxiuanã. Many studies need to be done in this place to understand the ant community pattern to give base for other studies and proposal for use, management and conservation of this interesting Amazonia place.展开更多
The ants are one of the mega diverse insets found in all terrestrial environments, and occur in great diversity, richness and abundance, acting at all trophic levels. The present study was conducted to verify the know...The ants are one of the mega diverse insets found in all terrestrial environments, and occur in great diversity, richness and abundance, acting at all trophic levels. The present study was conducted to verify the knowledge of ant fauna at Caxiuanã National forest. All available ant literature and some collection in Caxiuanã were compiled and analyzed in EXCEL program. Caxiuanã is one Brazilian Amazonia forest that has good biological conservation. A total of 197 species belonging to 52 genera of the nine subfamilies are present in Caxiuanã. Many studies need to be done in this place to understand the ant community pattern to give base for other studies and proposal for use, management and conservation of this interesting Amazonia place.展开更多
Remote sensing and climate digital products have become increasingly available in recent years.Access to these products has favored a variety of Digital Earth studies,such as the analysis of the impact of global warmi...Remote sensing and climate digital products have become increasingly available in recent years.Access to these products has favored a variety of Digital Earth studies,such as the analysis of the impact of global warming over different biomes.The study of the Amazon forest response to drought has recently received particular attention from the scientific community due to the occurrence of extreme droughts and anomalous warming over the last decade.This paper focuses on the differences observed between surface thermal anomalies obtained from remote sensing moderate resolution imaging spectroradiometer(MODIS)and climatic(ERA-Interim)monthly products over the Amazon forest.With a few exceptions,results show that the spatial pattern of standardized anomalies is similar for both products.In terms of absolute anomalies,the differences between the two products show a bias near to zero with a standard deviation of around 0.2 K,although the differences can be up to 1 K over particular regions and months.Despite this general agreement,the proper filtering of MODIS daily values in order to construct a new monthly product showed a dramatic reduction in the number of reliable pixels during the rainy season,while for the dry season this reduction is only seen in Northern Amazonia.展开更多
We report for the first time the presence of self-sustaining populations of Macrobrachium rosenbergii in French Guiana.Genetic analyses of the cytochrome c oxidase subunit I marker(COI)confirmed the identity of the sp...We report for the first time the presence of self-sustaining populations of Macrobrachium rosenbergii in French Guiana.Genetic analyses of the cytochrome c oxidase subunit I marker(COI)confirmed the identity of the species as well as historical records about the introduction of the species from commercial stocks.Despite the limited presence of Macrobrachium rosenbergii in French Guiana,the species is recorded in several river basins,including two where the species has never been farmed.This suggests that the species is able to disperse locally and highlights its potential invasive nature in the territory.展开更多
文摘The present study focuses on the impacts of extreme drought and flooding situations in Amazonia, using level/discharge data from some rivers in the Amazon region as indicators of impacts. The last 10 years have featured various “once in a century” droughts and floods in the Amazon basin, which have affected human and natural systems in the region. We assess a history of such hazards based on river data, and discuss some of the observed impacts in terms of vulnerability of human and natural systems, as well as some of adaptation strategies implemented by regional and local governments to cope with them. A critical perspective of mitigation of drought and flood policies in Amazonia suggests that they have been mostly ineffective in reducing vulnerability for the majority of the population, constituting, perhaps, examples of maladaptation via the undermining of resilience.
基金This study was funded in part by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Brazil(CAPES)Finance Code 001.A master’s scholarship was granted by CAPES to JIMR(Process 88887.716287/2022-00)a doctoral scholarship to VPO(Process 88887.644953/2021-00).
文摘Among the impacts of climate change,there is the intensification of phenomena such as the El Niño South-ern Oscillation(ENSO)responsible for El Niño and La Niña.However,understanding their effects on the functional pro-cesses of forests is limited.Therefore,this study evaluated the effects of ENSO on litter stock and water holding capac-ity(WHC)in a successional forest in eastern Amazonia.Evaluations occurred in periods with the most rainfall in El Niño(2019)and least in La Niña(2021)years.Twelve permanent plots were used to sample litter.ENSO effects were evident for WHC,higher during El Niño.However,this influence was not clear for litter,as only in the rainy season effects were found.There was a positive correlation of WHC with precipitation and humidity,while litter stocks were negatively correlated with temperature and wind speed.Although the subject of this study requires long-term assessments,preliminary results suggests that,depending on the intensity of ENSO,forest functional processes can be strongly impacted and altered.The conclusion reinforces warnings by the scientific community about the impacts of climate change on the maintenance of litter stocks,decomposition and,consequently,the biogeochemical cycle and essential ecosystem services for the maintenance of Amazonia biodiversity.The need to develop long-term research to understand the effects of climatic change on litter stocks and water holding capacity is highlighted,especially in Amazonia.
文摘High-resolution U–Pb(ID-TIMS,baddeleyite)ages are presented for mafic dykes from selected swarms in two important Amazonian regions:the Carajás Province in the east,and the Rio Apa block in the southwest–areas
文摘The present study evaluates the performance of three numerical weather forecasting models: Global Forecast System (GFS), Brazilian Regional Atmospheric Modelling System (BRAMS) and ETA Regional Model (ETA), by means of the Mean Error (ME) and the Root Mean Square Error (RMSE), during the most rainy four months period (January to April 2012) on Eastern Amazonia. The models displayed errors of superestimation and underestimation with respect to the observed precipitation, mainly over center-north of Pará and all of Amapá, where the precipitation is higher. Among the analyzed models, GFS shows the best performance, except during January and March, when the model to underestimated precipitation, possibly due to the anomalously high values recorded.
基金funded by the GFclim project(FEDER 2014–2020,Project GY0006894)an Investissement d’avenir grant of the ANR(CEBA:ANR-10-LABEX-0025)
文摘Background： Natural disturbance is a fundamental component of the functioning of tropical rainforests let to natural dynamics, with tree mortality the driving force of forest renewal. With ongoing global （i.e. land-use and climate） changes, tropical forests are currently facing deep and rapid modifications in disturbance regimes that may hamper their recovering capacity so that developing robust predictive model able to predict ecosystem resilience and recovery becomes of primary importance for decision-making： （i） Do regenerating forests recover faster than mature forests given the same level of disturbance？ （ii） is the local topography an important predictor of the post-disturbance forest trajectories？ （iii） Is the community functional composition, assessed with community weighted-mean functional traits, a good predictor of carbon stock recovery？ （iv） How important is the climate stress （seasonal drought and/or soil water saturation） in shaping the recovery trajectory？ Methods： Paracou is a large scale forest disturbance experiment set up in 1984 with nine 6.25 ha plots spanning on a large disturbance gradient where 15 to 60% of the initial forest ecosystem biomass were removed. More than 70,000 trees belonging to ca. 700 tree species have then been censused every 2 years up today. Using this unique dataset, we aim at deciphering the endogenous （forest structure and composition） and exogenous （local environment and climate stress） drivers of ecosystem recovery in time. To do so, we disentangle carbon recovery into demographic processes （recruitment, growth, mortality fluxes） and cohorts （recruited trees, survivors）. Results： Variations in the pre-disturbance forest structure or in local environment do not shape significantly the ecosystem recovery rates. Variations in the pre-disturbance forest composition and in the post-disturbance climate significantly change the forest recovery trajectory. Pioneer-rich forests have slower recovery rates than assemblages of late-successional species. Soil water saturation during the wet season strongly impedes ecosystem recovery but not seasonal drought. From a sensitivity analysis, we highlight the pre-disturbance forest composition and the post-disturbance climate conditions as the primary factors controlling the recovery trajectory. Conclusions＂ Highly-disturbed forests and secondary forests because they are composed of a lot of pioneer species will be less able to cope with new disturbance. In the context of increasing tree mortality due to both （i） severe droughts imputable to climate change and （ii） human-induced perturbations, tropical forest management should focus on reducing disturbances by developing Reduced Impact Logging techniques.
文摘It is known that the Amazon region plays an important role in the global energy, hydrological cycle and carbon balance. This region has been suffering from the course of the past 40 years intense land use and land cover changes. With this in mind, this study has examined possible associations between change in spatial and temporal rainfall variability and land cover change in the Amazon, using the PRECIS regional modelling system. It has been found that the impacts of land cover change by forest removal are more intense in the so-called “Arc of deforestation” over central and southern Amazonia. However, the relative impact of the simulated rainfall changes seems to be more important in the JJA dry season. In addition, the simulations under the deforestation scenarios also show the occurrence of extreme rainfall events as well as more frequent dry periods. Therefore, the results found show to be potentially important in the modulation of regional climate variations which have several environmental and socio-economic impacts.
基金supported by the Universidade Federal Rural da Amazonia
文摘The objective of this work was to evaluate the effect of different water deficiency and rehydration levels on the concentrations of osmoregulators in two plant species（Hymenaea courbaril and H. Stigonocarpa） in the Amazon. We adopted a 2×5×5 factorial system,referring to 2 species（H. courbaril and H. stigonocarpa）and 5 stages of hydration and rehydration. The five hydration and rehydration stages were established in:（1）Control treatment E0;（2） Plants with 13 days of stress after incubation—E13;（3） Plants with 26 days of stress E26;（4）The plants that were established after 26 days after incubation and rehydrated for two days（RD2）;（5） rehydrated for two days（RD4）. The plants that were established after 26 days after incubation and rehydrated for four days. The experiment totaled fifty young plants with five replicates.Biochemical measurements were performed at the beginning of the experiment（E0） at 13（E13） and 26（E26） days after the water stress, in which the plants were rehydrated,repeating the analyses after two（RD2） and four（RD4）days. Both species increased the sucrose concentration by18%, with a decrease of 52% in starch content. The RD4 time presented the highest mean starch concentration(0.19 mmol g-1 of the residue for H. courbaril and0.27 mmol g;of residue for H. stigonocarpa). Increased proline concentrations were recorded for controls until RD2 for both species. For glycine betaine, the highest increases in treatments E26 and RD2 were observed for the H. courbaril species. Our rehydration period was not sufficient for total recovery of pre-stress concentrations of all studied solutes.
基金This study was funded in part by the US National Science Foundation sponsored Research Coordination Network for Haemosporida of Terrestrial Vertebrates(malariarch.org,NSF 0954891)the Spanish Ministry of Economy and Competitiveness(CGL2015-64650P)+3 种基金Junta de Extremadura(Consejerıa de Economıa e Infraestructuras),FEDER(IB16121).S.M.and A.M.R were supported by a PhD grant from the Ministry of Economy and Competition of Spain and a mobility grant of Junta de Extremadura(129/2015)respectively.L.G.-L.was supported by the Junta de Extremadura(PO17024,Post-Doc grant)J.M.was supported by a postdoctoral contract from the University of Extremadura(Junta de Extremadura—IB16121)a postdoctoral grant from the Juan de la Cierva Subprogram(FJCI-2017-34109),with the financial sponsorship of the MICINN.
文摘Characterizing the diversity and structure of host–parasite communities is crucial to understandingtheir eco-evolutionary dynamics.Malaria and related haemosporidian parasites are responsible forfitness loss and mortality in bird species worldwide.However,despite exhibiting the greatest ornithologicalbiodiversity,avian haemosporidians from Neotropical regions are quite unexplored.Here,we analyze the genetic diversity of bird haemosporidian parasites(Plasmodium andHaemoproteus)in 1,336 individuals belonging to 206 bird species to explore for differences in diversityof parasite lineages and bird species across 5 well-differentiated Peruvian ecoregions.Wedetected 70 different haemosporidian lineages infecting 74 bird species.We showed that 25 out ofthe 70 haplotypes had not been previously recorded.Moreover,we also identified 81 new host–parasite interactions representing new host records for these haemosporidian parasites.Our outcomesrevealed that the effective diversity(as well as the richness,abundance,and Shannon–Weaver index)for both birds and parasite lineages was higher in Amazon basin ecoregions.Furthermore,we also showed that ecoregions with greater diversity of bird species also had highparasite richness,hence suggesting that host community is crucial in explaining parasite richness.Generalist parasites were found in ecoregions with lower bird diversity,implying that the abundanceand richness of hosts may shape the exploitation strategy followed by haemosporidian parasites.These outcomes reveal that Neotropical region is a major reservoir of unidentified haemosporidianlineages.Further studies analyzing host distribution and specificity of these parasites inthe tropics will provide important knowledge about phylogenetic relationships,phylogeography,and patterns of evolution and distribution of haemosporidian parasites.
文摘Understanding the ecological dynamics of weed populations in no-tillage systems is important to establish strategies for integrated weed control capable of increasing agroecosystem sustainability. This study sought to evaluate the effect of succession systems on the seed bank in a no-tillage system. The effects of fifteen succession systems, composed of seven grasses, seven Leguminosae, and a fallow condition, were evaluated on the seed bank at two soil depths (0 to 10 and 10 to 20 cm). The species found in the seed bank were quantified and identified by species and family. The precision of sampling, density, dominance, the indices of diversity of Simpson and Shannon-Weiner;index of sustainability;analysis of groupings of dissimilarities;and the value of importance of each species were calculated. High weed diversity was observed;29 species were counted, including members of 12 different families. The highest expression of weeds was observed at soil depths of 0 to 10 cm. The Simpson and Shannon-Weiner coefficients indicated high diversity in both systems of succession. The index of sustainability did not indicate significant alterations in the different systems of succession. The coefficients of confenetic correlation were 0.74% and 0.82% for the 0 - 10 and the 10 - 20 cm soil depths respectively. It is concluded that there is a high diversity of weeds in the agroecosystems of Amazonia, and different cover crops promote modifications in the community and expression of the weeds’ seed bank.
文摘Livestock is the most important economic activity in San Vicente del Caguán municipality, Caquetá department (located in Colombian Amazon region). Indeed, livestock activities have a big responsibility of Colombian Amazon forest deforestation for extensive grazing lands formation, causing soil degradation processes. However, recently some cattle ranchers have changed their thoughts to a sustainable production, applying different ecological strategies. So, application of silvopastoral systems, which is a very important mode of agroforestry, consists that in the same area and time, it can interact in the ecosystem stratums different species among grasses, shrubs, and trees. On this way, the objective of this study is to determine descriptively the arboreal/arbustive component associated to livestock systems, represented according to its uses in San Vicente del Caguán, Colombia. It was made through a direct survey to 13 smallholders in this municipality. As a result, mainly, we found 58 plant species (49 arboreal and nine arbustive, corresponding to 84.48% and 15.52%, respectively). Of these, 20 species had more than one use at a time. In fact, the shade was the use most common with 29 species, corresponding to 34.94% of total species (25 arboreal and just four arbustive, corresponding to 30.12% and 4.82%, respectively). On this way, according to smallholders surveyed, we can conclude that shade provided by trees integration in silvopastoral systems is for diminishing heat stress on cattle caused by enduring climate change of tropical, thus contributing to good welfare for animals.
文摘In this study, we used the Standard Precipitation Index (SPI) to identify and to characterize the dry extreme events in the Amazon region. The results showed that the drought of 1998 was the most intense (SPI average equal to -1.69) in the period from 1979 to 2014. However, some papers have characterized the years 2005 and 2010 as the two largest droughts of the century. Thus, it was also carried out a comparative study of these droughts. The results showed that the drought 1998 was more intensive and extreme than the droughts of 2005 and 2010, although droughts of 2005 and 2010 lasted longer than 1998 due to oceanic and atmospheric conditions with influencing to cause greater social and economic impacts. Furthermore, it is suggested that the impact of the 2005 and 2010 droughts is a response from the dry occurred in 1993-1994 and 1997-1998.
文摘Scientists regularly lament that development and habitat destruction in once isolated and distant areas are promoting species extinction before species can even be known by science. In the Brazilian Amazon, the government’s Plan for Growth Acceleration in part involves major improvements and expansion of highways. Such infrastructure has long been linked to the main causes of deforestation in this region. It is essential for scientists to assess where to target bio-diversity collections in relation to the location of road development and existing protected areas. The objective of this study was to amass all of the records of occurrence of orchid bees in digital form, in order to obtain a spatial picture of our knowledge thus far and to make recommendations about priority areas for future collections and the role of protected areas in species conservation. The collection data used for this study come from various collection efforts, and were also gathered from the literature. The collection data were then imported into a Geographic Information System, making it possible to integrate other spatial data layers such as highways, conservation units, indigenous lands and forest cover. Results show a major need for collections along the BR 163 and BR 230 highways, heavily deforested areas with few conservation units. We suggest the creation of conservation units and recommend that abandoned areas be allowed to remain fallow as a way to help save additional biodiversity in the area of influence of these two main highways.
文摘The family farmer’s knowledge about floodplains agroecosystems dynamics is part of agrobiodiversity conservation cognitive strategies. This is because the conservation in floodplains is conditioned by the ecophysiological adaptation to the period and flood gradient of the agricultural lands and by the transformations promoted in the environment by the waters pulse. The aim of this study was to understand the cognitive strategies expressed in the organized meaning of agroecosystems by local knowledge, related to the geomorphological dynamics of the Aramaçá Island, Amazonas, Brazil. In this research, the Case Study and Ethnoecology were adopted as approach, taking the systemic complexity paradigm as a theoretical framework. To do so, it was necessary to establish a dialogue with the local knowledge through multitemporal analyses of satellite images, historical series of hydrological data, as well as cartographic documents of the locality. The floodplains amphibian mark, as a living organism in permanent autopoietic process, seems to be imprinted in the family farmer’s knowledge. In order to live in the floodplains and of floodplains, it is necessary, above all, to develop a cognitive ability capable of understanding not only the rivers action on the lands, but also that of the lands on the rivers as well. Therefore, the geomorphological dynamics in the spaces managed by the family farmers impose on them, risks and uncertainties, demanding from them strategies that allow knowing and dealing with this complexity.
文摘The ants are one of the mega diverse insets found in all terrestrial environments, and occur in great diversity, richness and abundance, acting at all trophic levels. The present study was conducted to verify the knowledge of ant fauna at Caxiuanã National forest. All available ant literature and some collection in Caxiuanã were compiled and analyzed in EXCEL program. Caxiuanã is one Brazilian Amazonia forest that has good biological conservation. A total of 197 species belonging to 52 genera of the nine subfamilies are present in Caxiuanã. Many studies need to be done in this place to understand the ant community pattern to give base for other studies and proposal for use, management and conservation of this interesting Amazonia place.
文摘The ants are one of the mega diverse insets found in all terrestrial environments, and occur in great diversity, richness and abundance, acting at all trophic levels. The present study was conducted to verify the knowledge of ant fauna at Caxiuanã National forest. All available ant literature and some collection in Caxiuanã were compiled and analyzed in EXCEL program. Caxiuanã is one Brazilian Amazonia forest that has good biological conservation. A total of 197 species belonging to 52 genera of the nine subfamilies are present in Caxiuanã. Many studies need to be done in this place to understand the ant community pattern to give base for other studies and proposal for use, management and conservation of this interesting Amazonia place.
基金funded by the University of Valencia[UV-INV-PRECOMP13-115366]Ministerio de Ciencia e Innovación[CEOS-Spain,AYA2011-29334-C02-01],CONICYT[Fondecyt Iniciacion–1130359]the University of Chile[Ayuda U Viajes,VID-Uchile 2014–2015].
文摘Remote sensing and climate digital products have become increasingly available in recent years.Access to these products has favored a variety of Digital Earth studies,such as the analysis of the impact of global warming over different biomes.The study of the Amazon forest response to drought has recently received particular attention from the scientific community due to the occurrence of extreme droughts and anomalous warming over the last decade.This paper focuses on the differences observed between surface thermal anomalies obtained from remote sensing moderate resolution imaging spectroradiometer(MODIS)and climatic(ERA-Interim)monthly products over the Amazon forest.With a few exceptions,results show that the spatial pattern of standardized anomalies is similar for both products.In terms of absolute anomalies,the differences between the two products show a bias near to zero with a standard deviation of around 0.2 K,although the differences can be up to 1 K over particular regions and months.Despite this general agreement,the proper filtering of MODIS daily values in order to construct a new monthly product showed a dramatic reduction in the number of reliable pixels during the rainy season,while for the dry season this reduction is only seen in Northern Amazonia.
基金a grant“Initiatives pour la reconqu^ete de la biodiversite dans les outre-mer”from the Office Français de Biodiversite(OFB)and by the DGTM Guyane and from the Office de l’Eau Guyane under the project CRIQUESthe Agence Nationale de la Recherche(CEBA:ANR-10-LABX-25-01TULIP:ANR-10-LABX-0041)and ANR grant(DEBIT:ANR-17-CE02-0007-01).
文摘We report for the first time the presence of self-sustaining populations of Macrobrachium rosenbergii in French Guiana.Genetic analyses of the cytochrome c oxidase subunit I marker(COI)confirmed the identity of the species as well as historical records about the introduction of the species from commercial stocks.Despite the limited presence of Macrobrachium rosenbergii in French Guiana,the species is recorded in several river basins,including two where the species has never been farmed.This suggests that the species is able to disperse locally and highlights its potential invasive nature in the territory.
