Potential global distribution of the guava root-knot nematode Meloidogyne enterolobii under different climate change scenarios using MaxEnt ecological niche modeling

In recent years,Meloidogyne enterolobii has emerged as a major parasitic nematode infesting many plants in tropical or subtropical areas.However,the regions of potential distribution and the main contributing environmental variables for this nematode are unclear.Under the current climate scenario,we predicted the potential geographic distributions of M.enterolobii worldwide and in China using a Maximum Entropy(MaxEnt)model with the occurrence data of this species.Furthermore,the potential distributions of M.enterolobii were projected under three future climate scenarios(BCC-CSM2-MR,CanESM5 and CNRM-CM6-1)for the periods 2050s and 2090s.Changes in the potential distribution were also predicted under different climate conditions.The results showed that highly suitable regions for M.enterolobii were concentrated in Africa,South America,Asia,and North America between latitudes 30°S to 30°N.Bio16(precipitation of the wettest quarter),bio10(mean temperature of the warmest quarter),and bio11(mean temperature of the coldest quarter)were the variables contributing most in predicting potential distributions of M.enterolobii.In addition,the potential suitable areas for M.enterolobii will shift toward higher latitudes under future climate scenarios.This study provides a theoretical basis for controlling and managing this nematode.

conomic losses from reduced freshwater under future climate scenarios: An example from the Urumqi River,Tianshan Mountains

As important freshwater resources in alpine basins,glaciers and snow cover tend to decline due to climate warming,thus affecting the amount of water available downstream and even regional economic development.However,impact assessments of the economic losses caused by reductions in freshwater supply are quite limited.This study aims to project changes in glacier meltwater and snowmelt of the Urumqi River in the Tianshan Mountains under future climate change scenarios(RCP2.6(RCP,Representative Concentration Pathway),RCP4.5,and RCP8.5)by applying a hydrological model and estimate the economic losses from future meltwater reduction for industrial,agricultural,service,and domestic water uses combined with the present value method for the 2030 s,2050 s,2070 s,and 2090 s.The results indicate that total annual glacier meltwater and snowmelt will decrease by 65.6%and 74.5%under the RCP4.5 and RCP8.5 scenarios by the 2090 s relative to the baseline period(1980-2010),respectively.Compared to the RCP2.6 scenario,the projected economic loss values of total water use from reduced glacier meltwater and snowmelt under the RCP8.5 scenario will increase by 435.10×10^(6) and 537.20×10^(6) CNY in the 2050 s and 2090 s,respectively,and the cumulative economic loss value for 2099 is approximately 2124.00×10^(6) CNY.We also find that the industrial and agricultural sectors would likely face the largest and smallest economic losses,respectively.The economic loss value of snowmelt in different sectorial sectors is greater than that of glacier meltwater.These findings highlight the need for climate mitigation actions,industrial transformation,and rational water allocation to be considered in decision-making in the Tianshan Mountains in the future.

Climate Suitability of Schima superba in Subtropical Zone of China under Future Climate Scenario

[ Objective] The research aimed to study climate suitability of S. superba in subtropical zone of China under future climate scenario and response of its regional distribution on climate change. [ Metbed] Based on climate- vegetation related Kira model, Holdridge model and ecological suitability theory, climate suitability model of S. superba was established by using fuzzy mathematics. Based on the daily meteorological data at 246 stations of the subtropical zone from 1960 to 2005, by using spatial interpolation method, suitability of S. superba on temperature, precipitation, po- tential evapotranspiration rate was analyzed. According to Intergovernmental Panel on Climate Change （IPCC） Special Report on Emissions Sce- nario （SRES）, future scenario simulation result was used. Under IPCC A2 scenario, climate suitability of S. superba and its change were studied in subtropical zone of China under future climate scenario. Climate suitability of S. superba in future was classified. [ Result] Under future climate scenario, climate suitability of S. superba was stronger in most of areas in Hunan, north Guangdong, northeast Guangxi and east coast of Zhe- jiang. It was suitable for growth of S. superba in central Guangxi, east Guizhou, central Jiangxi and Fuzhou. Growth suitability of S. superba was still lower in the north of Gongshan - Weixi - Lijiang - Yuanjiang - Huize - Leibo - Emei - Neijiang - Nanchong - Bazhong - Zhongxiang - zaoyang - Xinyang -Lu＇an -Chuzhou -Gaoyou -Taitong. Climate suitability in west Yunnan and Sichuan had big change. Future climate suitability change of S. superba was greatly affected by temperature and potential evapotranspiration rate. [ Conclusion] Future climate suitability decreased toward west and north from Hunan. The climate suitability had a decline trend as time went by under future climate scenario. The research provided theoretical basis for studying geographic distribution of the vegetation population.

Extreme Rainfall Indices in the Hydrographic Basins of Brazil

The authors analyze climate extremes indices (CEI) of rainfall over the largest basins of the Brazilian territory: Amazon (AMA), S?o Francisco (SF), Tocantins (TO) and Paraná (PAR) rivers. The CEI represent the frequency of heavy precipitation events (R30mm and R95p) and short duration extreme rainfall (RX5day and RX1day). Droughts (CDDd) are identified based on two indicators: The longest dry period (CDD) and the annual cycle. The results demonstrate that CDDd, RX1day and RX5day occurred with more frequency and intensity in SF basin during El Ni?o events. CDDd was of greater magnitude in the TO basin during La Ni?a events, while an increase of RX1day occurred in El Ni?o. The strong El Ni?o events (1983 and 1997) caused more intense and frequent RX1day and R30mm over the PAR basin. Amazon droughts occurred in two out of the six El Ni?o events. Moreover, the relationship between the positive (negative) sea superficial temperatures anomalies in North (South) Tropical Atlantic and drought in AMA basin was corroborated. A gradual warming of SST was observed at the start of 2003 until it achieved a maximum in 2005 associated with the southwestern Amazon drought. The second highest anomaly of SST was in 2010 linked with drought that was more spatially extensive than the 2005 drought. The spatial distribution of annual trends showed a significant increase of CDD in south-eastern AMA, Upper SF, northern PAR and throughout the TO basins. R20mm, RX1day and RX5day tend to increase significantly in southwestern (northeast) PAR (AMA) and northwestern TO basins. Comparisons between CEI derived from daily precipitation data from Climate Prediction Center (CPCp) and of the ETA_HadCM3 model showed that the model overestimated RX1day, RX5day and CDD, in the four basins. Future scenarios show that dry periods will occur with greatest magnitude in all the basins until 2071-2099 time slice, while RX1day will be more intense in the TO and SF basins.

Potential geographical distribution of Anopheles gambiae worldwide under climate change

Background:Anopheles gambiae(An.gambiae)is considered the most effective malaria vector worldwide and is widely distributed in Africa.The purpose of this study is to determine the potential impact of climate change on An.gambiae and predict the present and future potential suitable habitat globally.Methods:In this study,environmental variables,global occurrence data of An.gambiae,and the maximum entropy model(MaxEnt)were used to evaluate the contribution of environmental factors and predict the habitat suitability of An.gambiae under the current and future scenarios.Results:Among all environmental variables,isothermality(Bio3,34.5%)contributed the most to An.gambiae distribution.Under current climate conditions,the potential suitable areas for An.gambiae are mainly located near the equator(approximately 30°N-30°S),with a total area of 16.58 million km2,including central and northern South America,a fraction of areas near the equator of North America,central and southern Africa,some tropical regions of southern Asia,and small areas of Oceania.The areas of potential suitable habitats would be reduced to varying degrees in future climate scenarios.Conclusions:Potential suitable habitats for An.gambiae may not be limited to Africa.Necessary surveillance and preventive measures should be undertaken in high-risk regions,including those outside Africa,to monitor and control the spread of An.gambiae.