Aims Trait-based approaches are increasingly being used in ecology due to their potential to explain and predict community structure and dynamic regardless of species identities.Here,we asked whether coastal heath veg...Aims Trait-based approaches are increasingly being used in ecology due to their potential to explain and predict community structure and dynamic regardless of species identities.Here,we asked whether coastal heath vegetation established in stressful habitats could be assembled by quasi-neutral mechanisms based on functional trait distribution.Communities are organized through quasi-neutral dynamics if abiotic gradients and/or species interactions impose sorting on functional traits and species performances,but not on species phylogenetic relatedness and occurrence.Methods The study was conducted in a coastal area containing tall dunes near the sea,and relatively flat areas punctuated by short palaeodunes further inland,Northeastern South America.We evaluated 10 traits of the 21 most abundant species,as well as eight abiotic variables in 70 plots(25 m^(2))established in dune tops,valleys,flat and steep microenvironments.The effect of environmental filter was tested by linear mixed models(LMM)between each community-weighted mean(CWM)trait and the abiotic variables,and by two indices of environmental filtering based on intra-and interspecific-trait vari-ability relative to null models.To evaluate the effect of species inter-actions,we used an index of niche overlap relative to null models,and LMMs between this index and the species richness of plots.Important Findings The environmental filtering index did not deviate from null expect-ations for any trait.Models that included individual variability per-formed similarly to models that used species mean traits.However,the explicit consideration of environmental gradients by CWM ana-lyses revealed functional patterns that would remain undetected if trait distribution was analyzed only.In addition,intraspecific vari-ation in the stem length was an important driver of species diversity as suggested by the relationship between species richness and the niche overlap index.Based on the occurrence and phylogenetic re-latedness of species,previous work in the same system found展开更多
Binadhan-10 & Binadhan-11 are climate smart stress tolerant high yielding rice varieties (yield > 4 t⋅ha−1) have saline tolerant EC up to 12 ds/m and submergence tolerant up to 20 - 25 days ...Binadhan-10 & Binadhan-11 are climate smart stress tolerant high yielding rice varieties (yield > 4 t⋅ha−1) have saline tolerant EC up to 12 ds/m and submergence tolerant up to 20 - 25 days capacity. The present study was an attempt to analyze the yield gap of stress tolerant varieties Binadhan-10 & Binadhan-11 in some selected areas of Bangladesh. The objectives of the study were: 1) to estimate the yield gap of Binadhan-10 &-11 growers among the study areas;2) to identify the factors affecting the yield of these variety;and 3) to suggest some policy guidelines to minimize the yield gap. The study was conducted in eight Binadhan-10 & Binadhan-11 growing areas in Bangladesh. In this study, four districts namely Satkhira, Khulna, Barishal, and Cox’s Bazar were used for Binadhan-10 and Mymensingh, Jamalpur, Sherpur and Sunamgonj were taken for Binadhan-11. It is based on primary level data from eight sub-districts among the study areas. A total of 240 farmers were randomly selected (30 from each location) to collect the data with a pre-designed questionnaire. Farmer were grouped according to saline affected and not-affected for saline tolerant variety Binadhan-10 and not affected, affected (1 - 10 days) and highly affected (10 - 20 days) for submergence tolerant rice variety Binadhan-11 to identify existing yield gap. Tabular as well as Zandstra method were applied for analysis the data. The study also found factors affecting the gap and some policy guidelines to minimize the gap.展开更多
Climate extremes, characterized by droughts and floods, have become one of the major constraints to sustainable improvement of rice productivity. Variety choice, considered as one of the main adaptation measures, coul...Climate extremes, characterized by droughts and floods, have become one of the major constraints to sustainable improvement of rice productivity. Variety choice, considered as one of the main adaptation measures, could help farmers reduce yield loss resulting from these extremes. Based on a three-year panel survey of 1 080 Chinese rice farms in major rice producing provinces, we assume Hicksian neutral technology and employ an IV regression to estimate the average treatment effect(ATE) on rice yield for adopting stress tolerant variety, and find that farmers who adopted the stress tolerant variety on average increased rice yield by 15.5% in comparison to the non-adopters.展开更多
文摘Aims Trait-based approaches are increasingly being used in ecology due to their potential to explain and predict community structure and dynamic regardless of species identities.Here,we asked whether coastal heath vegetation established in stressful habitats could be assembled by quasi-neutral mechanisms based on functional trait distribution.Communities are organized through quasi-neutral dynamics if abiotic gradients and/or species interactions impose sorting on functional traits and species performances,but not on species phylogenetic relatedness and occurrence.Methods The study was conducted in a coastal area containing tall dunes near the sea,and relatively flat areas punctuated by short palaeodunes further inland,Northeastern South America.We evaluated 10 traits of the 21 most abundant species,as well as eight abiotic variables in 70 plots(25 m^(2))established in dune tops,valleys,flat and steep microenvironments.The effect of environmental filter was tested by linear mixed models(LMM)between each community-weighted mean(CWM)trait and the abiotic variables,and by two indices of environmental filtering based on intra-and interspecific-trait vari-ability relative to null models.To evaluate the effect of species inter-actions,we used an index of niche overlap relative to null models,and LMMs between this index and the species richness of plots.Important Findings The environmental filtering index did not deviate from null expect-ations for any trait.Models that included individual variability per-formed similarly to models that used species mean traits.However,the explicit consideration of environmental gradients by CWM ana-lyses revealed functional patterns that would remain undetected if trait distribution was analyzed only.In addition,intraspecific vari-ation in the stem length was an important driver of species diversity as suggested by the relationship between species richness and the niche overlap index.Based on the occurrence and phylogenetic re-latedness of species,previous work in the same system found
文摘Binadhan-10 & Binadhan-11 are climate smart stress tolerant high yielding rice varieties (yield > 4 t⋅ha−1) have saline tolerant EC up to 12 ds/m and submergence tolerant up to 20 - 25 days capacity. The present study was an attempt to analyze the yield gap of stress tolerant varieties Binadhan-10 & Binadhan-11 in some selected areas of Bangladesh. The objectives of the study were: 1) to estimate the yield gap of Binadhan-10 &-11 growers among the study areas;2) to identify the factors affecting the yield of these variety;and 3) to suggest some policy guidelines to minimize the yield gap. The study was conducted in eight Binadhan-10 & Binadhan-11 growing areas in Bangladesh. In this study, four districts namely Satkhira, Khulna, Barishal, and Cox’s Bazar were used for Binadhan-10 and Mymensingh, Jamalpur, Sherpur and Sunamgonj were taken for Binadhan-11. It is based on primary level data from eight sub-districts among the study areas. A total of 240 farmers were randomly selected (30 from each location) to collect the data with a pre-designed questionnaire. Farmer were grouped according to saline affected and not-affected for saline tolerant variety Binadhan-10 and not affected, affected (1 - 10 days) and highly affected (10 - 20 days) for submergence tolerant rice variety Binadhan-11 to identify existing yield gap. Tabular as well as Zandstra method were applied for analysis the data. The study also found factors affecting the gap and some policy guidelines to minimize the gap.
基金This project is supported by Key National Basic Research Development Program of China(973Program,No.2007CB106800)National Key Project for the Eleventh Five Year Plan(2006BAC01A08,2007BAD65B02-6)+4 种基金the Foundation of the Knowledge Innovation Projectof Chinese Academy of Sciences(No.KZCX3-SW-NA3-05)the One Hundred Talent Project of Chinese Academy of Sciences(C08B8)Key Lab-oratory of Ecological Restoration and Ecosystem Management of Jilin Province(K09M6)Project of Science and Technology Cooperation of JilinProvince and Chinese Academy of Sciences(2005SYHZ0007)Project of the CAS Action-Planfor West Development(KZCX2-XB2-13)
基金supported by the National Natural Science Foundation of China(NSFC,71773109 and 71273234)the Key Project of the Ministry of Education of China(16JJD63007)
文摘Climate extremes, characterized by droughts and floods, have become one of the major constraints to sustainable improvement of rice productivity. Variety choice, considered as one of the main adaptation measures, could help farmers reduce yield loss resulting from these extremes. Based on a three-year panel survey of 1 080 Chinese rice farms in major rice producing provinces, we assume Hicksian neutral technology and employ an IV regression to estimate the average treatment effect(ATE) on rice yield for adopting stress tolerant variety, and find that farmers who adopted the stress tolerant variety on average increased rice yield by 15.5% in comparison to the non-adopters.
