Manglietia ventii is a wild plant species with extremely small populations endemic to Yunnan,mainly distributed in southeast Yunnan.Due to the continuous deterioration of natural habitats,excessive felling and utiliza...Manglietia ventii is a wild plant species with extremely small populations endemic to Yunnan,mainly distributed in southeast Yunnan.Due to the continuous deterioration of natural habitats,excessive felling and utilization of human beings,and the decline of breeding ability,the number of individuals in the population has decreased significantly.Through field investigation and literature review,the research status of M.ventii in systematics,conservation ecology,reproductive biology,genetic diversity,endangered mechanism and resource protection at home and abroad are systematically reviewed.And the future research direction is prospected.It is necessary to strengthen the research on the basic characteristics of M.ventii,explore the transmission route of M.ventii and deepen the development and utilization of resources,in order to provide a theoretical support for the protection and sustainable utilization of germplasm resources of M.ventii,and provide a reference for the protection of other wild plant species with extremely small populations.展开更多
In recent years,the protection of PSESP has gradually become a hot issue in biodiversity research.Through the investigation and analysis of PSESP in Xinjiang,it is shown that:①there are 75 species of PSESP in Xinjian...In recent years,the protection of PSESP has gradually become a hot issue in biodiversity research.Through the investigation and analysis of PSESP in Xinjiang,it is shown that:①there are 75 species of PSESP in Xinjiang,including 22 species of trees,18 species of shrubs and 35 species of herbs.The habitats are mainly in extremely cold,extremely dry or extremely narrow conditions such as snow line,desert,mountain,wetland and so on.②53 species(70.67%)are listed as national or autonomous region protected plants,and 22 species of PSESP are not listed in the protection;there are 70 species of PSESP listed in the red list,accounting for 93.33%.③The PSESP in Xinjiang are mainly distributed in the Altai Mountains,western Tianshan Mountains,Pamir Plateau and Karakoram Mountains;they are distributed in all kinds of nature reserves,forest parks,wetland parks and other natural ecological protection areas in Xinjiang.Ammopiptanthus nanus(M.Pop.)Cheng F.,Cistanche tubulosa(Schenk)Wight,Calligonum roborovskii A.Los.and Prunus cerasifera Ehrhart have not been found in the literature,indicating that they are distributed in protected areas.In order to provide a theoretical basis for the conservation of biodiversity in Xinjiang,this paper puts forward some suggestions on the protection of PSESP.展开更多
Many biological conservationists take actions to conserve plant species with extremely small populations (PSESP) in China; however, there have been few studies on the spatial distribution of threats to PSESP. Hence,...Many biological conservationists take actions to conserve plant species with extremely small populations (PSESP) in China; however, there have been few studies on the spatial distribution of threats to PSESP. Hence, we selected distribution data of PSESP and made a map of the spatial distribution of threats to PSESP in China. First, we used the weight assignment method to evaluate the threat risk to PSESP at both country and county scales. Second, we used a geographic information system to map the spatial distribution of threats to PSESP, and explored the threat factors based on linear regression analysis. Finally, we suggested some effective conservation options. We found that the PSESP with high values of protection, such as the plants with high scientific research values and ornamental plants, were threatened by over-exploitation and utilization, habitat fragmentation, and a small sized wild population in broad-leaved forests and bush fallows. We also identified some risk hotspots for PSESP in China. Regions with low elevation should be given priority for ex- and in-situ conservation. Moreover, climate change should be considered for conservation of PSESP. To avoid intensive over-exploitation or utilization and habitat fragmentation, in-situ conservation should be practiced in regions with high temperatures and low temperature seasonality, particularly in the high risk hotspots for PSESP that we proposed. Ex-situ conservation should be applied in these same regions, and over-exploitation and utilization of natural resources should be prevented. It is our goal to apply the concept of PSESP to the global scale in the future.展开更多
Background:Silent circulation of polioviruses complicates the polio endgame and motivates analyses that explore the probability of undetected circulation for different scenarios.A recent analysis suggested a relativel...Background:Silent circulation of polioviruses complicates the polio endgame and motivates analyses that explore the probability of undetected circulation for different scenarios.A recent analysis suggested a relatively high probability of unusually long silent circulation of polioviruses in small populations(defined as 10,000 people or smaller).Methods:We independently replicated the simple,hypothetical model by Vallejo et al.(2017)and repeated their analyses to explore the model behavior,interpretation of the results,and implications of simplifying assumptions.Results:We found a similar trend of increasing times between detected cases with increasing basic reproduction number(R0)and population size.However,we found substantially lower estimates of the probability of at least 3 years between successive polio cases than they reported,which appear more consistent with the prior literature.While small and isolated populations may sustain prolonged silent circulation,our reanalysis suggests that the existing rule of thumb of less than a 5%chance of 3 or more years of undetected circulation with perfect surveillance holds for most conditions of the model used by Vallejo et al.and most realistic conditions.Conclusions:Avoiding gaps in surveillance remains critical to declaring wild poliovirus elimination with high confidence as soon as possible after the last detected poliovirus,but concern about transmission in small populations with adequate surveillance should not significantly change the criteria for the certification of wild polioviruses.展开更多
The rarity of limestone cave species due to habitat degradation makes them of special interest in conservation biology.The wild Chinese Giant Salamander Andrias davidianus,an evolutionarily distinct and globally endan...The rarity of limestone cave species due to habitat degradation makes them of special interest in conservation biology.The wild Chinese Giant Salamander Andrias davidianus,an evolutionarily distinct and globally endangered species,are nearly all obligate into living in inaccessible mountain caves now.We detected that only 14-29 breeders,with the effective population size of 9-25(5-44 of 95% confidence interval),were in each of three caves,through genotyping 20 microsatellite loci on larvae that were flushed out of caves.Both heterzygosity excess and M(ratios of allele number to allele size range) tests indicated severe genetic bottlenecks among populations.Both mitochondrial,with only one or two haplotypes of D-loop region(770-771bp) in each population,and nuclear genetic structure showed clear divergence between populations.Considering the long life history,small population size,and genetic differentiationof the Chinese Giant Salamander,putting an end to poaching and recovering the karst ecosystem instead of releasing may be the sole measures to save this severely threated species.展开更多
The Fagaceae,a plant family with a wide distribution and diverse adaptability,has garnered significant interest as a subject of study in plant speciation and adaptation.Meanwhile,certain Fagaceae species are regarded ...The Fagaceae,a plant family with a wide distribution and diverse adaptability,has garnered significant interest as a subject of study in plant speciation and adaptation.Meanwhile,certain Fagaceae species are regarded as highly valuable wood resources due to the exceptional quality of their wood.In this study,we present two high-quality,chromosome-scale genome sequences for Quercus sichourensis(848.75 Mb)and Quercus rex(883.46 Mb).Comparative genomics analysis reveals that the difference in the number of plant disease resistance genes and the nonsynonymous and synonymous substitution ratio(Ka/Ks)of protein-coding genes among Fagaceae species are related to different environmental adaptations.Interestingly,most genes related to starch synthesis in the investigated Quercoideae species are located on a single chromosome,as compared to the outgroup species,Fagus sylvatica.Furthermore,resequencing and population analysis of Q.sichourensis and Q.rex reveal that Q.sichourensis has lower genetic diversity and higher deleterious mutations compared to Q.rex.The high-quality,chromosome-level genomes and the population genomic analysis of the critically endangered Q.sichourensis and Q.rex will provide an invaluable resource as well as insights for future study in these two species,even the genus Quercus,to facilitate their conservation.展开更多
Demography determines the strength of genetic drift,which generally reduces genetic variation and the efficacy of selection.Here,we disentangled the importance of demographic processes at a local scale(census size and...Demography determines the strength of genetic drift,which generally reduces genetic variation and the efficacy of selection.Here,we disentangled the importance of demographic processes at a local scale(census size and mating system)and at a species-range scale(old split between population clusters,recolonization after the last glaciation cycle,and admixture)in determining within-population genomic diversity and genomic signatures of positive selection.Analyses were based on re-sequence data from 52 populations of North American Arabidopsis lyrata collected across its entire distribution.The mating system and range dynamics since the last glaciation cycle explained around 60%of the variation in genomic diversity among populations and 52%of the variation in the signature of positive selection.Diversity was lowest in selfing compared with outcrossing populations and in areas further away from glacial refugia.In parallel,reduced positive selectionwas found in selfing populations and in populations with a longer route of postglacial range expansion.The signature of positive selection was also reduced in populations without admixture.We conclude that recent range expansion can have a profound influence on diversity in coding and non-coding DNA,similar in magnitude to the shift toward selfing.Distribution limits may in fact be caused by reduced effective population size and compromised positive selection in recently colonized parts of the range.展开更多
基金Supported by National Natural Science Foundation of China(31960069).
文摘Manglietia ventii is a wild plant species with extremely small populations endemic to Yunnan,mainly distributed in southeast Yunnan.Due to the continuous deterioration of natural habitats,excessive felling and utilization of human beings,and the decline of breeding ability,the number of individuals in the population has decreased significantly.Through field investigation and literature review,the research status of M.ventii in systematics,conservation ecology,reproductive biology,genetic diversity,endangered mechanism and resource protection at home and abroad are systematically reviewed.And the future research direction is prospected.It is necessary to strengthen the research on the basic characteristics of M.ventii,explore the transmission route of M.ventii and deepen the development and utilization of resources,in order to provide a theoretical support for the protection and sustainable utilization of germplasm resources of M.ventii,and provide a reference for the protection of other wild plant species with extremely small populations.
基金Supported by Basic Scientific Research Business Funds of Public Welfare Scientific Research Institutes of the Autonomous Region in 2022 (kyys202201)
文摘In recent years,the protection of PSESP has gradually become a hot issue in biodiversity research.Through the investigation and analysis of PSESP in Xinjiang,it is shown that:①there are 75 species of PSESP in Xinjiang,including 22 species of trees,18 species of shrubs and 35 species of herbs.The habitats are mainly in extremely cold,extremely dry or extremely narrow conditions such as snow line,desert,mountain,wetland and so on.②53 species(70.67%)are listed as national or autonomous region protected plants,and 22 species of PSESP are not listed in the protection;there are 70 species of PSESP listed in the red list,accounting for 93.33%.③The PSESP in Xinjiang are mainly distributed in the Altai Mountains,western Tianshan Mountains,Pamir Plateau and Karakoram Mountains;they are distributed in all kinds of nature reserves,forest parks,wetland parks and other natural ecological protection areas in Xinjiang.Ammopiptanthus nanus(M.Pop.)Cheng F.,Cistanche tubulosa(Schenk)Wight,Calligonum roborovskii A.Los.and Prunus cerasifera Ehrhart have not been found in the literature,indicating that they are distributed in protected areas.In order to provide a theoretical basis for the conservation of biodiversity in Xinjiang,this paper puts forward some suggestions on the protection of PSESP.
文摘Many biological conservationists take actions to conserve plant species with extremely small populations (PSESP) in China; however, there have been few studies on the spatial distribution of threats to PSESP. Hence, we selected distribution data of PSESP and made a map of the spatial distribution of threats to PSESP in China. First, we used the weight assignment method to evaluate the threat risk to PSESP at both country and county scales. Second, we used a geographic information system to map the spatial distribution of threats to PSESP, and explored the threat factors based on linear regression analysis. Finally, we suggested some effective conservation options. We found that the PSESP with high values of protection, such as the plants with high scientific research values and ornamental plants, were threatened by over-exploitation and utilization, habitat fragmentation, and a small sized wild population in broad-leaved forests and bush fallows. We also identified some risk hotspots for PSESP in China. Regions with low elevation should be given priority for ex- and in-situ conservation. Moreover, climate change should be considered for conservation of PSESP. To avoid intensive over-exploitation or utilization and habitat fragmentation, in-situ conservation should be practiced in regions with high temperatures and low temperature seasonality, particularly in the high risk hotspots for PSESP that we proposed. Ex-situ conservation should be applied in these same regions, and over-exploitation and utilization of natural resources should be prevented. It is our goal to apply the concept of PSESP to the global scale in the future.
基金We thank the Bill and Melinda Gates Foundation for support for this work under grant OPP1129391.
文摘Background:Silent circulation of polioviruses complicates the polio endgame and motivates analyses that explore the probability of undetected circulation for different scenarios.A recent analysis suggested a relatively high probability of unusually long silent circulation of polioviruses in small populations(defined as 10,000 people or smaller).Methods:We independently replicated the simple,hypothetical model by Vallejo et al.(2017)and repeated their analyses to explore the model behavior,interpretation of the results,and implications of simplifying assumptions.Results:We found a similar trend of increasing times between detected cases with increasing basic reproduction number(R0)and population size.However,we found substantially lower estimates of the probability of at least 3 years between successive polio cases than they reported,which appear more consistent with the prior literature.While small and isolated populations may sustain prolonged silent circulation,our reanalysis suggests that the existing rule of thumb of less than a 5%chance of 3 or more years of undetected circulation with perfect surveillance holds for most conditions of the model used by Vallejo et al.and most realistic conditions.Conclusions:Avoiding gaps in surveillance remains critical to declaring wild poliovirus elimination with high confidence as soon as possible after the last detected poliovirus,but concern about transmission in small populations with adequate surveillance should not significantly change the criteria for the certification of wild polioviruses.
基金supported by National Key Programme of Research and Development (Ministry of Science and Technology,2016YFC0503200)NSFC (31570391,31200411,31360144 )+1 种基金Science and Technology Department of Sichuan Province (2012JY0101)Chinese Academy of Sciences (Y3C3011100).
文摘The rarity of limestone cave species due to habitat degradation makes them of special interest in conservation biology.The wild Chinese Giant Salamander Andrias davidianus,an evolutionarily distinct and globally endangered species,are nearly all obligate into living in inaccessible mountain caves now.We detected that only 14-29 breeders,with the effective population size of 9-25(5-44 of 95% confidence interval),were in each of three caves,through genotyping 20 microsatellite loci on larvae that were flushed out of caves.Both heterzygosity excess and M(ratios of allele number to allele size range) tests indicated severe genetic bottlenecks among populations.Both mitochondrial,with only one or two haplotypes of D-loop region(770-771bp) in each population,and nuclear genetic structure showed clear divergence between populations.Considering the long life history,small population size,and genetic differentiationof the Chinese Giant Salamander,putting an end to poaching and recovering the karst ecosystem instead of releasing may be the sole measures to save this severely threated species.
基金“the Thousand Talents Plan”(5113190037 to J.C.)Fundamental Research Funds for the Central Universities(3102019JC007)+1 种基金Science and Technology Basic Resources Investigation Program of China(2017FY100100)NSFC(National Natural Science Foundation of China)-Yunnan Joint Fund(U1302262).
文摘The Fagaceae,a plant family with a wide distribution and diverse adaptability,has garnered significant interest as a subject of study in plant speciation and adaptation.Meanwhile,certain Fagaceae species are regarded as highly valuable wood resources due to the exceptional quality of their wood.In this study,we present two high-quality,chromosome-scale genome sequences for Quercus sichourensis(848.75 Mb)and Quercus rex(883.46 Mb).Comparative genomics analysis reveals that the difference in the number of plant disease resistance genes and the nonsynonymous and synonymous substitution ratio(Ka/Ks)of protein-coding genes among Fagaceae species are related to different environmental adaptations.Interestingly,most genes related to starch synthesis in the investigated Quercoideae species are located on a single chromosome,as compared to the outgroup species,Fagus sylvatica.Furthermore,resequencing and population analysis of Q.sichourensis and Q.rex reveal that Q.sichourensis has lower genetic diversity and higher deleterious mutations compared to Q.rex.The high-quality,chromosome-level genomes and the population genomic analysis of the critically endangered Q.sichourensis and Q.rex will provide an invaluable resource as well as insights for future study in these two species,even the genus Quercus,to facilitate their conservation.
基金supported by the Swiss National Science Foundation(PP00P3-123396,PP00P3_146342,31003A_166322)the Fondation Pierre Mercier pour la Science,Lausanne.
文摘Demography determines the strength of genetic drift,which generally reduces genetic variation and the efficacy of selection.Here,we disentangled the importance of demographic processes at a local scale(census size and mating system)and at a species-range scale(old split between population clusters,recolonization after the last glaciation cycle,and admixture)in determining within-population genomic diversity and genomic signatures of positive selection.Analyses were based on re-sequence data from 52 populations of North American Arabidopsis lyrata collected across its entire distribution.The mating system and range dynamics since the last glaciation cycle explained around 60%of the variation in genomic diversity among populations and 52%of the variation in the signature of positive selection.Diversity was lowest in selfing compared with outcrossing populations and in areas further away from glacial refugia.In parallel,reduced positive selectionwas found in selfing populations and in populations with a longer route of postglacial range expansion.The signature of positive selection was also reduced in populations without admixture.We conclude that recent range expansion can have a profound influence on diversity in coding and non-coding DNA,similar in magnitude to the shift toward selfing.Distribution limits may in fact be caused by reduced effective population size and compromised positive selection in recently colonized parts of the range.