Identification of the effect of anthropogenic threats on ecosystem is crucial.We used molecular tools and remote sensing to evaluate the population status of an isolated Asian elephant population in southwestern China ...Identification of the effect of anthropogenic threats on ecosystem is crucial.We used molecular tools and remote sensing to evaluate the population status of an isolated Asian elephant population in southwestern China in response to changes in habitat suitability between 1989 and 2019.A total of 22 unique genotypes were identified from 117 dung samples collected between March and June 2018 using microsatellite DNA analysis,including 13 males and 9 females.Based on the size of fecal boli,1 animal was a juvenile,9 were subadults,and 12 were adults,indicating that recruitment was limited.The effective population size was small(15.3)but there was no signature of a recent population bottleneck.We observed a low genetic diversity(He=0.46±0.05)and a high level of inbreeding(Fis of 0.43±0.11),suggesting low population viability and high risk of extinction.In total,these elephants lost nearly two thirds(62%)of their habitat in 3 decades.The expansion of agriculture and rubber plantations followed by an increase in human settlements after 1989 increased the isolation of this population.We recommend that resettlement of 800 inhabitants of 2 villages and the abandonment of associated farmland and rubber plantations would make an additional 20 km2 of suitable habitat available.This could allow a population increase of 14 elephants,possibly by translocating individuals from elsewhere in China.Ourfindings can be applied to the management and conservation of other fragmented populations in China or in other range countries of Asian elephants.展开更多
Background Mountain ecosystems are critical hotspots of global biodiversity,yet the dynamics of community assembly along their elevational gradients are not well understood.This gap is primarily due to the complexity ...Background Mountain ecosystems are critical hotspots of global biodiversity,yet the dynamics of community assembly along their elevational gradients are not well understood.This gap is primarily due to the complexity of environmental and biotic interactions that influence species distribution and community structure.Although extensive research has been conducted on certain taxa,such as small mammals and bats,comprehensive stud-ies encompassing entire mammal assemblages are lacking.Our research aims to bridge this gap by examining the taxonomic,phylogenetic,and functional diversity,as well as the assemblage structures of mammal communities across elevational gradients in the Central and East Himalayas,exploring how diverse ecological and evolutionary processes impact community assembly.Methods We analyzed mammal elevational diversity patterns using species richness,functional diversity(FD),and phylogenetic diversity(PD).We compared the observed values of community structure,such as mean pairwise phylogenetic distance(MPD)and mean pairwise functional distance(MFD),with null-model corrected effect sizes to identify patterns and processes of community assembly.Using structural equation modeling and hierarchical par-titioning,we investigated the relationships between climate,productivity,and various facets of diversity,describing the organization of each component across different elevations.Results Taxonomic,functional,and phylogenetic diversity generally decreased with elevation but showed var-ied patterns such as mid-elevation peaks,low-elevation plateaus,or monotonic declines across different regions.Richness-controlled functional diversity increased towards mid-low elevations and decreased at higher elevations in both regions,whereas richness-controlled phylogenetic diversity lacked consistent patterns.Phylogenetic struc-tures tended to cluster from mid to high elevations,indicating closer relationships than those observed in random communities,likely due to significant environmental turnover near tree lines.Functional structure showed greater clustering at high elevations and increased over-dispersion at lower elevations,suggesting that species are more functionally similar than expected at higher elevations and more diverse at lower elevations.Our results revealed that environmental factors,evolutionary histories,and trait-driven ecological processes collectively shape species rich-ness along these gradients.Conclusions Our results showed incongruent community structures across phylogenetic and functional diversity.Generally,functional traits are closely linked to environmental conditions,reducing the chance of observing traits that are misaligned with their surroundings.Species with similar ecological roles or distinct evolutionary lineages often show convergent adaptations to highland environments.Additionally,our fiindings emphasize that commu-nity assembly varies with the biogeography and diversification history of individual mountain ranges,complicating the development of a generalized theory.Using multiple measures is important for accurate community structure assessments and effective conservation planning,as variable elevational patterns exist across different diversity dimensions.展开更多
基金supported by the“Second National Survey of Terrestrial Wildlife Project”(grant number:20080131)funded by National Forestry and Grassland Administration of China.
文摘Identification of the effect of anthropogenic threats on ecosystem is crucial.We used molecular tools and remote sensing to evaluate the population status of an isolated Asian elephant population in southwestern China in response to changes in habitat suitability between 1989 and 2019.A total of 22 unique genotypes were identified from 117 dung samples collected between March and June 2018 using microsatellite DNA analysis,including 13 males and 9 females.Based on the size of fecal boli,1 animal was a juvenile,9 were subadults,and 12 were adults,indicating that recruitment was limited.The effective population size was small(15.3)but there was no signature of a recent population bottleneck.We observed a low genetic diversity(He=0.46±0.05)and a high level of inbreeding(Fis of 0.43±0.11),suggesting low population viability and high risk of extinction.In total,these elephants lost nearly two thirds(62%)of their habitat in 3 decades.The expansion of agriculture and rubber plantations followed by an increase in human settlements after 1989 increased the isolation of this population.We recommend that resettlement of 800 inhabitants of 2 villages and the abandonment of associated farmland and rubber plantations would make an additional 20 km2 of suitable habitat available.This could allow a population increase of 14 elephants,possibly by translocating individuals from elsewhere in China.Ourfindings can be applied to the management and conservation of other fragmented populations in China or in other range countries of Asian elephants.
基金National Natural Science Foundation of China(no.31901109)GDAS Special Project of Science and Technology Development(2022GDASZH-2022010105)+2 种基金the China Postdoctoral Foundation(2021M700891)the National Natural Science Foundation of China(no.32271736)Survey of Wildlife Resources in Key Areas of Tibet(ZL202203601).
文摘Background Mountain ecosystems are critical hotspots of global biodiversity,yet the dynamics of community assembly along their elevational gradients are not well understood.This gap is primarily due to the complexity of environmental and biotic interactions that influence species distribution and community structure.Although extensive research has been conducted on certain taxa,such as small mammals and bats,comprehensive stud-ies encompassing entire mammal assemblages are lacking.Our research aims to bridge this gap by examining the taxonomic,phylogenetic,and functional diversity,as well as the assemblage structures of mammal communities across elevational gradients in the Central and East Himalayas,exploring how diverse ecological and evolutionary processes impact community assembly.Methods We analyzed mammal elevational diversity patterns using species richness,functional diversity(FD),and phylogenetic diversity(PD).We compared the observed values of community structure,such as mean pairwise phylogenetic distance(MPD)and mean pairwise functional distance(MFD),with null-model corrected effect sizes to identify patterns and processes of community assembly.Using structural equation modeling and hierarchical par-titioning,we investigated the relationships between climate,productivity,and various facets of diversity,describing the organization of each component across different elevations.Results Taxonomic,functional,and phylogenetic diversity generally decreased with elevation but showed var-ied patterns such as mid-elevation peaks,low-elevation plateaus,or monotonic declines across different regions.Richness-controlled functional diversity increased towards mid-low elevations and decreased at higher elevations in both regions,whereas richness-controlled phylogenetic diversity lacked consistent patterns.Phylogenetic struc-tures tended to cluster from mid to high elevations,indicating closer relationships than those observed in random communities,likely due to significant environmental turnover near tree lines.Functional structure showed greater clustering at high elevations and increased over-dispersion at lower elevations,suggesting that species are more functionally similar than expected at higher elevations and more diverse at lower elevations.Our results revealed that environmental factors,evolutionary histories,and trait-driven ecological processes collectively shape species rich-ness along these gradients.Conclusions Our results showed incongruent community structures across phylogenetic and functional diversity.Generally,functional traits are closely linked to environmental conditions,reducing the chance of observing traits that are misaligned with their surroundings.Species with similar ecological roles or distinct evolutionary lineages often show convergent adaptations to highland environments.Additionally,our fiindings emphasize that commu-nity assembly varies with the biogeography and diversification history of individual mountain ranges,complicating the development of a generalized theory.Using multiple measures is important for accurate community structure assessments and effective conservation planning,as variable elevational patterns exist across different diversity dimensions.
