The Gandaki River Basin(GRB),located in the central Himalaya,provides habitats for a large number of important flora and fauna species.The habitats of key protected species have changed over time as a result of climat...The Gandaki River Basin(GRB),located in the central Himalaya,provides habitats for a large number of important flora and fauna species.The habitats of key protected species have changed over time as a result of climate changes and human activities related to land use change,including the development of roads.This study assessed the present and future distributions of sloth bear(Melursus ursinus)habitats using the maximum entropy(Max Ent)model.Bioclimatic data,a digital elevation model and roads were used as environmental layers to assess current and future distributions of habitat.Results show that the overall habitat within the study area is likely to undergo important changes in the future.Bio 8(the mean temperature of the wettest quarter)and slope were found to be important variables affecting the distribution of the species.The habitats very highly suitable for sloth bears currently cover an area of 148 km^(2) within the GRB.These habitats are predicted to increase by 122 km^(2) more by 2050.Overall,a net change by 680.38 km^(2) was found in the GRB.Conservation measures are necessary for this key protected species and its habitat within the GRB and elsewhere in Nepal.展开更多
Three new heptelidic acid derivatives(1-3)including two new dimeric esters and two known heptelidic acid analogues(4 and 5)were isolated from the solid culture of mushroom Lentinellus ursinus.The structures of new com...Three new heptelidic acid derivatives(1-3)including two new dimeric esters and two known heptelidic acid analogues(4 and 5)were isolated from the solid culture of mushroom Lentinellus ursinus.The structures of new compounds were confirmed by the analysis of NMR and HRESIMS spectroscopic data.The biosynthetic origin of compounds 1-5 was postulated.Compounds 1-5 exhibited no antibacterial activity against Staphylococcus aureus and Escherichia coli at the dose of 100 μM.展开更多
The aim of this study was to determine the susceptibility, intensity and distribution of pine trees to bark stripping by chacma baboons Papio ursinus in three plantations in the Eastern Highlands of Zimbabwe. The numb...The aim of this study was to determine the susceptibility, intensity and distribution of pine trees to bark stripping by chacma baboons Papio ursinus in three plantations in the Eastern Highlands of Zimbabwe. The number of plots/ha, stripped trees/ plot and stripped trees/ha was recorded during the pre-rainy, rainy and post-rainy seasons from August 2006 to May 2007. During data collection, altitude, aspect, season and other site predictor variables （e. g., roads and fire traces, water points, indigenous vegetation conservation areas, crop felds, human settlements, wattle scrubs, rocky areas, open grasslands, earlier stripped sites and roost sites） were recorded for each plot in association with selected predictor variables within plantation estates. Data on the number of stripped plots/ha, stripped trees/plot and stripped trees/ha were analysed as dependent variables using the Generalised Linear Model （GLM） through SPSS version 15 （2006） to determine which predictor variables were significantly related to bark stripping. Differences between means were tested using Bonferroni tests with a 5 % level of significance. Our findings show that bark stripping of pine trees by baboons occurred at all altitudes and aspects. Overall, the number of bark stripped trees/ha did not significandy vary by season. The number of bark stripped plots/ha was lower during the pre-rainy season than the rainy season, whereas the number of bark stripped trees/plot was higher during the pre-rainy than the rainy season. Bark stripping of pines occurred more often in the vicinities of areas with abundant food and water展开更多
The eastern Pacific stock of northern fur seals(Callorhinus ursinus)on the Pribilof Islands,Alaska represents over 50%of the global breeding population,but it has experienced population declines of unknown cause(s)sin...The eastern Pacific stock of northern fur seals(Callorhinus ursinus)on the Pribilof Islands,Alaska represents over 50%of the global breeding population,but it has experienced population declines of unknown cause(s)since 1980.One contributing factor to the decline may be exposure to anthropogenic contaminants such as persistent organic pollutants(POPs)which are biologically accumulative in nature,toxic to organisms,and environmentally persistent.This study conducted a decadal comparison of 21 organochlorine(OC)and 39 polybrominated diphenyl ether(PBDE)analyte concentrations utilizing archived vibrissae(whiskers)from individual fur seals sampled in 1993(n=30)and 2013(n=41)during subsistence harvests on the Pribilof Islands.The recently phased out PBDEs had values five times greater than the legacy status OCs,reflecting both the global shift away from chlorinated chemicals over the past 50 years and the widespread use of brominated flame retardants within the past two decades.No significant mean concentration differences were detected between 1993 and 2013 for total organochlorines(SOCs)(266 and 294 ng/g,respectively),or total polybrominated diphenyl ethers(SPBDEs)(1377 and 1521 ng/g,respectively),indicating the enduring environmental presence of these pollutants.Recently phased out PBDEs were detected at five times greater concentrations than phased out OCs.The presence of all analytes in vibrissae indicate that there is an adaptive advantage to partitioning contaminants into this inert tissue,suggesting keratinous tissue is a reliable matrix for assessing long-term for POP exposure and introducing the potential for less invasive sampling for future monitoring efforts.展开更多
Background:Habitat resources occur across the range of spatial scales in the environment.The environmental resources are characterized by upper and lower limits,which define organisms’distribution in their communitie...Background:Habitat resources occur across the range of spatial scales in the environment.The environmental resources are characterized by upper and lower limits,which define organisms’distribution in their communities.Animals respond to these resources at the optimal spatial scale.Therefore,multi-scale assessments are critical to identifying the correct spatial scale at which habitat resources are most influential in determining the specieshabitat relationships.This study used a machine learning algorithm random forest(RF),to evaluate the scaledependent habitat selection of sloth bears(Melursus ursinus)in and around Bandhavgarh Tiger Reserve,Madhya Pradesh,India.Results:We used 155 spatially rarified occurrences out of 248 occurrence records of sloth bears obtained from camera trap captures(n=36)and scats located(n=212)in the field.We calculated focal statistics for 13 habitat variables across ten spatial scales surrounding each presence-absence record of sloth bears.Large(>5000 m)and small(1000–2000 m)spatial scales were the most dominant scales at which sloth bears perceived the habitat features.Among the habitat covariates,farmlands and degraded forests were the essential patches associated with sloth bear occurrences,followed by sal and dry deciduous forests.The final habitat suitability model was highly accurate and had a very low out-of-bag(OOB)error rate.The high accuracy rate was also obtained using alternate validation matrices.Conclusions:Human-dominated landscapes are characterized by expanding human populations,changing landuse patterns,and increasing habitat fragmentation.Farmland and degraded habitats constitute~40%of the landform in the buffer zone of the reserve.One of the management implications may be identifying the highly suitable bear habitats in human-modified landscapes and integrating them with the existing conservation landscapes.展开更多
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(2019QZKK0603)the Strategic Priority Research Program of Chinese Academy of Sciences(XDA20040201)the Chinese Academy of Sciences-The World Academy of Sciences(CAS-TWAS)President’s Fellowship Program for international PhD students and the Chinese Academy of Sciences President’s International Fellowship Initiative for postdoctoral research(2018PC0030)。
文摘The Gandaki River Basin(GRB),located in the central Himalaya,provides habitats for a large number of important flora and fauna species.The habitats of key protected species have changed over time as a result of climate changes and human activities related to land use change,including the development of roads.This study assessed the present and future distributions of sloth bear(Melursus ursinus)habitats using the maximum entropy(Max Ent)model.Bioclimatic data,a digital elevation model and roads were used as environmental layers to assess current and future distributions of habitat.Results show that the overall habitat within the study area is likely to undergo important changes in the future.Bio 8(the mean temperature of the wettest quarter)and slope were found to be important variables affecting the distribution of the species.The habitats very highly suitable for sloth bears currently cover an area of 148 km^(2) within the GRB.These habitats are predicted to increase by 122 km^(2) more by 2050.Overall,a net change by 680.38 km^(2) was found in the GRB.Conservation measures are necessary for this key protected species and its habitat within the GRB and elsewhere in Nepal.
基金supported by the National Natural Science Foundation of China(21472233 and 81673334).
文摘Three new heptelidic acid derivatives(1-3)including two new dimeric esters and two known heptelidic acid analogues(4 and 5)were isolated from the solid culture of mushroom Lentinellus ursinus.The structures of new compounds were confirmed by the analysis of NMR and HRESIMS spectroscopic data.The biosynthetic origin of compounds 1-5 was postulated.Compounds 1-5 exhibited no antibacterial activity against Staphylococcus aureus and Escherichia coli at the dose of 100 μM.
基金funded by the African Forest Research network (AFORNET) Grant number 17/01/2005
文摘The aim of this study was to determine the susceptibility, intensity and distribution of pine trees to bark stripping by chacma baboons Papio ursinus in three plantations in the Eastern Highlands of Zimbabwe. The number of plots/ha, stripped trees/ plot and stripped trees/ha was recorded during the pre-rainy, rainy and post-rainy seasons from August 2006 to May 2007. During data collection, altitude, aspect, season and other site predictor variables （e. g., roads and fire traces, water points, indigenous vegetation conservation areas, crop felds, human settlements, wattle scrubs, rocky areas, open grasslands, earlier stripped sites and roost sites） were recorded for each plot in association with selected predictor variables within plantation estates. Data on the number of stripped plots/ha, stripped trees/plot and stripped trees/ha were analysed as dependent variables using the Generalised Linear Model （GLM） through SPSS version 15 （2006） to determine which predictor variables were significantly related to bark stripping. Differences between means were tested using Bonferroni tests with a 5 % level of significance. Our findings show that bark stripping of pine trees by baboons occurred at all altitudes and aspects. Overall, the number of bark stripped trees/ha did not significandy vary by season. The number of bark stripped plots/ha was lower during the pre-rainy season than the rainy season, whereas the number of bark stripped trees/plot was higher during the pre-rainy than the rainy season. Bark stripping of pines occurred more often in the vicinities of areas with abundant food and water
文摘The eastern Pacific stock of northern fur seals(Callorhinus ursinus)on the Pribilof Islands,Alaska represents over 50%of the global breeding population,but it has experienced population declines of unknown cause(s)since 1980.One contributing factor to the decline may be exposure to anthropogenic contaminants such as persistent organic pollutants(POPs)which are biologically accumulative in nature,toxic to organisms,and environmentally persistent.This study conducted a decadal comparison of 21 organochlorine(OC)and 39 polybrominated diphenyl ether(PBDE)analyte concentrations utilizing archived vibrissae(whiskers)from individual fur seals sampled in 1993(n=30)and 2013(n=41)during subsistence harvests on the Pribilof Islands.The recently phased out PBDEs had values five times greater than the legacy status OCs,reflecting both the global shift away from chlorinated chemicals over the past 50 years and the widespread use of brominated flame retardants within the past two decades.No significant mean concentration differences were detected between 1993 and 2013 for total organochlorines(SOCs)(266 and 294 ng/g,respectively),or total polybrominated diphenyl ethers(SPBDEs)(1377 and 1521 ng/g,respectively),indicating the enduring environmental presence of these pollutants.Recently phased out PBDEs were detected at five times greater concentrations than phased out OCs.The presence of all analytes in vibrissae indicate that there is an adaptive advantage to partitioning contaminants into this inert tissue,suggesting keratinous tissue is a reliable matrix for assessing long-term for POP exposure and introducing the potential for less invasive sampling for future monitoring efforts.
基金The field expanses were facilitated by a local NGO(The Corbett Foundation).
文摘Background:Habitat resources occur across the range of spatial scales in the environment.The environmental resources are characterized by upper and lower limits,which define organisms’distribution in their communities.Animals respond to these resources at the optimal spatial scale.Therefore,multi-scale assessments are critical to identifying the correct spatial scale at which habitat resources are most influential in determining the specieshabitat relationships.This study used a machine learning algorithm random forest(RF),to evaluate the scaledependent habitat selection of sloth bears(Melursus ursinus)in and around Bandhavgarh Tiger Reserve,Madhya Pradesh,India.Results:We used 155 spatially rarified occurrences out of 248 occurrence records of sloth bears obtained from camera trap captures(n=36)and scats located(n=212)in the field.We calculated focal statistics for 13 habitat variables across ten spatial scales surrounding each presence-absence record of sloth bears.Large(>5000 m)and small(1000–2000 m)spatial scales were the most dominant scales at which sloth bears perceived the habitat features.Among the habitat covariates,farmlands and degraded forests were the essential patches associated with sloth bear occurrences,followed by sal and dry deciduous forests.The final habitat suitability model was highly accurate and had a very low out-of-bag(OOB)error rate.The high accuracy rate was also obtained using alternate validation matrices.Conclusions:Human-dominated landscapes are characterized by expanding human populations,changing landuse patterns,and increasing habitat fragmentation.Farmland and degraded habitats constitute~40%of the landform in the buffer zone of the reserve.One of the management implications may be identifying the highly suitable bear habitats in human-modified landscapes and integrating them with the existing conservation landscapes.
