新疆马鹿(Cervus elaphus)有3个亚种(塔里木亚种C. e . yarkandensis、天山亚种C. e . songaricus和阿勒泰亚种C. e . sibiricus)。本文报道新疆马鹿3个亚种头骨形态学特征描述和14项形态学指标测定。被测定的指标主要有颅全长(GLC)、...新疆马鹿(Cervus elaphus)有3个亚种(塔里木亚种C. e . yarkandensis、天山亚种C. e . songaricus和阿勒泰亚种C. e . sibiricus)。本文报道新疆马鹿3个亚种头骨形态学特征描述和14项形态学指标测定。被测定的指标主要有颅全长(GLC)、颜面长(FL)、鼻骨全长(GLN)、前头长( MFL)、眼窝长(OFW)、基底全长(CBL)、口盖最大幅(GPB)、前臼齿间距离(Pm-P)、眼间最小幅(ZB)、筋突起高(CH)、关筋突起高(LH)、牙齿间隙裂高(DH)、前下颚骨高(HMP2)、后下颚骨高(HMM3) ,采用主成分分析并在这3个亚种之间进行了比较。结果表明: 1)阿勒泰亚种的头骨长度和高度值比塔里木亚种大,宽度值比塔里木亚种小; 2)天山亚种的头骨大小一般处在塔里木亚种和阿勒泰亚种的中间,但三者之间没有显著性差异; 3)阿勒泰亚种和天山亚种的头骨形态测量数据比较接近,塔里木亚种的头骨形态比较特殊(塔里木亚种的头骨短而宽,明显区别于其他两亚种的特征)。在新疆导致马鹿3个亚种头骨形态差异的主要因素有栖息地环境和气候因素的差异。阿勒泰亚种和天山亚种栖息在大陆性气候寒冷区的针叶林中,冬天气候比较寒冷;塔里木亚种栖息在大陆性气候温热区的塔里木河流域胡杨林中,气候干旱炎热。因此,阿勒泰和天山亚种在适应寒冷的气候并适应生软食物的食性过程中头骨变成长细,而塔里木亚种长期适应干旱炎热并适应生硬食物的食性使头骨变的短而宽。展开更多
Objective:To assess the larvicidal and egg hatching inhibition property of the leaf essential oil of Cocrinia indica(C.indica) against Anopheles stephensi(An.stephensi).Methods:The larvicidal potential of C.indica...Objective:To assess the larvicidal and egg hatching inhibition property of the leaf essential oil of Cocrinia indica(C.indica) against Anopheles stephensi(An.stephensi).Methods:The larvicidal potential of C.indica leaf essential oil was evaluated against 1st.2nd.3rd and 4th instars larvae of An.stephensi using WHO protocol.The 24h LC<sub>50</sub>and LC<sub>90</sub> values of the essential oil were determined following probit analysis.The egg hatching inhibition activity was also tested at 10.20.40.and 60 mg/L The IC<sub>50</sub> value of essential oil was determined against eggs of An. stephensi.Results:The essential oil extracted from C.indica possessed excellent larvicidal and egg hatching inhibition activity against An.stephensi.The bioassays showed LC<sub>50</sub>—LC<sub>90</sub>of 54.3- 140.3.65.5-155.6,86.8-180.7 and 95.3-192.6 for 1 st.2nd.3rd.and 4th larval insiars.respectively. The 5095 egg hatching inhibition concentration(IC<sub>50</sub>) was noted at 16.5 mg/L.Conclusions:The present finding suggest that the C.indica leaf essential oil provided an excellent potential for controlling An.slephemi mosquito at earlier stage of their life cycle.展开更多
The biodiversity of natural or semi-natural native,old oak woodlands have high conservation importance,especially in landscapes of monocultural forest plantations and arable fields.With a wider variety of microhabitat...The biodiversity of natural or semi-natural native,old oak woodlands have high conservation importance,especially in landscapes of monocultural forest plantations and arable fields.With a wider variety of microhabitats and foraging sources,such old oak forests can provide essential habitat for native forest bird communities.We conducted a study using bird point counts to compare the forest bird communities of old pedunculate oak(Quercus robur)remnants with native and non-native plantations in central Hungary in a landscape of mostly arable fields,settlements,and monocultural plantations.Avian surveys were carried out in old oak forest remnants,middle-aged oak,white poplar(Populus alba),hybrid poplar(Populus×euramericana),black locust(Robinia pseudoacacia),and pine(Pinus spp.)plantations.Fieldwork has been carried out in nine study sites,where all six habitat types were represented(with a few exceptions),to determine total abundance,species richness,Shannon–Wiener diversity,species evenness,dominant and indicator species,and guild abundances.We found that old oak forest remnants were the most diverse habitats among the studied forest types,while hybrid poplar and pine plantations exhibited the lowest avian biodiversity.The avian guilds most sensitive to the loss of old oak forest remnants were ground foragers,bark foragers,cavity-nesters,residents,and Mediterranean migratory birds.Native habitats were more diverse than non-native plantations.Our results suggest that it is important to conserve all remaining high biodiversity old oak stands and to avoid clear-cutting of monocultural plantations in favour of practices such as mixed-species plantations,longer rotation lengths,or retention forestry.展开更多
Non-human primates(NHPs)serve as necessary reservoir hosts of parasites that create diseases to human.A close interaction between human and NHP can make a pathway for transmission of zoonotic diseases.To prevent zoono...Non-human primates(NHPs)serve as necessary reservoir hosts of parasites that create diseases to human.A close interaction between human and NHP can make a pathway for transmission of zoonotic diseases.To prevent zoonotic infection of zoo keepers,park visitors as well as keeping the captive NHPs in healthy state,it is necessary to carry out regular parasitological examination and treatment.A total of 72 fecal samples of Olive Baboon(n=39)and Common Langur(n=33)irrespective of their age and sex were collected from two zoological gardens of Bangladesh.Eggs and oocysts of seven gastrointestinal(GI)parasites were observed and identified in samples of both host species.The prevalence of GI parasites recorded was 100%.In case of Olive Baboon,the protozoan prevalence was higher(53.83%)than that of helminths,but opposite scenario was seen in case of Common Langur.Besides,higher intensity of coccidian oocysts in both hosts was recorded in the study.展开更多
Salinity(sodium chloride,NaCl)from anthropogenic sources is a persistent contaminant that negatively affects freshwater taxa.Amphibians can be susceptible to salinity,but some species are innately or adaptively tolera...Salinity(sodium chloride,NaCl)from anthropogenic sources is a persistent contaminant that negatively affects freshwater taxa.Amphibians can be susceptible to salinity,but some species are innately or adaptively tolerant.Physiological mechanisms mediating tolerance to salinity are still unclear,but changes in osmoregulatory hor-mones such as corticosterone(CORT)and aldosterone(ALDO)are prime candidates.We exposed larval barred tiger salamanders(Ambystoma mavortium)to environmentally relevant NaCl treatments(<32–4000 mg·L-1)for 24 days to test effects on growth,survival,and waterborne CORT responses.Of those sampled,we also quantified waterborne ALDO from a subset.Using a glucocorticoid antagonist(RU486),we also experimentally suppressed CORT signaling of some larvae to determine if CORT mediates effects of salinity.There were no strong differ-ences in survival among salinity treatments,but salinity reduced dry mass,snout–vent length,and body condition while increasing water content of larvae.High survival and sublethal effects demonstrated that salamanders were physiologically challenged but could tolerate the experimental concentrations.CORT signaling did not attenuate sublethal effects of salinity.Baseline and stress-induced(after an acute stressor,shaking)CORT were not influ-enced by salinity.ALDO was correlated with baseline CORT,suggesting it could be difficult to decouple the roles of CORT and ALDO.Future studies comparing ALDO and CORT responses of adaptively tolerant and previously unexposed populations could be beneficial to understand the roles of these hormones in tolerance to salinity.Nev-ertheless,our study enhances our understanding of the roles of corticosteroid hormones in mediating effects of a prominent anthropogenic stressor.展开更多
Species with especially close dependence on the environment to meet physiological requirements,such as ectotherms,are highly susceptible to the impacts of climate change.Climate change is occurring rapidly in the Suba...Species with especially close dependence on the environment to meet physiological requirements,such as ectotherms,are highly susceptible to the impacts of climate change.Climate change is occurring rapidly in the Subarctic and Arctic,but there is limited knowledge on ectotherm physiology in these landscapes.We investigated how environmental conditions and habitat characteristics influence the physiological conditions and habitat use of wood frogs(Rana sylvatica)in a Subarctic landscape near Churchill,Manitoba(Canada).We used plaster models to estimate water loss rates and surface body temperatures among different habitat types and at specific locations used by radio-tracked frogs.Water loss(R2=0.67)and surface temperature(R2=0.80)of plaster models was similar to that of live frogs.Model-based water loss rates were greater in tundra habitat than in boreal forest and ecotone habitat.Habitat use of wood frogs was strongly tied with available surface moisture and decreased water loss rates that were observed with plaster models.Environmental conditions,such as wind speed and ground tem-perature,explained 58%and 91%of the variation in water balance and temperature of plaster models.Maintaining physiological conditions may be challenging for semi-aquatic ectotherms in environments vulnerable to future cli-mate change.The ability to predict physiological conditions based on environmental conditions,as demonstrated in our study,can help understand how wildlife will respond to climatic changes.展开更多
As an apex predator the Amur tiger(Panthera tigris altaica)could play a pivotal role in maintaining the integrity of forest ecosystems in Northeast Asia.Due to habitat loss and harvest over the past century,tige...As an apex predator the Amur tiger(Panthera tigris altaica)could play a pivotal role in maintaining the integrity of forest ecosystems in Northeast Asia.Due to habitat loss and harvest over the past century,tigers rapidly declined in China and are now restricted to the Russian Far East and bordering habitat in nearby China.To facilitate restoration of the tiger in its historical range,reliable estimates of population size are essential to assess effectiveness of conservation interventions.Here we used camera trap data collected in Hunchun National Nature Reserve from April to June 2013 and 2014 to estimate tiger density and abundance using both maximum likelihood and Bayesian spatially explicit capture-recapture(SECR)methods.A minimum of 8 individuals were detected in both sample periods and the documentation of marking behavior and reproduction suggests the presence of a resident population.Using Bayesian SECR modeling within the 11400 km2 state space,density estimates were 0.33 and 0.40 individuals/100 km^(2) in 2013 and 2014,respectively,corresponding to an estimated abundance of 38 and 45 animals for this transboundary Sino-Russian population.In a maximum likelihood framework,we estimated densities of 0.30 and 0.24 individuals/100 km^(2) corresponding to abundances of 34 and 27,in 2013 and 2014,respectively.These density estimates are comparable to other published estimates for resident Amur tiger populations in the Russian Far East.This study reveals promising signs of tiger recovery in Northeast China,and demonstrates the importance of connectivity between the Russian and Chinese populations for recovering tigers in Northeast China.展开更多
Poaching as well as loss of habitat and prey are identified as causes of tiger population declines.Although some studies have examined habitat requirements and prey availability,few studies have quantified cause-speci...Poaching as well as loss of habitat and prey are identified as causes of tiger population declines.Although some studies have examined habitat requirements and prey availability,few studies have quantified cause-specific mortality of tigers.We used cumulative incidence functions(CIFs)to quantify cause-specific mortality rates of tigers,expanding and refining earlier studies to assess the potential impact of a newly emerging disease.To quantify changes in tiger mortality over time,we re-examined data first collected by Goodrich et al.(2008;study period 1:1992–2004)as well as new telemetry data collected since January 2005(study period 2:2005–2012)using a total of 57 tigers(27 males and 30 females)monitored for an average of 747 days(range 26–4718 days).Across the entire study period(1992 to 2012)we found an estimated average annual survival rate of 0.75 for all tigers combined.Poaching was the primary cause of mortality during both study periods,followed by suspected poaching,distemper and natural/unknown causes.Since 2005,poaching mortality has remained relatively constant and,if combined with suspected poaching,may account for a loss of 17–19%of the population each year.Canine distemper virus(CDV)may be an additive form of mortality to the population,currently accounting for an additional 5%.Despite this relatively new source of mortality,poaching remains the main threat to Amur tiger survival and,therefore,population growth.展开更多
Over the past half century,wildlife research has relied on technological advances to gain additional insight into the secretive lives of animals.This revolution started in the 1960s with the development of radio telem...Over the past half century,wildlife research has relied on technological advances to gain additional insight into the secretive lives of animals.This revolution started in the 1960s with the development of radio telemetry and continues today with the use of Global Positioning System(GPS)-based research techniques.In the present paper we review the history of radio telemetry from its origins with grizzly bears in Yellowstone to its early applications in tiger research and conservation in Asia.We address the different types of data that are available using radio telemetry as opposed to using other research techniques,such as behavioral observations,camera trapping,DNA analysis and scat analysis.In the late 1990s,the rapid development of GPS collar technology revolutionized wildlife research.This new technology has enabled researchers to dramatically improve their ability to gather data on animal movements and ecology.Despite the ecological and conservation benefits of radio telemetry,there have been few telemetry studies of tigers in the wild,and most have been on the Bengal or Amur subspecies.We close with an assessment of the current tiger conservation efforts using GPS technology and discuss how this new information can help to preserve tigers for future generations.展开更多
Literature on spot-billed pelican has not been reviewed lately which could provide a critique of the emerging data. We have now chosen it as a key species through which we suggest a conservation action plan which will...Literature on spot-billed pelican has not been reviewed lately which could provide a critique of the emerging data. We have now chosen it as a key species through which we suggest a conservation action plan which will benefit several waterbird species. The information provided here is scholastic in nature and is meant to focus on aspects that require attention and help plan future work for applied conservation. All known information on this species is brought together in this review which will also provide an update of its biology. Notes on the breeding biology of the species first published in the Journal of the Bombay Natural History Society. So far, 380 works have appeared on the species; of these, 36 contain material reported in earlier works or appeared as papers subsequently. Most appeared as articles in journals, both national and regional, a few international journals, newsletters/bulletins (48.2%), 4 dissertations, 76 reports and 6 popular science articles in magazines. This review on the species will provide an insight into different factors that can be weighed and combined while making a decision in investing resources in species conservation, i.e. importance of the species, level of threat and the time frame over which results are to be achieved.展开更多
The dynamics of red deer Cervus elaphus populations has been investigated across different environmental conditions,with the notable exception of the European Alps.Although the population dynamics of mountain-dwelling...The dynamics of red deer Cervus elaphus populations has been investigated across different environmental conditions,with the notable exception of the European Alps.Although the population dynamics of mountain-dwelling ungulates is typically influenced by the interaction between winter severity and density,the increase of temperatures and the reduction of snowpack occurring on the Alps since the 1980s may be expected to alter this pattern,especially in populations dwelling at medium-low elevations.Taking advantage of a 29-year time series of spring count data,we explored the role of weather stochasticity and density dependence on growth rate and vital rates(mortality and weaning success),and the density-dependent variation in body mass in a red deer population of the Italian Alps.The interaction between increasing values of density and snow depth exerted negative and positive effects on growth and mortality rates,respectively,while weaning success was negatively affected by increasing values of density,female-biased sex ratio and snow depth.Body mass of males and females of different age classes declined as population size increased.Our data support the role of winter severity and density dependence as key components of red deer population dynamics,and provide insight into the species’ecology on the European Alps.Despite the recent decline of snowpack on the Alpine Region,the negative impacts of winter severity and population abundance on growth rrate(possibly mediated by the density-dependent decline in body mass)confirms the importance of overwinter mortality in affecting the population dynamics of Alpine-dwelling red deer.展开更多
Aims Central Hungarian inland dune ranges harbor heterogeneous grassland vegetation with an extensive network of ecotones,arranged perpendicular to topography-driven hydrologic gradients.The area suffers from severe a...Aims Central Hungarian inland dune ranges harbor heterogeneous grassland vegetation with an extensive network of ecotones,arranged perpendicular to topography-driven hydrologic gradients.The area suffers from severe aridification due to climate change and local anthropogenic factors,which have led to a dramatic decline of the water table.As a result,groundwater is no longer reachable for lowlying plant communities;thus,we expect they are bound to undergo profound changes.This study investigates how the plant communities respond to this changing environment over time by monitoring ecotones,since they are frequently the hotspots of ecosystem change.We monitored five ecotones along permanent belt transects for 15 years to characterize their dynamic response,and to identify the internal structural changes of the plant communities the ecotones delimit.Methods Ecotones were delineated with the split moving window technique.The dynamics of two ecotone parameters,location and contrast,were analyzed with linear regression models incorporating two independent variables:study year as a measure of time since the loss of groundwater,and precipitation as a possible driver of interannual variations.The internal changes of the patches separated by the ecotones were analyzed using plant functional groups.Important Findings Precipitation had no detectable effect on the ecotone descriptors,but study year influenced ecotones in an unusual fashion.The position of the ecotones appeared to be very stable in time;their dynamics are stationary,not directional as we predicted.The contrasts had clear tendencies;two ecotones disappeared,one new one was formed and two ecotones showed no trend.The internal changes of the patches over time were dramatic,showing a shift toward more xeric and more open plant assemblages in most stretches of the transects.Thus,the dynamic response of the vegetation was not patch expansion vs.shrinking,but fusion vs.division,which profoundly restructured the vegetation pattern.Analysis of plant functional groups revealed that the trends of the ecotone contrasts could be traced back to internal changes of the patches and not to processes within ecotones.Hence,in situations where stationary ecotone dynamics prevail,ecotone position may be a poor indicator of the effects of strong directional environmental changes.However,in this study we show that ecotone contrast can serve as a sensitive tool for monitoring landscape pattern transformations in these cases.Also,this highlights the long-term nature of ecotone responses,which can have implications in landscape planning and restoration measures.展开更多
Many lizard species use caudal autotomy to escape entrapment. Conspicuous coloration may increase the likelihood of being attacked, but if that attack can be directed towards the autotomous tail this may ultimately in...Many lizard species use caudal autotomy to escape entrapment. Conspicuous coloration may increase the likelihood of being attacked, but if that attack can be directed towards the autotomous tail this may ultimately increase the chances of the lizard surviving a predatory attack. We tested the hypothesis that brightly-colored tails function to divert predatory attention away from the head and body using pairs of blue-tailed and all-brown clay model lizards. Predatory bird attacks on the 24 blue-tailed models occurred sooner (P = 0.001) than attacks on the 24 all-brown models, and over 7 days blue-tailed models were attacked more often than all-brown models (P = 0.007). Blue-tailed models were, however, more frequently attacked on the tail than other parts of the body (P 〈 0.001), while all-brown models were more frequently attacked on the head and body (P = 0.019) which would be more likely to be fatal for a real lizard. Our results suggest that models with a blue tail were more conspicuous than all-brown models, attracting attacks sooner and more often, but that the attacks were predominantly directed at the tail. It is better for individuals to be attacked unsuccessfully many times, than successfully just once. Having a brightly-colored tail may, therefore, act as a 'risky decoy'. Despite increased conspicuousness, a blue tail increases the likelihood that the lizard would be able to effect escape through caudal autotomy rather than being grabbed by the head or body [Current Zoology 60 (3): 333-337, 2014].展开更多
文摘Objective:To assess the larvicidal and egg hatching inhibition property of the leaf essential oil of Cocrinia indica(C.indica) against Anopheles stephensi(An.stephensi).Methods:The larvicidal potential of C.indica leaf essential oil was evaluated against 1st.2nd.3rd and 4th instars larvae of An.stephensi using WHO protocol.The 24h LC<sub>50</sub>and LC<sub>90</sub> values of the essential oil were determined following probit analysis.The egg hatching inhibition activity was also tested at 10.20.40.and 60 mg/L The IC<sub>50</sub> value of essential oil was determined against eggs of An. stephensi.Results:The essential oil extracted from C.indica possessed excellent larvicidal and egg hatching inhibition activity against An.stephensi.The bioassays showed LC<sub>50</sub>—LC<sub>90</sub>of 54.3- 140.3.65.5-155.6,86.8-180.7 and 95.3-192.6 for 1 st.2nd.3rd.and 4th larval insiars.respectively. The 5095 egg hatching inhibition concentration(IC<sub>50</sub>) was noted at 16.5 mg/L.Conclusions:The present finding suggest that the C.indica leaf essential oil provided an excellent potential for controlling An.slephemi mosquito at earlier stage of their life cycle.
基金supported financially by the projects(LIFE16NAT/IT/000245)(Oe AD-Gmb H-ICM-2020-00204)GINOP-2.3.2-15-2016-00019。
文摘The biodiversity of natural or semi-natural native,old oak woodlands have high conservation importance,especially in landscapes of monocultural forest plantations and arable fields.With a wider variety of microhabitats and foraging sources,such old oak forests can provide essential habitat for native forest bird communities.We conducted a study using bird point counts to compare the forest bird communities of old pedunculate oak(Quercus robur)remnants with native and non-native plantations in central Hungary in a landscape of mostly arable fields,settlements,and monocultural plantations.Avian surveys were carried out in old oak forest remnants,middle-aged oak,white poplar(Populus alba),hybrid poplar(Populus×euramericana),black locust(Robinia pseudoacacia),and pine(Pinus spp.)plantations.Fieldwork has been carried out in nine study sites,where all six habitat types were represented(with a few exceptions),to determine total abundance,species richness,Shannon–Wiener diversity,species evenness,dominant and indicator species,and guild abundances.We found that old oak forest remnants were the most diverse habitats among the studied forest types,while hybrid poplar and pine plantations exhibited the lowest avian biodiversity.The avian guilds most sensitive to the loss of old oak forest remnants were ground foragers,bark foragers,cavity-nesters,residents,and Mediterranean migratory birds.Native habitats were more diverse than non-native plantations.Our results suggest that it is important to conserve all remaining high biodiversity old oak stands and to avoid clear-cutting of monocultural plantations in favour of practices such as mixed-species plantations,longer rotation lengths,or retention forestry.
基金Ministry of Science and Technology,Government of the People's Republic of Bangladesh.
文摘Non-human primates(NHPs)serve as necessary reservoir hosts of parasites that create diseases to human.A close interaction between human and NHP can make a pathway for transmission of zoonotic diseases.To prevent zoonotic infection of zoo keepers,park visitors as well as keeping the captive NHPs in healthy state,it is necessary to carry out regular parasitological examination and treatment.A total of 72 fecal samples of Olive Baboon(n=39)and Common Langur(n=33)irrespective of their age and sex were collected from two zoological gardens of Bangladesh.Eggs and oocysts of seven gastrointestinal(GI)parasites were observed and identified in samples of both host species.The prevalence of GI parasites recorded was 100%.In case of Olive Baboon,the protozoan prevalence was higher(53.83%)than that of helminths,but opposite scenario was seen in case of Common Langur.Besides,higher intensity of coccidian oocysts in both hosts was recorded in the study.
基金funded by University of Montana,U.S.Geological Survey(USGS RWO#103 to CWB),National Science Foundation(NSF-DEB 1754474 to EJC)the Nelson Schwab Family Foundation。
文摘Salinity(sodium chloride,NaCl)from anthropogenic sources is a persistent contaminant that negatively affects freshwater taxa.Amphibians can be susceptible to salinity,but some species are innately or adaptively tolerant.Physiological mechanisms mediating tolerance to salinity are still unclear,but changes in osmoregulatory hor-mones such as corticosterone(CORT)and aldosterone(ALDO)are prime candidates.We exposed larval barred tiger salamanders(Ambystoma mavortium)to environmentally relevant NaCl treatments(<32–4000 mg·L-1)for 24 days to test effects on growth,survival,and waterborne CORT responses.Of those sampled,we also quantified waterborne ALDO from a subset.Using a glucocorticoid antagonist(RU486),we also experimentally suppressed CORT signaling of some larvae to determine if CORT mediates effects of salinity.There were no strong differ-ences in survival among salinity treatments,but salinity reduced dry mass,snout–vent length,and body condition while increasing water content of larvae.High survival and sublethal effects demonstrated that salamanders were physiologically challenged but could tolerate the experimental concentrations.CORT signaling did not attenuate sublethal effects of salinity.Baseline and stress-induced(after an acute stressor,shaking)CORT were not influ-enced by salinity.ALDO was correlated with baseline CORT,suggesting it could be difficult to decouple the roles of CORT and ALDO.Future studies comparing ALDO and CORT responses of adaptively tolerant and previously unexposed populations could be beneficial to understand the roles of these hormones in tolerance to salinity.Nev-ertheless,our study enhances our understanding of the roles of corticosteroid hormones in mediating effects of a prominent anthropogenic stressor.
基金approved by IACUC at Southeast Missouri State University and funded by Earthwatch Institute,the Northern Research Fund from the Churchill Northern Studies Centre,and the Office of Student Research at Appalachian State University。
文摘Species with especially close dependence on the environment to meet physiological requirements,such as ectotherms,are highly susceptible to the impacts of climate change.Climate change is occurring rapidly in the Subarctic and Arctic,but there is limited knowledge on ectotherm physiology in these landscapes.We investigated how environmental conditions and habitat characteristics influence the physiological conditions and habitat use of wood frogs(Rana sylvatica)in a Subarctic landscape near Churchill,Manitoba(Canada).We used plaster models to estimate water loss rates and surface body temperatures among different habitat types and at specific locations used by radio-tracked frogs.Water loss(R2=0.67)and surface temperature(R2=0.80)of plaster models was similar to that of live frogs.Model-based water loss rates were greater in tundra habitat than in boreal forest and ecotone habitat.Habitat use of wood frogs was strongly tied with available surface moisture and decreased water loss rates that were observed with plaster models.Environmental conditions,such as wind speed and ground tem-perature,explained 58%and 91%of the variation in water balance and temperature of plaster models.Maintaining physiological conditions may be challenging for semi-aquatic ectotherms in environments vulnerable to future cli-mate change.The ability to predict physiological conditions based on environmental conditions,as demonstrated in our study,can help understand how wildlife will respond to climatic changes.
基金supported by grants from the Natural Science Foundation of China(31270567,31210103911,31421063,31200410 and 31470566)the National Scientific and Technical Foundation Project of China(2012FY112000).
文摘As an apex predator the Amur tiger(Panthera tigris altaica)could play a pivotal role in maintaining the integrity of forest ecosystems in Northeast Asia.Due to habitat loss and harvest over the past century,tigers rapidly declined in China and are now restricted to the Russian Far East and bordering habitat in nearby China.To facilitate restoration of the tiger in its historical range,reliable estimates of population size are essential to assess effectiveness of conservation interventions.Here we used camera trap data collected in Hunchun National Nature Reserve from April to June 2013 and 2014 to estimate tiger density and abundance using both maximum likelihood and Bayesian spatially explicit capture-recapture(SECR)methods.A minimum of 8 individuals were detected in both sample periods and the documentation of marking behavior and reproduction suggests the presence of a resident population.Using Bayesian SECR modeling within the 11400 km2 state space,density estimates were 0.33 and 0.40 individuals/100 km^(2) in 2013 and 2014,respectively,corresponding to an estimated abundance of 38 and 45 animals for this transboundary Sino-Russian population.In a maximum likelihood framework,we estimated densities of 0.30 and 0.24 individuals/100 km^(2) corresponding to abundances of 34 and 27,in 2013 and 2014,respectively.These density estimates are comparable to other published estimates for resident Amur tiger populations in the Russian Far East.This study reveals promising signs of tiger recovery in Northeast China,and demonstrates the importance of connectivity between the Russian and Chinese populations for recovering tigers in Northeast China.
文摘Poaching as well as loss of habitat and prey are identified as causes of tiger population declines.Although some studies have examined habitat requirements and prey availability,few studies have quantified cause-specific mortality of tigers.We used cumulative incidence functions(CIFs)to quantify cause-specific mortality rates of tigers,expanding and refining earlier studies to assess the potential impact of a newly emerging disease.To quantify changes in tiger mortality over time,we re-examined data first collected by Goodrich et al.(2008;study period 1:1992–2004)as well as new telemetry data collected since January 2005(study period 2:2005–2012)using a total of 57 tigers(27 males and 30 females)monitored for an average of 747 days(range 26–4718 days).Across the entire study period(1992 to 2012)we found an estimated average annual survival rate of 0.75 for all tigers combined.Poaching was the primary cause of mortality during both study periods,followed by suspected poaching,distemper and natural/unknown causes.Since 2005,poaching mortality has remained relatively constant and,if combined with suspected poaching,may account for a loss of 17–19%of the population each year.Canine distemper virus(CDV)may be an additive form of mortality to the population,currently accounting for an additional 5%.Despite this relatively new source of mortality,poaching remains the main threat to Amur tiger survival and,therefore,population growth.
文摘Over the past half century,wildlife research has relied on technological advances to gain additional insight into the secretive lives of animals.This revolution started in the 1960s with the development of radio telemetry and continues today with the use of Global Positioning System(GPS)-based research techniques.In the present paper we review the history of radio telemetry from its origins with grizzly bears in Yellowstone to its early applications in tiger research and conservation in Asia.We address the different types of data that are available using radio telemetry as opposed to using other research techniques,such as behavioral observations,camera trapping,DNA analysis and scat analysis.In the late 1990s,the rapid development of GPS collar technology revolutionized wildlife research.This new technology has enabled researchers to dramatically improve their ability to gather data on animal movements and ecology.Despite the ecological and conservation benefits of radio telemetry,there have been few telemetry studies of tigers in the wild,and most have been on the Bengal or Amur subspecies.We close with an assessment of the current tiger conservation efforts using GPS technology and discuss how this new information can help to preserve tigers for future generations.
文摘Literature on spot-billed pelican has not been reviewed lately which could provide a critique of the emerging data. We have now chosen it as a key species through which we suggest a conservation action plan which will benefit several waterbird species. The information provided here is scholastic in nature and is meant to focus on aspects that require attention and help plan future work for applied conservation. All known information on this species is brought together in this review which will also provide an update of its biology. Notes on the breeding biology of the species first published in the Journal of the Bombay Natural History Society. So far, 380 works have appeared on the species; of these, 36 contain material reported in earlier works or appeared as papers subsequently. Most appeared as articles in journals, both national and regional, a few international journals, newsletters/bulletins (48.2%), 4 dissertations, 76 reports and 6 popular science articles in magazines. This review on the species will provide an insight into different factors that can be weighed and combined while making a decision in investing resources in species conservation, i.e. importance of the species, level of threat and the time frame over which results are to be achieved.
文摘The dynamics of red deer Cervus elaphus populations has been investigated across different environmental conditions,with the notable exception of the European Alps.Although the population dynamics of mountain-dwelling ungulates is typically influenced by the interaction between winter severity and density,the increase of temperatures and the reduction of snowpack occurring on the Alps since the 1980s may be expected to alter this pattern,especially in populations dwelling at medium-low elevations.Taking advantage of a 29-year time series of spring count data,we explored the role of weather stochasticity and density dependence on growth rate and vital rates(mortality and weaning success),and the density-dependent variation in body mass in a red deer population of the Italian Alps.The interaction between increasing values of density and snow depth exerted negative and positive effects on growth and mortality rates,respectively,while weaning success was negatively affected by increasing values of density,female-biased sex ratio and snow depth.Body mass of males and females of different age classes declined as population size increased.Our data support the role of winter severity and density dependence as key components of red deer population dynamics,and provide insight into the species’ecology on the European Alps.Despite the recent decline of snowpack on the Alpine Region,the negative impacts of winter severity and population abundance on growth rrate(possibly mediated by the density-dependent decline in body mass)confirms the importance of overwinter mortality in affecting the population dynamics of Alpine-dwelling red deer.
基金European Union and the State of Hungary,co-financed by the European Social Fund in the framework of TÁMOP 4.2.4.A/1-11-1-2012-0001‘National Excellence Program’.Conflict of interest statement.None declared.
文摘Aims Central Hungarian inland dune ranges harbor heterogeneous grassland vegetation with an extensive network of ecotones,arranged perpendicular to topography-driven hydrologic gradients.The area suffers from severe aridification due to climate change and local anthropogenic factors,which have led to a dramatic decline of the water table.As a result,groundwater is no longer reachable for lowlying plant communities;thus,we expect they are bound to undergo profound changes.This study investigates how the plant communities respond to this changing environment over time by monitoring ecotones,since they are frequently the hotspots of ecosystem change.We monitored five ecotones along permanent belt transects for 15 years to characterize their dynamic response,and to identify the internal structural changes of the plant communities the ecotones delimit.Methods Ecotones were delineated with the split moving window technique.The dynamics of two ecotone parameters,location and contrast,were analyzed with linear regression models incorporating two independent variables:study year as a measure of time since the loss of groundwater,and precipitation as a possible driver of interannual variations.The internal changes of the patches separated by the ecotones were analyzed using plant functional groups.Important Findings Precipitation had no detectable effect on the ecotone descriptors,but study year influenced ecotones in an unusual fashion.The position of the ecotones appeared to be very stable in time;their dynamics are stationary,not directional as we predicted.The contrasts had clear tendencies;two ecotones disappeared,one new one was formed and two ecotones showed no trend.The internal changes of the patches over time were dramatic,showing a shift toward more xeric and more open plant assemblages in most stretches of the transects.Thus,the dynamic response of the vegetation was not patch expansion vs.shrinking,but fusion vs.division,which profoundly restructured the vegetation pattern.Analysis of plant functional groups revealed that the trends of the ecotone contrasts could be traced back to internal changes of the patches and not to processes within ecotones.Hence,in situations where stationary ecotone dynamics prevail,ecotone position may be a poor indicator of the effects of strong directional environmental changes.However,in this study we show that ecotone contrast can serve as a sensitive tool for monitoring landscape pattern transformations in these cases.Also,this highlights the long-term nature of ecotone responses,which can have implications in landscape planning and restoration measures.
文摘Many lizard species use caudal autotomy to escape entrapment. Conspicuous coloration may increase the likelihood of being attacked, but if that attack can be directed towards the autotomous tail this may ultimately increase the chances of the lizard surviving a predatory attack. We tested the hypothesis that brightly-colored tails function to divert predatory attention away from the head and body using pairs of blue-tailed and all-brown clay model lizards. Predatory bird attacks on the 24 blue-tailed models occurred sooner (P = 0.001) than attacks on the 24 all-brown models, and over 7 days blue-tailed models were attacked more often than all-brown models (P = 0.007). Blue-tailed models were, however, more frequently attacked on the tail than other parts of the body (P 〈 0.001), while all-brown models were more frequently attacked on the head and body (P = 0.019) which would be more likely to be fatal for a real lizard. Our results suggest that models with a blue tail were more conspicuous than all-brown models, attracting attacks sooner and more often, but that the attacks were predominantly directed at the tail. It is better for individuals to be attacked unsuccessfully many times, than successfully just once. Having a brightly-colored tail may, therefore, act as a 'risky decoy'. Despite increased conspicuousness, a blue tail increases the likelihood that the lizard would be able to effect escape through caudal autotomy rather than being grabbed by the head or body [Current Zoology 60 (3): 333-337, 2014].