Understanding the spatial distribution and habitat preference for rare and endangered species are essential for effective conservation practice.We examined the spatial distribution and habitat preference of four Diplo...Understanding the spatial distribution and habitat preference for rare and endangered species are essential for effective conservation practice.We examined the spatial distribution and habitat preference of four Diploderma species(Diploderma drukdaypo,D.laeviventre,D.batangense,and D.vela),which are endemic to the Qinghai-Tibet Plateau and are currently under state protection.We used the ensembles of small models(ESM)approach and predicted potential distribution ranges of the species in current and two future climate scenarios(SSP126 and SSP585).The degree of overlap between the predicted distribution ranges and existing natural reserves was further analyzed.Habitat preference was examined using a paired quadrat method.Our results predicted that D.drukdaypo has a current distribution range of 600 km^(2),which would decrease to 50 km^(2)and 55 km^(2)under the SSP126 and SSP585 respectively.For D.laeviventre,the current distribution range is 817 km^(2),with minimum changes in the two future climate scenarios(774 km^(2)and 902 km^(2)).For D.batangense,the current distribution range is 875 km^(2),which would expand to 1522 km^(2)and 3340 km^(2)in the two future climate scenarios.Similarly for D.vela,the current distribution range is 1369 km^(2),which would change to 1825 km^(2)and 2043 km^(2)respectively under the two future climate scenarios.The effect of protection of current nature reserves are likely low for those species;we found no overlap(D.drukdaypo,D.laeviventre)or little overlap(D.batangense 2.04%–3.56%,D.vela 15.52%–16.87%)between the currently designated protection area and distribution range under current and future climate scenarios.For habitat preference,stones appear to be the critical habitat element for those species although different species had different stone requirements.Taken together,we provided critical information on potential distribution ranges and habitat preference for four endangered Diploderma species,and confirmed the inadequacy of current nature reserves.The establishment of new or expansion of existing nature reserves is urgent for the conservation of those species.展开更多
Snow leopards are one of the least known large cats, the population of which has dramatically de- creased. Their habitat loss was considered the main reason for the decline during the last decade, but their habitat pr...Snow leopards are one of the least known large cats, the population of which has dramatically de- creased. Their habitat loss was considered the main reason for the decline during the last decade, but their habitat preferences are still not well known. In this paper, we studied the winter habitat preferences of snow leopards in the Tomur National Nature Reserve (TNNR) in Northwest China during 2004-2005. We used sign surveys and tran- sects to study the winter habitat selection of snow leopards. The results indicated that snow leopards showed a preference for habitat variabilities in slope aspect, vegetation cover, dominant topographical features, landform ruggedness and grazing status. We found that prey availability and dominant topographical features were the most important factors that determined the winter habitat selection of snow leopards. Our results supported the idea that the habitat preferences of snow leopards are a tradeoff between suitable habitat features and avoidance of potential human interactions.展开更多
Two species of babblers, Black-lored Babbler (Turdoides sharpie) and Arrow-marked Babbler (Turdoides jardeneii) are sympatric around lakes Naivasha and Nakuru, Kenya. This study was carried out to assess the habitat p...Two species of babblers, Black-lored Babbler (Turdoides sharpie) and Arrow-marked Babbler (Turdoides jardeneii) are sympatric around lakes Naivasha and Nakuru, Kenya. This study was carried out to assess the habitat partitioning mechanisms of the two species around Lake Naivasha area. The charactretistics of habitats used by seven groups of each species were studied along the shorelines of lakes Naivasha and Oloiden. The two species differed significantly in the habitat characteristics. Arrow-marked Babbler is restricted to shorelines with dense tree and ground vegetation cover while Black-lored Babbler occupies open areas with sparsely distributed small trees and short ground vegetation cover. Observations on the feeding habits and social behaviours of the two species are also discussed.展开更多
Diff erent sea cucumbers have diff erent preferred habitats and seasonal changes,which is still lack of detailed research.This study selects two common tropical sea cucumbers(Holothuria edulis and Stichopus chloronotu...Diff erent sea cucumbers have diff erent preferred habitats and seasonal changes,which is still lack of detailed research.This study selects two common tropical sea cucumbers(Holothuria edulis and Stichopus chloronotus)to explore the reasons that aff ect their habitat selection and seasonal changes,so as to provide support for the spatial planning of sea cucumbers reserve in coral reef area.The study area is a compound distribution area of living coral reefs and sandy bottom in the north of Wuzhizhou Island.The survey time is January,April-September,2019.Three fi xed transects(G,H,and Q)were selected to reveal the population ecological characteristics of them in the typical dry season(January,April,May,and June)and rainy season(July,August,and September).The variation range of density for H.edulis and S.chloronotus were 2.0-8.9 inds./10 m^(2) and 0.2-0.7 inds./10 m^(2),respectively.The population density in rainy season was signifi cantly higher than that in dry season(P<0.05).H.edulis tends to be distributed in deeper water.The distribution of H.edulis was signifi cant positively correlated with the sand coverage and sand continuity in G transect(P<0.05),and signifi cant negatively correlated with live coral coverage in three transects(P<0.01).The shift from dry season to rainy season is a key factor aff ecting their habitat preference.In dry season,the preferred habitats of S.chloronotus are small rock(SR),sand(S),and small coral reef(SCR),while the H.edulis is S,SR,and dead coral rubbles(DCR).In rainy season,the preferred habitats of S.chloronotus are shift to SCR and SR,while the H.edulis is SCR,DCR,and sand.展开更多
To understand the effects of sand grain size on habitat selection, we conducted a field study on the steppe toad-headed lizard in Hunshandake Desert northern China. Methods of mark-recapture and transect survey were u...To understand the effects of sand grain size on habitat selection, we conducted a field study on the steppe toad-headed lizard in Hunshandake Desert northern China. Methods of mark-recapture and transect survey were used to investigate the density of steppe toad-headed lizards and the environmental variables. The comparison on lizard densities among the habitats with different environmental factors revealed that: 1) population density of the steppe toad-headed lizard differed significantly among the habitats with different sand grain size indexes(SGSIs, representing roughness of sand substrate): the highest lizard density was found in the group with an SGSI of 〉 0.30, whereas the lowest density was found in the group with an SGSI of 0–0.15; and 2) vegetation cover, soil moisture, invertebrate diversity index, and abundance had no significant effects on the lizard density. These results implied that the sand grain size was the most important determinant of habitat selection for steppe toad-headed lizards in Hunshandake Desert. Steppe toad-headed lizards could avoid structural habitats that have negative effects on their maximal sprinting capabilities. Considering the changing sand grain size in the development phase of sand dunes, the sand lizard could be used as an indicator of the process of desertification.展开更多
Atlantic blue crabs(Callinectes sapidus)are ecologically and commercially fundamental.Life stages are punctuated with migration.Adults and juveniles live in estuaries and sounds.Larval stages develop in the coastal oc...Atlantic blue crabs(Callinectes sapidus)are ecologically and commercially fundamental.Life stages are punctuated with migration.Adults and juveniles live in estuaries and sounds.Larval stages develop in the coastal ocean.Juvenile and adult crabs occupy habitats from high salinities to fresh water.We determined whether maturing juvenile and adult blue crab habitat use is reflected in mitochondrial cytochrome oxidase 1 haplotypes.High salinity crabs had lower haplotype diversity(0.7260±.03900)compared to spawning crabs(0.9841±.00021)and low salinity crabs(0.94154±.00118).Significant pairwise differences in haplotypes were found between high salinity and spawning crabs(Nm=0.26018,p<0.001),and between high salinity and low salinity crabs(Nm=0.19482,p<0.001)indicating a lack of gene flow.Crabs from high salinity had highly significant genetic differentiation compared to spawning crabs(Fst=0.11830,p<0.001)and low salinity crabs(Fst=0.09689,p<0.001).Results support the hypothesis that genetics influence habitat selection.Crab larvae mix in the coastal ocean but occupy specific habitats upon return to sounds and estuaries.These findings have implications for the management of fisheries.展开更多
The House Martin(Delichon urbicum)is a common farmland bird species in the European landscape,yet its population numbers are currently in decline.However,it is not yet sufficiently explained why this long-term decline...The House Martin(Delichon urbicum)is a common farmland bird species in the European landscape,yet its population numbers are currently in decline.However,it is not yet sufficiently explained why this long-term decline occurs.To fill this gap in our knowledge,we investigated how land cover composition affects the abundance of House Martins on the landscape scale by using nationwide citizen science data.Utilizing a generalised linear mixed-effect model(GLMM),we evaluated 12,094 records from the Czech Republic spanning 2009-2017.Our analysis underscores the significance of land cover type in shaping House Martin abundance.More specifically,our results indicate that within agricultural land covers“naturally managed arable lands”exhibited significant positive effect,while forests,orchards,and vineyards were deemed less favourable for House Martin populations.Within urban land covers,we found a clear distinction in the impact on House Martin populations,with a positive effect observed in urban infrastructure,development areas,and post-industrial sites(i.e.,UrbanAreas),while an indifferent impact was noted within urban green spaces and landscaped areas(i.e.,GreenUrban).Notably,our findings suggest that the simple spatial,age,and species structure typical of forests in Europe,and similarly,the uniform structure of parks and gardens,may be responsible for the decline in the abundance of the House Martin.We advocate for the preservation or enhancement of urban greenery,expansion of natural vegetation in rural areas and adoption of ecological management practices in orchards and vineyards to mitigate further declines in House Martin populations.展开更多
Subalpine forests are known as outstanding habitats due to co-existence of both temperate and alpine vegetation and are classic example of ecotonal zones. Limited but diverse physiognomy of trees inhabiting in subalpi...Subalpine forests are known as outstanding habitats due to co-existence of both temperate and alpine vegetation and are classic example of ecotonal zones. Limited but diverse physiognomy of trees inhabiting in subalpine forest results in variability within under-canopy habitat conditions. Studies were undertaken to assess population status, habitat preference and interferences to the trees and associated under-canopy herbs in a subalpine forest of western Himalaya. A total of lo woody and 23 under-canopy herbs were recorded in the selected subalpine forest area. At each stand, the number of tree species and under-canopy herbs ranged from 2 to 4 and 8 to lo respectively. Abies spectabilis, Acer caesium, Quercus floribunda, Q. semecarpifolia and Rhododendron arboreum were key tree species in this area. The density of main woody species was 280 to 119o individuals ha-1 at different stands. Herbaceous plants with rosette and clump growth habits were observed to have higher values for total basal cover and importance value index. Presence of some under- canopy herbs like; Dactylorhiza hatagirea, Malaxis muscifera, Picrorhiza kurrooa, Polygonatum cirrhifolium habitats also and Skimmia laureola showed that they are in the habitat specific specific. However, the presence of Frageria nubicola and Viola sp. was common in the selected stands. Felling of trees for timber, construction of temporary huts, fuel wood and lopping for fodder were main interferences for trees. On the other hand, trampling driven damage due to grazing, habitats degradation and overexploitation were observed key threats for under-canopy herbs. Integrated analysis including population studies, habitats preference and interferences to the trees and under-canopy herbs in this sensitive and important ecosystem will be useful for determining the conservation plans and ecosystem management.展开更多
Aims Interspecific and intraspecific variation in flower color in natural populations provides an opportunity for us to understand the evolu-tion and maintenance of diversity of floral traits.Compared to cor-olla colo...Aims Interspecific and intraspecific variation in flower color in natural populations provides an opportunity for us to understand the evolu-tion and maintenance of diversity of floral traits.Compared to cor-olla color,little is known about the color polymorphism of sexual organs in flowering plants.to explore evolutionary transitions of androecium color and polymorphism within species,interspecific and intraspecific variation in androecium(anther and pollen)color in the genus Epimedium(Berberidaceae)was investigated.Methods to explore the geographical patterns of anther/pollen color variation in Epimedium species,data of 45 species were collected and their phyl-ogeny was constructed based on available DNA sequences.to investi-gate whether intraspecific variation in androecium color relates to habitat preference,three environmental factors were measured in the field popu-lation of Epimedium pubescens in northeastern Sichuan,China,which plants had green or yellow androecia.Vegetative and reproductive traits of this species were compared between the two color morphs.Important Findings Androecium(anther and pollen)color polymorphism in field populations of Epimedium pubescens is reported here where nine populations are monomorphic with a green androecium but three populations are dimorphic with individuals having either a green or a yellow androecium.Inflorescence stalk height,stalk diameter,leaf number,flower number and spur length(as well as spur and nectar volume)were not significantly different between two morphs.Compared to the yellow morph,the green morph had relatively larger leaves and anthers,but smaller sepals.the green morph produced more pollen and larger seeds,but the same number of ovules.Seed set was not significantly different between green and yellow morph.Investigations of environmental factors in the color dimorphic popu-lations of E.pubescens indicated that the green morph was more likely to occur in habitats with relatively lower light intensity.the distribution survey of 45 Epimedium species showed that species with a green androecium tended to appear at lower elevations.Comparative phylogenetic analysis showed that transitions from yellow to a green androecium or to androecial color dimorphism occurred at least seven times.this genus,characterized by anther color diversity and containing some species with anther color polymorphism,provides a model system in which to study the evolution and maintenance of colorful sexual organs in flowering plants.展开更多
The involvement of communities in ecological studies has been shown to augment conservation efforts,especially for cryptic species.However,there is a lack of studies addressing the utility of incidental sighting recor...The involvement of communities in ecological studies has been shown to augment conservation efforts,especially for cryptic species.However,there is a lack of studies addressing the utility of incidental sighting records from community members in gaining knowledge on habitat preferences and distribution of suitable habitat for these organisms.This study compares preferences of the Lumholtz’s tree kangaroo(Dendrolagus lumholtzi;LTK),a cryptic rainforest folivore in northeastern Australia,for various habitat and climatic variables derived from data collected during scientific projects to those derived from incidental sighting records using ArcGIS and Maxent.Incidental sighting records suggest that the species uses a wider range of altitudes,annual rainfalls,annual mean temperatures and vegetation types than predicted by scientific studies.Incidental records also show that the species can persist in areas of lower rainfall during the wettest month and lower minimum temperature during the coldest month.Both data place the species within a comparable range of rainfalls during the driest month,maximum temperatures of the warmest month and soil types.When using identified preferences to assess the extent and distribution of suitable habitat,incidental records predicted more areas of suitable habitat than scientific records with an overlap of up to 91%between them.The present study proves that incidental sighting records can be a valuable part of the study of cryptic species and should be considered complementarily alongside scientific studies to obtain comprehensive ecological information of a species that can assist in its conservation.展开更多
Land-use sprawl in the Himalayas has caused the conversion of natural habitat into human-modified habitats,thus degrading ecosystem health.Adaptation of birds to changing physical environment can be well understood by...Land-use sprawl in the Himalayas has caused the conversion of natural habitat into human-modified habitats,thus degrading ecosystem health.Adaptation of birds to changing physical environment can be well understood by analyzing their habitat preferences,and foraging dynamics explored to a limited extent in the Himalayan region,as yet.To achieve a comprehensive understanding of avian guild structure,we used multivariate statistical techniques to classify bird species according to their similarities in foraging patterns and habitat preferences.Observations based on habitat and diet affinities accounted for rich avian diversity with a total of 208 bird species(about 15%of country’s avifauna)recorded from six different sites during 1 year survey.Unweighted pair-group average cluster analysis performed on the families revealed ten feeding and fifteen habitat guilds among 63 bird families observed.Subtropical forests harbored more species followed by urban forests and agricultural landscapes.Insectivorous and omnivorous outnumbered other feeding guilds in the study area.Bird assemblages were richer in protected areas and semidisturbed landscapes and did not show significant variation between the seasons.Results of the study revealed that different functional groups of birds behaved differently,primarily induced by choice of food.The site heterogeneity favored avifaunal persistence by providing favorable foraging,roosting,and nesting opportunities to birds.Composition of avian guilds indicated level of intactness and ecological integrity of ecosystems studied.This outcome thus sets the background for long-term analysis of bird-habitat relationship and their foraging dynamics.The study has the relevance for decision-makers to integrate avian guild structure as an essential ingredient in formulating conservation strategies.展开更多
While theory suggests that at conception the sex ratio should be balanced(1:1),this can be variable across space and time in wild populations.Currently,studies of the environmental factors that regulate adult sex rati...While theory suggests that at conception the sex ratio should be balanced(1:1),this can be variable across space and time in wild populations.Currently,studies of the environmental factors that regulate adult sex ratio(ASR)in species with different life history traits are scarce.Using capture–recapture over a year,we analyzed the influence of habitat type(forest and nonforest)and season(rainy and dry)on variation in ASR,male aggregation and the trajectory movement of 2 dung beetle species with different life history traits:Deltochilum mexicanum(a hornless roller species)and Dichotomius satanas(a tunneler species with horns on its head and thorax).We found opposite tendencies.The D.mexicanum population tends to be female-biased,but the population of D.satanas tends to be predominantly male,and observed values were not related to habitat type or season.However,the 95%confidence intervals estimated were highly variable between seasons depending on habitat.On examining the monthly variation in ASR for both habitats,we found that it depends on the species.In addition,male aggregation differed between species depending on habitat type and season,and species movement patterns were closely related to their habitat preferences.Based on our results,we argue that comparative population studies of species with different life history traits are necessary to understand the variation in demographic parameters as well as its ecological and evolutionary implications in the face of spatial and climatic environmental variation.展开更多
Urbanization effects on living organisms are spatially heterogeneous.Here we quantified the abundance of birds per tree in forested urban and rural habitats for 85,829 trees mainly in China and Europe.A population mod...Urbanization effects on living organisms are spatially heterogeneous.Here we quantified the abundance of birds per tree in forested urban and rural habitats for 85,829 trees mainly in China and Europe.A population model was based on the assumption that:1)birds have a normally distributed habitat preference;2)an increase in population size linked to the habitat preference;3)a population size dependent on the habitat preference;and 4)the removal of a certain fraction of individuals giving rise to extinction.We tested for large-scale differences in the impact of urbanization on the frequency distribution of the difference in abundance between urban and rural habitats in China and parts of Europe.The difference in the frequency distribution of urban population density of birds in trees minus rural population density of birds in trees in China and Europe was statistically significant suggesting that the abundance of birds differed between trees in urban and rural habitats,but more so in China than in Europe.We hypothesize that more pronounced differences in China than in Europe may have arisen due to the Four Pests Campaign in 1958-1962 that resulted in death of hundreds of millions of birds(mainly tree sparrows Passer monfanus,but also numerous other less common species that were starting to become urbanized around 1960).Species that were less common in 1960 could not sustain reductions in population size in urban areas and hence these species are still rare or absent in urban areas today 60 years later.展开更多
基金This work was supported by the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(Grant No.2019QZKK0402)Science and Technology Plan Project of Tibet Autonomous Region to Yin QI(Grant No.XZ202201ZY0030G)China Biodiversity Observation Networks(Sino BON-Amphibian and Reptile)。
文摘Understanding the spatial distribution and habitat preference for rare and endangered species are essential for effective conservation practice.We examined the spatial distribution and habitat preference of four Diploderma species(Diploderma drukdaypo,D.laeviventre,D.batangense,and D.vela),which are endemic to the Qinghai-Tibet Plateau and are currently under state protection.We used the ensembles of small models(ESM)approach and predicted potential distribution ranges of the species in current and two future climate scenarios(SSP126 and SSP585).The degree of overlap between the predicted distribution ranges and existing natural reserves was further analyzed.Habitat preference was examined using a paired quadrat method.Our results predicted that D.drukdaypo has a current distribution range of 600 km^(2),which would decrease to 50 km^(2)and 55 km^(2)under the SSP126 and SSP585 respectively.For D.laeviventre,the current distribution range is 817 km^(2),with minimum changes in the two future climate scenarios(774 km^(2)and 902 km^(2)).For D.batangense,the current distribution range is 875 km^(2),which would expand to 1522 km^(2)and 3340 km^(2)in the two future climate scenarios.Similarly for D.vela,the current distribution range is 1369 km^(2),which would change to 1825 km^(2)and 2043 km^(2)respectively under the two future climate scenarios.The effect of protection of current nature reserves are likely low for those species;we found no overlap(D.drukdaypo,D.laeviventre)or little overlap(D.batangense 2.04%–3.56%,D.vela 15.52%–16.87%)between the currently designated protection area and distribution range under current and future climate scenarios.For habitat preference,stones appear to be the critical habitat element for those species although different species had different stone requirements.Taken together,we provided critical information on potential distribution ranges and habitat preference for four endangered Diploderma species,and confirmed the inadequacy of current nature reserves.The establishment of new or expansion of existing nature reserves is urgent for the conservation of those species.
基金supported by the Science Supporting Project of the National Ministry of Science and Technology(2008BA C39B04)the National Natural Science Foundation of China (30470262 and 30970340)+1 种基金the International Science and Technology Cooperation Program of China(2010DFA92720)the Chinese Academy of Sciences Visiting Professorships for Senior International Scientists(2009Z2-5)
文摘Snow leopards are one of the least known large cats, the population of which has dramatically de- creased. Their habitat loss was considered the main reason for the decline during the last decade, but their habitat preferences are still not well known. In this paper, we studied the winter habitat preferences of snow leopards in the Tomur National Nature Reserve (TNNR) in Northwest China during 2004-2005. We used sign surveys and tran- sects to study the winter habitat selection of snow leopards. The results indicated that snow leopards showed a preference for habitat variabilities in slope aspect, vegetation cover, dominant topographical features, landform ruggedness and grazing status. We found that prey availability and dominant topographical features were the most important factors that determined the winter habitat selection of snow leopards. Our results supported the idea that the habitat preferences of snow leopards are a tradeoff between suitable habitat features and avoidance of potential human interactions.
基金The study was supported by the Tropical Biology Association through a grant from the Darwin Intiative and the European Commission (B7-6201).
文摘Two species of babblers, Black-lored Babbler (Turdoides sharpie) and Arrow-marked Babbler (Turdoides jardeneii) are sympatric around lakes Naivasha and Nakuru, Kenya. This study was carried out to assess the habitat partitioning mechanisms of the two species around Lake Naivasha area. The charactretistics of habitats used by seven groups of each species were studied along the shorelines of lakes Naivasha and Oloiden. The two species differed significantly in the habitat characteristics. Arrow-marked Babbler is restricted to shorelines with dense tree and ground vegetation cover while Black-lored Babbler occupies open areas with sparsely distributed small trees and short ground vegetation cover. Observations on the feeding habits and social behaviours of the two species are also discussed.
基金Supported by the National Key R&D Project of China(No.2019YFD0901304)the National Natural Science Foundation of China(Nos.42076097,31760757)the National Natural Science Foundation of Hainan Province,China(No.2019RC070)。
文摘Diff erent sea cucumbers have diff erent preferred habitats and seasonal changes,which is still lack of detailed research.This study selects two common tropical sea cucumbers(Holothuria edulis and Stichopus chloronotus)to explore the reasons that aff ect their habitat selection and seasonal changes,so as to provide support for the spatial planning of sea cucumbers reserve in coral reef area.The study area is a compound distribution area of living coral reefs and sandy bottom in the north of Wuzhizhou Island.The survey time is January,April-September,2019.Three fi xed transects(G,H,and Q)were selected to reveal the population ecological characteristics of them in the typical dry season(January,April,May,and June)and rainy season(July,August,and September).The variation range of density for H.edulis and S.chloronotus were 2.0-8.9 inds./10 m^(2) and 0.2-0.7 inds./10 m^(2),respectively.The population density in rainy season was signifi cantly higher than that in dry season(P<0.05).H.edulis tends to be distributed in deeper water.The distribution of H.edulis was signifi cant positively correlated with the sand coverage and sand continuity in G transect(P<0.05),and signifi cant negatively correlated with live coral coverage in three transects(P<0.01).The shift from dry season to rainy season is a key factor aff ecting their habitat preference.In dry season,the preferred habitats of S.chloronotus are small rock(SR),sand(S),and small coral reef(SCR),while the H.edulis is S,SR,and dead coral rubbles(DCR).In rainy season,the preferred habitats of S.chloronotus are shift to SCR and SR,while the H.edulis is SCR,DCR,and sand.
基金financial support of the Key Basic Science and Technology Project of the Ministry of Science and Technology, China (2013FY110300)the National Natural Science Foundation of China (No. 31572260)the Knowledge Innovation Project of the Chinese Academy of Sciences (KSCX2-EW-J-2)
文摘To understand the effects of sand grain size on habitat selection, we conducted a field study on the steppe toad-headed lizard in Hunshandake Desert northern China. Methods of mark-recapture and transect survey were used to investigate the density of steppe toad-headed lizards and the environmental variables. The comparison on lizard densities among the habitats with different environmental factors revealed that: 1) population density of the steppe toad-headed lizard differed significantly among the habitats with different sand grain size indexes(SGSIs, representing roughness of sand substrate): the highest lizard density was found in the group with an SGSI of 〉 0.30, whereas the lowest density was found in the group with an SGSI of 0–0.15; and 2) vegetation cover, soil moisture, invertebrate diversity index, and abundance had no significant effects on the lizard density. These results implied that the sand grain size was the most important determinant of habitat selection for steppe toad-headed lizards in Hunshandake Desert. Steppe toad-headed lizards could avoid structural habitats that have negative effects on their maximal sprinting capabilities. Considering the changing sand grain size in the development phase of sand dunes, the sand lizard could be used as an indicator of the process of desertification.
文摘Atlantic blue crabs(Callinectes sapidus)are ecologically and commercially fundamental.Life stages are punctuated with migration.Adults and juveniles live in estuaries and sounds.Larval stages develop in the coastal ocean.Juvenile and adult crabs occupy habitats from high salinities to fresh water.We determined whether maturing juvenile and adult blue crab habitat use is reflected in mitochondrial cytochrome oxidase 1 haplotypes.High salinity crabs had lower haplotype diversity(0.7260±.03900)compared to spawning crabs(0.9841±.00021)and low salinity crabs(0.94154±.00118).Significant pairwise differences in haplotypes were found between high salinity and spawning crabs(Nm=0.26018,p<0.001),and between high salinity and low salinity crabs(Nm=0.19482,p<0.001)indicating a lack of gene flow.Crabs from high salinity had highly significant genetic differentiation compared to spawning crabs(Fst=0.11830,p<0.001)and low salinity crabs(Fst=0.09689,p<0.001).Results support the hypothesis that genetics influence habitat selection.Crab larvae mix in the coastal ocean but occupy specific habitats upon return to sounds and estuaries.These findings have implications for the management of fisheries.
基金supported by an internal grant agency from the Faculty of AgriSciences of Mendel University in Brno(AF-IGA2022-IP-034).
文摘The House Martin(Delichon urbicum)is a common farmland bird species in the European landscape,yet its population numbers are currently in decline.However,it is not yet sufficiently explained why this long-term decline occurs.To fill this gap in our knowledge,we investigated how land cover composition affects the abundance of House Martins on the landscape scale by using nationwide citizen science data.Utilizing a generalised linear mixed-effect model(GLMM),we evaluated 12,094 records from the Czech Republic spanning 2009-2017.Our analysis underscores the significance of land cover type in shaping House Martin abundance.More specifically,our results indicate that within agricultural land covers“naturally managed arable lands”exhibited significant positive effect,while forests,orchards,and vineyards were deemed less favourable for House Martin populations.Within urban land covers,we found a clear distinction in the impact on House Martin populations,with a positive effect observed in urban infrastructure,development areas,and post-industrial sites(i.e.,UrbanAreas),while an indifferent impact was noted within urban green spaces and landscaped areas(i.e.,GreenUrban).Notably,our findings suggest that the simple spatial,age,and species structure typical of forests in Europe,and similarly,the uniform structure of parks and gardens,may be responsible for the decline in the abundance of the House Martin.We advocate for the preservation or enhancement of urban greenery,expansion of natural vegetation in rural areas and adoption of ecological management practices in orchards and vineyards to mitigate further declines in House Martin populations.
文摘Subalpine forests are known as outstanding habitats due to co-existence of both temperate and alpine vegetation and are classic example of ecotonal zones. Limited but diverse physiognomy of trees inhabiting in subalpine forest results in variability within under-canopy habitat conditions. Studies were undertaken to assess population status, habitat preference and interferences to the trees and associated under-canopy herbs in a subalpine forest of western Himalaya. A total of lo woody and 23 under-canopy herbs were recorded in the selected subalpine forest area. At each stand, the number of tree species and under-canopy herbs ranged from 2 to 4 and 8 to lo respectively. Abies spectabilis, Acer caesium, Quercus floribunda, Q. semecarpifolia and Rhododendron arboreum were key tree species in this area. The density of main woody species was 280 to 119o individuals ha-1 at different stands. Herbaceous plants with rosette and clump growth habits were observed to have higher values for total basal cover and importance value index. Presence of some under- canopy herbs like; Dactylorhiza hatagirea, Malaxis muscifera, Picrorhiza kurrooa, Polygonatum cirrhifolium habitats also and Skimmia laureola showed that they are in the habitat specific specific. However, the presence of Frageria nubicola and Viola sp. was common in the selected stands. Felling of trees for timber, construction of temporary huts, fuel wood and lopping for fodder were main interferences for trees. On the other hand, trampling driven damage due to grazing, habitats degradation and overexploitation were observed key threats for under-canopy herbs. Integrated analysis including population studies, habitats preference and interferences to the trees and under-canopy herbs in this sensitive and important ecosystem will be useful for determining the conservation plans and ecosystem management.
基金This work was supported by the National Science Foundation of China(No.U1402267,31270281)to S.Q.H.
文摘Aims Interspecific and intraspecific variation in flower color in natural populations provides an opportunity for us to understand the evolu-tion and maintenance of diversity of floral traits.Compared to cor-olla color,little is known about the color polymorphism of sexual organs in flowering plants.to explore evolutionary transitions of androecium color and polymorphism within species,interspecific and intraspecific variation in androecium(anther and pollen)color in the genus Epimedium(Berberidaceae)was investigated.Methods to explore the geographical patterns of anther/pollen color variation in Epimedium species,data of 45 species were collected and their phyl-ogeny was constructed based on available DNA sequences.to investi-gate whether intraspecific variation in androecium color relates to habitat preference,three environmental factors were measured in the field popu-lation of Epimedium pubescens in northeastern Sichuan,China,which plants had green or yellow androecia.Vegetative and reproductive traits of this species were compared between the two color morphs.Important Findings Androecium(anther and pollen)color polymorphism in field populations of Epimedium pubescens is reported here where nine populations are monomorphic with a green androecium but three populations are dimorphic with individuals having either a green or a yellow androecium.Inflorescence stalk height,stalk diameter,leaf number,flower number and spur length(as well as spur and nectar volume)were not significantly different between two morphs.Compared to the yellow morph,the green morph had relatively larger leaves and anthers,but smaller sepals.the green morph produced more pollen and larger seeds,but the same number of ovules.Seed set was not significantly different between green and yellow morph.Investigations of environmental factors in the color dimorphic popu-lations of E.pubescens indicated that the green morph was more likely to occur in habitats with relatively lower light intensity.the distribution survey of 45 Epimedium species showed that species with a green androecium tended to appear at lower elevations.Comparative phylogenetic analysis showed that transitions from yellow to a green androecium or to androecial color dimorphism occurred at least seven times.this genus,characterized by anther color diversity and containing some species with anther color polymorphism,provides a model system in which to study the evolution and maintenance of colorful sexual organs in flowering plants.
文摘The involvement of communities in ecological studies has been shown to augment conservation efforts,especially for cryptic species.However,there is a lack of studies addressing the utility of incidental sighting records from community members in gaining knowledge on habitat preferences and distribution of suitable habitat for these organisms.This study compares preferences of the Lumholtz’s tree kangaroo(Dendrolagus lumholtzi;LTK),a cryptic rainforest folivore in northeastern Australia,for various habitat and climatic variables derived from data collected during scientific projects to those derived from incidental sighting records using ArcGIS and Maxent.Incidental sighting records suggest that the species uses a wider range of altitudes,annual rainfalls,annual mean temperatures and vegetation types than predicted by scientific studies.Incidental records also show that the species can persist in areas of lower rainfall during the wettest month and lower minimum temperature during the coldest month.Both data place the species within a comparable range of rainfalls during the driest month,maximum temperatures of the warmest month and soil types.When using identified preferences to assess the extent and distribution of suitable habitat,incidental records predicted more areas of suitable habitat than scientific records with an overlap of up to 91%between them.The present study proves that incidental sighting records can be a valuable part of the study of cryptic species and should be considered complementarily alongside scientific studies to obtain comprehensive ecological information of a species that can assist in its conservation.
文摘Land-use sprawl in the Himalayas has caused the conversion of natural habitat into human-modified habitats,thus degrading ecosystem health.Adaptation of birds to changing physical environment can be well understood by analyzing their habitat preferences,and foraging dynamics explored to a limited extent in the Himalayan region,as yet.To achieve a comprehensive understanding of avian guild structure,we used multivariate statistical techniques to classify bird species according to their similarities in foraging patterns and habitat preferences.Observations based on habitat and diet affinities accounted for rich avian diversity with a total of 208 bird species(about 15%of country’s avifauna)recorded from six different sites during 1 year survey.Unweighted pair-group average cluster analysis performed on the families revealed ten feeding and fifteen habitat guilds among 63 bird families observed.Subtropical forests harbored more species followed by urban forests and agricultural landscapes.Insectivorous and omnivorous outnumbered other feeding guilds in the study area.Bird assemblages were richer in protected areas and semidisturbed landscapes and did not show significant variation between the seasons.Results of the study revealed that different functional groups of birds behaved differently,primarily induced by choice of food.The site heterogeneity favored avifaunal persistence by providing favorable foraging,roosting,and nesting opportunities to birds.Composition of avian guilds indicated level of intactness and ecological integrity of ecosystems studied.This outcome thus sets the background for long-term analysis of bird-habitat relationship and their foraging dynamics.The study has the relevance for decision-makers to integrate avian guild structure as an essential ingredient in formulating conservation strategies.
基金This study was funded by the Instituto de Ecologıa,A.C.(project INECOL 20030-11189 to F.E).J.B received a PhD scholarship(No 589280)from the Mexican National Council for Science and Technology(CONACYT).
文摘While theory suggests that at conception the sex ratio should be balanced(1:1),this can be variable across space and time in wild populations.Currently,studies of the environmental factors that regulate adult sex ratio(ASR)in species with different life history traits are scarce.Using capture–recapture over a year,we analyzed the influence of habitat type(forest and nonforest)and season(rainy and dry)on variation in ASR,male aggregation and the trajectory movement of 2 dung beetle species with different life history traits:Deltochilum mexicanum(a hornless roller species)and Dichotomius satanas(a tunneler species with horns on its head and thorax).We found opposite tendencies.The D.mexicanum population tends to be female-biased,but the population of D.satanas tends to be predominantly male,and observed values were not related to habitat type or season.However,the 95%confidence intervals estimated were highly variable between seasons depending on habitat.On examining the monthly variation in ASR for both habitats,we found that it depends on the species.In addition,male aggregation differed between species depending on habitat type and season,and species movement patterns were closely related to their habitat preferences.Based on our results,we argue that comparative population studies of species with different life history traits are necessary to understand the variation in demographic parameters as well as its ecological and evolutionary implications in the face of spatial and climatic environmental variation.
基金This study was supported by the National Natural Science Foundation of China(Nos 31472013 and 31772453 to W.L.)GDAS Special Project of Science and Technology Development(Nos 2017 GDASCX-0107,2018 GDASCX-0107)to F.S.Z.
文摘Urbanization effects on living organisms are spatially heterogeneous.Here we quantified the abundance of birds per tree in forested urban and rural habitats for 85,829 trees mainly in China and Europe.A population model was based on the assumption that:1)birds have a normally distributed habitat preference;2)an increase in population size linked to the habitat preference;3)a population size dependent on the habitat preference;and 4)the removal of a certain fraction of individuals giving rise to extinction.We tested for large-scale differences in the impact of urbanization on the frequency distribution of the difference in abundance between urban and rural habitats in China and parts of Europe.The difference in the frequency distribution of urban population density of birds in trees minus rural population density of birds in trees in China and Europe was statistically significant suggesting that the abundance of birds differed between trees in urban and rural habitats,but more so in China than in Europe.We hypothesize that more pronounced differences in China than in Europe may have arisen due to the Four Pests Campaign in 1958-1962 that resulted in death of hundreds of millions of birds(mainly tree sparrows Passer monfanus,but also numerous other less common species that were starting to become urbanized around 1960).Species that were less common in 1960 could not sustain reductions in population size in urban areas and hence these species are still rare or absent in urban areas today 60 years later.