Cupressus atlantica Gaussen （Cupressaceae） is an endemic and endangered coniferous tree geographically restricted to the N＇Fis valley in South-Western Morocco. Like many forest species, C. atlantica exhibits dorman...Cupressus atlantica Gaussen （Cupressaceae） is an endemic and endangered coniferous tree geographically restricted to the N＇Fis valley in South-Western Morocco. Like many forest species, C. atlantica exhibits dormancy which delays and reduces germination. To improve seed germination, different pre-treatments were conducted on C. atlantica seeds after storage for different periods （one, two and five years） including： scarification with sandy paper; soaking seeds in hot distilled water at 60℃ and 80℃ for 15 min and soaking seeds for 48 h in a gibberellic acid （GA3） at 1,000 and 2,000 mg·L-1. Results showed that scarification with sandy paper increased the germination rate of Atlas cypress by up to 67%, indicating that the species possess essentially an exogenous dormancy （physical dormancy） due to the hard seed coat （hardseededness）. Exogenous application of gibberellic acid （GA3） at 1,000 mg.L-1 was also effective in breaking seed dormancy and germination induction. These two treatments induced faster speed germination expressed by low number of days to first germination （8-10 days） and low values of mean germination times （MGT）. However, germination rate, under any treatment, is greatly dependent on the year of seed collection. Seeds collected in year 2004 gave the highest value, suggesting that even after five years of storage, the germination capacity of C. atlantica seeds could remain high. This observation is very interesting in the ex-situ conservation of such endemic and endangered species where the production of seeds is irregular over the years.展开更多
We used energy dispersive X-ray fluorescence（EDXRF） to determine the seasonal variation of selected trace elements（Cr, Mn, Zn, Cu, Se and Fe） and some potential toxic elements（Cd, Pb and Br） in Juniperus thurife...We used energy dispersive X-ray fluorescence（EDXRF） to determine the seasonal variation of selected trace elements（Cr, Mn, Zn, Cu, Se and Fe） and some potential toxic elements（Cd, Pb and Br） in Juniperus thurifera subsp. africana Maire（Cupressaceae） a rare medicinal tree, growing indigenously in Aures Mountains of Algeria. The precision of the results was assessed by analyzing the certified reference material IPE44（WEPAL）grass leaves. Results showed J. thurifera was characterized by high Cr and Mn contents. During autumn and winter mineral concentrations were higher in general. The levels of Cr, Se and Mn were higher during autumn and winter than during spring and summer. Zn contents were higher during summer than in other seasons. Cu content did not vary by season. The potential toxic elements in J. thurifera（Pb [ Cd [ Br） were below the permissible limits recommended by the Joint WHO/FAO guidelines except for Pb in autumn and winter.展开更多
We are currently faced with the question of how the CoV-2 severity may change in the years ahead.Our analysis of immunological and epidemiological data on endemic human coronaviruses(HCoVs)shows that infection-blockin...We are currently faced with the question of how the CoV-2 severity may change in the years ahead.Our analysis of immunological and epidemiological data on endemic human coronaviruses(HCoVs)shows that infection-blocking immunity wanes rapidly,but disease-reducing immunity is long-lived.Our model,incorporating these components of immunity,recapitulates both the current severity of CoV-2 and the benign nature of HCoVs,suggesting that once the endemic phase is reached and primary exposure is in childhood,CoV-2 may be no more virulent than the common cold.展开更多
A disease transmission model of SI type with stage structure is formulated. The stability of disease free equilibrium, the existence and uniqueness of an endemic equilibrium, the existence of a global attractor are in...A disease transmission model of SI type with stage structure is formulated. The stability of disease free equilibrium, the existence and uniqueness of an endemic equilibrium, the existence of a global attractor are investigated.展开更多
We study a proposed model describing the propagation of computer virus in the network with antidote in vulnerable system. Mathematical analysis shows that dynamics of the spread of computer viruses is determined by th...We study a proposed model describing the propagation of computer virus in the network with antidote in vulnerable system. Mathematical analysis shows that dynamics of the spread of computer viruses is determined by the threshold Ro. If Ro 〈 1, the virusfree equilibrium is globally asymptotically stable, and if R0 〉 1, the endemic equilibrium is globally asymptotically stable. Lyapunov functional method as well as geometric approach are used for proving the global stability of equilibria. A numerical investigation is carried out to confirm the analytical results. Through parameter analysis, some effective strategies for eliminating viruses are suggested.展开更多
Populus caspica Bornm.(section Leuce and subsection Albida), one of the most endangered endemic tree species in the Hyrcanian Forest in Iran, has numerous morphological characteristics that are closely similar to Popu...Populus caspica Bornm.(section Leuce and subsection Albida), one of the most endangered endemic tree species in the Hyrcanian Forest in Iran, has numerous morphological characteristics that are closely similar to Populus alba; to clarify their taxonomic relatedness and genetic differentiation and thus inform conservation strategies, we used the noncoding regions of chloroplast DNA(cpDNA; trnL-F and trnH-psbA) and the internal transcribed spacer(ITS). Leaf samples were collected from six populations across northern Iran. cpDNA and ITS fragments were amplified by universal primers using the PCR technique and directed sequencing. The results showed that P. caspica is genetically differentiated from P.alba, and two ITS variants were detected within some P.caspica individuals. Conflicts between topologies from ITS and plastid genomes were observed. High differentiation of P. caspica from the other Populus species shown in this study confirmed the diverging taxonomic status of this endangered species. We recommend in situ conservation measures(e.g., protected areas) for at least several populations of this species, especially in the plain regions of the Hyrcanian forest.展开更多
Determining climatic and physiographic variables in Mexico’s major ecoregions that are limiting to biodiversity and species of high conservation concern is essential for their conservation.Yet,at the national level t...Determining climatic and physiographic variables in Mexico’s major ecoregions that are limiting to biodiversity and species of high conservation concern is essential for their conservation.Yet,at the national level to date,few studies have been performed with large data sets and crossconfirmation using multiple statistical analyses.Here,we used 25 endemic,rare and endangered species from 3610 sampling points throughout Mexico and 25 environmental attributes,including average precipitation for different seasons of the year,annual dryness index,slope of the terrain;and maximum,minimum and average temperatures to test our hypothesis that these species could be assessed with the same weight among all variables,showing similar indices of importance.Our results using principal component analysis,covariation analysis by permutations,and random forest regression showed that summer precipitation,length of the frost-free period,spring precipitation,winter precipitation and growing season precipitation all strongly influence the abundance of tropical species.In contrast,annual precipitation and the balance at different seasons(summer and growing season)were the most relevant variables on the temperate region species.For dry areas,the minimum temperature of the coldest month and the maximum temperature of the warmest month were the most significant variables.Using these different associations in different climatic regions could support a more precise management and conservation plan for the preservation of plant species diversity in forests under different global warming scenarios.展开更多
Sacred groves preserve a rich religious and socio-cultural heritage of Indian biodiversity from primeval times,due to their values.They act as a bridge between man and nature.Groves help to improve soil quality,replen...Sacred groves preserve a rich religious and socio-cultural heritage of Indian biodiversity from primeval times,due to their values.They act as a bridge between man and nature.Groves help to improve soil quality,replenish water resources and are pivotal for biodiversity conservation of plants and animals including rare,endemic,threatened,vulnerable species and ethnobotanical species.Most of India's sacred groves are associated with a deity or a spiritual being,who protects the grove and local people.Vegetation cover of these groves has traditional ethnobotanical value,especially in the field of ethnomedicine,which accounts for the conservation of groves over the years.Numerous plant species from sacred groves are used according to tradition and culture to prevent or cure various health problems.However,modernisation,industrialisation,increased encroachment and misuse of forest resources increasingly threaten sacred groves.These treasures of nature must be conserved by formulating and applying new laws and policies while creating awareness among people about the value of sacred groves.Toward this aim,we review the distribution,ecological and socio-cultural significance of sacred groves of India and strategies to conserve them.展开更多
Dry evergreen montane forests in Ethiopia are severely threatened.The status of species composition and structure of forest vegetation are important indicators to understand the trends of threats on local plant commun...Dry evergreen montane forests in Ethiopia are severely threatened.The status of species composition and structure of forest vegetation are important indicators to understand the trends of threats on local plant communities.In the present study,we examined the floristic composition and structure of the Kibate Forest,Wonchi Highland,Ethiopia along environmental gradients.Sixty-six(30 m×30 m)plots were established every 100 m interval along altitudinal gradients(2811‒3073 m a.s.l.)in five transect lines for vegetation and environmental data collection.In total,125 vascular plant species belonging to 104 genera and 52 families were identified.Eighteen species(14%)were endemic to Ethiopia and Eritrea.The two most dominant families,Asteraceae(29 species)and Lamiaceae(eight species)accounted for 30%of the total number of species.The highest number of species(54%)was herbs.Four major community types(viz.,Olinia rochetiana-Myrsine melanophloeos,Ilex mitis-Galiniera saxifraga,Erica arborea-Protea gaguedi,and Hagenia abyssinica-Juniperus procera)were identified.The highest species richness,evenness,diversity,and importance value index were in community types 2 and 4.About 82%of the species and all endemic taxa except five were recorded in these two community types.The most dominant woody species were O.rochetiana,E.arborea,Olea europaea subsp.cuspidata,Myrica salicifolia,I.mitis var.mitis,and H.abyssinica with different patterns of population structure.The results show that there was a weak correlation between species richness and altitude.Our findings confirm that environmental variables both with interactions(such as altitude)and without interactions(such as livestock grazing)significantly(p<0.05)affect species richness.Anthropogenic activities and overgrazing by livestock appear to be the main threat in community types 2 and 3.Urgent management practices and conservation measures such as prohibiting forest clearing and overgrazing and planting indigenous trees through community participation should be considered in community types that are rich in endemic species but are highly threatened.展开更多
Background:Tree species with narrow ranges are a conservation concern because heightened extinction risk accompanies their small populations.Assessing risks for these species is challenging,however,especially in tropi...Background:Tree species with narrow ranges are a conservation concern because heightened extinction risk accompanies their small populations.Assessing risks for these species is challenging,however,especially in tropical flora where their sparse populations seldom appear in traditional plots and inventories.Here,we utilize instead large scale databases that combine tree records from many sources to test whether the narrow-range tree species of Panama are concentrated at certain elevations or in certain provinces.Past investigations have suggested that the Choco region of eastern Panama and the high mountains of western Panama may be potential hotspots of narrow-range tree species.Methods:All individual records were collected from public databases,and the range size of each tree species found in Panama was estimated as a polygon enclosing all its locations.Species with ranges<20,000 km^(2) were defined as narrow endemics.We divided Panama into geographic regions and elevation zones and counted the number of individual records and the species richness in each,separating narrow-range species from all other species.Results:The proportion of narrow endemics peaked at elevations above 2000 m,reaching 17.2% of the species recorded.At elevation<1500 m across the country,the proportion was 6-11%,except in the dry Pacific region,where it was 1.5%.Wet forests of the Caribbean coast had 8.4% narrow-range species,slightly higher than other regions.The total number of narrow endemics,however,peaked at mid-elevation,not high elevation,because total species richness was highest at mid-elevation.Conclusions:High elevation forests of west Panama had higher proportions of narrow endemic trees than low-elevation regions,supporting their hot-spot status,while dry lowland forests had the lowest proportion.This supports the notion that montane forests of Central America should be a conservation focus.However,given generally higher diversity at low-to mid-elevation,lowlands are also important habitats for narrow-range tree species,though conservation efforts here may not protect narrow-range tree species as efficiently.展开更多
Numerous amphibian species occupy microhabitats with buffered thermal and moisture conditions,typically under forest canopies.Here,we assessed whether the insular endemic Salamandra corsica also uses this type of habi...Numerous amphibian species occupy microhabitats with buffered thermal and moisture conditions,typically under forest canopies.Here,we assessed whether the insular endemic Salamandra corsica also uses this type of habitat,which could have important implications for its conservation.We used data loggers to record the air temperature and air humidity at 4 h intervals over a period of 2 years,at 13 stations with a confirmed presence of S.corsica.These data were compared with those recorded at Corsican weather stations and those generated by a climate model(WorldClim 2).The weather station data showed significant deviations from the probe data,by an average of-1.26℃(minimum temperature),+2.61℃(maximum temperature),and-0.04%(relative humidity).Similarly,the WorldClim 2 data showed significant deviations from the probe data,by an average of-2.49°C(minimum temperature)and+1.69℃(maximum temperature).These discrepancies refl ect the use of densely vegetated and topographically complex habitats by S.corsica,which reduce temperature fluctuations.Overall,our results highlight the importance of natural vegetal cover in the conservation of populations of this endemic salamander.展开更多
Sacred groves are patches of forests preserved for their spiri- tual and religious significance. The practice gained relevance with the spread of agriculture that caused large-scale deforestation affecting bio- divers...Sacred groves are patches of forests preserved for their spiri- tual and religious significance. The practice gained relevance with the spread of agriculture that caused large-scale deforestation affecting bio- diversity and watersheds. Sacred groves may lose their prominence nowadays, but are still relevant in Indian rural landscapes inhabited by traditional communities. The recent rise of interest in this tradition encouraged scientific study that despite its pan-Indian distribution, focused on India＇s northeast, Western Ghats and east coast either for their global/regional importance or unique ecosystems. Most studies focused on flora, mainly angiosperms, and the faunal studies concentrated on vertebrates while lower life fomas were grossly neglected. Studies on ecosystem functioning are few although observations are available. Most studies attributed watershed protection values to sacred groves but hardly highlighted hydrological process or water yield in comparison with other land use types. The grove studies require diversification from a stereo- typed path and must move towards creating credible scientific foundations for conservation. Documentation should continue in unexplored areas but more work is needed on basic ecological functions and ecosystem dynamics to strengthen planning for scientifically sound sacred grove management.展开更多
Ethiopian moist evergreen Afromontane forests are vital for the conservation of plant diversity,including genetic pools of Coffea arabica L.However,these forests are continuously shrinking and need empirical scientifi...Ethiopian moist evergreen Afromontane forests are vital for the conservation of plant diversity,including genetic pools of Coffea arabica L.However,these forests are continuously shrinking and need empirical scientific studies for their effective conservation and sustainable management.This study was,therefore,conducted to assess woody species composition,diversity,endemicity,structure,plant communities,and environmental determinants in Sirso moist evergreen Afromontane forest of southern Ethiopia.Environmental variables such as altitude,slope,aspect,disturbance levels,and geographical location were recorded for each main plots.Vegetation structure and importance value index(IVI),diversity,vegetation classification,and correlation with environmental factors were analyzed.A total of 74 woody species representing 70 genera and 34 families were identified.Seven species were endemic.Rhus glutinosa A.Rich subsp.glutinosa and Prunus africana(Hook.f.)Kalkm.were species categorized as vulnerable according to the IUCN red list category.The highest number of species was recorded for the Rubiaceae family(8),followed by Euphorbiaceae(6),and Asteraceae(6).Five plant communities were identified:Maesa lanceolata-Dombeya torrida,Galiniera saxifraga-Cyathea manniana,Vepris dainellii-Triumfetta tomentosa,Dracaena fragrans-Rytigynia neglecta,and Arundinaria alpina.The distribution of these communities depends on altitude,slope,and disturbance factors.Syzygium guineense(Wild.)DC.,Schefflera abyssinica(Hochst.ex A.Rich.)Harms,and Galiniera saxifraga(Hochst.)Bridson were species with the highest IVI,while P.africana,Cordia africana Lam.,Hagenia abyssinica(Bruce)J.F.Gmelin,Bridelia micrantha(Hochst.)Baill.,and C.arabica had the lowest.Population structure of woody species showed an inverted J-shape,a J-shape,a bell-shape,and an irregular shaped pattern.These latter three population structure revealed signs of disturbances,and were negatively correlated with altitude and slope.The study showed that the Sirso moist evergreen Afromontane forest is species rich and should be given conservation priority to maintain endemic and native species.展开更多
In Yunnan, 8 major aspects of biodiversity and fragility in landforms, ecosystems, distribution populations, alien invasion, segregation, pollution and maladministration with various menace factors causing biodiversit...In Yunnan, 8 major aspects of biodiversity and fragility in landforms, ecosystems, distribution populations, alien invasion, segregation, pollution and maladministration with various menace factors causing biodiversity loss have been described. It is revealed that the facts that the biodiversity and fragility coexists in this paper. Accordingly, 6 major countermeasures for effective conservation and rational utilization of the provincial biodiversity were suggested on the basis of the scientific development concepts, principles of nature protection, conservation biology, resource management and ethnobotany and present status in Yunnan with rich intangible resources such as climatic, ethnical and cultural diversity, etc.展开更多
With an area of 394,000 km^2 （4.1% of China＇s total area） and specific diversified geographical environments, Yunnan houses over 18,000 species of higher plants （51.6% of China＇s total）, 1,836 vertebrate species...With an area of 394,000 km^2 （4.1% of China＇s total area） and specific diversified geographical environments, Yunnan houses over 18,000 species of higher plants （51.6% of China＇s total）, 1,836 vertebrate species （54.8% of China＇s total） and multitudinous species of rare, endemic and epibiotic wildlife, ranking first in species richness value and endemicity rate of China＇s biodiversity, thus becoming a rare gene bank of wildlife species with the most concentrated distribution of important wildlife taxa and a key terrestrial biodiversity region of global significance. Despite its evident abundance and endemism, however, the biodiversity is faced with threats of ecological fragility and human disturbances in socioeconomic development resulting in attenuation of biodiversity, degradation of ecosystems and serious loss of species, thus, it needs to be carefully studied for its sustainability. Based on the analyses of the geographical diversity, the macro material bases of Yunnan＇s biodiversity were reviewed and six characteristics of the provincial biodiversity were described in the ecosystems, forest types, species compositions, endemic species, genetic resources, etc. By appraising the present status of the provincial biodiversity conservation, the facts that the biodiversity coexisted with fragility were revealed so that eight key disadvantageous factors in the provincial ecological fragility causing serious biodiversity loss were summarized and described in this paper. In order to satisfy the two-fold needs of biodiversity sustainability and socioeconomic development, eight strategies for the sustainable development were intensively elaborated by borrowing certain theories in modern conservation biology, recycling economics and some successful innovations, and by giving comprehensive consideration to the ecological fragility mechanism, nature reserve construction, environmental protection and the exploitability of resources for biodiversity sustainability and socioeconomic development. Accordingly, relevant targets, principles, tactics and measures for effective biodiversity conservation and sustainability were suggested to lay a solid theoretical foundation and reliable scientific basis for the biodiversity and socioeconomic sustainable development.展开更多
We investigated the floristic composition of the Hyrcanian forests and the related forest-steppe ecotone in Northern Iran by using two long ecological transects, from lowland to upper mountain areas. The study was con...We investigated the floristic composition of the Hyrcanian forests and the related forest-steppe ecotone in Northern Iran by using two long ecological transects, from lowland to upper mountain areas. The study was conducted during 2008 and 2009 and yielded the identification of 395 plant taxa belonging to 233 genera and 78 families. Dicots with 300 taxa were the richest groups of the flora, followed by monocots with 75 taxa, pteridophytes with 18 species,and gymnosperms with two species. The largest families were Asteraceae（33 taxa）; Rosaceae（32 taxa）; and Poaceae（30 taxa）, and the most diverse genera included Carex（15 taxa）; Alchemilla（7 taxa）; and Poa, Geranium and Acer（6 taxa each）. Hemicryptophytes were the most dominant life forms in the area（40 %）; followed by geophytes（31.4 %）; phanerophytes（15.4 %）; therophytes（11.4 %）; and chamaephytes（1.8 %）. Phytogeographically,Euro-Siberian/Irano-Turanian elements（86 taxa, 21.8 %）and Euro-Siberian elements（85 taxa, 21.5 %） were the most common chorotypes in the area. Out of 395 taxa, 66taxa（16.7 %） were endemics and subendemics in Iran, of which 26 taxa were exclusively endemics of Iran.According to the IUCN Red List Categories, 48 threatened plant taxa were found in the study area. Plant diversity, life form, and chorotypes in the current study were compared with similar transect studies in other areas of the Hyrcanian forests and in different altitudinal belts, using S？renson similarity indices. Floristic composition of the surveyed transects demonstrated almost 50 % similarity between them.展开更多
文摘Cupressus atlantica Gaussen （Cupressaceae） is an endemic and endangered coniferous tree geographically restricted to the N＇Fis valley in South-Western Morocco. Like many forest species, C. atlantica exhibits dormancy which delays and reduces germination. To improve seed germination, different pre-treatments were conducted on C. atlantica seeds after storage for different periods （one, two and five years） including： scarification with sandy paper; soaking seeds in hot distilled water at 60℃ and 80℃ for 15 min and soaking seeds for 48 h in a gibberellic acid （GA3） at 1,000 and 2,000 mg·L-1. Results showed that scarification with sandy paper increased the germination rate of Atlas cypress by up to 67%, indicating that the species possess essentially an exogenous dormancy （physical dormancy） due to the hard seed coat （hardseededness）. Exogenous application of gibberellic acid （GA3） at 1,000 mg.L-1 was also effective in breaking seed dormancy and germination induction. These two treatments induced faster speed germination expressed by low number of days to first germination （8-10 days） and low values of mean germination times （MGT）. However, germination rate, under any treatment, is greatly dependent on the year of seed collection. Seeds collected in year 2004 gave the highest value, suggesting that even after five years of storage, the germination capacity of C. atlantica seeds could remain high. This observation is very interesting in the ex-situ conservation of such endemic and endangered species where the production of seeds is irregular over the years.
基金funded by Algerian Ministry of Higher Education and Scientific Research through the Project(CNEPRU No.D04N01UN170120140017)
文摘We used energy dispersive X-ray fluorescence（EDXRF） to determine the seasonal variation of selected trace elements（Cr, Mn, Zn, Cu, Se and Fe） and some potential toxic elements（Cd, Pb and Br） in Juniperus thurifera subsp. africana Maire（Cupressaceae） a rare medicinal tree, growing indigenously in Aures Mountains of Algeria. The precision of the results was assessed by analyzing the certified reference material IPE44（WEPAL）grass leaves. Results showed J. thurifera was characterized by high Cr and Mn contents. During autumn and winter mineral concentrations were higher in general. The levels of Cr, Se and Mn were higher during autumn and winter than during spring and summer. Zn contents were higher during summer than in other seasons. Cu content did not vary by season. The potential toxic elements in J. thurifera（Pb [ Cd [ Br） were below the permissible limits recommended by the Joint WHO/FAO guidelines except for Pb in autumn and winter.
文摘We are currently faced with the question of how the CoV-2 severity may change in the years ahead.Our analysis of immunological and epidemiological data on endemic human coronaviruses(HCoVs)shows that infection-blocking immunity wanes rapidly,but disease-reducing immunity is long-lived.Our model,incorporating these components of immunity,recapitulates both the current severity of CoV-2 and the benign nature of HCoVs,suggesting that once the endemic phase is reached and primary exposure is in childhood,CoV-2 may be no more virulent than the common cold.
基金This work is supported by National Natural Science Foundation of China (10171106)the Special Fund for Major State Basic Research Projects (G1999032805)
文摘A disease transmission model of SI type with stage structure is formulated. The stability of disease free equilibrium, the existence and uniqueness of an endemic equilibrium, the existence of a global attractor are investigated.
文摘We study a proposed model describing the propagation of computer virus in the network with antidote in vulnerable system. Mathematical analysis shows that dynamics of the spread of computer viruses is determined by the threshold Ro. If Ro 〈 1, the virusfree equilibrium is globally asymptotically stable, and if R0 〉 1, the endemic equilibrium is globally asymptotically stable. Lyapunov functional method as well as geometric approach are used for proving the global stability of equilibria. A numerical investigation is carried out to confirm the analytical results. Through parameter analysis, some effective strategies for eliminating viruses are suggested.
基金supported by grant funding from the Tarbiat Modares University and Mazandaran University
文摘Populus caspica Bornm.(section Leuce and subsection Albida), one of the most endangered endemic tree species in the Hyrcanian Forest in Iran, has numerous morphological characteristics that are closely similar to Populus alba; to clarify their taxonomic relatedness and genetic differentiation and thus inform conservation strategies, we used the noncoding regions of chloroplast DNA(cpDNA; trnL-F and trnH-psbA) and the internal transcribed spacer(ITS). Leaf samples were collected from six populations across northern Iran. cpDNA and ITS fragments were amplified by universal primers using the PCR technique and directed sequencing. The results showed that P. caspica is genetically differentiated from P.alba, and two ITS variants were detected within some P.caspica individuals. Conflicts between topologies from ITS and plastid genomes were observed. High differentiation of P. caspica from the other Populus species shown in this study confirmed the diverging taxonomic status of this endangered species. We recommend in situ conservation measures(e.g., protected areas) for at least several populations of this species, especially in the plain regions of the Hyrcanian forest.
基金the National Council of Science and Technology of Mexico for the postdoc fellowship awarded。
文摘Determining climatic and physiographic variables in Mexico’s major ecoregions that are limiting to biodiversity and species of high conservation concern is essential for their conservation.Yet,at the national level to date,few studies have been performed with large data sets and crossconfirmation using multiple statistical analyses.Here,we used 25 endemic,rare and endangered species from 3610 sampling points throughout Mexico and 25 environmental attributes,including average precipitation for different seasons of the year,annual dryness index,slope of the terrain;and maximum,minimum and average temperatures to test our hypothesis that these species could be assessed with the same weight among all variables,showing similar indices of importance.Our results using principal component analysis,covariation analysis by permutations,and random forest regression showed that summer precipitation,length of the frost-free period,spring precipitation,winter precipitation and growing season precipitation all strongly influence the abundance of tropical species.In contrast,annual precipitation and the balance at different seasons(summer and growing season)were the most relevant variables on the temperate region species.For dry areas,the minimum temperature of the coldest month and the maximum temperature of the warmest month were the most significant variables.Using these different associations in different climatic regions could support a more precise management and conservation plan for the preservation of plant species diversity in forests under different global warming scenarios.
文摘Sacred groves preserve a rich religious and socio-cultural heritage of Indian biodiversity from primeval times,due to their values.They act as a bridge between man and nature.Groves help to improve soil quality,replenish water resources and are pivotal for biodiversity conservation of plants and animals including rare,endemic,threatened,vulnerable species and ethnobotanical species.Most of India's sacred groves are associated with a deity or a spiritual being,who protects the grove and local people.Vegetation cover of these groves has traditional ethnobotanical value,especially in the field of ethnomedicine,which accounts for the conservation of groves over the years.Numerous plant species from sacred groves are used according to tradition and culture to prevent or cure various health problems.However,modernisation,industrialisation,increased encroachment and misuse of forest resources increasingly threaten sacred groves.These treasures of nature must be conserved by formulating and applying new laws and policies while creating awareness among people about the value of sacred groves.Toward this aim,we review the distribution,ecological and socio-cultural significance of sacred groves of India and strategies to conserve them.
基金The work was supported by the Regional Capacity Building for Sustainable Natural Resource Management and Agricultural Improvement under Climate Change(CAPSNAC)Project of the Norwegian Program for Capacity Building in Higher Education and Research for Development(NORHED).
文摘Dry evergreen montane forests in Ethiopia are severely threatened.The status of species composition and structure of forest vegetation are important indicators to understand the trends of threats on local plant communities.In the present study,we examined the floristic composition and structure of the Kibate Forest,Wonchi Highland,Ethiopia along environmental gradients.Sixty-six(30 m×30 m)plots were established every 100 m interval along altitudinal gradients(2811‒3073 m a.s.l.)in five transect lines for vegetation and environmental data collection.In total,125 vascular plant species belonging to 104 genera and 52 families were identified.Eighteen species(14%)were endemic to Ethiopia and Eritrea.The two most dominant families,Asteraceae(29 species)and Lamiaceae(eight species)accounted for 30%of the total number of species.The highest number of species(54%)was herbs.Four major community types(viz.,Olinia rochetiana-Myrsine melanophloeos,Ilex mitis-Galiniera saxifraga,Erica arborea-Protea gaguedi,and Hagenia abyssinica-Juniperus procera)were identified.The highest species richness,evenness,diversity,and importance value index were in community types 2 and 4.About 82%of the species and all endemic taxa except five were recorded in these two community types.The most dominant woody species were O.rochetiana,E.arborea,Olea europaea subsp.cuspidata,Myrica salicifolia,I.mitis var.mitis,and H.abyssinica with different patterns of population structure.The results show that there was a weak correlation between species richness and altitude.Our findings confirm that environmental variables both with interactions(such as altitude)and without interactions(such as livestock grazing)significantly(p<0.05)affect species richness.Anthropogenic activities and overgrazing by livestock appear to be the main threat in community types 2 and 3.Urgent management practices and conservation measures such as prohibiting forest clearing and overgrazing and planting indigenous trees through community participation should be considered in community types that are rich in endemic species but are highly threatened.
基金The Center for Tree Science at the Morton Arboretum provided financial support for the lead authorby the Smithsonian Institution and the National Science Foundation(US).
文摘Background:Tree species with narrow ranges are a conservation concern because heightened extinction risk accompanies their small populations.Assessing risks for these species is challenging,however,especially in tropical flora where their sparse populations seldom appear in traditional plots and inventories.Here,we utilize instead large scale databases that combine tree records from many sources to test whether the narrow-range tree species of Panama are concentrated at certain elevations or in certain provinces.Past investigations have suggested that the Choco region of eastern Panama and the high mountains of western Panama may be potential hotspots of narrow-range tree species.Methods:All individual records were collected from public databases,and the range size of each tree species found in Panama was estimated as a polygon enclosing all its locations.Species with ranges<20,000 km^(2) were defined as narrow endemics.We divided Panama into geographic regions and elevation zones and counted the number of individual records and the species richness in each,separating narrow-range species from all other species.Results:The proportion of narrow endemics peaked at elevations above 2000 m,reaching 17.2% of the species recorded.At elevation<1500 m across the country,the proportion was 6-11%,except in the dry Pacific region,where it was 1.5%.Wet forests of the Caribbean coast had 8.4% narrow-range species,slightly higher than other regions.The total number of narrow endemics,however,peaked at mid-elevation,not high elevation,because total species richness was highest at mid-elevation.Conclusions:High elevation forests of west Panama had higher proportions of narrow endemic trees than low-elevation regions,supporting their hot-spot status,while dry lowland forests had the lowest proportion.This supports the notion that montane forests of Central America should be a conservation focus.However,given generally higher diversity at low-to mid-elevation,lowlands are also important habitats for narrow-range tree species,though conservation efforts here may not protect narrow-range tree species as efficiently.
文摘Numerous amphibian species occupy microhabitats with buffered thermal and moisture conditions,typically under forest canopies.Here,we assessed whether the insular endemic Salamandra corsica also uses this type of habitat,which could have important implications for its conservation.We used data loggers to record the air temperature and air humidity at 4 h intervals over a period of 2 years,at 13 stations with a confirmed presence of S.corsica.These data were compared with those recorded at Corsican weather stations and those generated by a climate model(WorldClim 2).The weather station data showed significant deviations from the probe data,by an average of-1.26℃(minimum temperature),+2.61℃(maximum temperature),and-0.04%(relative humidity).Similarly,the WorldClim 2 data showed significant deviations from the probe data,by an average of-2.49°C(minimum temperature)and+1.69℃(maximum temperature).These discrepancies refl ect the use of densely vegetated and topographically complex habitats by S.corsica,which reduce temperature fluctuations.Overall,our results highlight the importance of natural vegetal cover in the conservation of populations of this endemic salamander.
基金the funding from Indian Institute of Science for pursuing the research work
文摘Sacred groves are patches of forests preserved for their spiri- tual and religious significance. The practice gained relevance with the spread of agriculture that caused large-scale deforestation affecting bio- diversity and watersheds. Sacred groves may lose their prominence nowadays, but are still relevant in Indian rural landscapes inhabited by traditional communities. The recent rise of interest in this tradition encouraged scientific study that despite its pan-Indian distribution, focused on India＇s northeast, Western Ghats and east coast either for their global/regional importance or unique ecosystems. Most studies focused on flora, mainly angiosperms, and the faunal studies concentrated on vertebrates while lower life fomas were grossly neglected. Studies on ecosystem functioning are few although observations are available. Most studies attributed watershed protection values to sacred groves but hardly highlighted hydrological process or water yield in comparison with other land use types. The grove studies require diversification from a stereo- typed path and must move towards creating credible scientific foundations for conservation. Documentation should continue in unexplored areas but more work is needed on basic ecological functions and ecosystem dynamics to strengthen planning for scientifically sound sacred grove management.
基金The project was fully funded by the Ethiopian Biodiversity Institute and NORAD project,Hawassa University.
文摘Ethiopian moist evergreen Afromontane forests are vital for the conservation of plant diversity,including genetic pools of Coffea arabica L.However,these forests are continuously shrinking and need empirical scientific studies for their effective conservation and sustainable management.This study was,therefore,conducted to assess woody species composition,diversity,endemicity,structure,plant communities,and environmental determinants in Sirso moist evergreen Afromontane forest of southern Ethiopia.Environmental variables such as altitude,slope,aspect,disturbance levels,and geographical location were recorded for each main plots.Vegetation structure and importance value index(IVI),diversity,vegetation classification,and correlation with environmental factors were analyzed.A total of 74 woody species representing 70 genera and 34 families were identified.Seven species were endemic.Rhus glutinosa A.Rich subsp.glutinosa and Prunus africana(Hook.f.)Kalkm.were species categorized as vulnerable according to the IUCN red list category.The highest number of species was recorded for the Rubiaceae family(8),followed by Euphorbiaceae(6),and Asteraceae(6).Five plant communities were identified:Maesa lanceolata-Dombeya torrida,Galiniera saxifraga-Cyathea manniana,Vepris dainellii-Triumfetta tomentosa,Dracaena fragrans-Rytigynia neglecta,and Arundinaria alpina.The distribution of these communities depends on altitude,slope,and disturbance factors.Syzygium guineense(Wild.)DC.,Schefflera abyssinica(Hochst.ex A.Rich.)Harms,and Galiniera saxifraga(Hochst.)Bridson were species with the highest IVI,while P.africana,Cordia africana Lam.,Hagenia abyssinica(Bruce)J.F.Gmelin,Bridelia micrantha(Hochst.)Baill.,and C.arabica had the lowest.Population structure of woody species showed an inverted J-shape,a J-shape,a bell-shape,and an irregular shaped pattern.These latter three population structure revealed signs of disturbances,and were negatively correlated with altitude and slope.The study showed that the Sirso moist evergreen Afromontane forest is species rich and should be given conservation priority to maintain endemic and native species.
基金This work was supported by a grant from the National Natural Science Foundation of China (No.30560127/C020608)
文摘In Yunnan, 8 major aspects of biodiversity and fragility in landforms, ecosystems, distribution populations, alien invasion, segregation, pollution and maladministration with various menace factors causing biodiversity loss have been described. It is revealed that the facts that the biodiversity and fragility coexists in this paper. Accordingly, 6 major countermeasures for effective conservation and rational utilization of the provincial biodiversity were suggested on the basis of the scientific development concepts, principles of nature protection, conservation biology, resource management and ethnobotany and present status in Yunnan with rich intangible resources such as climatic, ethnical and cultural diversity, etc.
文摘With an area of 394,000 km^2 （4.1% of China＇s total area） and specific diversified geographical environments, Yunnan houses over 18,000 species of higher plants （51.6% of China＇s total）, 1,836 vertebrate species （54.8% of China＇s total） and multitudinous species of rare, endemic and epibiotic wildlife, ranking first in species richness value and endemicity rate of China＇s biodiversity, thus becoming a rare gene bank of wildlife species with the most concentrated distribution of important wildlife taxa and a key terrestrial biodiversity region of global significance. Despite its evident abundance and endemism, however, the biodiversity is faced with threats of ecological fragility and human disturbances in socioeconomic development resulting in attenuation of biodiversity, degradation of ecosystems and serious loss of species, thus, it needs to be carefully studied for its sustainability. Based on the analyses of the geographical diversity, the macro material bases of Yunnan＇s biodiversity were reviewed and six characteristics of the provincial biodiversity were described in the ecosystems, forest types, species compositions, endemic species, genetic resources, etc. By appraising the present status of the provincial biodiversity conservation, the facts that the biodiversity coexisted with fragility were revealed so that eight key disadvantageous factors in the provincial ecological fragility causing serious biodiversity loss were summarized and described in this paper. In order to satisfy the two-fold needs of biodiversity sustainability and socioeconomic development, eight strategies for the sustainable development were intensively elaborated by borrowing certain theories in modern conservation biology, recycling economics and some successful innovations, and by giving comprehensive consideration to the ecological fragility mechanism, nature reserve construction, environmental protection and the exploitability of resources for biodiversity sustainability and socioeconomic development. Accordingly, relevant targets, principles, tactics and measures for effective biodiversity conservation and sustainability were suggested to lay a solid theoretical foundation and reliable scientific basis for the biodiversity and socioeconomic sustainable development.
文摘We investigated the floristic composition of the Hyrcanian forests and the related forest-steppe ecotone in Northern Iran by using two long ecological transects, from lowland to upper mountain areas. The study was conducted during 2008 and 2009 and yielded the identification of 395 plant taxa belonging to 233 genera and 78 families. Dicots with 300 taxa were the richest groups of the flora, followed by monocots with 75 taxa, pteridophytes with 18 species,and gymnosperms with two species. The largest families were Asteraceae（33 taxa）; Rosaceae（32 taxa）; and Poaceae（30 taxa）, and the most diverse genera included Carex（15 taxa）; Alchemilla（7 taxa）; and Poa, Geranium and Acer（6 taxa each）. Hemicryptophytes were the most dominant life forms in the area（40 %）; followed by geophytes（31.4 %）; phanerophytes（15.4 %）; therophytes（11.4 %）; and chamaephytes（1.8 %）. Phytogeographically,Euro-Siberian/Irano-Turanian elements（86 taxa, 21.8 %）and Euro-Siberian elements（85 taxa, 21.5 %） were the most common chorotypes in the area. Out of 395 taxa, 66taxa（16.7 %） were endemics and subendemics in Iran, of which 26 taxa were exclusively endemics of Iran.According to the IUCN Red List Categories, 48 threatened plant taxa were found in the study area. Plant diversity, life form, and chorotypes in the current study were compared with similar transect studies in other areas of the Hyrcanian forests and in different altitudinal belts, using S？renson similarity indices. Floristic composition of the surveyed transects demonstrated almost 50 % similarity between them.
