期刊文献+
共找到153篇文章
< 1 2 8 >
每页显示 20 50 100
Designated critical habitats for U.S.imperiled species are not protected from climate and land-use change
1
作者 Aimee Delach Laura A.Nunes +1 位作者 Alex Borowicz Theodore C.Weber 《Geography and Sustainability》 CSCD 2024年第3期482-490,共9页
Designation of critical habitat is an important conservation tool for species listed as threatened or endangered under the United States(U.S.)Endangered Species Act(ESA).While this is an important protective mechanism... Designation of critical habitat is an important conservation tool for species listed as threatened or endangered under the United States(U.S.)Endangered Species Act(ESA).While this is an important protective mechanism,lands designated as critical habitat could still be subject to degradation and fragmentation if they are not also in a protected status that prioritizes biodiversity conservation.Additionally,most designations of critical habitat do not explicitly take climate change into account.The objective of our study was to determine whether and to what extent critical habitats for species listed under the ESA are located within protected areas and areas previously identified as climate refugia or climate corridors,to inform management strategies to better conserve and recover these species.We mapped the designated critical habitats of 153 ESA-listed species and measured their overlap with previously-identified areas of climate refugia and corridors(CRC),and also with lands designated as nature-protected by U.S.Geological Survey’s Gap Analysis Project(GAP Status 1 or 2)and working lands with wildlife habitat potential(GAP Status 3).Only 18%of all designated critical habitat is located on lands that are both in CRC and nature-protected,and only 9%of species had over half of their designated critical habitats in such lands.84%of species had<25%overlap of their critical habitats with these areas.Critical habitats may therefore not fulfill their essential role of helping imperiled species persist and recover. 展开更多
关键词 Endangered Species Act Critical habitat Climate refugia Climate corridors Protected areas Biodiversity conservation
下载PDF
Bird Habitats in Urban Environments: A Case from an Urban Landfill in and around Tayba Al Hasanab Landfill, Khartoum, Sudan
2
作者 Mutasim Essa Abdallah Adam Mawya Ahmed Elshafea Mohamed 《Journal of Environmental Protection》 2024年第8期887-905,共19页
Managed open landfill sites can serve as crucial feeding grounds for birds. Studies have demonstrated that garbage dumps offer favorable feeding habitats for various trophic generalist species, including storks and sc... Managed open landfill sites can serve as crucial feeding grounds for birds. Studies have demonstrated that garbage dumps offer favorable feeding habitats for various trophic generalist species, including storks and scavenger raptors. This study aimed to assess bird diversity and abundance in and around Tayba Al Hasanab Landfill, Khartoum. A bird census was conducted using block counts in January 2021. A questionnaire complemented field observations, and interviews were conducted with landfill authorities and waste collectors to gather information on bird availability, numbers, and diversity. During the block counts, 23 bird species were recorded inside and around the landfill. These species directly relied on food resources available at and around the landfill, belonging to 8 orders and 11 families. The four most abundant species foraging at the landfill were Sparrow House (Passer domesticus) with 97 individuals, Black kite (Milvus migrans) with 67 individuals, cattle egret (Bubulcus ibis) with 42 individuals, and Laughing Dove (Spilopelia senegalensis) with 36 individuals. This suggests that these species are the primary exploiters of food resources at the landfill. The results indicate that all species are considered least concerned except the Egyptian Vulture (Neophron percnopterus), which is classified as endangered. Most of the interviewed individuals reported seeing birds in the study area. The study recorded instances of dead birds, such as a white stork colliding and being electrocuted with a transition line observed at different sites along transmission lines near the landfill. Surveys around Tayba landfill need to be conducted to identify deadly power lines for replacement or implement possible mitigation measures on power lines running parallel and close to the Tayba landfills. The avian community foraging at the landfill displayed fluctuations in abundance and interspecific interactions across seasons. Given that the substantial influx of birds to landfills can pose various environmental challenges in urban settings, this study underscores the significance of examining the seasonal dynamics of bird communities concerning the location and management of landfills. 展开更多
关键词 Bird Diversity Block Counts Endangered Species COLLISIONS Electrocutions Landfill Management
下载PDF
The Current Conservation Efforts and Future Prospects for the Endangered Nubian Ibex (Capra nubiana ibex) in Sudan
3
作者 Lubna Mohammed Abdallah Hassan Mutasim Essa Abdallah Adam +1 位作者 Latifa Altigani Adam Abakar Nasir Yousif Gaboush Brema 《Journal of Environmental Protection》 2024年第1期39-62,共24页
A comprehensive action plan for the conservation of the endangered species, the Nubian ibex in Sudan, can be developed by gaining a thorough understanding of their current status, conservation strategy, and relevant l... A comprehensive action plan for the conservation of the endangered species, the Nubian ibex in Sudan, can be developed by gaining a thorough understanding of their current status, conservation strategy, and relevant laws and regulations, as well as raising awareness about the importance of protecting endangered species. The Nubian ibex is listed as an endangered species on The International Union for Conservation of Nature (IUCN) Red List, highlighting the need for further research on population conservation efforts due to insufficient population data. To address this knowledge gap, a questionnaire was conducted with various stakeholders, including police officers, researchers, and lecturers, representing a diverse range of organizations and universities. The findings revealed that hunting is the primary factor contributing to endangerment. Mammals account for 80% of endangered species, while reptiles comprise less than one-tenth. Research centers are recognized as the main governing body, and 85% of participants are concerned about the declining population. Hunting accounted for less than half of the threats to the ibex population in Sudan, while habitat loss made up a quarter. Mining, climate change, human activity, and agriculture were also identified as risks. However, there were no plans, strategies, procedures, or measures in place to conserve the Nubian ibex. There were also no initiatives to preserve its biodiversity, and awareness about endangered species was lacking. Although participants believed that laws were effective in protecting the ibex, no licenses were issued for its conservation, and annual surveys were not conducted. Additionally, there were no recorded instances of Mukhalfat related to the Nubian ibex. In light of these findings, we propose various conservation measures to address these challenges. These measures include the implementation of laws and regulations, conducting annual surveys to monitor population trends, protecting habitats, establishing breeding and releasing programs, launching awareness campaigns, undertaking rehabilitation efforts, enhancing research efforts, and developing comprehensive conservation strategies. Additionally, it is crucial to foster cooperation among wildlife institutes to ensure the effective implementation of these conservation measures. 展开更多
关键词 Nubian Ibex SUDAN Endangered Species Conservation Status Law REGULATIONS AWARENESS
下载PDF
Geographical differences of leaf traits of the endangered plant Litsea coreana Levl.var.sinensis and its relationship with climate 被引量:3
4
作者 Gangyi Yuan Qiqiang Guo +3 位作者 Yaqin Zhang Qin Gui Na Xie Siqiong Luo 《Journal of Forestry Research》 SCIE CAS CSCD 2023年第1期125-135,共11页
Seventeen morphological and anatomical characteristics of the leaves were selected from five natural populations to explore the variation in leaf traits of Lits ea core ana var.sinensis and the effects of geographical... Seventeen morphological and anatomical characteristics of the leaves were selected from five natural populations to explore the variation in leaf traits of Lits ea core ana var.sinensis and the effects of geographical environment on these variations.Nested analysis of variance,multiple comparisons,principal component analysis(PCA),and correlation analysis were conducted to explore the variations within and between populations and their correlation with geographical and climatic factors.Significant differences in the 17 leaf traits were observed within and among populations.On average,the relative contribution of within population variation to total variation was 24.8%,which was lower than among population variation(54.6%).The average differentiation coefficient of the traits was 65.8%,and the average coefficient of variation 11.8%,ranging from6.7%for main vein thickness to 21.4%for petiole length.The PC A results showed that morphological characteristics were divided into two categories,and the level of variation was greater than that of leaf anatomy.Most of the leaf traits were significantly correlated with geography and climate and showed a gradual variation with longitude,latitude,and altitude.In areas with high temperatures,less rainfall,and strong seasonal rainfall,the leaves are larger,longer and thicker.This study shows that variations in leaf traits of L.coreana var.sinensis mainly come from variations among populations.The level of trait differentiation among populations is high and the level of variation within populations low.These findings help further understand leaf morphological characteristics of this species and can provide a valuable reference for the protection and sustainable utilization of this natural resource. 展开更多
关键词 Litsea coreana var.sinensis CLIMATE Leaf trait variations Natural populations Endangered species
下载PDF
The diameter of beech snags is an important factor for saproxylic beetle richness: Implications for forest management and conservation 被引量:1
5
作者 Václav Zumr Oto Nakládal +1 位作者 Lukás Bílek JiríRemes 《Forest Ecosystems》 SCIE CSCD 2023年第5期635-645,共11页
Snags are an important component of beech forests that promote biodiversity.However,their occurrence is completely marginal in managed stands.Creating snags in these stands would greatly enhance biodiversity.We invest... Snags are an important component of beech forests that promote biodiversity.However,their occurrence is completely marginal in managed stands.Creating snags in these stands would greatly enhance biodiversity.We investigated whether snag dimensions were important for saproxylic beetle richness since they were easily transferable parameters to forest management and assessed the presence of other snag microhabitats affecting beetle communities.Data collection was performed using passive flight traps placed on thirty snags in a recent beech reserve.A total of 6706 adults belonging to 231 saproxylic species(53 Red List species,23%)were captured.The results showed that the most important snag parameters were the diameter(thickness)and canopy openness of the surrounding stands.The occurrence of Fomes fomentarius,the volume of snag and decay class 3 were marginally significant in terms of the preference of all saproxylic species.Alpha diversity was reduced by an advanced degree of decay and a surprisingly deep stem cavity.After dividing snag thickness into categories(<35 cm;35–70 cm and>70 cm DBH),we found that categories with snag diameter greater than 35 cm showed little differences in all saproxylic and Red List species richness and diversity indices and exhibited the highest similarity in beetle communities.Regarding recommendations to forest managers in terms of optimization and simplification of practical procedures,we suggest actively creating high stumps to act as snags greater than 35 cm in DBH diameter to promote biodiversity in beech management stands. 展开更多
关键词 DEADWOOD Coleoptera Biodiversity Active management Endangered beetles
下载PDF
The whole-genome survey of Acer griseum,its polymorphic simple sequence repeats development and application
6
作者 XIAO-JUN ZHOU YU-WEI TIAN RUI-HAN LI 《BIOCELL》 SCIE 2023年第8期1907-1913,共7页
Background:Acer griseum Pax is an endangered species endemic to China with both ornamental and economic value.However,the lack of information on its genome size and characteristics hinders further work at the genome l... Background:Acer griseum Pax is an endangered species endemic to China with both ornamental and economic value.However,the lack of information on its genome size and characteristics hinders further work at the genome level.Methods:This paper applied bioinformatics methods to predict the characteristics and patterns of the A.griseum genome,providing an important basis for formulating its whole-genome sequencing scheme.This study also characterized the simple sequence repeats(SSRs)of A.griseum,laying the foundation for the development and application of genome-wide SSR markers.In this study,PE150 sequencing was performed by the BGI MGISEQ platform,and the sequence files were analyzed by the K-mer method to estimate the characteristic information by GCE software.Results:The genome size was finally determined to be 739.63 Mb,its heterozygosity ratio was 1.33%,and the repetition ratio was 65.68%.A total of 825,960 SSR loci were identified in the assembled genome sequence,and primers were successfully designed for 526,020 loci.To verify the effectiveness of these primers,100 pairs of primers were randomly selected and synthesized,and 81 pairs successfully amplified the target fragments.Fourteen pairs of primers with good polymorphism were selected for principal component analysis of 31 A.griseum individuals from two populations,showing favorable heterozygosity and PIC values.According to the findings,these SSRs might identify genetic variations based on geographic areas.Conclusion:It is suggested that Illumina+PacBio assembly strategy should be used for whole-genome sequencing due to the high heterozygosity rate and high repetition rate of the genome.In addition,the SSR primers designed in batches in this study laid a foundation for the in-depth study of population structure and population maintenance mechanism of A.griseum,which is helpful for the effective conservation and sustainable utilization of this germplasm resource. 展开更多
关键词 Endangered plant Paperbark maple GENOME Genetic conservation
下载PDF
First Successful Nesting of Black Oystercatchers among Endangered California Least Terns along the West Coast of North America
7
作者 David L.Riensche Ben Pearl Susan Ramos 《Journal of Environmental Science and Engineering(A)》 2023年第3期100-105,共6页
A pair of Black Oystercatchers(Haematopus bachmani)established a nest in June 2022 at“Tern Town”,an island located in Hayward,California along the eastern side of the San Francisco Bay.This is the first documented o... A pair of Black Oystercatchers(Haematopus bachmani)established a nest in June 2022 at“Tern Town”,an island located in Hayward,California along the eastern side of the San Francisco Bay.This is the first documented occurrence of oystercatchers successfully nesting and fledgling young in association with California Least Terns.The island provides nesting habitat for three special status species.Since 2015,and for a total of six breeding seasons,the endangered California Least Tern(Sternula antillarum browni),the threatened Western Snowy Plover(Charadrius alexandrinus nivosus)and species-of-special-concern Black Skimmer(Rynchops niger),have nested successfully,in association with American Avocet(Recurvirostra americana)and Black-necked Stilt(Himantopus mexicanus).We collected shells near the oystercatcher nest to assess their diet.Diet data showed the oystercatchers foraged on,in decreasing order of abundance,Japanese Little-necked Clams(Ruditapes philippinarum),Ribbed Mussels(Geukensia demissa),Bent-nose Clams(Macoma nasuta),Limpets(Patellogastropoda sp.)and Bay Mussels(Mytilus edulis).This new report on breeding Black Oystercatchers indicates that managing habitat for California Least Tern,Western Snowy Plover,and Black Skimmer can also benefit Black Oystercatcher.This site-specific information on breeding Black Oystercatchers supports recovery plan tasks that are consistent with managing habitat for California Least Tern,Western Snowy Plover and Black Skimmer. 展开更多
关键词 Black Oystercatcher REPRODUCTION diet endangered species California Least Tern Western Snowy Plover Black Skimmer
下载PDF
Tropical Climates May Be Suitable for Endangered Desert Tortoise Exhibits, Rescues, Adoptions
8
作者 Emily Richards John Nogawski 《Open Journal of Animal Sciences》 2023年第3期364-378,共15页
Governmental, educational, environmental and other nonprofit organizations have placed efforts on conservation action for the threatened Mojave desert tortoise (Gopherus agassizii). While federal and state institution... Governmental, educational, environmental and other nonprofit organizations have placed efforts on conservation action for the threatened Mojave desert tortoise (Gopherus agassizii). While federal and state institutions have focused on the desert tortoise in its native habitat of the southwestern United States, there are other conservation groups whose work has been dedicated to the rescue, rehabilitation, rescue, placement and adoption of the desert tortoise in civilian homes and neighborhoods as well as sanctuaries, reserves and exhibits. AWAKE Community (AWAKE), a nonprofit organization dedicated to natural wildlife habitats and endangered species, has focused its research on desert tortoises in captivity. The California Turtle and Tortoise Club (CTTC), the official adoption arm of California’s Department of Fish and Wildlife (CDFW), has provided instruction on methods of care for desert tortoises raised in captivity including housing, feeding, sexing, health and hibernation for both adults and hatchlings. AWAKE’s research has been aimed at benefiting and supplementing the guidelines provided by CTTC, specifically for coastal climates. AWAKE’s research has also aimed to provide insight to be considered for expanding adoption possibilities to other locations, specifically tropical climates, as adoption needs for desert tortoises have increased. This manuscript presents an analysis of one coastal and one tropical climate that can serve as a basis for: 1) understanding and evaluating climate in both existing and potential habitats for desert tortoise adoptions, rescues and exhibits, 2) providing insight and special instruction for desert tortoise adoptions in coastal communities, and 3) expanding awareness around desert tortoise needs in captivity. 展开更多
关键词 Desert Tortoise Mojave Desert Tortoise Gopherus agassizii Tortoise Adoptions Threatened Species Endangered Species Desert Tortoises in Captivity Desert Tortoise Climate
下载PDF
鲸鱼防撞“神器”
9
作者 胡牧 《疯狂英语(新读写)》 2023年第4期24-25,28,76,共4页
为了保护鲸鱼,科学家们研发出了名为“鲸鱼安全”的系统,它可以通过浮标内监测到的声音,识别鲸鱼的种类和鲸鱼群的位置,从而帮助鲸鱼降低撞船的风险。主题语境:动物保护篇幅:334词建议用时:6分钟1Humpback whales(座头鲸)are among the ... 为了保护鲸鱼,科学家们研发出了名为“鲸鱼安全”的系统,它可以通过浮标内监测到的声音,识别鲸鱼的种类和鲸鱼群的位置,从而帮助鲸鱼降低撞船的风险。主题语境:动物保护篇幅:334词建议用时:6分钟1Humpback whales(座头鲸)are among the world’s most endangered whales.The main threats humpback whales face are strikes from ships and waste equipment. 展开更多
关键词 ENDANGERED 鲸鱼 THREAT
下载PDF
Investigation on the Rare and Endangered Plants in the Fenhe Source
10
作者 郭春燕 岳建英 +5 位作者 李晋川 王文英 Chun-yan Jian-ying Jin-chuan Wen-ying 《Agricultural Science & Technology》 CAS 2010年第5期112-116,共5页
Fouty-eight species of rare and endanged plants in the Fenhe Source,belong to 21 families 37 genera.There were 1specie of national second-class protected plant and 3 species of national third-class plants;4 species of... Fouty-eight species of rare and endanged plants in the Fenhe Source,belong to 21 families 37 genera.There were 1specie of national second-class protected plant and 3 species of national third-class plants;4 species of first-class protected plants,6 species of second-class protected plants and 14 species of third-class protected plants in Shanxi Province.On the basis of analyzing the endanged reasons,related protection countemeasures were put forward in this article. 展开更多
关键词 Fenhe Source Rare and endanged plants Flora Conservation countemeasura
下载PDF
Genetic Diversity of Cephalotaxus mannii, a Rare and Endangered Plant 被引量:14
11
作者 杜道林 苏洁 +3 位作者 付永川 周鹏 马文儒 向志强 《Acta Botanica Sinica》 CSCD 2002年第2期193-198,共6页
Using RAPD technique, the DNA diversity of Cephalotaxus mannii Hook. f., its genetic diversity pattern, the reasons for its endangered position and conservative approaches were studied. The results show that: 1. The... Using RAPD technique, the DNA diversity of Cephalotaxus mannii Hook. f., its genetic diversity pattern, the reasons for its endangered position and conservative approaches were studied. The results show that: 1. The genetic diversity of C. mannii collected from five localities in Hainan is low, and its adaptability to environmental change is weak. 2. The differences of genetic diversity between intra- and inter-populations are great, and the major variation distributes within the population (DNA diversity is 85.1%). 3. The excessive lumbering, man-made destruction, violent typhoon, edible value of the seeds and genetic drift were the main reasons for the low-level genetic diversity of C. mannii and its endangered position. 4. The difference of the micro-environment and other random factors affecting the population should also be taken into full consideration in the study and in protection of such occasionally scattered plants. 5. Enforced measures should be taken to protect the present population, enlarge the population and lower the loss rate of its gene. Mt. Limulin should be chosen as a conservative spot because of its high genetic diversity and less destruction of the forest. Meanwhile, the protection of other populations should be enforced. 6. The differences within and between the populations are great based on different primers used. The change of proportions in polymorphic loci between the populations is more than that between the primers. 展开更多
关键词 rare and endangered plant Cephalotaxus mannii genetic diversity RAPD
下载PDF
Studies on the Reproductive Biology and Endangerment Mechanism of the Endangered Plant Manglietia aromatica 被引量:12
12
作者 潘跃芝 梁汉兴 龚洵 《Acta Botanica Sinica》 CSCD 2003年第3期311-316,共6页
The embryogenesis, pollen germination, floral character and seed physiology of the endangered plant Manglietia aromatica Dandy were investigated. Based on this study, this species has very low seed set rate. The abort... The embryogenesis, pollen germination, floral character and seed physiology of the endangered plant Manglietia aromatica Dandy were investigated. Based on this study, this species has very low seed set rate. The abortion rate of functional megaspores in all the ovules is 27.9%, the egg cell abortion rate of mature embryo sacs is up to 80%, and the germination rate of pollen grains is as low as nearly 0.01%. In addition, the floral structure appears to be another limited factor for the effective pollination of this species. The endangerment mechanism of this species seems to be comprehensive. Human's destroying actions are the direct factors that have made the population degenerate quickly; low reproductive ability and the destroyed environments are the main reasons that prevent the population from renovating and spreading. Therefore, the conservation measures suggested by this study are to research the breed technology, artificial population renovating, in situ conservation, and ex situ conservation. 展开更多
关键词 endangered plant Manglietia aromatica reproductive biology endangerment mechanisms
下载PDF
Genetic Analysis of Six Endangered Local Duck Populations in China Based on Microsatellite Markers 被引量:3
13
作者 苏瑛 龙瑞军 +3 位作者 陈国宏 吴信生 谢凯舟 万江红 《Journal of Genetics and Genomics》 SCIE CAS CSCD 北大核心 2007年第11期1010-1018,共9页
Seventeen microsatellite loci were used to assess the genetic variation and population structure of six endangered duck populations in China. PIC, heterozygosity with two estimators of genetic differentiation (FST an... Seventeen microsatellite loci were used to assess the genetic variation and population structure of six endangered duck populations in China. PIC, heterozygosity with two estimators of genetic differentiation (FST and GST), and Nei's standard genetic distance were evaluated. The results showed that these six endangered duck populations showed high polymorphism. The propor- tion of inter-population subdivision among the six duck populations ranged between 17.0 and 14.7%. The average heterozygosity was 0.706, 0.702, 0.691, 0.676, 0.604, and 0.660 in the Gaoyou, Liancheng, Jinding, Beijing, Shaoxing, and Jianchang ducks, respectively. The average PIC ranged from 0.561 to 0.663. Finally, the results showed higher genetic diversity and difference above the levels of genetic variation among all the populations. 展开更多
关键词 endangered duck breeds microsatellite DNA genetic diversity conservation
下载PDF
Efficient in vitro Propagation of an Endangered Species Kolkwitzia amabilis Graebn
14
作者 袁秀云 蒋素华 +1 位作者 王默霏 崔波 《Agricultural Science & Technology》 CAS 2013年第4期564-567,共4页
This study developed an efficient in vitro cultivation and propagation sys- tem for an endangered species Kolkwitzia amabilis using nodal segments as ex- plants. Multiple shoots were induced through axillary bud forma... This study developed an efficient in vitro cultivation and propagation sys- tem for an endangered species Kolkwitzia amabilis using nodal segments as ex- plants. Multiple shoots were induced through axillary bud formation. The highest fre- quency of multiple shoot induction was achieved when the nodal segment explants were incubated in Murashige and Skoog (MS) medium supplemented with 4.44 pM 6-benzyladenine (6-BA) in combination with 0.54 μM a-naphthaleneacetic acid (NAA), followed by treatment with 4.44 μM 6-BA in combination with 0.27 μM NAA. Shoot multiplication could be induced in MS medium supplemented with stand-alone 6-BA or 6-BA in combination with indole-3-acetic acid (1.71 μM) or NAA (0.27 or 0.54 μM), with 6-BA and either compound, exhibiting a stronger effect on shoot multiplication. The optimum combination of plant growth regulators for shoot multiplication was 4.44 μM 6-BA with 0.27 μM NAA. The maximum rooting percentage was obtained in a half-strength MS medium supplemented with indole-3-butyric acid alone and in com- bination with NAA and 2,4-dichlorophenoxyacetic acid, but the best combination of plant growth regulators for rooting was 1.48 μM indole-3-butyric acid with 1.08 μM NAA and 0.05 μM 2,4-dichlorophenoxyacetic acid. The rooted shoots were trans- ferred to a greenhouse with a success rate of 100%. 展开更多
关键词 Kolkwitzia amabilis Endangered species Nodal segment In vitro propa- gation Plant growth regulator
下载PDF
前缀en-与后缀-en
15
作者 尹继友 彭爱武 《英语自学》 2007年第9期45-45,共1页
前缀en-和后缀-en尽管词缀形式相同,但两者的构词功能迥然不同,前者仅用作动词词缀,而后者可作动词、形容词及名词词缀。因此不能将两者混为一谈。现分述如下:
关键词 EN SPOKEN enlarge deepen encourage endanger silenc
下载PDF
阅读理解表格式填空题专练(英文)
16
作者 郝昌明 《中学英语园地(高三版)》 2006年第Z1期68-73,共6页
关键词 填空题 中学英语园地 asked RESPONSIBILITY endanger packed an
下载PDF
Advance of New Researches on Tissue Culture of Rare and Endangered Plant Elaeagnus mollis 被引量:1
17
作者 刘庚伟 陈惠 《Agricultural Science & Technology》 CAS 2010年第9期63-67,208,共6页
This review summarized the recent research achievements on the process of tissue culture of the rare and endangered plant Elaeagnus mollis,including sterilizing protocols of different explants derived from adult plant... This review summarized the recent research achievements on the process of tissue culture of the rare and endangered plant Elaeagnus mollis,including sterilizing protocols of different explants derived from adult plants and seeds for tube germination,two types of plants regeneration(organ type and organ genesis type),methods of rooting and transplanting,factors affecting culture,as well as browning and vitrification phenomena and avoiding measures.And the further biotechnology research fields of E.mollis were prospected. 展开更多
关键词 Rare and endangered plant Elaeagnus mollis Tissue culture
下载PDF
Comparative study on population age structures between Adenophora lobophylla and A. potaninii 被引量:7
18
作者 张文辉 祖元刚 阎秀峰 《Journal of Forestry Research》 SCIE CAS CSCD 1999年第1期1-6,共6页
Comparing with an affinity and widespread species Adenophora potaninii the age structures of A. loboPhylla population, an endangered plant species were studied. 29 sample plots were investigated in the centered distri... Comparing with an affinity and widespread species Adenophora potaninii the age structures of A. loboPhylla population, an endangered plant species were studied. 29 sample plots were investigated in the centered distribution area, Jinchuan county from altitude 2 300 m to 3 400 m. The main factors which influence the population age structures of A. lobophylla were analyzed. The principal characteristics of A. lobophylla populations are that the number of seedling and the density of population are much less than these of A. potaninii population. Below aititude of 2 700 m, the age structures of most A. lobophylla populations show the declining status, only above altitude of 2 700 m they are stable, while age structures of all populations of A. potaninll populations at corresponding altitude perform stable and developing features. The age structure patterns, relations between age (X) and number of individual (y) of stable populations of A. lobophylla can be expressed by equation : y =e(a-bx), and the longest life spah is 25a. Whereas A. potaninii populations can be expressed by the equationf y =ax-b, and the longest life span of individual is 21a. The external factors, which constrain the extension of A. lobophylla population, are extreme environmental conditions such as serious drought, external disturbance and low temperature. 展开更多
关键词 ADENOPHORA lobophylla POPULATION A. potaninii Age STRUCTURE ENDANGERED PLANT
下载PDF
RAPD Analysis for Genetic Variation within the Endangered Quillwort Isoetes hypsophila (Isoetaceae) 被引量:9
19
作者 CHENJin-ming WANGJing-yuan +2 位作者 LIUXing GituruWahitiRobert WANGQing-feng 《Wuhan University Journal of Natural Sciences》 EI CAS 2005年第2期455-459,共5页
The genetic variation in the critically endangered speciesIsoetes hypsophila was investigated using Random Amplified Polymorphism DNA (RAPD) markers. Thirteen primers were screened from sixty primers, and a total of 1... The genetic variation in the critically endangered speciesIsoetes hypsophila was investigated using Random Amplified Polymorphism DNA (RAPD) markers. Thirteen primers were screened from sixty primers, and a total of 104 DNA fragments were scored, of which, 52 were polymorphic loci. Low-level genetic diversity within populations with PPB values ranging from 7.69%to 25.96%was found. An Anal ysis of Molecular Variance (AMOVA) indicated that the most of variance (78.30%) occurred between Yunnan and Si chuan. The variances among populations within regions and within populations were only 3.89%and 17.82%, respectively. 展开更多
关键词 Key words conservation ENDANGERED genetic diversity Isoetes hypsophila RAPI
下载PDF
Biodiversity and conservation in the Tibetan Plateau 被引量:8
20
作者 Zhang Bai-ping Chen Xiao-dong +1 位作者 Li Bao-lin Yao Yong-hui 《Journal of Geographical Sciences》 SCIE CSCD 2002年第2期12-20,共9页
The Tibetan Plateau (Qinghai-Xizang Plateau) is a unique biogeographic region in the world, where various landscapes, altitudinal belts, alpine ecosystems, and endangered and endemic species have been developed. A tot... The Tibetan Plateau (Qinghai-Xizang Plateau) is a unique biogeographic region in the world, where various landscapes, altitudinal belts, alpine ecosystems, and endangered and endemic species have been developed. A total of 26 altitudinal belts, 28 spectra of altitudinal belts, 12,000 species of vascular plant, 5,000 species of epiphytes, 210 species of mammals, and 532 species of birds have been recorded. The plateau is also one of the centers of species formation and differentiation in the world. To protect the biodiversity of the plateau, about 80 nature reserves have been designated, of which 45 are national or provincial, covering about 22% of the plateau area. Most of the nature reserves are distributed in the southeastern plateau. Recently, the Chinese government has initiated the Natural Forests Protection Project of China, mainly in the upper reaches of the Yangtze and Yellow rivers. No logging policies have been made and implemented for these areas. 展开更多
关键词 Tibetan Plateau BIODIVERSITY nature reserve endangered species
下载PDF
上一页 1 2 8 下一页 到第
使用帮助 返回顶部