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91.
Cypripedium macranthos var. rebunense is an endangered plant endemic to Rebun Island, Japan. A proper understanding of genetic diversity is needed when conducting conservation programs for rare and endangered species. We therefore examined the genetic diversity of C. macranthos var. rebunense using allozyme markers with a view to future conservation. Our study revealed that C. macranthos var. rebunense has relatively high genetic diversity (P was 0.62, n a and n e were 1.85 and 1.28 respectively, and H o and H e were 0.163 and 0.187, respectively) when compared with other plant taxa. The natural habitats of C. macranthos var. rebunense are geographically separated into northern and the southern populations. Disappearance of alleles and increase in homozygosity expected as a result of the bottleneck effect were observed, particularly in the southern populations composed of a small number of plants. As additional negative effects (inbreeding depression and further genetic drift) due to fragmentation are predicted in these populations, the southern populations may show deterioration of genetic diversity in the near future.  相似文献   
92.
Mentha longifolia is an important medicinal and aromatic perennial herb that exhibits wide distribution range from sub-tropical to temperate regions. In the present study, agro-morphological traits and genetic differences in 19 different populations of M. longifolia were studied to evaluate the level and extent of its diversity. Analysis of variance (ANOVA) showed that the different phenotypic characters show considerable differences among various populations and was significant at p < 0.05. Molecular diversity analysis performed by using arbitrary amplified eleven ISSR primers generated a total of 121 amplicons that range within the size of 200–2500 base pairs (bp). Each primer on average generated 11 amplicons with percentage polymorphism being 100. The analysis of molecular variance (AMOVA) showed more (64%) among population genetic diversity and less (36%) within the populations. Greater genetic differentiation (Gst = 0.6852) among these populations occurs due to low gene flow (Nm = 0.2297) and greater habitat variability. Geographic and genetic distances were positively correlated according to Mantel’s test. In order to remove any kind of biases, we used R software to perform cluster and redundancy analysis to analyse the extent of relatedness among studied populations. In terms of morphological and molecular aspects, the populations were grouped into four and five clusters respectively based on hierarchical clustering method. The results demonstrated that M. longifolia displays a great degree of morphological and genetic variation and can be utilized in breeding, genetic improvement, and gene bank conservation programmes in future.  相似文献   
93.
Bali, Indonesia sits within the coral triangle and is internationally recognised for its high coral reef diversity. The health of Bali’s marine ecosystems has declined in recent decades, and this is thought to be due to threats from climate change, destructive fishing practices, pollution, outbreaks coral eating invertebrates, coral disease and unsustainable tourism. As a response, multiple conservation strategies have been introduced by the island’s communities, non-government organisations and governments, with the aim of preventing further decline, as well as restoring already degraded coral reefs. This literature review provides an in-depth analysis of the tools used to conserve Bali’s coral reefs, and compares them to those used in other countries. In light of international ‘best practice’ in coral reef conservation, this review makes suggestions on how Bali could better conserve its coral reef ecosystems. These include (1) increasing its designation of official Marine Protected Areas (MPAS) and strengthening management of existing ones, (2) creating an MPA network, (3) substantially reducing marine plastic pollution, (4) continuing artificial reef construction in degraded habitats, (5) continuing to develop Bali as an ecotourism destination, (6) increasing engagement in global science to inform marine conservation decision-making, and (7) developing more marine monitoring programmes.  相似文献   
94.
Reintroduction or translocation of threatened plant species, as part of in situ conservation efforts, often failed because of the lack or the poor quality of remaining natural habitats due to human disturbances and invasion by alien species, especially in island ecosystems. We conducted a study on Ochrosia tahitensis (Apocynaceae), a critically endangered endemic small tree in the tropical high volcanic island of Tahiti (French Polynesia, South Pacific) to find the most suitable sites for future translocation. Distribution models were produced based on climate, topography, and plant community inventories (i.e. species composition and abundance, canopy height and openness, basal area of woody species) of the few remnant populations. Results show that this species, comprising 32 reproductive trees within 16 populations known in the wild, remains restricted to a few ecological refuges representing a very small part of its potential ecological range located on the northwest side of the island, and shares its current habitats with a set of more common native woody species found in mesic-wet forests. The use of native plant communities as a proxy for habitat suitability along with species distribution modelling can enhance translocation success in island ecosystems, but only if the major threats causing population decrease, mainly forest destruction and fragmentation and invasive alien species, are effectively managed.  相似文献   
95.
Habitat banking in its many iterations is an established and popular mechanism to deliver environmental offsets. The United States can look back at over 30 years of banking experience with the underlying framework and policies being consistently updated and improved. Given the increased demand in habitat banking, we provide insights into how bank area capacity is distributed across the United States for four different bank targets (wetlands, streams, multiple ecosystems, species) based on information extracted from the Regulatory In-lieu Fee and Bank Information Tracking System, as well as, estimating future capacities and area reserves through a predictive modeling approach based on data from the past 26 years. Future predictions indicate a decrease in available reserves for banks targeting wetlands or multiple ecosystems, with potential bottlenecks relating to large reserves being limited to the southeast and release schedules not catching up to the current and anticipated demand. Banks targeting species or streams are predicted to meet future demand, with species banks (conservation banks) following a different legislative and operational approach based on the listing of endangered species and pro-active approaches with anticipated future demand. Most current reserves for all four bank types are restricted to very few service areas with around one-third of all bank areas still awaiting release, limiting their availability on a broader scale. Strategic planning networks are necessary to meet future demand on a national scale and to identify areas suitable for banking or likely to experience future environmental or developmental stress.  相似文献   
96.
The Hondo River is the natural border between Mexico and Belize, and it is part of the distribution area of the Endangered Antillean manatee Trichechus manatus manatus. Currently, the Hondo River does not have any special protection. Employing qualitative research methods, we documented the social perception and local knowledge from riverside communities to assess conservation status and trends of manatees in the area. Fifty semi-structured interviews were carried out to river users in 16 Mexican communities, distributed in six segments along the riverbed. The claims of the inhabitants agree with boat-based surveys: most of the current and historical manatee sightings were reported in segments of the main watercourses, but also in small tributaries, which are usually shallow and rich in aquatic vegetation. Additionally, the local perception about manatee conservation status can be helpful to understand population trends and threats: 48 % of the interviewees claimed that nowadays the number of sighted manatees is less than that observed 10 years ago. The responders identified water pollution due to cane cultivation practices, motorized vessels traffic, and presence of fishing nets as potential threats to manatees. This study provides evidence of relevant local knowledge about the manatee ecology and its habitat, critical in the construction of binational conservation strategies for the species. Therefore, local resources users may play an increasingly significant role in manatee management and monitoring. Although manatees are poached for their meat in several areas of their distribution, the most common value attributed to manatees in Hondo River was non-use existence values. Local people recognize the challenges to observe this cryptic species in this river, but also identified manatees as potential flag species, suggesting that it may represent a valuable resource for ecotourism. We suggest that the non-extractive use of manatees has the potential for promoting species conservation and local economic growth.  相似文献   
97.
该文系统介绍了植物子平台所采取的以数字标本质量为导向的数字化技术规范和管理策略,以及CVH网站数据共享规则, 并指出存在的问题及今后努力方向。  相似文献   
98.
Artemisia arborescens L. (Asteraceae) is an endemic and a valuable medicinal and ornamental species in the Mediterranean regions. Despite the interest given to A. arborescens L. as promising medicinal crop, this species is becoming threatened of extinction in Tunisia as a result of the fragmentation of its habitat and the absence of any specific measures for its conservation and valorisation. Based on the last considerations, extent information about their volatile metabolites profiling, contents and antimicrobial potential were undertaken based on fourteen populations originated from various geographical and bioclimatic habitats of Tunisia. The obtained results reveal an essential oil content mean value of 1.47%. The leaves of Tunisian tree wormwood populations were dominated by camphor (15.05–58.05%), chamazulene (11.72–45.26%) and β-thujone (0–36.53%). Based on the three first major compounds detected for each population, four different oil types were defined (Oil type I: camphor-chamazulene-β-thujone; Oil type II: camphor-chamazulene-terpinen-4-ol; Oil type III: camphor-chamazulene-bornyl acetate; Oil type IV: camphor-chamazulene-linalool). PCA, HCA and Heatmap chemometric analyses revealed three classification clusters defined mainly by minor compounds. These minor volatile metabolites succeed to discriminate among the fourteen studied populations which promote their chemotaxonomic interest. Our findings confirm previous reports concerning this species in the world and show chamazulene, camphor and β-thujone as the major compounds of this species which define their well known chemotypes independently of the geographical, bioclimatic and genotypic factors. This makes of these three components promising chemosystematic tool for the discrimination of A. arborescens L. in the genus Artemisia. The results showed that the four tested oils were effective against the nine tested microbial strains. The highest antimicrobial potential was revealed for the population AAr_MB characterized by camphor, chamazulene and β-thujone as the dominant components. The pattern of essential oils concentration offers wide range of possibilities for the initiation of breeding programs according to the desired bioactive compounds. Both in situ and ex situ conservation strategies were suggested for the maintenance of the highest chemical polymorphism of this valuable medicinal species.  相似文献   
99.
Highly conserved antigen-presenting function of CD1d molecules   总被引:6,自引:0,他引:6  
 The lack of polymorphism of nonclassical antigen-presenting molecules has led to the proposal that they may carry out some conserved and essential antigen-presenting function. Although this is a plausible hypothesis, the major histocompatibility complex has undergone dramatic expansions and contractions through evolution, and there is surprisingly little evidence for interspecies conservation of nonclassical class I molecules. The CD1d molecule, by contrast, shows an extremely high degree of functional conservation between mice and humans, with regard to its interaction with the relatively invariant TCRs that are expressed by NK T cells. This conservation for CD1d recognition is observed either in the absence of exogenous Ag or together with a lipoglycan antigen. The close functional and phenotypic conservation of NK T cells, in mammalian species separated by approximately 50 million years, suggests an essential role in the immune system for CD1d recognition by NK T cells.  相似文献   
100.
Orangutans are the only great ape in Asia. Since orangutan densities vary between habitat types within regions and within similar habitat types among regions, it is important to determine areas with high densities for their protection. In this paper we show that orangutan density in old-growth dryland forests in the Leuser Ecosystem, Sumatra is significantly related to the density of large strangling figs and topsoil pH. In addition, large fig density depends on topsoil pH. Provided that orangutans are present and no hunting or logging occur, topsoil pH seems a promising method for rapid assessment of potential orangutan density over large areas.  相似文献   
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