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1.
为明确兜兰属(Paphiopedilum)宽瓣亚属(Subgenus.Brachypetalum)植物各物种在我国的生存现状与濒危状况,在大量的野外调查和文献、标本数据收集的基础上,对其种群分布、数量、生境特征、市场贸易、受威胁因素、保护现状与保护成效进行统计分析,并依据《IUCN红色名录等级和标准(3.1版)》对该类群的濒危等级进行重新评估.结果表明,野外调查到硬叶兜兰(Paphiopedilum.micranthum)、麻栗坡兜兰(P.malipoense)、杏黄兜兰(P.armeniacum)、白花兜兰(P.emersonii)、巨瓣兜兰(P.bellatulum)、文山兜兰(P.wenshanense)、同色兜兰(P.concolor)7个目标物种,已知分布于我国50个县(市、区),共计194个自然分布点.宽瓣亚属植物在我国水平方向上主要分布于滇东南、黔西南、黔东北、滇西北、桂北与黔南交界处以及桂西北至桂西南等地区;垂直方向上集中分布于中高海拔段(780~1267m),平均海拔997m;在全国大尺度上,该亚属整体呈零散分布,区域小尺度上个体呈聚集生长;其小生境具有高海拔、透水、透气、喜阴、喜钙的特点.市场调查的贸易率为36.67%,贸易价格高低不等,具有较强的随机性;贸易来源主要为野外采挖,占贸易数量的88.32%,具有较强的地域性;贸易方式为现场和线上网络交易,具有较强的灵活性.该类群主要受到采挖和生境退化的威胁,分别占所有分布点的44.85%、29.83%.宽瓣亚属整体就地保率仅为34.53%,保护成效为一般保护;调查的29个保育地中,有20个保育地对该类群累计保育98次,除文山兜兰和绿叶兜兰外,其他7种迁地保护成效被评估为合适.巨瓣兜兰、文山兜兰由原来的濒危(EN)评估为极危(CR);麻栗坡兜兰、白花兜兰、杏黄兜兰评估等级未发生变化,仍为极危(CR);硬叶兜兰和同色兜兰由原来的易危(VU)评估为濒危(EN);德氏兜兰、绿叶兜兰被评为数据缺乏(DD).  相似文献   
2.
Two closely related forms ofOphrys insectifera were observed in the field to attract different pollinator species selectively.O. i. ssp.insectifera attracted males of two species ofArgogorytes (Sphecidae, Hymenoptera Aculeata) andO. i. ssp.aymoninii attractedAndrena combinata males (Andrenidae, Apoidea, Hymenoptera Aculeata). A third form,O. aff.i. ssp.insectifera, attracted none of these three species. Volatile compounds from flowers and inflorescences of the three forms (originating from Öland, Sweden, and Aveyron, France) were collected, using entrainment, enfleurage, and solvent extraction techniques, and identified by gas chromatography — mass spectrometry. Scent differences between the three forms were confirmed in the amounts of aliphatic hydrocarbons (C11–C19), methyl esters (C14–C18), short chain aliphatic 1-alcohols (C6–C12), and monoterpene alcohols (C10).  相似文献   
3.
The effect of climatic conditions on the dynamics of 21 populations of 10 species of the family Orchidaceae at the northern limit of their range in Europe was studied between 1992 and 2004. The abundance of orchid populations proved to depend primarily on air temperature during the previous and current growing seasons.  相似文献   
4.
Xishuangbanna is on the northern margins of tropical Asia in southwestern China and has the largest area of tropical forest remaining in the country. It is in the Indo‐Burma hotspot and contains 16% of China's vascular flora in <0.2% of the country's total area (19,690 km2). Rapid expansion of monoculture crops in the last 20 years, particularly rubber, threatens this region's exceptional biodiversity. To understand the effects of land‐use change and collection on orchid species diversity and determine protection priorities, we conducted systematic field surveys, observed markets, interviewed orchid collectors, and then determined the conservation status of all orchids. We identified 426 orchid species in 115 genera in Xishuangbanna: 31% of all orchid species that occur in China. Species richness was highest at 1000–1200 m elevation. Three orchid species were assessed as possibly extinct in the wild, 15 as critically endangered, 82 as endangered, 124 as vulnerable, 186 as least concern, and 16 as data deficient. Declines over 20 years in harvested species suggested over‐collection was the major threat, and utility value (i.e., medicinal or ornamental value) was significantly related to endangerment. Expansion of rubber tree plantations was less of a threat to orchids than to other taxa because only 75 orchid species (17.6%) occurred below the 1000‐m‐elevation ceiling for rubber cultivation, and most of these (46) occurred in nature reserves. However, climate change is projected to lift this ceiling to around 1300 m by 2050, and the limited area at higher elevations reduces the potential for upslope range expansion. The Xishuangbanna Tropical Botanical Garden is committed to achieving zero plant extinctions in Xishuangbanna, and orchids are a high priority. Appropriate in and ex situ conservation strategies, including new protected areas and seed banking, have been developed for every threatened orchid species and are being implemented.  相似文献   
5.
International Union for Conservation of Nature (IUCN) Red List assessments are essential for prioritizing conservation needs but are resource intensive and therefore available only for a fraction of global species richness. Automated conservation assessments based on digitally available geographic occurrence records can be a rapid alternative, but it is unclear how reliable these assessments are. We conducted automated conservation assessments for 13,910 species (47.3% of the known species in the family) of the diverse and globally distributed orchid family (Orchidaceae), for which most species (13,049) were previously unassessed by IUCN. We used a novel method based on a deep neural network (IUC-NN). We identified 4,342 orchid species (31.2% of the evaluated species) as possibly threatened with extinction (equivalent to IUCN categories critically endangered [CR], endangered [EN], or vulnerable [VU]) and Madagascar, East Africa, Southeast Asia, and several oceanic islands as priority areas for orchid conservation. Orchidaceae provided a model with which to test the sensitivity of automated assessment methods to problems with data availability, data quality, and geographic sampling bias. The IUC-NN identified possibly threatened species with an accuracy of 84.3%, with significantly lower geographic evaluation bias relative to the IUCN Red List and was robust even when data availability was low and there were geographic errors in the input data. Overall, our results demonstrate that automated assessments have an important role to play in identifying species at the greatest risk of extinction.  相似文献   
6.
Abstract: Fragmentation of natural habitats can increase numbers of rare species. Conservation of rare species requires experts and resources, which may be lacking for many species. In the absence of regular surveys and expert knowledge, historical sighting records can provide data on the distribution of a species. Numerous models have been developed recently to make inferences regarding the threat status of a taxon on the basis of variation in trends of sightings over time. We applied 5 such models to national and regional (county) data on 3 red‐listed orchid species (Cephalanthera longifolia, Hammarbya paludosa, and Pseudorchis albida) and 1 species that has recently come to the attention of conservation authorities (Neotinea maculata) in the Republic of Ireland. In addition, we used an optimal linear estimate to calculate the time of extinction for each species overall and within each county. To account for bias in recording effort over time, we used rarefaction analysis. On the basis of sighting records, we inferred that these species are not threatened with extinction and, although there have been declines, there is no clear geographical pattern of decline in any species. Most counties where these orchid species occurred had a low number of sightings; hence, we were cautious in our interpretation of output from statistical models. We suggest the main drivers of decline in these species in Ireland are modification of habitats for increased agricultural production and lack of appropriate management. Our results show that the application of probabilistic models can be used even when sighting data are scarce, provided multiple models are used simultaneously and rarefaction is used to account for bias in recording effort among species over time. These models could be used frequently when making an initial conservation assessment of species in a region, particularly if there is a relatively constant recording rate and some knowledge of the underlying recording process. Regional‐scale analyses, such as ours, complement World Conservation Union criteria for assessment of the extinct category and are useful for highlighting areas of under recording and focusing conservation efforts of rare and endangered species.  相似文献   
7.
This study investigated the genetic relationships between the rare terrestrial orchid Diuris fragrantissima and three closely related purple flowered species using Amplified Fragment Length Polymorphisms. The purple-flowered species were found to form individual phenetic clusters confirming recognition of D. fragrantissima at the rank of species. Levels of genetic variation were lower within D. fragrantissima than within its closest relatives but were higher than expected for severely bottlenecked species. Gene flow was detected among all species (Nm = 2.34) and populations (Nm = 0.65) however low among population gene flow indicates that populations may be at risk of divergence. This study has implications for the conservation of D. fragrantissima.  相似文献   
8.
The study of relationships between symbiotic fungi and germinating seeds of the Orchidaceae showed that the effect of a fungus on germination depends on the presence of seed dormancy and its pattern. The specificity of symbiosis varies widely. The development of symbiotic sprouts in situand in vitro differs only in the rate, whereas the morphogenesis of asymbiotic sprouts is characterized by several anomalies.  相似文献   
9.
Abstract:  Conservation currently relies largely on hindsight because demographic studies identify population decline after the event. Nevertheless, the degree of aggregation within a population is an "instantaneous" characteristic with the potential to identify populations presently at greatest risk of genetic impoverishment (via Allee effects and in-breeding depression) and local decline. We sought to determine the relative extinction risk for sympatric orchid species throughout Monte Barro natural park (Lecco, Italy), based on an index of dispersion ( I ) calculated from the size and location of subpopulations (recorded with GPS and mapped with GIS). Three population dispersion types were identified: (1) highly aggregated and locally abundant (large subpopulations restricted to particular sites; e.g., Gymnadenia conopsea [L.] R.Br.; I = 54.5); (2) widespread and moderately aggregated (opportunistic throughout the elevational range of the mountain; e.g., Listera ovata [L.] R.Br.; I = 18.9); and (3) weakly aggregated and locally rare (small, highly diffuse subpopulations; e.g., endemic Ophrys benacensis [Reisigl] O. & E. Danesch & Ehrend.; I = 4.4). Type 1 populations are more likely to respond to in situ intervention, whereas type 2 are relatively invasive species for which conservation intervention is not necessary, and type 3 are rare species that are least likely to respond to habitat management, for which ex situ conservation and population reinforcement would be most appropriate. Although our methodology provides only a "snapshot" of aboveground patterns of population dispersion, it can help target the application of in situ and ex situ conservation activities proactively and is of particular utility for parks for which a rapid assessment of local extinction risks is needed.  相似文献   
10.
为合理开发利用九阜山省级自然保护区野生兰科植物资源,对该区野生兰科植物资源进行了调查。结果表明,该区共有野生兰科植物12属16种,列出了该区每种野生兰科植物的属名、学名、生活型、主要用途、生境及其分布海拔,对其种类组成、属的分布区类型、生活型、生态环境、开发利用价值、资源分布与贮量进行了分析,提出了保护与开发利用措施。  相似文献   
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