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291.
贡嘎山地区位于青藏高原的东南缘,横断山系的东北段,现有杜鹃属植物73种4变种2亚种。在贡嘎山地区东坡的不同垂直高度上分布有43种(包括变、亚种)杜鹃,西坡则分布有63种(包括变、亚种)。贡嘎山地区杜鹃属植物的区系组成属于泛北极植物区,大致分为:1、中国-日本森林植物亚区,只有1种杜鹃。2、中国-喜马拉雅森林植物亚区,有78种(包括4变种, 2亚种),其中(1)1种分布于西藏、云南,并经云南入缅甸分布;(2)44种为四川特产;(3)5种为贡嘎山地区特有种。另外,贡嘎山地区杜鹃属植物区系还有其特点:1、贡嘎山地区是杜鹃属植物分布中心之一;2、贡嘎山地区是杜鹃属植物分化中心之一;3、贡嘎山地区杜鹃属植物有垂直替代现象。 相似文献
292.
区域生态建设与景观生态学的使命 总被引:44,自引:7,他引:37
区域和景观尺度上的生态建设是指一定地域、跨生态系统、适用于特定景观类型的生态建设,即实行科学的生态系统管理和优化环境的建设工程.近年来国家实施了一系列重大的生态工程项目,如天然林保护工程、部分地区退耕还林还草、内陆河流域的生态调水等,取得了显著的效果.加强区域生态建设,维护国土安全已成为国家的战略需求.依据不同类型区的特点应实行不同的生态建设战略,如生态敏感区、脆弱区和高人口密度的生态压力区,可分别实施以生态安全保障、生态负荷调整和生态秩序重建为重点的生态建设战略,调控人类活动,实行有序开发,统筹人与自然的和谐发展.面对转型期的国家需求,我国景观生态学的发展迎来了挑战与机遇并存的重要契机.研究的关键议题包括:景观生态安全格局;土地利用与生态过程;人类活动胁迫下的景观变化;区域开发人类活动生态影响的定量评价;区域生态安全评价与预警;景观生态建设的模式设计与优化组合. 相似文献
293.
Roger Antabe Kilian N. Atuoye Vincent Z. Kuuire Yujiro Sano Godwin Arku Isaac Luginaah 《人类与生态风险评估》2017,23(4):798-813
The emergence of the gold mining industry and the influx of artisanal and small-scale mining following recent discoveries of gold deposits in Northern Ghana have posed new socio-cultural, economic, environment and health challenges for residents in this dry savannah zone that is already facing negative consequences of environmental change. Yet, the extent to which residents in close proximity (impacted) and distant (affected) host communities perceive the impact of mining on their health has been nascent. Using cross sectional survey data (n=801) and applying the negative log-log regression technique, we examine residents’ self-rated health in mining communities in the Upper West Region of Ghana. The findings suggest that residents in impacted communities who believed that odors from mining activities could have health impact were twice more likely to report their health as poor, while those who were uncertain were 98% more likely to rate their health poor compared to those who disbelieved. However, sighting of dust was not significantly associated with subjective health in both impacted and affected communities. Based on these findings, it is recommended that Ghana's Minerals and Mining Act be reviewed to include the active involvement of host communities in mine leases while enforcing strict environmental best practices. 相似文献
294.
295.
Martyn P. Powell Alexander S. T. Papadopulos Priscilla M. Burgoyne Vincent Savolainen 《Botanical journal of the Linnean Society. Linnean Society of London》2014,174(1):110-129
The exceptionally high plant diversity of the Greater Cape Floristic Region (GCFR) comprises a combination of ancient lineages and young radiations. A previous phylogenetic study of Aizoaceae subfamily Ruschioideae dated the radiation of this clade of > 1500 species in the GCFR to 3.8–8.7 Mya, establishing it as a flagship example of a diversification event triggered by the onset of a summer‐arid climate in the region. However, a more recent analysis found an older age for the Ruschioideae lineage (17 Mya), suggesting that the group may in fact have originated much before the aridification of the region 10–15 Mya. Here, we reassess the tempo of radiation of ice plants by using the most complete generic‐level phylogenetic tree for Aizoaceae to date, a revised calibration age and a new dating method. Our estimates of the age of the clade are even younger than initially thought (stem age 1.13–6.49 Mya), supporting the hypothesis that the radiation post‐dates the establishment of an arid environment in the GCFR and firmly placing the radiation among the fastest in angiosperms (diversification rate of 4.4 species per million years). We also statistically examine environmental and morphological correlates of richness in ice plants and find that diversity is strongly linked with precipitation, temperature, topographic complexity and the evolution of highly succulent leaves and wide‐band tracheids. © 2013 The Authors. Botanical Journal of the Linnean Society published by John Wiley & Sons Ltd on behalf of The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 174 , 110–129. 相似文献
296.
297.
《朊病毒》2013,7(4):304-314
ABSTRACT. Since 2006, China has conducted the surveillance program for Creutzfeldt-Jakob disease (CJD) and other subtypes of prion diseases covering 12 provinces. In this study, the characteristics and special role of Beijing CJD surveillance network in the national CJD surveillance system were analyzed. Based on the registered permanent resident places, all reporting suspected CJD cases and diagnosed CJD cases via Beijing CJD surveillance network between 2006 and 2013 were grouped as the cases from Beijing and from outside of Beijing. Both numbers of the suspected and diagnosed CJD cases via Beijing CJD surveillance network constantly increased along with the years, totally 532 reporting cases and 192 diagnosed CJD cases were obtained in the past 8 y. About 75% of suspected and diagnosed CJD cases via Beijing CJD surveillance network came from other provinces, mainly from neighboring provinces. Altogether, 46 different hospitals in the Beijing region have reported suspected CJD cases to the CJD surveillance system during the period from 2006 to 2013. Five hospitals continually reported suspected CJD cases during those 8 y and 5 other hospitals had reported cases except for 1 to 2 y. Additionally, we found that the diagnosed CJD patients from Beijing region had less numbers of hospital transfer and shorter interval from the disease onset to the final diagnosis than those outside of Beijing. It indicates that as the most important component, Beijing CJD surveillance network functions more actively, which supplies the special medical services not only for Beijing residents but also for patients from all of China. 相似文献
298.
El?d Kondorosy 《ZooKeys》2013,(319):211-221
The history of the taxonomic research of Rhyparochromidae and especially Drymini is briefly reviewed. Two new species level synonyms are proposed: Taphropeltus javanus Bergroth, 1916, syn. n. = Taphropeltus australis Bergroth, 1916, syn. n. = Brentiscerus putoni (Buchanan White, 1878). A monotypic new genus, Malipatilius
gen. n. (type species: Scolopostethus forticornis Gross, 1965 from Australia) is established. 相似文献
299.
300.
A new species of the Drosophila obscura species group is described here, namely Drosophila glabra sp. nov. It was recently found from the Maoershan National Nature Reserve, Guangxi, China. The characteristics of the new species are based not only on morphological characters but also on DNA sequences of the mitochondrial COII(cytochrome c oxidase subunit II) gene. 相似文献