青海省冬虫夏草资源适宜性区划分析

冬虫夏草是青藏高原的珍稀物种,具有较高的药用和经济价值,然而其资源的数量特征、空间分布格局及适宜度尚不清晰。本研究以青海省冬虫夏草资源生境条件为依据,以海拔、植被、土壤、气温和降水量作为主要指标,利用地理信息系统(geographic information system,GIS)的空间分析方法对青海省冬虫夏草资源适宜性及空间分布进行分析,并用野外实地采样进行验证。研究表明：玉树州的玉树市、杂多县、称多县、曲麻莱县;果洛州的玛沁县、达日县、甘德县等区域多处在适宜区;海北州的祁连县、刚察县,黄南州的泽库县、河南县、同仁县,玉树州的治多县、囊谦县,海南州的兴海县、同德县、贵南县及其他产冬虫夏草县的部分区域为较适宜区;西宁市的大通县,海东市的互助县和海西州的低海拔地区为不适宜区。整个青藏高原具有冬虫夏草分布面积占当地县域国土面积的76.2%。在青海省具有冬虫夏草分布的地区(市/州)中,玉树州和果洛州冬虫夏草分布的面积占当地县域国土面积的88.3%-99.6%,海北州、海东市、海南州、海西州、黄南州和西宁市冬虫夏草分布面积占当地县域国土面积的30.2%-96.5%。综合区划图能比较真实地反映青海省冬虫夏草资源的空间分布格局,区划结果与实地调查结果相符,表明利用空间分析方法进行冬虫夏草资源的适宜性分布区域的划分是可行的,该研究为合理开发和科学利用冬虫夏草野生资源提供理论依据。     

西藏人工造林作业区土壤肥力评价

为了掌握西藏将要造林作业区的土壤肥力水平,对6个地市524个造林作业区的土壤样本进行了养分测定,采用改进的内梅罗综合指数法分析土壤肥力水平.结果表明: 西藏造林作业区土壤综合肥力指数为0.425～1.972,土壤综合肥力水平一般的作业区数量占64.9%,贫瘠的占34.9%,肥沃的占0.2%.各属性分肥力指数均值表现为: 碱解氮>pH>全氮>速效钾>有机质>有效磷>全磷>全钾,指数值为0.654～2.643,全氮、碱解氮的肥力水平主要为肥沃、很肥沃,速效钾、有机质、全磷的肥力水平主要为一般,有效磷、全钾的肥力水平主要为贫瘠,土壤酸碱度适宜.各地市造林作业区平均土壤综合肥力指数表现为: 林芝市>昌都市>山南市>拉萨市>日喀则市>阿里地区,其中,阿里地区、日喀则市、拉萨市造林作业区土壤综合肥力水平为贫瘠,昌都市、林芝市为一般,而山南市一般和贫瘠的数量相当.西藏造林作业区土壤综合肥力水平总体偏低,土壤综合肥力、土壤各属性肥力水平由西北部的阿里地区至东南部的林芝市逐渐趋好,具有明显的水平地带性规律.     

西藏城乡居民点空间分异特征与影响因素

西藏地处青藏高原腹地,区内适宜人类生活的空间十分有限,居民点空间分布受多因素制约.为揭示西藏居民点的空间分布特征和主要影响因素,采用高分影像,基于目视与机器解译结合提取西藏城乡居民点斑块数据,运用核密度、空间热点探测、GeoDetector等方法探索其空间分异特征与影响因素,以期为今后高原地区宜居地选址、制定区域经济发展等相关政策提供参考.结果表明: 西藏城乡居民点呈聚集分布模式,整体密度分布差异较大;呈以拉萨市为高密度核心,昌都市、林芝市、阿里地区为低密度边缘的“核心-边缘”结构;高密度核心区拉萨市斑块密度多达220 ind·km^-2,而低密度边缘区密度最大仅为5.7 ind·km^-2,两个区域相差43倍.西藏城乡居民点规模高低值聚簇现象显著,大斑块高值数量稀少,小斑块低值数量绝对优势突出;大斑块高值占比仅为3.7%,集中分布于拉萨市和山南市,低值聚簇区占比达到67.2%,主要分布于羌塘高原的阿里地区和那曲市.西藏城乡居民点被划分成6种类型,形成了以“一江两河”地区和“三江流域”为中心的两个圈层结构,由内到外依次为大斑块主导型、中密度团簇型、高密度散点型、低密度散点型和高寒地无人型;拉萨市以中密度团簇型为主,占比为31%,山南市以低密度散点型为主,占比为38%,昌都市以低密度散点型为主,占比高达51%,阿里地区、那曲市和日喀则市均以高寒地无人型为主,其中,在阿里地区占比高达64%.不同影响因子对西藏城乡居民点空间分布的影响程度差异性显著;人口和GDP对城乡居民点的分布均具有很强的决定性;此外,城镇居民点表现出强烈的道路指向性,农村居民点更多地表现为河流指向性.     

青藏高原那曲地区冬虫夏草资源分布空间分析方法

冬虫夏草(Cordyceps sinensis)是分布在我国青藏高原的可再生资源,具有极其名贵的中药材价值,而目前我国冬虫夏草资源的分布区域尚不清楚。以西藏那曲地区为例,根据冬虫夏草资源分布的生境条件,结合冬虫夏草的生态特性指标,利用地理信息系统(GIS)空间分析方法对冬虫夏草的空间分布区域进行了分析。结果表明,那曲地区冬虫夏草资源主要分布于那曲的东部,分布面积约为4.93万km2,占地区总面积的12.54%。与实地调查结果比较,提出的基于GIS空间分析的冬虫夏草分布区分析方法精度较高,说明空间分析方法在冬虫夏草资源调查评价上具有一定的可行性,为今后的冬虫夏草资源调查等相关研究提供方法支持。     

三江源区冬虫夏草资源适宜性空间分布

冬虫夏草(Ophiocordyceps sinensis)是生长在青藏高原高寒地区的一种珍稀物种资源,具有极高的药用和经济价值,然而冬虫夏草资源的数量特征与空间格局尚不明确。以三江源区为例,结合冬虫夏草的生境条件,选取适宜冬虫夏草生长的生态环境指标,利用地理信息系统(GIS)中的空间分析方法对冬虫夏草资源的适宜性空间分布进行了研究,并用野外实地采样和入户调研数据进行验证。结果表明:三江源区冬虫夏草资源主要分布在东南部和中南部,分布面积约为18.45×10~4km~2,占该区总面积的50.74%。达日县、甘德县、玉树县、称多县、玛沁县、班玛县、久治县这7个县冬虫夏草适宜性面积占到了该县50%以上的面积,是三江源区冬虫夏草资源的主产区。基于GIS空间分析的结果与实地调查结果相符,说明利用空间分析方法划分冬虫夏草资源的适宜性分布区域是可行的,可为系统的全面调查冬虫夏草资源的分布及保护与合理开发利用冬虫夏草资源提供科学依据。     

基于GIS的石渠虫草气候生态适宜性区划

根据虫草生物学特性,结合当地农业气候资源时空分布特征与虫草资源调查资料,以海拔、年平均气温、年平均降水量、植被、土壤为主导指标,地形坡度为辅助指标,作为虫草资源适宜性区划的主要依据,应用数理统计分析法、集优法、地理信息系统(GIS)空间分析方法对石渠虫草的气候生态适宜性及空间分布进行分析.结果表明:石渠县大部分乡镇出产虫草,但是分布区破碎分散,呈零星片状和块状,主要分布在石渠县东部、西部的部分乡镇,以及中部扎曲流域两岸部分乡镇;石渠虫草分布的适宜区海拔4000~4700 m,年平均气温-2.5~3℃,年降水量550~850 mm,生长环境一般为疏水性好、坡度15°~50°的高山草甸、亚高山草甸,适宜区生长环境和气象条件有利于取食植物和蝙蝠蛾的生长发育;不适宜区在河流宽谷区、牧区、湿地或雪线以上的高山区.     

我国北方赤霞珠葡萄生态区划

根据前期研究结果,制定了赤霞珠的生态区划指标体系。采用逐步分区法和集优法相结合的方法,在GIS技术的支持下,开展了中国北方赤霞珠葡萄的精细化生态区划研究,制作了区划图。结果表明,中国北方赤霞珠葡萄生态区可划分为最适宜区、适宜区、次适宜区、不适宜区和不可种植区5类。作为中晚熟品种的赤霞珠葡萄,其最适宜生态区在中国北方呈零星分布,面积较小,并且主要分布在西北地区。适宜生态区的分布较为广泛,西北、华北、东北和中原地区均有分布,涵盖了目前北方主要的酿酒葡萄产区。在进行赤霞珠葡萄的原料基地建设布局时,要重点考虑在最适宜区和适宜区发展,有条件地选择在次适宜区发展,尽量避免建在不适宜区和不可种植区。本研究结果可为中国北方酿酒葡萄产业规划、酿酒葡萄基地建设布局提供参考。     

GIS支持下的山区苹果园地优化布局

栖霞市是中国苹果主产区之一,光、热条件及地形是影响当地苹果分布和品质的主要因素.基于生态适宜性,建立苹果园地单项土地利用优化模式,是栖霞市农业结构调整所需要的.本研究在对光、热条件及地形空间分布模拟的基础上,以土地利用现状类型为景观介质表面,利用GIS的空间信息处理技术,建立了苹果园地最小累积阻力模型(MCR),探讨山区苹果园地单项土地利用优化的技术途径.将栖霞市划分为极度适宜区、高度适宜区、适宜区和初度适宜区4个适宜分区,各区的面积分别为20466、38392、97367和41301 hm2,极度适宜区和高度适宜区面积占县域面积的29%,苹果园地开发的适宜性较大.MCR模型为当地苹果产业开发和农业结构调整提供决策依据.     

南药青天葵全球产地生态适宜性分析

搜集青天葵Nervilia fordii主产区及野生分布区的分布样点,应用药用植物全球产地生态适宜性区划信息系统(GMPGIS)对南药青天葵进行全球产地生态适宜性分析。对青天葵各生态因子进行聚类分析,得到青天葵在全球范围的生态适宜区和潜在的人工栽培区。中国、巴西、越南、老挝等11个国家和地区境内皆有青天葵生长的适宜区;其中适宜区面积最大的为中国,总面积为406 980.1 km~2,占全部面积的69%;青天葵在中国的适宜分布区主要位于广西、广东、福建、海南、云南等省(区)。GMPGIS分析结果为青天葵的人工栽培提供科学依据,有助于保护青天葵药用资源,以期促进稀缺药用资源青天葵的区划研究和人工栽培。     

利用增强回归树分析中国野火空间分布格局的影响因素

确定野火空间分布区格局的影响因素,对野火的预测、火险区划具有重要的意义,同时也为制定合理的野火管理措施提供科学依据。以中国2006—2011年野火发生面积和次数作为因变量,选取了5个影响因素,利用增强回归树(boosted regression tree,BRT)方法分析了影响野火空间分布格局的主要因素。结果表明:影响中国野火过火面积空间分布的因素从大到小依次是海拔(36.92%)、年平均气温(27.85%)、年平均降雨量(13.17%)、人口密度(13.00%)和植被类型(9.07%),总体来说,气候因子和海拔的差异决定了研究区过火面积的空间分布格局;影响中国野火火烧次数空间分布的因素从大到小依次是人口密度(27.44%)、海拔(25.97%)、植被类型(22.84%)、年平均气温(18.98%)和年平均降雨量(4.77%),可以看出,人类活动、地形和可燃物共同影响火烧次数的空间分布格局。建议在制定全国火险区划时,除了气候和植被因素外,还应该重点考虑地形,特别是海拔的影响;并且加强野外用火管理,开展可燃物的处理以减少野火的发生。     

People,money, and protected areas: the collection of the caterpillar mushroom <Emphasis Type="Italic">Ophiocordyceps sinensis</Emphasis> in the <Emphasis Type="Italic">Baima Xueshan</Emphasis> Nature Reserve,Southwest China

The caterpillar mushroom Ophiocordyceps sinensis (syn. Cordyceps sinensis) is among the most valuable mushrooms in the world, and plays a major role for the local economies in its distribution area on the Tibetan Plateau and adjacent regions. Large proportions of its habitat fall into protected areas, and best practice of sustainable harvest is under discussion, considering both, O. sinensis as a valuable income source for rural poor and protection of its populations and habitat. This study aims for a detailed analysis of O. sinensis collection in a nature reserve in Southwest China. We found that harvesting is unevenly distributed among households and villages, with households who have access to the resource but lack adequate alternatives for income generation such as rewarding wage labor, fertile agricultural fields or harvest of other high value products being most involved. Although collection is de jure forbidden, authorities of the nature reserve apply adaptive management strategies for sustainable resource use. This includes the allocation of collection areas to communities based on their traditional land use strategies and the control of harvesters from outside, triggering self-policing of the resource by the local people. The strategies applied provide a promising model also for other protected areas where the caterpillar mushroom is collected.     

Genetic diversity of Ophiocordyceps sinensis, a medicinal fungus endemic to the Tibetan Plateau: Implications for its evolution and conservation

Background  

Ophiocordyceps sinensis (syn. Cordyceps sinensis), endemic to alpine regions on the Tibetan plateau, is one of the most valuable medicinal fungi in the world. Huge commercial demand has led to excessive harvest and a dramatic decline in its numbers. The diversity of terrains and climates on the Tibetan Plateau and the broad insect host range (more than 50 species in the family Hepialidae) may have resulted in substantial intraspecific genetic diversity for this fungus. The objective of this study was to evaluate the population distribution of O. sinensis from geographically diverse regions of the Tibetan Plateau based on nrDNA ITS and MAT1-2-1 gene sequences. Understanding of the genetic diversity and genesis of O. sinensis will provide important information for the evolution and conservation of this fungus.     

冬虫夏草生物学及生态学研究中的关键科学问题研究进展

冬虫夏草是一种具有极高药用和食用价值的珍稀菌类,其生物学特性和可持续发展关键技术一直是冬虫夏草研究关注的重点。总结了冬虫夏草生物学及生态学中的几个重要科学问题,包括冬虫夏草菌侵染蝙蝠蛾幼虫的途径及机制、冬虫夏草菌子实体形成及生长过程中的关键调控因子、冬虫夏草菌遗传多样性及基因组学研究、天然冬虫夏草及其微环境中的微生物群落组成、全球变暖背景下未来青藏高原地区的气候变化对冬虫夏草资源的影响等的研究进展,并分析了现有研究中尚未明确和不足之处。未来在冬虫夏草生物学及生态学的研究中,需要利用和研发更加先进的观测设备及试验方法,以实现天然冬虫夏草发生发育的原位观测和机理研究;充分利用冬虫夏草人工培植技术,结合分子生物学研究,从基因水平上揭示冬虫夏草菌生态适应性及侵染蝙蝠蛾幼虫的机理;建立冬虫夏草科学研究基地,开展长期定位观测试验并结合生态学模型构建明确未来气候变化对冬虫夏草资源的影响,以期进一步深入冬虫夏草生物学和生态学研究、推进我国冬虫夏草资源的合理利用及可持续发展的政策制定。     

Phylogeography and evolution of a fungal–insect association on the Tibetan Plateau

Parasitoidism refers to a major form of interspecies interactions where parasitoids sterilize and/or kill their hosts typically before hosts reach reproductive age. However, relatively little is known about the evolutionary dynamics of parasitoidism. Here, we investigate the spatial patterns of genetic variation of Chinese cordyceps, including both the parasitoidal fungus Ophiocordyceps sinensis and its host insects. We sampled broadly from alpine regions on the Tibetan Plateau and obtained sequences on seven fungal and three insect DNA fragments from each of the 125 samples. Seven and five divergent lineages/cryptic species were identified within the fungus and host insects, respectively. Our analyses suggested that O. sinensis and host insects originated at similar geographic regions in southern Tibet/Yunnan, followed by range expansion to their current distributions. Cophylogenetic analyses revealed a complex evolutionary relationship between O. sinensis and its host insects. Significant congruence was found between host and parasite phylogenies and the time estimates of divergence were similar, raising the possibility of the occurrence of cospeciation events, but the incongruences suggested that host shifts were also prevalent. Interestingly, one fungal genotype was broadly distributed, consistent with recent gene flow. In contrast, the high‐frequency insect genotypes showed limited geographic distributions. The dominant genotypes from both the fungus and the insect hosts may represent ideal materials from which to develop artificial cultivation of this important Chinese traditional medicine. Our results demonstrate that both historical and contemporary events have played important roles in the phylogeography and evolution of the O. sinensis–ghost moth parasitoidism on the Tibetan Plateau.     

Detection of Ophiocordyceps sinensis in the roots of plants in alpine meadows by nested-touchdown polymerase chain reaction

Ophiocordyceps sinensis, one of the most important income sources of rural Tibetan families, is an entomopathogenic fungus that parasitizes the ghost moth Thitarodes larvae, which live in alpine meadows on the Tibetan Plateau and in the Himalayas. The annual yield of O. sinensis has gradually declined in recent years. However, there is no effective method to sustain or increase the yield of O. sinensis artificially because the life cycle of the O. sinensis anamorph remains unclear. Here we detected O. sinensis in alpine plant roots by nested-touchdown polymerase chain reaction (PCR). Forty-two alpine plant species were screened. The roots from 23 alpine plant species (54.76 %) tested positive including 13 families and 18 genera. The detection results indicate that O. sinensis is present in the plant roots during the anamorph life cycle, to deal with harsh conditions in alpine habitats and have an increased opportunity to infect the larvae. The finding provides new information regarding the biology and ecology of O. sinensis that may be used to sustain this valuable resource.     

On the reliability of fungal materials used in studies on <Emphasis Type="Italic">Ophiocordyceps sinensis</Emphasis>

Ophiocordyceps sinensis (≡Cordyceps sinensis) is one of the best known traditional Chinese medicines, with great benefits to human health and huge economic value. The reliability of fungal materials used in studies of the species is particularly important because contradictory results have been found in various studies in the past decades. Examination of fungal materials specified in reports on O. sinensis showed great variation in both sources and culture conditions of living strains. To test the reliability of the materials used, experiments were carried out to study the effect of culture conditions on the growth of living strains of O. sinensis by using six reliable strains representing the major production regions of the fungus on the Tibetan Plateau. The results showed that O. sinensis is a slow-growing fungus at comparatively low temperature, and that temperature and growth period are crucial factors which can be verified by experiment. Analyses of fungal materials used in 152 papers on O. sinensis from PubMed since 1998 showed that 41 papers lacked detailed information on the fungal materials; 26 used natural products, 11 used artificially cultivated fruit bodies, and 80 used fermentation products from living strains. Of the latter category (using fermentation products), 64 of the papers were found to use unreliable (45) or uncertain (19) strains for fermentation products based on the temperature and growth period for O. sinensis strains verified in this study. Apart from the natural products of O. sinensis, which require scientific identification, a total of at least 116 papers (over three-quarters) used unreliable, uncertain or unspecified materials, including so-called cultivated fruit bodies which were apparently from other species. The reliability of materials or living strains used in studies on O. sinensis is discussed in this paper, and suggestions are made for use of reliable fungal materials in further studies of this fungus.     

Prevalence and spatial distribution characteristics of human echinococcosis in China

BackgroundEchinococcosis is a zoonotic parasitic disease caused by larval stages of cestodes belonging to the genus Echinococcus. The infection affects people’s health and safety as well as agropastoral sector. In China, human echinococcosis is a major public health burden, especially in western China. Echinococcosis affects people health as well as agricultural and pastoral economy. Therefore, it is important to understand the prevalence status and spatial distribution of human echinococcosis in order to advance our knowledge of basic information for prevention and control measures reinforcement.MethodsReport data on echinococcosis were collected in 370 counties in China in 2018 and were used to assess prevalence and spatial distribution. SPSS 21.0 was used to obtain the prevalence rate for CE and AE. For statistical analyses and mapping, all data were processed using SPSS 21.0 and ArcGIS 10.4, respectively. Chi-square test and Exact probability method were used to assess spatial autocorrelation and spatial clustering.ResultsA total of 47,278 cases of echinococcosis were recorded in 2018 in 370 endemic counties in China. The prevalence rate of human echinococcosis was 10.57 per 10,000. Analysis of the disease prevalence showed obvious spatial positive autocorrelation in globle spatial autocorrelation with two aggregation modes in local spatial autocorrelation, namely high-high and low-high aggregation areas. The high-high gathering areas were mainly concentrated in northern Tibet, western Qinghai, and Ganzi in the Tibetan Autonomous Region and in Sichuan. The low-high clusters were concentrated in Gamba, Kangma and Yadong counties of Tibet. In addition, spatial scanning analysis revealed two spatial clusters. One type of spatial clusters included 71 counties in Tibet Autonomous Region, 22 counties in Qinghai, 11 counties in Sichuan, three counties in Xinjiang Uygur Autonomous Region, two counties in Yunnan, and one county in Gansu. In the second category, six types of spatial clusters were observed in the counties of Xinjiang Uygur Autonomous Region, and the Qinghai, Gansu, and Sichuan Provinces.ConclusionThis study showed a serious prevalence of human echinococcosis with obvious spatial aggregation of the disease prevalence in China. The Qinghai-Tibet Plateau is the "hot spot" area of human echinococcosis in China. Findings from this study indicate that there is an urgent need of joint strategies to strengthen efforts for the prevention and control of echinococcosis in China, especially in the Qinghai-Tibet Plateau.