云南松毛虫越冬代幼虫自然种群空间分布型的研究   总被引：1，自引：0，他引：1  

张家胜  许国莲  尹安亮  杨承志 《林业科技》2004,29(6):21-23

通过样方调查计算，采用聚集度指标法，测定云南松毛虫越冬代幼虫的空问分布型，建立了最适抽样数关系式，并对其进行了序贯抽样分析。结果表明：云南松毛虫越冬代幼虫种群在林内呈聚集分布，其Iwao回归方程为m*=5．2181 1．0207x^-、复相关系数R=0．9918；最适抽样株数为：N=621．81/x^- 2．07。  相似文献   

巴黎翠凤蝶、红基美凤蝶生物学特性初步观察     

方健惠  田椰  孙天鑫 《甘肃林业科技》2005,30(1):13-15,53,F003

巴黎翠凤蝶在甘肃白水江自然保护区1年2代，以蛹越冬，翌年3月下旬越冬蛹开始羽化，4月下旬至5月初为第1代成虫羽化高峰期，第2代成虫羽化高峰期在6月底7月初；寄主为芸香科的飞龙掌血、柑橘类等植物；成虫喜访白色系的花，也好在臭水沟处群聚嬉戏，一般在常绿林带的高处活动，飞行迅速，警觉性高而且很少停息，难以捕捉。红基美凤蝶在白水江自然保护区1年2代，以蛹越冬，翌年4月初越冬蛹开始羽化，4月下旬为第1代成虫羽化高峰期，6月底7月上旬为第2代成虫羽化高峰期；7月下旬成虫数量减少，但直至9月仍可见到成虫；7月上旬产卵高峰期，9月初为化蛹高峰期；直到10月上中旬还可见幼虫；幼虫5龄，历期25～35d；寄主为柑桔等芸香科植物。  相似文献   

Genetic diversity of Populus euphratica populations in northwestern China determined by RAPD DNA analysis   总被引：1，自引：0，他引：1  

Saito  Y.  Shiraishi  S.  Tanimoto  T.  Yin  L.  Watanabe  S.  Ide  Y. 《New Forests》2002,23(2):97-103

Five Populus euphratica Oliver populations in northwestern China were analyzed using RAPD DNA markers to determine genetic diversity among and within populations. One hundred-and-five polymorphic bands were observed, ranging in size from 250 bp to 1700 bp, using 10 primers. Only one population on the north side of the Tianshern Range had a unique band common to all individuals that was not found in individuals from populations in the Tarim River valley. Intra-population genetic diversity was high in two populations along the Tarim River and low in the other three populations. There was no significant correlation between genetic distances and geographic distances. The result of correspondence analysis shows that the individuals from the three populations with low genetic diversity are isolated from each other. The result of cluster analysis based on genetic distance shows that the population in the Tianshern Range is genetically distant from the other populations. These results suggest that the Tianshern Range population was genetically isolated from the other populations.  相似文献   

Problems and relevant strategies on natural forest protection in Changbai Mountain forest area     

WANGXian-cheng 《林业研究》2003,14(3):259-262

Changbai Mountain forest area is not only is a national timber base but also a green ecological defense for Songliao Plain of NE China. The Natural Forest Protection Project of this area has an important bearing on the social and economic sustainable development of Jilin Province or even the whole forest area in NE China. This paper summarized general conditions of natural forest in Changbai Mountain state-owned forest area and put forward six problems need to be urgently solved and five strategic suggestions on natural forest protection and sustainable management.  相似文献   

不同干燥方法对苜蓿干草调制的影响   总被引：1，自引：0，他引：1  

张颖超  王伟  侯美玲  尹强  贾玉山 《中国草地学报》2015,37(1)

针对影响人工干燥苜蓿的水分、密度、摆放方式和人工辅助干燥方式4个因素进行人工鼓风干燥处理,设计L9(34)正交试验,监测高水分苜蓿草捆的湿度变化情况,比较不同处理营养物质、相对饲用价值和经济指标.对比分析结果可知:自然晾晒苜蓿干草时,营养物质损失严重;苜蓿高水分打捆后人工继续鼓风干燥处理有利于保存苜蓿干草的营养价值,其中水分为30％～35％、密度为120kg/m3、间隔20cm摆放、两台鼓风机每日鼓风干燥3h为最优组合,所得苜蓿草捆的品质较好.  相似文献   

One hundred years of population ecology: Successes,failures and the road ahead          下载免费PDF全文

Charles J. KREBS 《Integrative zoology》2015,10(3):233-240

Population ecology is the most mature of the three subdisciplines of ecology partly because it has a solid mathematical foundation and partly because it can address the primary questions of distribution and abundance with experimental protocols. Yet there is much left to do to integrate our population knowledge into community and ecosystem ecology to help address the global issues of food security and the conservation of biodiversity. Many different approaches are now being developed to bring about this integration and much more research will be necessary to decide which if any will be most useful in achieving our goals of explaining the changes we see in the distribution and abundance of animals and plants. Food web ecology would appear to be the best approach at present because it uses the detailed information of the population ecology of particular species in combination with data on consumer–resource interactions to apply to the applied problems of biodiversity conservation, food security, pest management and disease prevention. If we can use our understanding of population ecology to address the practical problems of our time in a creative way, we will benefit both the human population and the Earth's biodiversity. Much remains to be done.  相似文献   

Winter soil CO2 efflux in two contrasting forest ecosystems on the eastern Tibetan Plateau,China     

Zhenfeng Xu  Feifei Zhou  Huajun Yin  Qing Liu 《林业研究》2015,(3)

Significant CO2 fluxes from snow-covered soils occur in cold biomes. However, little is known about winter soil respiration on the eastern Tibetan Plateau of China. We therefore measured winter soil CO...  相似文献   

辽宁省大豆田杂草发生与危害   总被引：1，自引：0，他引：1  

王英姿  纪明山  祁之秋  谷祖敏  程根武  魏松红  张杨  李兴海 《植物保护》2007,33(4):116-118

采用倒置"W"九点取样法调查辽宁省大豆田杂草,明确了辽宁省大豆田杂草有19科35种,其中阔叶杂草占74.29%,禾本科杂草占14.29%,其他杂草占25.71%;一年生杂草占54.29%,多年生杂草占31.43%。相对多度达10%以上的杂草依次为藜、鸭跖草、稗草、苘麻、反枝苋、红蓼、马唐、铁苋菜、马齿苋和山苦菜。其中藜和鸭跖草相对多度在30%以上,为辽宁省大豆田杂草优势种群。  相似文献   

不同土地利用类型氨挥发氮同位素自然丰度特征     

白潇  遆超普  颜晓元  李淼  陶莉敏  彭凌云  周伟 《农业环境科学学报》2022,41(7):1590-1597

为了探讨不同土地利用类型下氨（NH3）挥发氮同位素自然丰度特征,采集3种土地利用类型（果园、菜地和林地）土壤,在可控条件下采用海绵吸收法开展了为期15d的室内培养试验,测定了不同土地利用类型下土壤NH3挥发全过程δ15N值及其变化规律。培养期间,3种土地利用类型下的土壤NH+4-N浓度均呈现先上升后下降的趋势;果园和菜...  相似文献   

尼勒克县荒漠草地植物种类调查及分析     

李建伟  罗志娜  张生楹  范天文  樊建忠 《农学学报》2022,12(11):24-31

为了更好的保护尼勒克县荒漠草地植物资源,采用样方和植物踏查法对尼勒克县荒漠草地的植物种类进行调查研究。结果表明：尼勒克县荒漠草地有23科68属98种（亚种）植物,植物种类组成较丰富,有害植物少。藜科、菊科和禾本科为优势科,含有54种（亚种）植物;小型科和单科种类众多,单科植物有12种。按照经济类群划分,豆科植物占8.16%,禾本科植物占13.27%,藜科植物占27.55%,菊科植物占14.29%,莎草科植物占3.06%,杂类草占33.67%。按照饲用价值划分,优良占14.29%、良好占27.55%、一般占36.73%、差占16.33%、有毒占5.10%。  相似文献