大兴安岭樟子松林组成植物种的分布区类型

大兴安岭樟子松林组成植物521种,其中包括地衣植物35种,苔藓植物48种,维管束植物441种;分析了大兴安岭地区樟子松林组成植物种的多样性。     

大兴安岭地区樟子松林植物组成属的分布区类型

大兴安岭地区樟子松林所含植物较丰富,据调查统计为76科230属520种,其中种子植物48科183属417种。通过对种子植物属进行研究,进一步分析了大兴安岭地区樟子松林组成植物属的多样性。     

扎龙国家级自然保护区的种子植物区系研究

扎龙保护区共有种子植物５２６种,其植物区系是温带性质,组成较丰富,地理成分较复杂。地理联系广泛;属世界分布的植物多。深受华北植物区系的影响,并无特有种。扎龙保护区植物组成中长白植物区系成分占２９．８４％,华北植物区系成分占２７．３２％,蒙古植物区系成分占２３．３３％,大兴安岭植物区系成分占１９．５１％,反映出植物区系组成的混杂性。     

大兴安岭呼玛县五味子分布区种子植物区系分析

五味子(Schisandrachinensis)为五味子科多年生木质藤本植物,是我国重要的中药材之一,在我国最北分布于大兴安岭呼玛县境内的呼玛河流域及黑龙江沿岸沟谷;其分布区有种子植物60科167属317种;该区系地理成分较复杂,具有14个种子植物属的分布类型,其中属温带分布成分的132个属占总属数的79.04%,为植物组成的主体,形成了与大兴安岭其他地区植物区系特征的差异,表明与五味子在其他分布区的植物区系的联系性。     

三江平原地区杂类草沼泽的植物区系研究

通过对三江平原的野外调查,统计出三江平原杂类草沼泽植物组成中含种子植物47科92属173种。三江平原地区杂类草沼泽的种子植物区系是东亚植物区系北部一个植物区系,该类沼泽植物区系是温带性质,但有较多温带性质的种分布中心偏北,表现了寒温带的特点。     

上海市海岛种子植物区系特征分析

上海市海岛共有种子植物314种,隶属于206属69科,其科包含6种分布型,属包含15种分布型。通过对上海市海岛种子植物区系的组成、地理成分、区系特征进行分析,得出主要结论如下：植物区系组成复杂、地理成分多样;广布性成分比例高、呈现出从热带向温带过渡的趋势;滨海植物区系丰富。     

东北产某些新植物资源——东北植物拾遗之一

东北地区位于我国的寒温带,由于自然历史条件及现代自然条件的综合影响,植物种类成分变化较大,在植物医系土可分成四个植物区系。即:长白植物区系、华北植物区系、蒙古植物区系及大兴安岭植物区系。各区系在植物种类成分上各有特点。其中长白植物区系中,以红松为代表的针阔混交林内的红松、黄波罗、水曲柳、胡桃揪等树种,以及木通、五味子、山葡萄和三种猕猴桃等藤本植物的存在,表现出它起源于第三纪的特点。而某些古老的种属,又表现了它和四     

黑龙江省中草药资源与开发利用的展望

一、我省中草药资源概况黑龙江省是我国最北部的省份,幅员辽阔,面积为四十六万余平方公里。本省绝大部分地处温带,仅大兴安岭北部属寒温带。从植被区域来讲,我省兼跨全国八个植被区域中的三个区域,即:温带针阔叶混交林区域(包括我省东部山区、小兴安岭及完达山区);温带草原区域(包括我省的松嫩平原);寒温带针叶林区域(大兴安岭北坡)。这种一省兼跨三个植被区域的情况,在全国是比较少的。另从植物区系来讲,我省跨有东北地区四个植物区系中的三个植物区系,     

石林彝族传统药用植物资源及其保护利用

通过野外调查、走村串户,访彝医问彝民、标本采集和鉴定、结合资料收集进行研究。结果发现石林重要的彝族传统药用植物资源有91科176属196种(含变种),生活型特征以草本为主,有109种占55.9%,其余87种占44.1%;药用种子植物区系中,种/属比例为1.12,远远低于我国植物区系的8.5,种/科比例为2.21,科多种少,反映了该植物区系具有一定程度的古老性。     

黑龙江省细鳞河国家级自然保护区种子植物区系研究

为进一步了解黑龙江细鳞河国家级自然保护区种子植物区系特点,通过实地调查并结合文献资料,对保护区内种子植物的种类组成及区系成分进行了研究与分析。结果表明,保护区内共有种子植物81科274属529种,其中裸子植物1科4属6种,被子植物80科270属523种。大科及较大科共13科,占总科数的16.05%,包含种数达313种,占总种数的59.17%,优势科现象明显。保护区内种子植物区系成分中,属级温带成分占比88.39%,种级温带成分占比90.16%。该保护区内种子植物分布型以温带成分占优势,与寒带及热带有少量交流,整体区系体现出强烈的温带性质。     

小陇山林区百合科观赏植物资源及其园林应用

小陇山地处温带南缘与北亚热带的过渡地带,气候温和湿润,适宜林木繁衍生长。作为我国华北、华中、喜马拉雅、蒙新四大自然植被区系的交汇处,植物种类繁多,是温带向亚热带过渡的植物基因库。通过多年的野外实地调查和文献研究,发现该地区约有百合科野生观赏植物23属55种,从资源分布、生态习性、观赏特性、栽培要求等方面对这些植物进行介绍,并对其园林应用做出分析建议。     

贺兰山的自然资源

贺兰山位于银川平原和阿拉善高原之间,地跨温带草原与荒漠两大植被区域的交接处,地理位置特殊,地形组合复杂,生物资源丰富;介绍了贺兰山的植物、动物、真菌及景观等资源,认为应保护好贺兰山的自然资源和自然环境,实施可持续发展战略,充分发挥贺兰山的多种功能效益。     

逊别拉河流域湿地种子植物组成及区系地理成分分析

逊别拉河流域湿地种子植物共有71 科218 属461 种,植物区系组成中最大科是菊科,其次为毛茛科、禾本科和莎草科;除世界分布科外,温带分布科占第一位;属的地理成分中以北温带(含变型)占优势,有102 属,占总属数的62.04%;种的区系以温带成分(74.15%)占绝对优势.区系特征表现为:优势科现象明显,单种属和寡种...     

松嫩平原湖泊湿地植物群落多样性及其保护研究

松嫩平原湖泊群是我国温带亚湿润地区低平原湖泊群,湖泊面积2750km2,湖泊率6%,是我国湖泊密度最大的地区之一,湖泊类型多样,有高等植物148种,隶属于38科77属;有16种植物群落,分属于挺水植物群落、浮叶植物群落、沉水植物群落、漂浮植物群落四大类;研究了松嫩平原湖泊湿地植物群落多样性现状,提出了生物多样性的保护对策;提出了相关的嫩平原湖泊湿地植物群落多样性保护对策。     

The economic benefits of rabbit control in Australian temperate pastures by the introduction of rabbit haemorrhagic disease

The European rabbit is present in most Australian environments and causes economic loss in agricultural systems by reducing production and imposing control costs on producers and governments. Research into rabbit control has recognised the need for reliable benefit‐cost analysis to justify inputs into rabbit management. This paper provides estimates of the costs of rabbits in Australian temperate pasture systems and of the long‐term benefits of reducing rabbits by the introduction of rabbit haemorrhagic disease (RHD). Rabbits impose annual costs on wool producers in the temperate pasture areas of between 7.1 and 38.7 million Australian dollars (mA$) depending on their density. Controlling rabbits by RHD has the potential to generate substantial long‐term economic benefits by reducing grazing competition with sheep. Reducing rabbit costs by 25% generated 15‐year net present values (NPVs) between 18.4 and 97.3 mA$ at various pre‐RHD rabbit densities. A 50% reduction in rabbit costs increased the total NPVs between 36.9 and 202.4 mA$, virtually all of which was captured by temperate area wool producers. The corresponding benefit‐cost ratios were between 2.9:1 and 16.2:1 for a 25% rabbit reduction and 5.9:1 and32.4:l for a 50% reduction, where the total costs of the RHD program in the temperate pasture areas were incurred by the wool industry. The analysis provides guidelines for the economic evaluation of other pest problems in agricultural production systems.     

THE IMPACT OF CHANGES IN TRADE POLICY ON DEVELOPING COUNTRY AGRICULTURE*

The Uruguay Round of trade negotiations has attracted much attention in the developing countries. It promises to weaken moves towards bilateral trade agreements, break open trade in temperate agricultural products, and should remove the last vestiges of protection against tropical products – although tariff escalation will remain. Overall, the main gains for the developing world will probably accrue to exporters of temperate products, above all those in Latin America; whilst for some of the poorer countries, losses may occur as the benefits of special and favoured access to the industrialised countries' markets will be eroded.     

世界森林生态系统概评

世界森林生态系统包括热带、亚热带、温带森林,北方针叶林以及其他有林地。由于人类社会经济活动,森林生态系统遭受了规模巨大的损失,表现出非完整性特征,并使森林火灾发生的频数增加,强度加大。目前全球有60%多的森林面积受到人类经济活动的干扰和影响,工业化国家绝大部分的森林是处于“半自然”状态下,或转变为人工林,发展中国家森林覆盖率下降,从而改变了森林生态系统提供的商品和服务。     

The Effect of Energy Price Increases on the U.S. Livestock Sector

This study is unique and crucial to the current time period because of the recent high energy price escalation. The uniqueness of this study pertains to the void in energy impact research of the agricultural sector, more specifically to livestock. The U.S. Department of Energy has models estimating economy-wide impacts, but not the specific impacts on agriculture. The Iowa State study concentrated on the grain sector.
The results presented here indicate that energy price increases will have substantial effects on livestock prices and production. Energy price increases will also result in differential impacts on livestock commodities (with poultry and eggs having the largest price and production effects). Furthermore, the multi-period framework enables the livestock model to capture lagged production responses. Noticeable is the higher impacts occurring in the third and fourth years.
In the future, higher energy costs may induce changes in U.S. production, processing and distribution patterns of livestock commodities. The highly vertically integrated poultry and egg industries may begin shifting production locations away from the colder northern regions to areas with more temperate climates. For industries like beef, pork and dairy, there may be increased range production to reduce impacts from higher feed costs. For all industries, closer proximity of processing plants to major livestock producing areas may occur.