恩施大峡谷生态旅游SWOT分析及对策

通过旅游地SWOT分析法,将恩施大峡谷生态旅游环境和资源规划与开发的内部优势和劣势、外部环境带来的机遇与挑战等因素通过调查研究列举,并依照矩阵形式,把各种因素相互匹配进行分析,最后提出可行性生态旅游发展战略。     

广东乳源大峡谷自然保护区植被景观特征分析

在调查大峡谷自然保护区植被和植物资源的基础上，对该区的植物区系和植被类型进行了分析．结果表明；该保护区的原生植被种类丰富，具有从南亚热带向中亚热带过渡的特点；区内植物区系成分复杂，组成以热带-亚热带和热带成分为主，热带性分布的植物类群甚多。使得区内沟谷常绿阔叶林具有某些雨林特征。小型板根、茎花现象、附生植物、藤萝密布等随处可见。而在其它中亚热带地区这种现象很少见；保护区内的植被有8个类型，包括具有雨林特征的常绿阔叶林、山地常绿针阔叶混交林、山顶常绿阔叶矮林、崖壁常绿矮林、亚热带针叶林、亚热带竹丛、亚热带灌丛草坡等，以及假苹婆、榕树林等18个群系；大峡谷自然保护区多样性植被类型具有与其独特的地形地貌相适应的特点．     

陕南金丝大峡谷生态旅游深度开发模式研究

分析了陕南金丝大峡谷生态资源环境、区位和交通等生态旅游发展的优势条件,指出其发展中存在旅游产品开发有待深化、开发资金缺乏、生态旅游系统和谐度较低等问题,提出了陕南金丝大峡谷生态旅游应创建"四位一体"的生态旅游系统、构建峡谷国家公园开发模式、开发深层次生态旅游产品、实现投资多元化,提高景区服务科技含量等开发模式。     

Age and evolution of the Grand Canyon revealed by U-Pb dating of water table-type speleothems

The age and evolution of the Grand Canyon have been subjects of great interest and debate since its discovery. We found that cave mammillaries (water table indicator speleothems) from nine sites in the Grand Canyon showed uranium-lead dating evidence for an old western Grand Canyon on the assumption that groundwater table decline rates are equivalent to incision rates. Samples in the western Grand Canyon yielded apparent water table decline rates of 55 to 123 meters per million years over the past 17 million years, in contrast to eastern Grand Canyon samples that yielded much faster rates (166 to 411 meters per million years). Chronology and inferred incision data indicate that the Grand Canyon evolved via headward erosion from west to east, together with late-stage ( approximately 3.7 million years ago) accelerated incision in the eastern block.     

天山大峡谷国家森林公园土地景观格局及生态风险分析

[目的]研究土地景观格局变化和生态风险进行分析评价,为天山大峡谷国家森林公园生态建设提供依据.[方法]以研究区1990年、2000年、2010年和2018年4期土地利用数据,利用ArcGIS和Fragstats软件计算分析景观格局指数和生态风险指数,进行景观生态风险评价.[结果]1990-2018年,区域以耕地、林地和...     

Comment on "Age and evolution of the Grand Canyon revealed by U-Pb dating of water table-type speleothems"

Polyak et al. (Reports, 7 March 2008, p. 1377) reported speleothem data leading to their inference that the western Grand Canyon incised much earlier than previously thought. This contradicts several lines of published geological knowledge in the region, hinges upon unjustified hydrogeological assumptions, and is based on two anomalous data points for which we offer alternative explanations.