湿性常绿阔叶林区次生环境鸟类群落动态研究     

王直军 《云南地理环境研究》1990,2(1):46-52

本文分析了云南哀牢山中山湿性常绿阔叶林区次生环境中鸟类群落的年动态。各类次生环境中,鸟类群落多样性和稳定性之间并非成简单的正相关。比气候顶极群落结构简单的林缘、林窗次生植被中的鸟类群落具有较高的物种多样性,但其群落稳定性较差;在植被简单的沼泽化草甸环境鸟类群落物种的多样性低,却表现其群落结构的稳定性。鸟类群落的稳定性与其生境的稳定性相关。在林缘、林窗鸟种类和密度变化显著,鸟类传播植物种子促进林缘、林窗地带自然更新和植被复化,能加速次生植被恢复到顶极群落的进程。  相似文献   

基于面向对象的城市地物信息提取方法研究   总被引：1，自引：0，他引：1  

徐涛  闫小平 《云南地理环境研究》2009,21(5):47-51

20世纪90年代以来,高空间分辨率遥感影像数据的处理已成为遥感领域中的热点与难点。利用具有人的思维特点的面向对象的信息提取技术,对高分辨率遥感影像中的城市用地进行分类,分析和利用高分辨率影像的空间信息、结构信息与光谱特征等,总结了面向对象解译方法的5个步骤,即影像分割、分类方法的选择、地物种类分类,知识库构建、计算机自动分类。分类结果表明：（1）克服了“椒盐现象”;（2）信息提取的总体精度为92.19％,而且各类地物信息的提取精度均有所提高,特别是利用前期分类的拓扑关系有效提取了城市水体与建筑物阴影。  相似文献   

利用Quick Bird全色遥感影像更新城市大比例尺地形图   总被引：10，自引：0，他引：10  

杨泽运  康家银  赵广东 《测绘工程》2005,14(2):29-31

利用现势的高分辨率遥感影像,经过精确的多项式变换正射几何纠正后,得到正射影像(DOM)与原有的数字线划图(DLG)叠加,经判读识别地物的变化,实现对原有地形图的快速更新.通过对地面控制点和检查点纠正的精度分析说明,利用Quick Bird遥感影像数据在地势较为平坦的城区更新1:2000比例尺的地形图是可行的.  相似文献   

New interpretations of Ignotornis, the first-reported Mesozoic avian footprints: implications for the paleoecology and behavior of an enigmatic Cretaceous bird     

Martin Lockley  Karen Chin  Karen Houck  Masaki Matsukawa  Reiji Kukihara 《Cretaceous Research》2009,30(4):1041-1061

  相似文献   

河北省中生代鸟类化石的首次发现及意义     

徐桂林  杨有世  邓绍颖 《地质通报》1999,18(4):2

河北省丰宁县北部侏罗系义县组底部首次发现鸟类化石。经对比研究,该鸟类与始祖鸟特征极为相近,但具明显进化,与新鸟亚纲存在显著差异,应为古鸟亚纲的一个新种新属,命名为丰宁河北鸟。  相似文献   

苏州湿地公园鸟类多样性与影响因子相关性研究     

范竟成  朱铮宇  冯育青 《湿地科学与管理》2016,(4):52-55

调查了苏州8个湿地公园的鸟类资源,分析了湿地公园鸟类多样性与影响因子的相关性。结果表明:8个湿地公园样地共记录到鸟类10目33科114种,总数量11 200只,湿地水鸟种类占31.6%。种群以鹭科Ardeidae、麻雀科Passeridae、莺科Sylviidae和鸭科Anatidae为优势种群,白鹭Egretta garzetta为广布种,8个湿地公园的鸟类多样性差异较大。湿地公园可达面积与鸟类密度呈显著负相关;湿地公园水域面积与鸟类多样性呈显著正相关,与鸟类密度呈显著负相关;湿地公园日均游客密度与鸟类多样性呈显著负相关;保育区管理的局限性导致湿地公园保育区占比与鸟类多样性相关性不显著。  相似文献   

青海湖鸟岛沙地植物群落物种多样性研究   总被引：16，自引：4，他引：12  

赵以莲  陈桂琛  周国英  彭敏 《中国沙漠》2003,23(3):295-299

根据野外样地调查资料,采用丰富度指数、物种多样性指数和均匀度指数对青海湖鸟岛沙地植物群落的多样性进行了研究,并用相关分析研究了多样性指数间的关系,结果表明:①鸟岛7个主要沙地群落间的植物多样性差异很大,分布于固定沙丘上的赖草、甘青铁线莲等群落均具有较高的丰富度指数、多样性指数,而西伯利亚蓼、藏虫实等分布在流动沙丘上的群落则最小,但均匀度指数最高。②从流动沙丘到固定沙丘阶段的变化过程中,丰富度指数、Shannon Wiener指数和Simpson指数的变化趋势基本一致,而均匀度指数则呈相反趋势,半固定沙丘是这一变化的重要转折点。③物种在各沙地类型中出现频率的多样性指数差异很大,特有种多样性指数在固定沙丘中最高,占主导地位,而在流动沙丘阶段,普通种的物种多样性指数最高。④植物生活型上各沙丘类型上的物种多样性指数均以多年生草本为最高,其次为一年生草本,而且从流动沙丘至固定沙丘阶段呈递增变化。⑤丰富度指数与多样性指数、均匀度指数之间存在极显著的相关性。  相似文献   

Importance of active tectonics during karst formation. A Middle Eocene to Pleistocene example of the Lina Moutains (Irian Jaya,Indonesia)     

J.-M. Thery  M. Pubellier  B. Thery  J. Butterlin  A. Blondeau  C. G. Adams 《Geodinamica Acta》2013,26(3-4):213-221

Abstract

The Lina Moutains show a typical example of karst formation associated to recent and active tectonics. The limestone samples were collected from giant potholes present beneath the heavy rainforest, during speleological expeditions to the Bird’s Head of Irian-Jaya. Micropalaeontological data allow us to give a Middle Pleistocene age for the most recent karst formation. A detailed stratigraphy between the Upper Lutetian and the Middle Pleistocene was recorded, with tectonic events during the Oligocene and Pleistocene. The edge of the resurgence layer was also dated. We also conclude the probable existence of a subterraneous network downhill of the karst within the most recent levels of the Kais Limestone formation. We replace this formation within the tectonic evolution of this area between the Eocene and the Middle Pleistocene, in conjunction with the oblique convergence of the Pacific plate carrying volcanic arc fragments and the Australian margin, which resulted in folding, normal faulting associated with local extension, and wrench motion, which are settings capable of creating uplift of the carbonated platform. © Elsevier, Paris  相似文献   

Do marine protected areas deliver flows of ecosystem services to support human welfare?     

《Marine Policy》2014

This paper examines the potential relationships between the ecosystem services provided by the coastal and marine environment and the designation of marine protected areas. The hypothesis is that relationships exist between the provision of ecosystem services and the features protected by marine protected areas. It is considered that protection will maintain these features in good ecological condition and in some cases will restore ecological functioning with positive effects on the delivery of ecosystem services, as pressures upon the protected features are reduced. As the number of marine protected area designations grows, system-wide effects to communities from improvements in delivery of a range of ecosystem services may be realised. This paper provides a comparative analysis of the jurisdictional marine protected area policies proposed by the English, Welsh and Scottish Governments. It presents structured assessment matrices developed from the literature and expert opinion, of ecosystem service provision by marine protected habitats and species and applies the findings to a range of existing UK marine protected areas to demonstrate its relevance. The approach and case study findings are discussed within the wider context of marine ecosystem services and marine protected area management.  相似文献   

Coastal defence and the Habitats Directive: predictions of habitat change in England and Wales   总被引：2，自引：0，他引：2  

Mark Lee 《The Geographical journal》2001,167(1):39-56

Future coastal defence policies and 'natural' processes will have an impact on habitats within Special Areas of Conservation (SAC), Special Protection Areas (SPA) and Ramsar sites. An overview of the potential nature and extent of these changes (losses or gains over the next 50 years) around the coast of England and Wales was carried out to inform policy decisions on the legal and funding aspects of coastal defence options and possible habitat replacement. It is predicted that there could be a net loss of freshwater and brackish habitat of around 4000 hectares, together with a net gain of intertidal (saltmarsh and mudflat/sandflat) habitats of around 770 hectares, with the gains associated with managed retreat ( c .12 500 ha) balancing the expected losses due to coastal squeeze and erosion on the unprotected coast. The likely costs of freshwater and brackish habitat replacement, on a hectare-for-hectare basis, is estimated to be in the order of £50–60 million, including site purchase, set-up and on-going management costs.  相似文献