Relationships of landform and vegetation
典型滩涂环境因子对植物群落空间分布的影响
典型滩涂环境因子对植物群落空间分布的影响沙晨燕;李玲;唐浩;王卿;王敏;熊丽君;吴健【摘要】Because of the relatively high environmental heterogeneity in tidal flats of Yangtze River estuary, the distribution characteristics of plant communities in different tidal flats are notably different. To analyze the relation between plant community and typical tidal flat environment factors, samples of environmental factors and plant communities in two typical tidal flats in Chongming Dongtan and Fengxian Jinhuigang were respectively collected for study. The result shows that with the increase of tidal flat elevation, the influence of the tide reduces gradually, the environmental factors changes regularly along elevation. One of the important factors leading to zonal distribution of salt marsh vegetation in Yangtze River estuary is the different adaptability of tidal flat plants to environmental factors. As the plant community is relatively mature in Chongming Dongtan, the growth performance of Phragmites australis and Spartina alterniflora along the elevation is in V shape. As the plant community is newborn and rela-tively young in Fengxian Jinhuigang, Spartina alterniflora growth performance presents a gradient distribution along the elevation. The main causes for the different growth performance of plant communities in two areas are likely to be different constructive time, different succession stage, different tidal action, and different site conditions.%长江口滩涂生境具有较高的环境异质性，导致不同滩涂植物群落的分布特征存在显著差异。
2022年教育部考试中心考研英语模拟试题(新题型4)
2022教育部考试中心考研英语模拟试题(新题型4)----新题型PartB汇编4、Directions:You are going to read a list of headings and a text about preparing in the academic community.Choose the most suitable heading from the list A-F for each numbered paragraph(41-45).The first and last paragraphs of the text are not numbered. There is one extra heading which you do not need to use. Mark your answers on ANSWER SHEET 1. (10 points)Until about two million years ago Africa’s vegetation had always been controlled by the interactions of climate; geology, soil, and groundwater conditions; and the activities of animals. The addition of humans to the latter group,however,has increasingly rendered unreal the concept of a fully developed “natural” vegetation—i.e., one approximating the ideal of a vegetational climax.(41).Early attempts at mapping and classifying Africa’s vegetation stressed this relationship:sometimes the names of plant zones were derived directly from climates.In this discussion the idea of zones is retained only ina broad descriptive sense.(42). In addition, over time more floral regions of varying shape and size have been recognized.Many schemes have arisen successively,all of which have had to take views on two important aspects: the general scale of treatment to be adopted, and the degree to which human modification is to be comprehended or discounted.(43).Quite the opposite assumption is now frequently advanced. An intimate combination of many species—in complex associations and related to localized soils, slopes, and drainage—has been detailed in many studies of the African tropics. In a few square miles there may be a visible succession from swamp with papyrus, the grass of which the ancient Egyptians made paper and from which the word“paper”originated,through swampy grassland and broad-leaved woodland and grass to a patch of forest on richer hillside soil,and finally to juicy fleshy plants on a nearly naked rock summit.(44). Correspondingly, classifications have differed greatlyin their principles for naming,grouping,and describing formations: some have chosen terms such as forest,woodland,thorn-bush, thicket, and shrub for much of the same broad tracts that others have grouped as wooded savanna (treeless grassy plain) and steppe (grassy plain with few trees).This is best seen in the nomenclature, naming of plants, adopted by two of the most comprehensive and authoritative maps of Africa’s vegetation that have been published: R. W. J. Keay’s Vegetation Map of Africa South of the Tropic of Cancer and its more widely based successor, The Vegetation Map of Africa,compiled by Frank White.In the Keay map the terms“savanna”and“steppe” were adopted as precise definition of formations, based on the herb layer and the coverage of woody vegetation; the White map, however, discarded these two categories as specific classifications.Yet any rapid absence of savanna as in its popular and more general sense is doubtful.(45).However,some100specific types of vegetation identified on the source map have been compressed into14broader classifications.[A] As more has become known of the many thousands of African plant species and their complex ecology, naming, classification,and mapping have also become more particular, stressing what was actually present rather than postulating about climatic potential.[B] In regions of higher rainfall, such as eastern Africa, savanna vegetation is maintained by periodic fires. Consuming dry grass at the end of the rainy season,the fires burn back the forest vegetation, check the invasion of trees and shrubs, and stimulate new grass growth.[C] Once, as with the scientific treatment of African soils, a much greater uniformity was attributed to the vegetation than would have been generally accepted in the same period for treatments of the lands of western Europe or the United States.[D] The vegetational map of Africa and general vegetation groupings used here follow the White map and its extensive annotations.[E] African vegetation zones are closely linked to climatic zones, with the same zones occurring both north and south of the equator in broadly similar patterns.As with climatic zones, differences in the amount and seasonal distribution of precipitation constitute the most important influence on the development of vegetation.[F]Nevertheless,in broad terms,climate remains the dominant control over vegetation.Zonal belts of precipitation,reflection latitude and contrasting exposure to the Atlantic and Indian oceans and their currents,give some reality to related belts of vegetation.[G]The span of human occupation in Africa is believed to exceed that of any other continent. All the resultant activities have tended, on balance, to reduce tree cover and increase grassland; but there has been considerable dispute among scholars concerning the natural versus human-caused development of most African grasslands at the regional level.答案41.F 42.A 43.C 44.G 45.D总体分析本文是一篇介绍非洲植被讨论的科普性文章。
新视野大学英语第三版b4u4texta课文中英对照版
unit4TextAAchievingsustainableenvironmentalism实现可持续性开展的环保主义1Environmentalsensitivityisnowasrequiredanattitudeinpolitesocietyasis,say,beliefindemocracyordisapprovalofplasticsurgery.ButnowthateveryonefromTedTurnertoGeorgeH.W.BushhasclaimedloveforMotherEarth,howarewetochooseamongthedozensofconflictingproposals,regulationsandlawsadvancedbycongressmenandconstituentsalikeinthenameoftheenvironmentClearly,noteverythingwithanenvironmentalclaimisworthdoing.Howdowesegregatet hebestoptionsandconsolidateourvaryinginterestsintoasingle,soundpolicy在上流社会,对环境的敏感就如同信仰民主、反对整容一样,是一种不可或缺的态度。
然而,既然从泰德·特纳到乔治·.布什,每个人都声称自己热爱地球母亲,那么,在由议员、选民之类的人以环境名义而提出的众多的相互矛盾的提案、规章和法规中,我们又该如何做出选择呢显而易见 ,并不是每一项冠以环境保护名义的事情都值得去做。
我们怎样才能别离出最正确选择,并且把我们各自不同的兴趣统一在同一个合理的政策当中呢2Thereisasimpleway.First,differentiatebetweenenvironmentalluxuriesandenvironmental necessities.Luxuriesarethosethingsthatwouldbenicetohaveifcostless.Necessitiesarethosethi ngswemusthaveregardless.Callthisdistinctionthedefinitiveruleofsaneenvironmentalism,which stipulatesthatcombatingecologicalchangethatdirectlythreatensthehealthandsafetyofpeopleis anenvironmentalnecessity.Allelseisluxury.有一种简便的方法。
季佩玉、范烨学术英语 第到课文翻译
Unit 4 翻译环保的当今时代是约半个世纪之久。
那段时间意识不断壮大，我们所面临的挑战知识增加，而重要的实践已经取得了进展，例如在一些减少各种污染，并在建立保护区。
我们是，但是，仍然由协调人什么我们的星球能提供可持续的要求很远。
人与自然之间的不平衡的后果是出现在改变地球的气候，动物和植物的势头，并在关键的资源，包括野生鱼类资源，淡水和土壤的枯竭的大灭绝。
而这些环境压力不是一成不变的。
他们不断升级，随着我国人口的增长和国家继续为更多的经济增长的不懈追求。
如果我们要避免这些趋势的最严重后果则毫无疑问是较为迅速的进展将需要比迄今取得的，但我们在这里应该关注我们的努力？什么可能是在未来的半个世纪行动的优先领域？这让我感到眼前的主要挑战主要不是相对于良好的信息，更好的技术和良好的政策思路。
这些东西是至关重要的当然的，但所有这些东西都已经可用。
我们知道如何让清洁电力，节约资源，培育生物多样性。
我们知道如何规范污染，防止损坏的生态系统，如果我们想。
我们有这些能力的事实是不够的。
如果我们继续前进的决定性方式的争论它需要被重新定义。
我们需要从“做正确的事'上移动，谈到风险管理，促进抗灾能力。
要查看关爱地球的自然系统为某种道德选择的是完全误解了危机，我们都在这个挑战是关于人类社会的未来，而不是一些可选的慈善事业，我们可以留给慈善事业慷慨解囊，做社会改良。
嵌入了使我们从保护自然的人们保护自然为人们的叙述是这样的重新规划的重要组成部分。
我们正处在一个时期的后果，世界必须知道，健康的本质不是一些可选的精密而是一组不可缺少的物质资产。
如果这样的叙述是为了获得实际效果再想找性质后必须立即被看作不仅是一个环境的挑战，也是一个经济问题。
只要我们继续滑向两个方向行进，一方面是促进环保目标的同时，对其他直接矛盾与措施，以实现更多的经济增长，我们不再将无法取得真正的进展。
当涉及到经济学和生态学有大量的好思已经完成。
例如，在不同的经济措施，以取代成功与失败，生态税的改革更为现实的措施，收入转移的负担，污染，生态系统服务补偿，补贴的重定向和如何调动国内生产总值的原油措施融资以扩大清洁行业。
地球脉动PPT课件英语
Objective 3
To develop students' ability to apply their knowledge to real world scenarios through case studies and practical exercises
Overview of the Earth
Epilogue
Course objectives: This course aims to introduce students to the basic concepts of Earth pulse and its applications in various fields, including physiology, volcanology, and paleontology
Loss of biodiversity can lead to a decrease in natural resources, such as food and medicine, and an increase in natural disasters
Measures to protect biodiversity including conservation of natural habitats, protection of extended specifications, and sustainable use of natural resources
Tides
Tides are changes in sea level caused by the gravitational pull of the Moon and Sun on Earth's oceans They result in regular ebbs and flows of water that has a significant impact on marine life and coastal environments
英语作文 人与动物
When it comes to the relationship between humans and animals,there are several key aspects to consider.Here is a detailed exploration of this topic:1.Coexistence:Humans and animals have coexisted on Earth for millennia.The relationship has evolved from one of survival,where humans hunted animals for food and clothing,to a more complex interaction where animals are seen as companions,workers, and even family members.2.Pets:Pets play a significant role in many peoples lives.Dogs,cats,birds,and other animals provide companionship,emotional support,and can even help with mental health issues such as anxiety and depression.The bond between humans and their pets is often deep and enduring.3.Wildlife Conservation:With the advancement of human civilization,there has been a growing awareness of the need to protect wildlife and their habitats.Conservation efforts aim to preserve biodiversity and ensure the survival of species that are endangered due to human activities such as deforestation and pollution.4.Animal Agriculture:The use of animals for food is a major part of human culture. However,this practice has raised ethical concerns regarding animal welfare and the environmental impact of largescale farming operations.There is a growing trend towards more sustainable and humane farming practices.5.Animal Labor:Animals have been used for labor throughout history,from horses pulling carriages to elephants used in logging.Today,the use of animals for labor is less common in developed countries,but it still exists in certain regions and industries.6.Animal Rights:The concept of animal rights has gained traction in recent years. Advocates argue that animals,like humans,have intrinsic rights and should not be subjected to unnecessary suffering or exploitation.This has led to stricter laws and regulations regarding the treatment of animals in various industries.7.Cultural Significance:Animals hold various symbolic meanings in different cultures. For example,in some cultures,certain animals are considered sacred and are protected by law.In others,animals may be used in traditional ceremonies or as symbols of strength or wisdom.cational Value:Interaction with animals can be educational for children and adults alike.Zoos,aquariums,and wildlife sanctuaries provide opportunities for people to learn about different species and their behaviors,fostering a sense of respect and understandingfor the natural world.9.Ecosystem Services:Animals play crucial roles in ecosystems,from pollination to pest control.They contribute to the balance of nature and are vital for maintaining the health of our planet.10.Ethical Dilemmas:The relationship between humans and animals also involves ethical dilemmas,such as the use of animals for scientific research or the consumption of animal products.These issues spark ongoing debates about the rights and treatment of animals.In conclusion,the relationship between humans and animals is multifaceted and complex. It encompasses companionship,conservation,ethical considerations,and the recognition of the intrinsic value of animals in our world.As society progresses,it is essential to continue the dialogue on how we can coexist with animals in a way that respects their wellbeing and the environment.。
地理科学进展英文版
地理科学进展英文版The Progress of Geographical ScienceGeographical science is a multidisciplinary field that studies the Earth's physical features, climate patterns, landforms, ecosystems, human settlements, and their interactions. Over the years, there have been significant advancements in geographical science that have greatly contributed to our understanding of the world. Here are some key areas of progress:1. Remote Sensing and GIS: Remote sensing technology has revolutionized the way we collect data about the Earth's surface. Satellites and airborne sensors provide high-resolution images that help in mapping and monitoring various phenomena such as land use, vegetation cover, and urban growth. Geographic Information Systems (GIS) enable the storage, analysis, and visualization of spatial data, facilitating advanced spatial modeling and decision-making processes.2. Climate Change Research: Geographical science plays acrucial role in studying the impacts of climate change. Scientists analyze temperature records, precipitation patterns, and sea level rise to understand the changing climate and its effects on ecosystems, agriculture, and human societies. This research helps in developing strategies for adaptation and mitigation.3. Geospatial Analysis: Geographical science has seen advancements in geospatial analysis techniques, allowing for more accurate and detailed investigations. Geographic data can be analyzed using statistical methods, spatial interpolation, and geostatistics to identify spatial patterns, trends, and relationships. This aids in solving complex spatial problems, such as disease mapping, urban planning, and transportation optimization.4. Human Geography: The study of human geography has advanced significantly, focusing on the relationships between people and the environment. It includes analyzing population dynamics, migration patterns, urbanization, cultural landscapes, and socioeconomic inequalities. Understanding these factors is crucial for effective urban planning, resource management, and sustainable development.5. Geographical Information Science (GIScience): GIScience is an emerging field that combines geographical science with computer science and artificial intelligence. It explores new methods and algorithms for spatial analysis, data integration, and modeling. GIScience contributes to advancements in location-based services, spatial data mining, and geovisualization techniques.6. Geographical Education: There have been improvements in geographical education, with innovative teaching methods and technologies being adopted. Interactive mapping tools, online data resources, and virtual field trips provide students with hands-on learning experiences and a deeper understanding of geographical concepts.These are just a few examples of the progress made in geographical science. With ongoing advancements in technology and interdisciplinary collaborations, geographical science continues to evolve and contribute to our knowledge of the world around us.。
小学下册Y卷英语第4单元真题[含答案]
![小学下册Y卷英语第4单元真题[含答案]](https://img.taocdn.com/s3/m/29823fe682d049649b6648d7c1c708a1284a0aa6.png)
小学下册英语第4单元真题[含答案]考试时间：90分钟（总分:120）B卷一、综合题(共计100题共100分)1. 听力题：I like to _____ (swim) in summer.2. 填空题：I love _____ (eating) fresh fruits and vegetables.3. 听力题：A ______ is a natural feature that influences local ecosystems.4. 选择题：What do we call the part of our body that helps us breathe?A. HeartB. LungsC. LiverD. Stomach答案:B5. 选择题：What is 5 + 3?A. 6B. 7C. 8D. 9答案:C6. 选择题：What do we call the soft material that covers the ground in a forest?A. SoilB. SandC. GrassD. Moss答案:DHow many days are there in a week?A. 5B. 6C. 7D. 8答案:C8. 听力题：A chemical that can act as a reducing agent is called a ______.9. 听力题：A chemical reaction can occur when reactants collide with sufficient ______.10. 听力题：We go to school by ______ (bus).11. 填空题：The pelican has a big _______ (嘴巴).12. 选择题：What do you call the process of water turning into vapor?A. PrecipitationB. EvaporationC. CondensationD. Freezing答案:B13. 听力题：A __________ is a small animal that loves to dig.14. 填空题：My brother always helps me ____.15. 听力题：The ________ (expedition) is adventurous.16. 填空题：The __________ was an important event in the fight for independence in Latin America. (独立战争)17. 填空题：Ancient Greece is known for its contribution to _______ (philosophy) and arts.18. 填空题：A caterpillar turns into a ______.What is the capital of Italy?A. RomeB. ParisC. MadridD. Lisbon20. 听力题：The chemical formula for calcium phosphate is ______.21. 选择题：Which season comes after winter?A. SummerB. FallC. SpringD. Autumn答案:C22. 选择题：What is the capital city of France?A. MadridB. BerlinC. ParisD. Lisbon答案:C23. 选择题：How do you say hello in Spanish?A. BonjourB. CiaoC. HolaD. Guten Tag答案:C24. 听力题：The color of litmus paper turns red in ______ solutions.25. 选择题：What type of animal is a dolphin?A. FishB. MammalC. ReptileD. Bird26. 听力题：I _____ (like/hate) broccoli.I have a _____ (遥控车) that can spin.28. 听力题：The ______ is known for her motivational speeches.29. 填空题：Planting in rows can help with ______ and maintenance. (成排种植可以帮助管理和维护。
与地理有关的英文参考文献
以下是一些与地理有关的英文参考文献，涵盖了地理学的不同分支和相关领域：1.《Physical Geography: The Global Environment》•作者：Strahler, Alan H., and Arthur N. Strahler•出版年份：2016•内容简介：介绍地球表面的物理地理学，包括气候、地形、水文等方面。
2.《Human Geography: Places and Regions in Global Context》•作者：Knox, Paul L., Sallie A. Marston, and Diana M. Liverman•出版年份：2016•内容简介：涵盖人文地理学的各个方面，包括文化、人口、城市等。
3.《Geography: Realms, Regions, and Concepts》•作者：De Blij, H. J., Peter O. Muller, and Jan Nijman•出版年份：2016•内容简介：全面介绍地理学领域，从全球范围到不同区域的理论和实践。
4.《The Penguin State of the World Atlas》•作者：Dan Smith•出版年份：2019•内容简介：通过地图和图表展示了世界各地的地理信息，包括人口、经济、环境等方面。
5.《Nature's Metropolis: Chicago and the Great West》•作者：William Cronon•出版年份：1991•内容简介：该书研究了城市和自然环境之间的关系，重点关注芝加哥和美国中西部的发展。
6.《The Revenge of Geography: What the Map Tells Us About Coming Conflictsand the Battle Against Fate》•作者：Robert D. Kaplan•出版年份：2012•内容简介：通过地理位置分析国际政治和地缘战略。
南海深海沉积中的孢粉记录及其古环境
2009年2月 海洋地质与第四纪地质 V ol.29,No.1第29卷第1期 M ARINE GEOLOGY&QUA TERNA RY GEOLOGY F eb.,2009 D OI:10.3724/SP.J.1140.2009.01025南海深海沉积中的孢粉记录及其古环境张玉兰1,2(1同济大学海洋与地球科学学院,上海200092; 2华东师范大学河口海岸学国家重点实验室,上海200062)摘要:通过对南海69站深海柱状剖面的孢粉成分的变化将该孔沉积层从下至上划分为5个孢粉组合带,1带: Quercus(常绿)-P inus-Cy athea-A rtemisia孢粉带(552.5～470cm);2带:P inus-Podocarpus-Quercus-Polypodiaceae 孢粉带(470～350cm);3带:Quercus(常绿)-Castanopsis-Pinus-Po ly po diaceae孢粉带(350～250cm);4带:Pinus-Podocarpus-Artemisia-Po ly po diaceae孢粉带(250～140cm);5带:Podocar pus-Cyathea-Quercus(常绿)-Pinus-Po l-y po diaceae孢粉带(140～0cm)。
并相应恢复了南海东部64ka以来3个植被、气候、古环境演替阶段,热带季雨林、热带北缘半常绿季雨林和热带季雨林。
对69站柱状地层时代作了划分,孢粉1带相当于氧同位素3期,时代为Q33-2;孢粉2～4带相当于氧同位素2期,时代为Q33-3;孢粉5带为氧同位素1期,时代为Q4。
关键词:孢粉记录;古环境;南海中图分类号:P736.2 文献标识码:A 文章编号:0256-1492(2009)01-0025-05 海洋沉积的孢粉研究虽开展得较晚,但在近几十年来得到迅速发展,各国的孢粉工作者对地中海、北海、亚速尔海、鄂霍次克海、白令海、日本海、智利海盆、加利福尼亚湾、太平洋西部、大西洋北部等海区都已进行了孢粉研究,并取得了令人瞩目的成果。
沙尘暴怎么形成英语作文
As a high school student with a keen interest in environmental science, Ive always been fascinated by the natural world and its many phenomena. One such phenomenon that has captured my attention is the dust storm, commonly known as a sandstorm. The formation of a sandstorm is a complex process, influenced by a variety of environmental factors. In this essay, I aim to explore the intricacies of how sandstorms form and the impact they have on our planet.Sandstorms are dramatic and powerful natural events that occur when strong winds lift and transport large amounts of sand and dust particles from the ground into the air. The process begins with the presence of loose, dry soil or sand, often found in arid and semiarid regions. These areas are typically characterized by sparse vegetation, which means there is little to anchor the soil in place. When the wind picks up, it can easily dislodge these particles, initiating the sandstorm.The role of wind is crucial in the formation of a sandstorm. It acts as the driving force, capable of increasing in speed and intensity to create the necessary conditions for a dust storm. The winds velocity must reach a certain threshold to lift the heavier sand particles. Once airborne, these particles can be carried great distances by the wind, sometimes crossing borders and affecting regions far from their origin.Another significant factor in the formation of sandstorms is the lack of vegetation. Vegetation plays a critical role in stabilizing soil and reducing erosion. In areas where vegetation has been removed, either naturally or through human activities such as deforestation and overgrazing, the soilbecomes more susceptible to being picked up by the wind. This contributes to the intensity and frequency of sandstorms.Climate change also plays a role in the increasing prevalence of sandstorms. Rising temperatures can lead to more frequent droughts, which in turn reduce vegetation cover and increase the likelihood of dust storms. Additionally, climate change can alter wind patterns, potentially increasing the strength and frequency of winds that can trigger sandstorms.The impact of sandstorms extends beyond the immediate area where they occur. When sand and dust particles are lifted into the air, they can reduce visibility, posing a risk to transportation and causing respiratory problems for humans and animals. Moreover, these particles can be carried by the wind and deposited in other regions, affecting air quality and contributing to the global spread of dust.A notable example of the effects of a sandstorm can be seen in the case of the Asian dust storms that occasionally reach as far as North America. These storms, originating from the deserts of China and Mongolia, can carry with them not only sand but also pollutants and microbes, which can have significant health and environmental implications for the regions they affect.In conclusion, the formation of a sandstorm is a multifaceted process involving the interplay of wind, soil conditions, vegetation cover, and broader environmental factors such as climate change. The consequencesof these natural events are farreaching, affecting air quality, visibility, and public health. As we continue to grapple with the challenges posed by sandstorms, it is essential to understand their formation and work towards sustainable land management practices to mitigate their impact.。
鸟类间的生态竞争英语作文
As a high school student with a keen interest in biology, Ive always been fascinated by the intricate dynamics of nature, especially the ecological competition among birds. This essay aims to delve into the fascinating world of avian interactions, exploring how different bird species compete for resources and coexist in the same environment.Growing up in a suburban area surrounded by lush greenery, Ive had the privilege of observing various bird species from my window. The sight of a majestic eagle soaring high in the sky, or a humble sparrow hopping around on the ground, always fills me with awe. But its not just their beauty that captivates me its the complex relationships they share with each other that truly intrigues me.One of the most evident forms of competition among birds is for food. Birds, like all living creatures, need to eat to survive, and the availability of food can be a scarce resource, especially during harsh seasons. Ive witnessed firsthand how a group of sparrows would aggressively chase away a larger bird, like a crow, from a feeder filled with seeds. This behavior is not just about survival its also about ensuring the survival of their offspring. By monopolizing a food source, these small birds increase their chances of raising healthy, strong young ones.Another form of competition is for nesting sites. Birds are not just picky about what they eat they are also very particular about where they lay their eggs. A safe and secure nesting site is crucial for the survival of their young. Ive observed how a pair of robins would defend their chosen tree hollow from other birds, even going as far as engaging in aerial battles. Thisterritorial behavior is not just about securing a home its also about ensuring the best possible start for their offspring.But competition among birds is not always a zerosum game. There are instances of cooperation and symbiosis that defy the cutthroat nature of survival. For example, some bird species, like the oxpeckers, have evolved to live in harmony with larger animals, such as buffaloes. These small birds feed on ticks and parasites found on the larger animals, providing a valuable service while also securing a meal for themselves. This mutualistic relationship is a beautiful example of how different species can coexist and thrive together.Moreover, the competition among birds can also drive evolutionary adaptations. For instance, the beak shape and size of different bird species have evolved to suit their specific feeding habits. Hummingbirds, with their long, slender beaks, are perfectly adapted to feed on nectar from flowers, while eagles, with their powerful talons, are built for hunting and catching prey. These adaptations not only help individual species survive but also contribute to the overall biodiversity of an ecosystem.However, the ecological competition among birds is not without its challenges. Human activities, such as deforestation and pollution, have disrupted the delicate balance of nature, putting many bird species at risk. The loss of habitat and food sources has forced some birds to compete more intensely for the remaining resources, leading to a decline in their populations.As a high school student, I feel a deep sense of responsibility to protect and preserve the natural world for future generations. By studying and understanding the ecological competition among birds, we can gain valuable insights into the interconnectedness of life and the importance of maintaining a healthy, balanced ecosystem.In conclusion, the ecological competition among birds is a fascinating and complex phenomenon that reflects the struggle for survival in the natural world. By observing and learning from these interactions, we can appreciate the beauty and resilience of life, as well as the importance of conservation efforts to protect our planets biodiversity. As we continue to explore and understand the intricate relationships among bird species, we can also learn valuable lessons about cooperation, adaptation, and the delicate balance of life on Earth.。
新视野大学英语第三版第四册第四单元sectionA课件ppt
Listen to a short passage concerning global warming.
If energy use per person and technology remain the same, total energy use and greenhouse gas _e_m_i_s_s_io_n_s_ (mainly, CO2) will be 42% higher in 2050. But that’s too low, because societies that grow richer use more energy. We need economic growth unless we _c_o_n_d_e_m_n__ the world’s poor to their present poverty and freeze everyone else’s living standards.
the environmental issues?
Tips These pictures remind us more of the environmental problems we human beings are encountered with at present, including air pollution (hazy weather), water pollution, deforestation, wild animals extinction and so on.
Warming-up Activities
Lead-in
Pre-reading Activities
Cultural Background
Lead-in
Short Answer Questions
全球暖化和冰河期
复 ｒ 它之前暂时放弃的领地 。 温暖与严寒 ，富足和饥荒 ．就像一 对如影随形 的孪生子 ，在人类历史 ． Ｉ ． 交替｝ Ｉ Ｊ 现 ：为什么大 一然
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育 ｍ 了大 麦 ”
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Ｋ Ｎ Ｏ Ｗ ｌ知 道
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荚同 加州大学 巴巴｛ 分 校 的 人 类 学 与考 学 教 授 布 莱 恩 ・费根 （ Ｂ ｒ ｉ ａ ｎ Ｆ ａ ｇ ａ ｎ） ， 是 一 位 环 境 史 的 积 极 倡 导 者 在 过 去 ２ ０多 年 ｆ ｆ ｌ ，他
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』 ｌ 】 罩收成富足 ，人们获得 ＿ ｒ 充足的食物 …－ － 葡萄
人 度 ｌ － 工 Ｊ 人 类的 尘仔
提 供 ｒｆ 宋障 “ Ｉ 温 窜 的 玻
自然与建筑的关系英语作文
自然与建筑的关系英语作文Nature and Architecture: A Harmonious RelationshipThe natural world and the built environment have long been intertwined, each influencing the other in profound and meaningful ways. As humans, we have an innate connection to nature, and this connection has played a significant role in shaping the way we design and construct our built spaces. From the earliest civilizations to the modern-day metropolises, the relationship between nature and architecture has been a constant source of inspiration and innovation.One of the most fundamental ways in which nature and architecture intersect is through the use of natural materials in construction. Throughout history, architects and builders have drawn upon the abundance of natural resources available to them, from stone and wood to clay and straw. These materials not only provide the structural foundation for our buildings but also lend a sense of warmth and authenticity that can be difficult to replicate with synthetic alternatives.Moreover, the incorporation of natural elements into architecturaldesign can have a profound impact on the overall aesthetic and emotional experience of a space. The inclusion of natural light, for instance, can transform a room, casting shadows and creating a sense of depth and movement that simply cannot be achieved through artificial lighting alone. Similarly, the integration of greenery, whether in the form of lush gardens, living walls, or strategically placed plants, can infuse a space with a calming and rejuvenating energy, connecting the occupants to the natural world.Beyond the aesthetic considerations, the relationship between nature and architecture also has significant implications for sustainability and environmental stewardship. As the global community becomes increasingly aware of the pressing need to mitigate the impact of human activity on the natural world, architects and designers have been at the forefront of the movement towards more eco-friendly and energy-efficient building practices.This shift towards sustainable design has led to the development of innovative technologies and strategies that seek to minimize the environmental footprint of our built environments. From the use of renewable energy sources and advanced insulation materials to the integration of water conservation systems and waste management solutions, the modern architectural landscape is being transformed by a growing emphasis on harmonizing human-made structures with the natural world.One particularly compelling example of this trend is the rise of biophilic design, a design philosophy that seeks to incorporate elements of nature into the built environment in order to enhance human health and well-being. By drawing upon the inherent human affinity for the natural world, biophilic design aims to create spaces that foster a sense of connection, calm, and inspiration, ultimately improving the overall quality of life for those who inhabit them.This approach to design has been shown to have a range of positive outcomes, from reduced stress and increased productivity to enhanced cognitive function and improved physical health. By integrating natural elements such as natural light, natural ventilation, and the presence of greenery, biophilic design recognizes the fundamental need for humans to maintain a strong connection to the natural world, even in the midst of our increasingly urbanized and technologically-driven lives.Of course, the relationship between nature and architecture is not without its challenges. As our cities continue to grow and the demand for housing and infrastructure increases, there is often a tension between the need to accommodate human development and the desire to preserve the natural environment. This tension has led to innovative approaches to urban planning and design, such as the incorporation of green spaces, the repurposing of abandonedindustrial sites, and the integration of renewable energy sources into the built environment.Despite these challenges, however, the relationship between nature and architecture remains a vital and enduring one. As we continue to grapple with the complex issues of sustainability, environmental stewardship, and human well-being, the role of architecture in fostering a harmonious balance between the natural and the built worlds will only become more crucial.Through thoughtful and intentional design, architects and designers have the power to create spaces that not only meet our functional needs but also nourish our innate connection to the natural world. By embracing the inherent beauty and resilience of nature, we can craft built environments that are not only aesthetically pleasing but also profoundly restorative, enriching the lives of those who inhabit them and contributing to the long-term health and vitality of our planet.。
TPO-41 Reading 3翻译
参考译文贸易和早期国家的形成以物易物是几千年里最基本的贸易方式；通常零星的出现，并且以互惠的观念为基础，它涉及到个体或群体之间商品和物品的互换。
这些商品在社会中的重新分配受酋长、宗教领袖或亲属群体的控制。
这种重新分配是酋长制社会的基本元素。
从再分配到正规贸易——主要为有管理的贸易，这类贸易可能包含固定的价格甚至产生货币——的转变与越来越复杂的政治和社会制度密不可分，所以与古代国家的发展是紧密的联系在一起的。
在20世纪70年代，很多考古学家认为贸易是古代国家出现的主要因素。
英国考古学家Colin Renfrew将克里特岛和爱琴海的米诺斯文明的繁荣发展归因于越来越多的贸易联系，以及在地方社区种植橄榄和葡萄藤带来的影响。
随着农业经济越来越多样，并且人们不仅可以在当地市场购买食物，也可以通过远距离的贸易来购买，这就产生了深远的经济上的相互影响。
最终，这导致了奢侈品和基本商品的重新分配系统，这个分配系统甶来自宫殿的米诺斯统治者组织并控制。
随着时间的流逝，自给自足的地区逐渐减少，地区间互相的依赖越来越多。
远程的贸易利益导致了一些文化的同质性，可能甚至导致文化抄袭的行为。
所以，贸易和互动越来越多，出现了专业化工艺品制造蓬勃发展，多种因素互相影响、正向促进，导致了以皇宫为核心和经济中心的复杂社会结构，也是新的米诺斯文化的经济中心。
Renfrew的模式包含一些假设，现在被证明是错误的。
比如说，他认为引入种植葡萄藤和橄榄使得一大片土地被开垦耕种，并且促进了复杂的社会的出现。
很多考古学家和古植物学家现在质疑这个观点，他们指出，现存的耕种葡萄藤和橄榄的证据表明它们只存在于青铜时代的晚期。
而贸易可能是众多导致米诺斯克里特宫殿经济体制出现的变量之一。
美国的考古学家William Rathje提出了一个假说，这个假说认为长距离易物交换的激增是中美洲玛雅文明出现的基本原因。
他指出，玛雅低地的环境缺乏很多必备的资源，比如黑曜石、盐、研磨玉米的石头，以及很多昂贵的材料。
必修一地理第四章问题研究
必修一地理第四章问题研究**必修一地理第四章问题研究**Geography, as a subject that explores the spatial patterns and processes of the Earth's surface, holds immense importance in understanding our planet. The fourth chapter of the compulsory geography textbook delves into a profound research topic, offering insights into the intricate relationships between human activities and the natural environment.地理作为一门探索地球表面空间格局和过程的学科，对于理解我们的星球具有重要意义。
必修地理课本的第四章深入探讨了一个深刻的研究课题，揭示了人类活动与自然环境之间复杂的关系。
One of the key issues explored in this chapter is the impact of urbanization on the natural environment. As cities expand, they consume vast amounts of land, often leading to deforestation and the loss of biodiversity. This process not only disrupts the ecological balance but also poses a threat to the sustainability of urban development.本章探讨的关键问题之一是城市化对自然环境的影响。
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六盘山小流域地形、植被特征与土壤水文物理性质的关系*王轶浩1,2 王彦辉1** 谢双喜3 于澎涛1 熊 伟1 郝 佳1(1中国林业科学研究院森林生态环境与保护研究所,北京100091;2重庆市林业科学研究院,重庆400036;3贵州大学林学院,贵阳550025)摘 要 利用多元统计方法,分析了六盘山分水岭沟小流域107个样地的地形㊁植被特征与土壤水文物理性质的关系㊂结果表明:饱和持水量㊁总孔隙度㊁毛管持水量㊁容重㊁石砾体积含量㊁非毛管孔隙度可作为土壤水文物理性质类型划分的6项重要指标,同时土壤毛管持水量还是一个敏感指标㊂将所有调查样地划分为土壤物理性质组间差别较大但组内接近的3组样地,发现各组样地的植被类型相近㊂土壤水文功能最好的第III 组是以桦树和山杨为主的天然阔叶次生林样地,其主要分布在阴坡㊁中坡位;华北落叶松人工林为第Ⅱ组,其土壤水文功能次之;土壤水文功能最差的第Ⅰ组多是位于陡坡悬崖的华山松天然林及杂灌丛样地㊂土壤孔隙性受到地形和植被特征的共同影响,影响显著的地形特征主要是相对高程㊁坡向和坡位;植被特征主要是胸径㊁乔木高度和灌木层盖度㊂关键词 六盘山;小流域;土壤水文功能;多元统计分析*林业公益性行业科研专项(201104005⁃02㊁200904056㊁200904005)㊁国家自然科学基金项目(40730631㊁41071023)㊁国家林业局森林生态环境重点实验室和重庆市三峡库区森林生态保护与恢复市级重点实验室资助㊂**通讯作者E⁃mail:wangyh@收稿日期:2011⁃07⁃25 接受日期:2011⁃09⁃23中图分类号 S159.2 文献标识码 A 文章编号 1000-4890(2012)1-0145-07Relationships of landform and vegetation characters with soil hydrophysical properties in a small watershed of Liupan Mountains ,Northwest China.WANG Yi⁃hao 1,2,WANG Yan⁃hui 1**,XIE Shuang⁃xi 3,YU Peng⁃tao 1,XIONG Wei 1,HAO Jia 1(1Institute of Forest Ecology ,Environment and Protection ,Chinese Academy of Forestry ,Beijing 100091,China ;2Forestry Academy of Chongqing ,Chongqing 400036,China ;3College of Forestry ,Guizhou University ,Guiyang 550025,China ).Chinese Journal of Ecology ,2012,31(1):145-151.Abstract :Based on the investigation data from 107sampling plots in a small watershed of Fen⁃shuilinggou in the Liupan Mountains of Northwest China,and by using multivariate statistical analysis,this paper analyzed the relationships of landform and vegetation characters with soil hy⁃drophysical properties in the watershed.Soil water⁃holding capacity,total porosity,capillary wa⁃ter⁃holding capacity,bulk density,volumetric fragment content,and non⁃capillary porosity were considered as the important soil hydrophysical parameters for classifying soil hydrophysical prop⁃erties,and soil capillary water⁃holding capacity was a sensitive parameter.The sampling plots were classified into 3groups,with great differences in soil hydrophysical properties and vegeta⁃tion types.Group III had the best soil hydrophysical properties,which was covered by the sec⁃ondary broad⁃leaved forests mainly composed of birch (Betula spp.)and poplar (Populus davidi⁃ana )and mostly located on the middle section of shady slopes.Group II had relatively good soil hydrophysical properties,which was covered by Larix principis⁃rupprechtii plantation.Group I had the worst soil hydrophysical properties,which was covered by the natural forests mainly com⁃posed of Pinus armandii or shrubs and mostly located on steep slopes.The soil porosity was con⁃trolled by landform and vegetation characters.The most important parameters of landform affect⁃生态学杂志Chinese Journal of Ecology 2012,31(1):145-151ing the soil porosity were relative elevation,slope position,and aspect,and the most important vegetation parameters affecting the soil porosity were DBH,tree height,and shrub layer cover⁃age.Key words:Liupan Mountains;small watershed;soil hydrological function;multivariate statisti⁃cal analysis. 土壤水文物理性质是评价和衡量森林水文功能的重要参数,对森林生态水文过程有重要影响,其在小流域内存在显著的空间差异(杜阿朋等,2006;王轶浩等,2008),并受到植被㊁地形的作用㊂前人在植被类型㊁地形条件的土壤水文特征影响㊁土壤物理性质空间分布等方面开展了不少研究(Alemi et al., 1988;何祥,1998;任青山,2002;邱扬等,2002;史竹叶等,2003)㊂但大多是对不同植被类型或地形特征的简单定性比较或对单因素影响单指标的相关分析(王勤等,2003;李东海等,2006;李志等,2008),尚未开展2个变量组之间影响的研究,尤其是利用多元统计分析方法研究地形㊁植被与土壤水文物理性质关系的报道尚不多见㊂如何揭示地形因子㊁植被特征和土壤水文物理性质变量组之间复杂的关系及其中的生态学机制,已成为一个重要科学问题㊂本文采用主成分分析㊁聚类分析㊁典型相关分析等方法,研究宁夏六盘山分水岭沟小流域的地形因子㊁植被特征与土壤水文物理性质的关系,以进一步了解土壤水文物理性质在小流域的空间分布规律和确定植被特征变量组㊁地形因子变量组中影响土壤水文物理性质的重要参数,为生态水文模型构建和参数选择以及深入研究小流域生态水文过程提供一定的理论参考㊂1 研究地区与研究方法1.1 自然概况试验地点位于宁夏六盘山自然保护区南段的分水岭沟小流域,年均气温5℃,7月平均气温为16.4℃,1月为-7.5℃,年均降水量600~820mm,全年蒸发量1214~1426mm㊂流域面积10.5km2,海拔高度为2253~2737m,坡度为20°~50°,为典型的石质山地㊂母岩主要为石灰页岩和红色砂岩㊂土壤以森林灰褐土为主,石砾含量较高㊂该小流域位于六盘山重要水源涵养林区,森林覆盖率高达74.2%,森林植被主要是天然次生林和部分人工林㊂天然次生林的主要树种有山杨(Popu⁃lus davidiana)㊁白桦(Betula platyphylla)㊁红桦(Betu⁃la albo⁃sinensis)㊁糙皮桦(Betula utilis)㊁椴木(Tilia paucicostata)和华山松(Pinus armandii)㊂人工林主要树种为华北落叶松(Larix principis⁃rupprechtii)㊂小流域内还生长有较大面积的灌木,主要有沙棘(Hippophae rhamnoides)㊁虎榛子(Ostyopsis davidi⁃ana)㊁灰栒子(Cotongeaster acutifolius)㊁峨嵋蔷薇(Rosa omeiensis)㊁李(Prunus salicina)和秦岭小檗(Berberis cinumsenata)等㊂草本植物主要有苔草(Cyperaceae carex)㊁艾蒿(Artemisia argyi)和东方草莓(Fragaria orientali)等㊂1.2 研究方法1.2.1 样地设置 在小流域内采用样线法进行样地布设㊂每条样线均以沟底为始点,并沿坡面延升至坡顶,共布设15条样线,107个样地,其中,20m×20m乔木样地95个,5m×5m灌木样地12个㊂在样地内用地质罗盘仪测定坡度和坡向,手持GPS测定经纬度和高程,并按乔⁃灌⁃草分层测定其植被特征,包括种名㊁郁闭度㊁高度㊁胸径(地径)㊁盖度等㊂1.2.2 土壤水文物理性质测定 在每个样地的典型地段开挖土壤剖面,取样深度为0~60cm,将土壤剖面按20cm间隔机械分层,并用容积200cm3的环刀取样,每层2~3个重复㊂然后带回室内测定土壤容重㊁毛管持水量㊁饱和持水量㊁毛管孔隙度㊁总孔隙度以及石砾体积含量,具体方法见森林土壤定位研究方法的 环刀法”(林业部科技司,1994)㊂1.2.3 数据处理 利用SPSS13.0对试验数据进行主成分分析㊁聚类分析和典型相关分析,其中,用于主成分分析的因子指标有土层厚度㊁土壤容重㊁土壤石砾体积含量㊁饱和持水量㊁毛管持水量㊁土壤总孔隙度㊁毛管孔隙度㊁非毛管孔隙度㊁坡度㊁相对高程㊁坡位㊁Sin(坡向)和Cos(坡向)等13个;典范相关分析中将相对高程(X1)㊁坡度(X2)㊁Sin(坡向) (X3)㊁Cos(坡向)(X4)㊁坡位(X5)地形因子构成第1集团;土壤容重(Y1)㊁土壤石砾体积含量(Y2)㊁饱和持水量(Y3)㊁毛管持水量(Y4)㊁总孔隙度(Y5)㊁毛管孔隙度(Y6)㊁非毛管孔隙度(Y7)㊁土层厚度(Y8)等土壤水文物理性质构成第二集团;郁闭度(Z1)㊁乔641 生态学杂志 第31卷 第1期 木高(Z2)㊁灌木层盖度(Z3)㊁草本层盖度(Z4)和胸径(Z5)等植被因子构成第3集团㊂数据预处理㊂首先对坡向和坡位等非数量指标进行数量化,对按以正北为起点(0°)顺时针旋转角度表示的坡向(如北坡取值0°,东坡取值90°,南坡取值180°)进行正弦和余弦转化,同时得到sin(坡向)和cos(坡向)2个分别代表偏东西向和偏南北向程度的指标;由于该研究区域与刘创民等(1996)的研究区域相似,均为典型土石山区,所以参照其研究方法将坡位按经验建立隶属函数换算成编码:坡顶0.1,上坡位0.5,中坡位1.0,下坡位0.8,坡脚0.9;相对高程取值为测点高程与流域出口高程的差值(邱扬等,2002);土壤物理性质数值均采用0~60 cm土层的算术平均值㊂2 结果与分析2.1 主要影响因子的确定利用主成分分析计算出相关系数阵以及阵的特征根㊁贡献率㊁累积贡献率和特征向量(表1)㊂根据常规方法,提取特征根>1的主成分,则4个主成分被提取㊂从表1可知,第Ⅰ主成分提供的信息量为32.49%,4个主成分所包含的原始变量信息量累积贡献率分别为32.49%㊁55.46%㊁67.25%和76.05%㊂第Ⅰ主成分中的土壤饱和持水量(0.959)㊁土壤总孔隙度(0.938)㊁毛管持水量(0.883)和土壤容重(-0.747)以及第Ⅱ主成分中的土壤石砾体积含量(-0.870)㊁非毛管孔隙度(-0.788)的负荷量最大,它们也是反映土壤生态水文功能的重要土壤物理性质㊂第III主成分中坡位和第Ⅳ主成分中Sin(坡向)的负荷量分别为0.821和0.784,其代表了影响土壤物理性质好坏的主要地形因子㊂故选用第Ⅰ主成分中的土壤饱和持水量㊁总孔隙度㊁毛管持水量和土壤容重,第Ⅱ主成分中的土壤石砾体积含量和非毛管孔隙度,第III主成分中的坡位以及第Ⅳ主成分中的坡向共8项指标用以开展聚类分析㊂2.2 土壤水文物理性质类型划分和比较采用离差平方和法(Ward’s method)对样地进行聚类(Q型聚类),使分出的类内各样本间差异最小,各类间的差异最大㊂在聚类分析树状图重标距离15处作为异质性划分水平,将107个样地划分为3组土壤水文物理性质类型(图1)㊂方差分析结果表明(表2),3组类型差异均极显著(P<0.01),同时结合查看野外调查资料,发现相邻样地属于同一组类型居多,说明分类比较合理㊂3组土壤水文物理类型的土壤毛管持水量差异最明显,第Ⅰ㊁第Ⅱ㊁第Ⅲ组的土壤毛管持水量分别为(26.91±6.74)%㊁(35.67±4.31)%和(49.16±16.64)%,它们之间相差分别为1.33倍和1.38倍,说明土壤毛管持水量是土壤水文物理性质类型组划分的一个最敏感指标㊂同时,这3组的土壤饱和持水量㊁土壤总孔隙度也遵循这样的大小排序,但第Ⅰ组的土壤饱表1 主成分(PCA)分析的因子负荷量㊁特征根及贡献率Table1 Factor loadings,eigenvalues and cumulative per⁃centages of principal component analysis因子主成分ⅠⅡⅢⅣ饱和持水量(%)0.9590.148-0.1100.047总孔隙度(%)0.9380.011-0.0640.208毛管持水量(%)0.8830.4030.027-0.108土壤容重(g㊃cm-3)-0.7470.5720.0240.086土壤石砾体积含量(%)0.040-0.8700.129-0.205非毛管孔隙度(%)0.191-0.788-0.1690.416毛管孔隙度(%)0.6710.6820.088-0.170坡位0.135-0.0250.8210.133相对高程-0.1710.574-0.5810.389 Sin(坡向)-0.0600.0590.2880.784土层厚度(m)0.1210.3020.4950.153坡度(°)0.312-0.384-0.3460.170 Cos(坡向)0.660-0.2480.045-0.021特征根4.2242.9871.5321.032贡献率(%)32.4922.9711.798.80累积贡献率(%)32.4955.4667.2576.05表2 3组土壤水文物理性质类型的土壤物理性质Table2 Soil physical indices of three groups组样地数石砾体积含量(%)饱和持水量(%)毛管持水量(%)总孔隙度(%)非毛管孔隙度(%)土壤容重(g㊃cm-3)Ⅰ929.71±8.0845.33±8.0526.91±6.7455.03±4.4022.73±5.660.75±0.20Ⅱ656.32±4.7947.97±5.5535.67±4.3155.54±3.3513.97±3.091.11±0.09Ⅲ3310.62±6.2969.24±15.6349.16±16.6463.66±3.5318.97±4.560.81±0.14 F值69.810**53.955**20.674**68.166**32.601**43.774** **差异极显著(P<0.01)㊂741王轶浩等:六盘山小流域地形㊁植被特征与土壤水文物理性质的关系图1 聚类分析树状图Fig.1 Dendrogram of cluster analysis841 生态学杂志 第31卷 第1期 和持水量和总孔隙度与第Ⅱ组非常接近,且远低于第Ⅲ组,说明第III组土壤水源涵养功能要好于第Ⅰ组和第Ⅱ组㊂第Ⅰ组的土壤石砾体积含量(29.71%)远高于第Ⅲ组(10.62%)和第Ⅱ组(6.32%),由于土壤石砾含量大小以及排列方式影响着土壤孔隙状况,尤其是非毛管孔隙度,因此,土壤非毛管孔隙度在3组中的排序与土壤石砾含量一致㊂从景观斑块异质性看,3组土壤水文物理性质类型样地又分别属于不同植被类型,且吻合较好,而不同植被类型外观差异较大(表3)㊂其中,第Ⅰ组的植被类型主要是多位于陡坡悬崖的华山松以及灌丛(占样地数比例为100%);第Ⅱ组的植被类型主要是华北落叶松人工林(81.54%);第Ⅲ组的植被类型主要是红桦㊁白桦㊁糙皮桦及山杨等天然阔叶次生林(72.73%)㊂土壤容重可整体反映土壤质地㊁结构㊁孔隙状况㊁有机质含量等土壤特性以及植被类型对其的改良作用㊂结合表2分析,土壤容重以第Ⅱ组最大,为1.11g㊃cm-3,而第Ⅱ组的植被又以华北落叶松为主(表3),说明华北落叶松人工林(第Ⅱ组)的土壤涵养水源功能和改良土壤作用要次于阔叶次生林(第Ⅲ组),这与马祥华等(2005)的研究结果一致㊂华山松林(第Ⅰ组)的土壤生态水文功能最差,这可能与华山松一般分布在悬崖陡壁等恶劣生境,土壤石砾含量较多有关㊂从表3地形特点可知,就坡向而言,第Ⅰ组以阳坡样地居多;第Ⅱ组以半阴坡㊁阳坡居多;第Ⅲ组以阴坡㊁半阴坡为主,这说明阴坡样地的土壤涵养水源功能要好㊂就坡位而言,第Ⅰ组以上坡位㊁中坡位样地居多;第Ⅱ组以中坡位㊁下坡位居多;第III组以中坡位为主(占45.45%)㊂2.3 地形㊁植被与土壤水文物理性质的典型相关分析典型相关分析是研究2组指标(变量)间相关关系的一种多变量统计分析方法,它将2组变量的每1组变量都作为整体考虑,所以比仅考虑一个指标与一个指标间关系或一个指标与多个指标间关系的一般相关分析更能反映现象的本质(李志辉和罗平,2005)㊂典型相关分析结果表明(表4),地形因子与土壤水文物理性质关系较为密切,它们的第1对典范相关系数为0.768,第2对典范相关系数为0.700,第3对典范相关系数为0.383㊂显著性检验表明,在显著性1%的水平上,第1㊁第2㊁第3对典范相关系数都显著,其余的不显著,所以认为地形与土壤水文物理性质两集团极显著相关㊂在它们的关系中, U1和V1组成第一对典范变量,U1是地形因子的线性组合,其中各因子的系数即其权重系数,其绝对值反映了其对因变量V1的贡献率大小,正负号表明作用表3 3组土壤水文物理性质类型的植被和地形特点Table3 Vegetation types and landform characteristics of three groups 组样本数植被类型华山松及灌丛华北落叶松桦树及山杨坡向南坡西坡东坡北坡坡位坡顶上坡中坡下坡坡脚Ⅰ91000044.4422.2233.330033.3333.3322.2211.11Ⅱ6512.3181.546.1516.9213.8555.3813.859.2316.9236.9221.5415.38Ⅲ3318.189.0972.7306.0633.3360.616.0618.1845.4521.219.09数据为各类型样地数占其组样地数的百分比(%)㊂表4 典范相关分析Table4 Results of canonical correlation analysis典范相关与变量地形因子与土壤水文物理性质植被特征与土壤水文物理性质第1对典范相关系数0.768 P<0.010.714 P<0.01第1对典范变量U1=-0.662X1+0.463X2-0.173X3+0.026X4+0.250X5V1=-0.156Y1+0.602Y2+0.566Y3-0.84Y4-196Y5+218Y6+139Y7+0.64Y8U1=-0.304Z1+0.397Z2+0.093Z3+0.370Z4-0.979Z5 V1=0.525Y1-0.508Y2+0.691Y3-0.943Y4+377Y5-420Y6-268Y7-0.306Y8第2对典范相关系数0.700 P<0.010.437P<0.01第2对典范变量U2=0.657X1+0.215X2-0.208X3+0.339X4+0.782X5V2=0.48Y1-0.408Y2+0.139Y3-0.148Y4-385Y5+429Y6+273Y7+0.719Y8U2=0.143Z1-1.41Z2+0.143Z3+1.234Z4+1.385Z5 V2=-0.33Y1+0.47Y2+2.625Y3-3.343Y4-382Y5+ 426Y6+270Y7-0.836Y8第3对典范相关系数0.383 P<0.010.377 P<0.01第3对典范变量U3=0.252X1+0.448X2+0.313X3-0.911X4+0.516X5V3=-0.427Y1-1.02Y2-4.778Y3+4.794Y4-132Y5+146Y6+95Y7+0.270Y8U3=0.027Z1+0.017Z2-0.969Z3-0.114Z4-0.233Z5 V3=-1.239Y1-0.295Y2+2.131Y3-2.029Y4-343Y5-383Y6-245Y7+0.094Y8941王轶浩等:六盘山小流域地形㊁植被特征与土壤水文物理性质的关系的方向性㊂第1对典范变量U1中X1㊁X2㊁X3㊁X4和X5的权重系数分别为-0.662㊁0.463㊁-0.173㊁0.026和0.250,其中以相对高程的权重系数最大,说明地形因子中以相对高程对土壤水文物理性质影响最大,且为负作用;在V1土壤因子的线性组合中,权重系数最大的是土壤的孔隙状况;在第2㊁第3对典范变量中,地形的线性组合权重系数最大的分别是坡位(0.782)和Cos(坡向)(-0.911),土壤因子的线性组合权重系数最大的依然是土壤总孔隙度㊁非毛管孔隙度和毛管孔隙度㊂由此可见,地形因子和土壤因子的典范变量构成中,相对高程㊁坡位和Cos(坡向)与土壤总孔隙度㊁非毛管孔隙度和毛管孔隙度密切相关㊂植被特征与土壤水文物理性质的典范相关分析表明(表4),植被与土壤因子关系密切㊂显著性检验表明,在显著性1%的水平上,第1㊁第2㊁第3对典范相关系数都是相关的,其余的不显著,它们的相关系数分别是0.714㊁0.437和0.377㊂第1对植被特征与土壤因子的典范变量中,植被因子线性组合U1中胸径权重系数最大,为-0.979,这说明胸径对土壤水文物理性质产生重要影响,乔木胸径一定程度上也反映了林木年龄㊁冠幅以及生物量等生物学特征;第2对典范变量中,植被线性组合权重系数最大的是乔木高(-1.410);第3对典范变量中,植被线性组合权重系数最大的是灌木层盖度(-0.969)㊂第1㊁第2㊁第3对典型变量中,土壤因子的线性组合V权重系数最大的均是土壤孔隙状况(土壤毛管㊁非毛管和总孔隙度)㊂这说明植被因子与土壤因子的极显著相关,实质上就是植被因子中的胸径㊁乔木高和灌木层盖度与土壤因子组合中土壤孔隙度的相关㊂3 讨 论从植被类型看,土壤涵养水源功能低的第Ⅰ组样地主要为分布在陡坡峭壁上的华山松和杂灌丛;土壤涵养水源功能较低的第Ⅱ组样地主要为华北落叶松人工林;土壤涵养水源功能最好的第III组样地主要为红桦㊁白桦和山杨天然次生林㊂这说明大面积营造华北落叶松这样的人工针叶纯林不利于维持㊁提高和发挥土壤涵养水源功能,许多研究表明,人工林容易造成地力衰退㊁土壤板结㊁水源涵养功能低下(刘剑斌,2003;肖洋等,2006)㊂鉴于该区域是泾河上游水源涵养林的核心区,森林经营的首要目标是充分发挥森林的涵养水源功能,因此,建议该区今后应对华北落叶松人工林实施近自然化经营改造,以不断提高其土壤水源涵养能力㊂本研究还表明,土壤水文物理性质受到地形因子中坡向和坡位的影响,表现为土壤水文功能较好的植被类型样地主要分布在阴坡坡向和中坡位的区域㊂典范相关分析进一步表明,地形因子组合与土壤水文物理性质组合的密切关系主要体现在坡位㊁Cos(坡向)㊁相对高程对土壤孔隙度的影响,其中,坡位与土壤孔隙度呈正相关;Cos(坡向)㊁相对高程与土壤孔隙度呈负相关㊂植被特征与土壤水文物理性质的极显著关系主要体现在胸径(冠幅)㊁乔木高㊁灌木层盖度对土壤孔隙度的影响,而胸径和树高是表征林木单株生物量和林龄的两个重要参数,一般林龄越大时生物量越高,改良土壤的作用就越强,当然这还可能受到林分密度㊁枯落物分解速率的影响(康冰等,2009)㊂本研究利用多元统计方法对大量野外试验数据进行分析,并对统计结果进行了机理解释,这对今后该区域的水源涵养林的功能评价和可持续经营实践具有一定指导意义;也为定量研究地形㊁植被和土壤水文物理性质的关系奠定了一定基础㊂然而,三者之间的相互影响机制较复杂,如何进一步揭示三者之间的协同变化和响应过程?还有待于深入的研究㊂参考文献杜阿朋,于澎涛,王彦辉,等.2006.六盘山北侧叠叠沟小流域土壤物理性质空间变异的研究.林业科学研究,9 (5):547-554.何 祥.1998.土壤某些特征的分布与地形的关系.云南师范大学学报(自然科学版),18(4):92-94.康 冰,刘世荣,蔡道雄,等.2009.马尾松人工林林分密度对林下植被及土壤性质的影响.应用生态学报,20 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