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1.
Wardle DA Hörnberg G Zackrisson O Kalela-Brundin M Coomes DA 《Science (New York, N.Y.)》2003,300(5621):972-975
Boreal forest soils play an important role in the global carbon cycle by functioning as a large terrestrial carbon sink or source, and the alteration of fire regime through global change phenomena may influence this role. We studied a system of forested lake islands in the boreal zone of Sweden for which fire frequency increases with increasing island size. Large islands supported higher plant productivity and litter decomposition rates than did smaller ones, and, with increasing time since fire, litter decomposition rates were suppressed sooner than was ecosystem productivity. This contributes to greater carbon storage with increasing time since fire; for every century without a major fire, an additional 0.5 kilograms per square meter of carbon becomes stored in the humus. 相似文献
2.
植被是海岛生态系统的重要组成部分。因海岛植被特征与大陆植被迥异,现有的陆域植被区划方案不能完全适用于海岛植被,亟须研究海岛植被区划方案,为海岛资源开发与管理、生物多样性保护、生态可持续发展提供重要依据。以浙江省普陀山岛为例,基于123个样地的群落调查、全岛地形地貌普查以及5类微生境的长期气象观测数据,综合提出海岛植被区划需遵循地域分异的相对一致性、植被类型和植物区系相统一、生物因子与非生物因子相结合的原则。制定了海岛植被区划的3级指标体系:一级指标为山体走势和气候;二级指标为海拔或地貌、植被类型;三级指标为微地形、群丛或群落。依据此方案将普陀山岛植被划分为东南坡温暖湿润区和西北坡冬季寒冷干旱区2个大区域,森林、灌丛、草丛等5个二级区域以及13个群落或群丛等三级区域,并详细阐述了每一级区域划分的依据,包括微气候、地形地貌、群落结构和物种组成等。针对区划结果,依据每一级区域中植被的特征提出相应的经营、管理措施,主要包括间伐、抚育、封育、自然演替等。 相似文献
3.
随着城市化进程的加速,人类正在不自觉地破坏自己赖以生存的自然生态系统,在城市建立"森林岛屿"能缓解由于城市化所导致的一系列的环境问题.在分析了国内外有关城市森林研究现状的基础上,提出了成都市城市森林岛屿营建的构想. 相似文献
4.
为了解西沙群岛的珊瑚礁区大型底栖生物群落组成和分布特征,于2016—2019年期间对西沙群岛附近珊瑚礁区的大型底栖生物进行了连续的采样调查,系统分析了该海域大型底栖生物的种类组成、丰度和生物量的分布、生物多样性等生物学特性。结果表明,5个生物大类中的252种底栖生物中,甲壳动物出现的种类最多,有120种;其次为软体动物,有72种;棘皮动物37种,环节动物17种,其他门类生物6种。大型底栖生物密度为（334.45±396.40） ind·m?2,生物量为（110.79±126.56）g·m?2,Shannon-Wiener多样性指数（H’）为3.85±0.84、丰富度指数（d）为5.51±2.64、均匀度指数（J’）为0.89±0.05;多样性指数显示,2016年永兴岛及2018年西沙州海域受到轻度扰动;群落聚类分析显示,该区域大型底栖生物群落随时间变化较显著;丰度-生物量比较曲线法（ABC曲线）评价显示,2017年和2018年的部分岛屿大型底栖生物群落受到一定程度干扰。结果说明西沙群岛珊瑚礁区大型底栖生物群落总体上以软体动物和甲壳动物为主,调查时间的变化比地理位置的变化对底栖生物群落的结构有更大影响。 相似文献
5.
食物链长度是生态系统的基本属性,其变化决定着群落结构和生态系统功能。稳定同位素分析技术的进步推进了生态系统中食物链长度决定因子相关研究的开展。尽管近期的研究证明了食物链长度与资源可利用性、生态系统大小、干扰等远因之间的关系,但是对于食物网内部结构变化这一近因对食物链长度的影响作用关注较少。综述了边界明确和开放类型淡水生态系统中食物链长度的相关研究进展;探讨了远因和近因机制在决定食物链长度中的作用;给出了判断不同层次和尺度上决定食物链长度机制的概念框架;为今后更好的开展不同生态系统间食物链长度的比较研究提出了建议。 相似文献
6.
利用浮游生物变化分析人工植物浮岛在治理锦江河中的作用 总被引：1，自引：0，他引：1
目的:了解人工植物浮岛在锦江河中的净化效果,通过浮游生物变化分析人工植物浮岛在治理锦江河中的作用。方法:在铜仁市锦江河市区段以美人蕉、菖蒲、空心菜为材料设置人工植物浮岛,5个月后对浮岛区、非浮岛区的浮游动、植物及其他主要水质指标等进行检测。结果:水体经过浮岛区后,水质净化效果较明显,浮游生物数量明显下降,各区域浮游生物数量为:浮岛区下游浮岛区浮岛区上游,经浮岛处理后的水体,总氮(TN)和总磷(TP)的去除率分别为13.61%和14.29%,水体p H值和透明度上升。结论:人工植物浮岛明显改善了锦江河的水质状况,同时对于锦江河水体中浮游生物的群落结构有一定的调控作用。 相似文献
7.
微生物是淡水生态系统的重要组成部分,其群落组成与水环境密切相关。在室内设置5个试验组,种植常绿型沉水植物苦草(Vallisneria natans)同时引入铜锈环棱螺(Bellamya aeruginosa)、三角帆蚌(Hyriopsis cumingii)和鲫(Carassius auratus)来模拟生态系统中的生物种群结构。通过构建多营养层级淡水生态系统,探究了不同水生生物对细菌群落结构的影响。结果表明,构建的几种淡水生态系统中优势细菌类群为变形菌门(Proteobacteria)、放线菌门(Actinobacteriota)、拟杆菌门(Bacteroidota)和蓝细菌门(Cyanobacteria),螺、蚌、鱼的存在极大地减少了水体中蓝细菌门的数量,能够有效控制蓝细菌过度繁殖。细菌多样性指数(Shannon指数)在草、草-螺-蚌组中较高,而在草-螺、草-螺-蚌-鱼组中较低。冗余分析(RDA)表明,各系统间微生物群落丰度存在明显的差异,不同水生生物的引入和溶解氧含量是影响微生物群落变化的直接因素,而营养盐浓度的变化主要依赖于水生生物与微生物的共同作用,是影响微生物群落变化的间接... 相似文献
8.
A marine ecosystem model seeded with many phytoplankton types, whose physiological traits were randomly assigned from ranges defined by field and laboratory data, generated an emergent community structure and biogeography consistent with observed global phytoplankton distributions. The modeled organisms included types analogous to the marine cyanobacterium Prochlorococcus. Their emergent global distributions and physiological properties simultaneously correspond to observations. This flexible representation of community structure can be used to explore relations between ecosystems, biogeochemical cycles, and climate change. 相似文献
9.
三江平原湿地岛状林土壤动物群落结构特征及影响因素 总被引：7，自引：0，他引：7
土壤动物是陆地生态系统结构的重要组成部分,对营养物质循环具有重要的作用。湿地土壤动物群落结构及影响因素研究,可为揭示湿地生物多样性及其功能提供基础资料。2005年生长季对三江平原湿地岛状林土壤动物进行了野外调查和室内分离、鉴定。结果表明,岛状林土壤动物隶属4门9纲24目,优势类群为线虫和膜翅目2类,常见类群7类,稀有类群15类;优势类群和常见类群都具有明显的季节动态变化。多样性分析表明,土壤动物的个体总数、类群数和丰富度指数最大值都出现在7月份,多样性指数和均匀度指数5月份最小,10月份最大,而优势度指数5月份最大,10月份最小。土壤动物垂直分布格局,除5月份外,其他各月都表现出明显的表聚性;5月份的逆向分布格局是由土壤动物的栖息特征和表层土壤温度特征共同决定的。土壤动物分布影响因素分析认为,在局域尺度内,土壤营养物质含量、容重和湿度是主要的影响因子。土壤动物功能类群可划分为腐食性、捕食性和植食性土壤动物,其数量比例关系整体上表现为腐食性土壤动物捕食性土壤动物植食性土壤动物。 相似文献
10.
粗木质残体（coarse woody debris,CWD）是森林生态系统中重要的结构性和功能性组成要素,是联系森林生态系统养分循环、碳库储存、群落更新以及为其他有机体提供生境等主要功能的载体和纽带,对森林生态系统的能量流动及物质循环以及在维护森林生态系统的完整性和稳定性方面具有重要作用,科学有效地对其进行定量化研究,对了解粗木质残体在生物地球化学循环过程中和全球碳循环与碳平衡中的地位与作用具有重要意义。从4个方面阐述森林生态系统粗木质残体的研究进展:①粗木质残体的来源及分类;②粗木质残体的研究内容;③粗木质残体的研究方法;④粗木质残体的生态功能。最后提出了提高粗木质残体定量化研究以及结构与功能研究的4种路径选择:①改进研究方法,提高粗木质残体基础数据的定量化研究,加强本底数据的积累,并构建丰富翔实的粗木质残体数据库;②重视粗木质残体结构与功能的研究,强化人类活动对粗木质残体的影响及其对森林生态系统结构和功能影响的研究;③发展粗木质残体生态功能定量化与模型化研究,定量研究粗木质残体的分解速率及其在生物地球化学循环和全球碳循环与碳平衡中的作用;④研究粗木质残体的动态特征与森林演替的交互关系,优化粗木质残体可持续经营管理方式及管理策略。参64 相似文献
11.
2009年7-11月及2010年3-11月,在千岛湖2个岛屿上进行社鼠(Niviventer confucianus)的标志重捕,根据春、夏、秋3个季节将重捕4次以上的社鼠进行最大活动距离计算,分析年龄、性别及季节对岛屿社鼠最大活动距离的影响。结果显示,岛屿间无显著差异;将2岛数据合并后,幼年、亚成年、成年及老年4个年龄组社鼠最大活动距离之间差异极显著;雄性社鼠最大活动距离极显著地大于雌性,4个年龄组雌雄之间的最大活动距离均表现为雄性>雌性,但仅成年组雌雄之间存在极显著差异;春、夏、秋3个季节之间的最大活动距离差异极显著,而仅亚成年组在3个季节之间存在极显著差异,雌性和雄性社鼠均表现春季<夏季<秋季,但只在春季表现出雌雄个体之间差异极显著,与以往巢区研究结果不一致,可能反映了岛屿环境下社鼠巢区活动的特殊性。显示岛屿隔离环境对小型哺乳动物巢区活动有影响,但这种岛屿效应仍有待深入研究。 相似文献
12.
平潭大屿岛植物资源及其多样性研究 总被引：3，自引：0，他引：3
对平潭无居民岛大屿岛进行全面勘察,调查其植物资源及其群落多样性。大屿岛共37科59属63种植物,其中木本27种,草本36种。对海岛植物种类组成、生活型、植物区系、群落结构特征及其多样性进行分析,结果表明:(1)无居民海岛面积小,海岛环境易变导致植物物种种类偏少;(2)海岛植物属地理起源具有一定复杂性。海岛植被异于陆地植被体现在海岛植物主要以高位芽植物占优势,比例较陆地植被小,且主要优势科属有所区别;(3)海岛植被受到一定生态干扰,外来植物占7.94%,黑松和海边月见草在该群落中占优势;(4)海岛植物群落结构简单,多样性偏低。 相似文献
13.
Reductions in bird numbers could hamper ecosystem services such as pollination, but experimental proof is lacking. We show that functional extinction of bird pollinators has reduced pollination, seed production, and plant density in the shrub Rhabdothamnus solandri (Gesneriaceae) on the North Island ("mainland") of New Zealand but not on three nearby island bird sanctuaries where birds remain abundant. Pollen limitation of fruit set is strong [pollen limitation index (PLI) = 0.69] and significant on the mainland but small (PLI = 0.15) and nonsignificant on islands. Seed production per flower on the mainland is reduced 84%. Mainland sites have similar adult densities, but 55% fewer juvenile plants per adult, than island sites. Seed addition experiments near adult R. solandri plants on the mainland found strong seed limitation 5 years after sowing for R. solandri but not for two other co-occurring woody species. This demonstrates a terrestrial trophic cascade. 相似文献
14.
矿区生态系统健康及其评价指标和方法 总被引：1，自引：0，他引：1
在总结一般生态系统健康理论的基础上,引申出矿区生态系统健康的概念及内涵;从自然、人为和社会经济因素3个方面分析矿区生态系统健康的影响因子,并以此为基础阐述了矿区生态系统健康评价指标体系的指标选取原则,将评价体系分解为活力、组织结构、恢复力、生态系统服务功能与人类健康5个要素;结合一般生态系统健康评价方法,简述了适用于矿区的生态系统健康度计量法、模糊综合评价方法和突变级数法。目前矿区生态系统健康研究还处在发展阶段,还需要在理论、“3S”等技术方面进行更深入及定量化的研究. 相似文献
15.
Population phenomena, which provide much of the underlying basis for the theoretical structure of island biogeography, have received little direct study. We determined a key population trait-survival-in the Bahamian lizard Anolis sagrei on islands with an experimentally introduced predatory lizard and on neighboring unmanipulated islands. On unmanipulated islands, survival declined with several variables, most notably vegetation height: The island with the shortest vegetation had nearly the highest survival recorded for any lizard. On islands with the introduced predator, which forages mostly on the ground, A. sagrei shifted to taller vegetation; unlike on unmanipulated islands, its survival was very low on islands with the shortest vegetation but was higher on the others. Thus, species introduction radically changed a resident species' relation of survival to a key island-biogeographical variable. 相似文献
16.
Diamond JM 《Science (New York, N.Y.)》1973,179(4075):759-769
The concepts by which MacArthur and Wilson have transformed the science of ecology in the past decade, and the results of ecological studies such as mine on New Guinea bird communities, have implications for conservation policies. For example, primary tropical rain forest, the most species-rich and ecologically complex habitat on earth, has for millions of years served as the ultimate evolutionary source of the world's dominant plant and animal groups. Throughout the tropics today, the rain forests are being destroyed at a rate such that little will be left in a few decades. When the rain forests have been reduced to isolated tracts separated by open country, the distribution of obligate rain forest species will come to resemble bird distributions on New Guinea land-bridge islands after severing of the land bridges. The smaller the tract, the more rapidly will forest species tend to disappear and be replaced by the widespread second-growth species that least need protection (13). This ominous process is illustrated by Barro Colorado Island, a former hill in Panama that became an island when construction of the Panama Canal flooded surrounding valleys to create Gatun Lake. In the succeeding 60 years several forest bird species have already disappeared from Barro Colorado and been unable to recolonize across the short intervening water gap from the forest on the nearby shore of Gatun Lake. The consequences of the species-area relation (Fig. 1) should be taken into consideration during the planning of tropical rain forest parks (13). In a geographical area that is relatively homogeneous with regard to the fauna, one large park would be preferable to an equivalent area in the form of several smaller parks. Continuous nonforest strips through the park (for example, wide highway swaths) would convert one rain forest "island" into two half-size islands and should be avoided. If other considerations require that an area be divided into several small parks, connecting them by forest corridors might significantly improve their conservation function at little further cost in land withdrawn from development. Modern ecological studies may also be relevant to the understanding of human populations. For instance, during a long period of human evolution there appear to have been not one but two coexistent hominid lines in Africa, the Australopithecus robustus-A. boisei ("Zinjanthropus") line, which became extinct, and the Australopithecus africanus-A. habilis line, which led to Homo sapiens (27). The need to maintain niche differences between these lines must have provided one of the most important selective pressures on the ancestors of modern man in the late Pliocene and early Pleistocene. Thus, any attempt to understand human evolution must confront the problem of what these ecological segregating mechanisms were. To what extent were contemporaneous species of the two lines separated by habitat, by diet, by size difference, or by foraging technique, and were their local spatial distributions broadly overlapping or else sharpened by behavioral interactions as in the case of the Crateroscelis warblers of Fig. 6? To take another example, there are striking parallels between the present distributions of human populations and of bird populations on the islands of Vitiaz and Dampier straits between New Guinea and New Britain. Some of these islands were sterilized by cataclysmic volcanic explosions within the last several centuries. The birds that recolonized these islands have been characterized as coastal and small-island specialists of high reproductive potential, high dispersal powers, and low competitive ability, unlike the geographically closer, competitively superior, slowly dispersing, and breeding birds of mainland New Guinea (10, 11, 13). It remains to be seen whether the people of the Vitiaz-Dampier islands, the Polynesians, and other human populations that colonize insular or unstable habitats also have distinctive population ecologies. 相似文献
17.
自然保护区面积确定方法探讨 总被引：5，自引：0，他引：5
自然保护区面积确定问题是自然保护区建设和管理以及自然保护区学中迫切需要解决的问题.该文分析了自然保护区面积确定问题的复杂性,阐述了岛屿生物地理学、种群生存力分析、最小可存活种群、有效种群理论、群落或生态系统稳定性等理论或观点在自然保护区面积确定中的应用和不足,并对解决自然保护区面积确定问题提出了一些可能的途径,包括集合种群理论、景观生态学理论的应用,加强种群生存力分析应用的研究,对某些自然保护区可以考虑种子雨与群落演替规律,有时也可以考虑动物行为学的特征等. 相似文献
18.
利用相关序列扩增多态性(SRAP)分子标记法,对千岛湖片段化生境中14个岛屿上的黄足厚结猛蚁(Pachycondyla luteipes)种群遗传结构和多样性进行研究。利用5对SRAP引物对42份材料的基因组进行扩增,共得到大小在50-800 bp之间的71个可重复位点,其中63个为多态性位点,多态性比率达88.73%。AMOVA分析结果显示,65.03%的遗传变异存在于种群间,34.97%的遗传变异来自种群内(P < 0.001)。利用PopGene Version 1.32软件对SRAP多态性数据进行分析,不同岛屿种群的多态位点比例和Nei''s基因多样性指数变化范围分别介于35.21%-91.55%和0.2662-0.4905之间,平均值分别为58.25%和0.3729,其中多态位点比率最高的岛屿为面积最大的JSE岛。多态位点比例和Nei''s基因多样性指数与岛屿面积、海拔均无显著相关性,但与隔离度呈显著正相关关系。种群间遗传分化指数介于0.0777-0.9328之间,平均值为0.4419,基因流值介于0.0360-5.9350之间,平均值为1.0451,种群间遗传分化程度较高,基因流较低。利用UPGMA聚类分析法对14岛屿上的42个个体进行遗传聚类分析,表明地理距离较近的个体和岛屿具有优先聚在一起的趋势。Mantel 检验表明黄足厚结猛蚁各种群间地理距离与遗传距离间存在显著相关性(r=0.7757,P < 0.01)。以上结果表明地理隔离是影响千岛湖黄足厚结猛蚁种群遗传结构和多样性的主要因素。 相似文献
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Blackburn TM Cassey P Duncan RP Evans KL Gaston KJ 《Science (New York, N.Y.)》2004,305(5692):1955-1958
The arrival of humans on oceanic islands has precipitated a wave of extinctions among the islands' native birds. Nevertheless, the magnitude of this extinction event varies markedly between avifaunas. We show that the probability that a bird species has been extirpated from each of 220 oceanic islands is positively correlated with the number of exotic predatory mammal species established on those islands after European colonization and that the effect of these predators is greater on island endemic species. In contrast, the proportions of currently threatened species are independent of the numbers of exotic mammalian predator species, suggesting that the principal threat to island birds has changed through time as species susceptible to exotic predators have been driven extinct. 相似文献