生态位维度分析 (Niche dimensions)

a view of the capability of niche occupying, the capability of niche adapting and the capability of niche evolving based on the niche theory.（三维生态位：占有能力、适应能力、进化能力） http://d.wanfangdata.com.cn/Periodical_bgxb2009z1003.aspx

来源：wiki.cn 作者：未知 发布时间：2006-08-26

生态位niche,ecological 　　物种在生物群落中的地位和作用。英文niche一词源自拉丁文nidus，意为巢，后引伸为龛,指墙壁上安放雕像的凹陷处，故曾译为“生态龛”或“小生境”，但后者与microhabitat（小生境）的译名相混。生态位通常是就物种而言，有时虽以个体为对象，也多是将其看作该物种的代表。不过也有人把生态位视为生境的同义词。 　　词义演变 　1910年，美国学者R.H.约翰逊第一次在生态学论述中使用生态位一词。1917年，J.格林内尔的《加州鸫的生态位关系》一文使该名词流传开来，但他当时所注意的是物种区系，所以侧重从生物分布的角度解释生态位概念,后人称之为空间生态位。1927年,C.埃尔顿著《动物生态学》一书，首次把生态位概念的重点转到生物群落上来。他认为：“一个动物的生态位是指它在生物环境中的地位，指它与食物和天敌的关系。”所以，埃尔顿强调的是功能生态位。 　　1957年，G.E.哈钦森建议用数学语言、用抽象空间来描绘生态位。例如，一个物种只能在一定的温度、湿度范围内生活，摄取食物的大小也常有一定限度，如果把温度、湿度和食物大小3个因子作为参数,这个物种的生态位就可以描绘在一个三维空间内；如果再添加其他生态因子,就得增加坐标轴，改三维空间为多维空间,所划定的多维体就可以看作生态位的抽象描绘，他称之为基本生态位。但在自然界中，因为各物种相互竞争，每一物种只能占据基本生态位的一部分，他称这部分为实际生态位。 　　后来R.H.惠特克等人建议：在生态位多维体的每一点上，还可累加一个表示物种反应的数量，如种群密度、资源利用情况等。于是，可以想象在多维体空间内弥漫着一片云雾，其各点的浓淡表示累加的数量，这样就进一步描绘了多维体内各点的情况。此外再增加一个时间轴，还可以把瞬时生态位转变为连续生态位，使不同时间内采用相同资源的两物种，在同一多维空间中各占不同的多维体；如果进一步把竞争的其他物种都纳入多维空间坐标系统，所得结果便相当于哈钦森的实际生态位。 　　生态位宽度 　用多维空间描述生态位有助于概念的精确化。但实际工作中只能对少数几个，通常只是一两个生态因子作定量分析。生态位宽度是就一个生态因子轴而言的。这方面实验较多的是动物的竞争取食，以食物种类或体积大小为变量。设某物种在s种食物资源中取食，取每种食物的个体数分别为N1…Ni…Ns,则 表示取食第 i种食物的个体数在总数中的比例。R.莱文斯提出的计算生态位宽度B的公式是： 简单举例:设置装有不同食物的食槽s个，使一种动物取食，统计每槽取食的个体数。一种极端情况是，每槽个体数相等，表明该物种在所测范围内占有最宽的生态位，此时B值最大；另一种极端情况是,所有个体都在同一食槽取食,表明该物种在所测范围内占有最窄的生态位,此时B值最小。自然,这里测的是种群的综合效果。各个个体取食范围可能都很广（称泛化取食者），也可能都很窄（称特化取食者），但可因各特化取食者分别采取不同食物，所以它们的综合效果仍很广。但绝大多数情况介乎两者之间。 　　一般说来，当主要食物缺乏时，动物会扩大取食种类，食性趋向泛化，生态位加宽；当食物丰富时，取食种类又可能缩小，食性趋向特化，生态位变窄。 　　生态位重叠 　生物群落中，多个物种取食相同食物的现象就是生态位重叠的一种表现，由此造成物种间的竞争，而食物缺乏时竞争加剧。R.莱文斯采用沃尔泰拉种群竞争公式中的竞争系数α表示重叠程度(见种群动态模型),用公式： 表示物种x对物种y的生态位重叠。以y的生态位宽度(By)代式中的(Bx),则得物种y对物种x的生态位重叠。公式表明：重叠程度取决于x和y取用同一食物的几率及生态位宽度。因为多数物种生态位宽度不等，所以重叠对两物种的影响也不相等，即可能（见图）。 　　生态位重叠与物种竞争密切相关，因此生态位概念是竞争排除原理的重要根据。 生态位 niche；ecological 　　物种在生物群落中的地位和作用 。英文niche一词源自拉丁文 nidus ， 意为巢 ， 后引申为龛 ，故曾译为生态龛 。1910 年美国学者 R.H. 约翰逊第一次在生态学论述中使用生态位一词。1917年J.格林内尔的《加州鸫的生态位关系》一文使该名词流传开来，但他当时侧重从生物空间分布的角度解释生态位概念，后人称之为空间生态位 。1927 年 C.S.埃尔顿著《动物生态学》一书，首次把生态位概念的重点转到生物群落上来，认为动物的生态位是指它在群落中的食物和天敌的关系，所以，他强调的是功能生态位。 　　1957 年 G.E.哈钦森建议用多维空间来描绘生态位 。例如，一个物种只能在一定的温度、湿度范围内生活，摄取食物的大小也常有一定限度，这个物种的生态位就可以描绘在一个三维空间内；如果再添加其他生态因子，就成为多维空间。 　　一般说来，动物取食种类多，生态位加宽；取食种类少；生态位变窄。多个物种取食相同食物，生态位重叠。 生态位（Ecological niche），又称小生境或是生态龛位，生态位是一个物种所处的环境以及其本身生活习性的总称。每个物种都有自己独特的生态位，借以跟其他物种作出区别。生态位包括该物种觅食的地点，食物的种类和大小，还有其每日的和季节性的生物节律。 生态位的概念是由Joseph Grinnell于1917年首次提出的。这个概念在许多方面有广泛应用，比如市场营销方面。 群落生境（其同义词为栖息地）只是生态位这个概念的一部分。生态位的含义远不止是“生活空间”（温度，空气湿度等环境因素的综合，它是生物生存的依据）的一个抽象概念，它描述了一个物种在其群落生境中的功能作用，而且它带有构成群落生境的自然因素所留下的烙印。它是一个物种为求生存而所需的广义“资源”。例如：蝙蝠需要在某地夜间捕食蚊子。这里面某地的自然因素（例如空气质量，其他关系到蝙蝠栖息地的因素），蝙蝠夜间运动的可行性，蚊子都是蝙蝠的生态位的一部分。一个物种只能占有一个生态位。 生态位的环境因素（温度，食物，地表湿度，生存环境等）的综合，构成概念生态位空间。这是一种n维超体积，但出于可视化的原因会将它简化为二维或三维龛位图进行显示。每种环境因素成为一个维度。在两个生态龛位中，考虑观察的维度越多，两个生态龛位的差别就越明显，越容易被区分开来。 生态位分两个层次： 基本生态位:是生态位空间的一部分，一个物种有在其中生存的可能。这个基本生态位是由物种的变异和适应能力决定的，而并非其地理因素。或者说基本生态位是实验室条件下的生态位，里面不存在捕食者和竞争。 现实生态位:是基本生态位的一部分，但考虑到生物因素和它们之间的相互作用。或者说是自然界中真实存在的生态位。 人们可以从特殊的性质或角度考虑，定义更多的生态位： 营养生态位: 根据营养情况划分的生态位。 最小环境: 对一个物种来说可持续生存的最小环境。 两个地区，虽然地理上被分隔，但却有着相似的非生物因素，在这两个地区生活的物种会占有相似的生态位。这会导致趋同演化的发生，即是两个物种虽然无亲缘关系，但却各自独立的发展出相似的身体构造去适应环境。南极的捕鱼能手，不会飞的鸟--企鹅和已灭绝的欧洲的大海雀一样占有相似的生态位。澳洲的袋鼹和欧洲的田鼠都有挖土铲的前肢，它们在泥土中挖掘通道，捕食细小的动物，它们占有相似的细小地下肉食性动物生态位。 生态平衡时，各个生物的生态位原则上不重合。若有重合，那么必然是不稳定的，它必然会通过物种间的竞争来削减生态位的重叠，直到平衡为止。竞争，比如需要相似生态位的入侵物种的进入，会导土著物种存在区域减少。如果存在区域太小，会导致一个物种的灭绝。这就是这就是竞争排除原则。 进化导致的是两个有亲缘关系的物种去占据不同的生态位，减少竞争的机会。一个很好的例子是拉帕戈斯群岛的

http://bioop.com/html/bioarticle/200608261305.html

Black smokers create ecological niches with their unusual environment

In ecology, a niche ( /ˈniːʃ/ or US /ˈnɪtʃ/)[1] is a term describing the relational position of a species or population in its ecosystem to each other; e.g. a dolphin could potentially be in another ecological niche from one that travels in a different pod if the members of these pods utilize significantly different food resources and foraging methods.[1] A shorthand definition of niche is how an organism makes a living. The ecological niche describes how an organism or population responds to the distribution of resources and competitors (e.g., by growing when resources are abundant, and when predators, parasites and pathogens are scarce) and how it in turn alters those same factors (e.g., limiting access to resources by other organisms, acting as a food source for predators and a consumer of prey).[2]

The word "niche" is derived from the Middle French word nicher, meaning to nest. The term was coined by the naturalist Joseph Grinnell in 1917, in his paper "The niche relationships of the California Thrasher."[3] The Grinnellian niche concept embodies the idea that the niche of a species is determined by the habitat in which it lives. In other words, the niche is the sum of the habitat requirements that allow a species to persist and produce offspring. For example, the behavior of the California Thrasher is consistent with the chaparral habitat it lives in—it breeds and feeds in the underbrush; and escapes from predators by shuffling from underbrush to underbrush.

This perspective of niche allows for the existence of ecological equivalents and also empty niches. For example, the anolis lizards of the Greater Antilles are a rare example of convergent evolution, adaptive radiation, and the existence of ecological equivalents—the anolis lizards evolved in similar microhabitats independently of each other and resulted in the same ecomorphs across all four islands.

In 1927 Charles Sutherland Elton, a British ecologist, gave the first working definition of the niche concept. He is credited with saying: "[W]hen an ecologist says 'there goes a badger,' he should include in his thoughts some definite idea of the animal's place in the community to which it belongs, just as if he had said, 'there goes the vicar.'"[4]

The Eltonian niche encompasses the idea that the niche is the role a species plays in a community, rather than a habitat.

The Hutchinsonian niche views niche as an n-dimensional hypervolume, where the dimensions are environmental conditions that define the range in which a species can persist.

The niche concept was popularized by the zoologist G. Evelyn Hutchinson in 1957.[5] Hutchinson wanted to know why there are so many different types of organisms in any one habitat.

The full range of environmental conditions (biological and physical) under which an organism can exist describes its fundamental niche. As a result of pressure from, and interactions with, other organisms (e.g. superior competitors), species are usually forced to occupy a niche that is narrower than this, and to which they are mostly highly adapted. This is termed the realized niche. The ecological niche has also been termed by G.E. Hutchinson a "hypervolume." This term defines the multi-dimensional space of resources (e.g., light, nutrients, structure, etc.) available to (and specifically used by) organisms. The term adaptive zone was coined by the paleontologist, George Gaylord Simpson, and refers to a set of ecological niches that may be occupied by a group of species that exploit the same resources in a similar manner. (Simpson, 1944; After Root, 1967.)[citation needed]

Hutchinson's "niche" (a description of the ecological space occupied by a species) is subtly different from the "niche" as defined by Grinnell (an ecological role, that may or may not be actually filled by a species—see vacant niches).

Different species cannot occupy the same niche (or guild). A niche is a very specific segment of ecospace occupied by a single species. Species can however share a 'mode of life' or 'autecological strategy' which are broader definitions of ecospace.[6] For example, Australian grasslands species, though different from those of the Great Plains grasslands, occupy the similar modes of life.[7]

Once a niche is left vacant, other organisms can fill that position. For example, the niche that was left vacant by the extinction of the tarpan has been filled by other animals (in particular a small horse breed, the konik). Also, when plants and animals are introduced into a new environment, they have the potential to occupy or invade the niche or niches of native organisms, often outcompeting the indigenous species. Introduction of non-indigenous species to non-native habitats by humans often results in biological pollution by the exotic or invasive species.

The mathematical representation of a species' fundamental niche in ecological space, and its subsequent projection back into geographic space, is the domain of niche modelling.

The different dimensions, or plot axes, of a niche represent different biotic and abiotic variables. These factors may include descriptions of the organism's life history, habitat, trophic position (place in the food chain), and geographic range. According to the competitive exclusion principle, no two species can occupy the same niche in the same environment for a long time.[8]

• Concept of ecological niche
• Environmental Niche - Extinction of the Dinosaurs
• Ontology of the niche
• Niche restriction and segregation
• Vacant niche
• Latitude-niche width hypothesis

http://en.wikipedia.org/wiki/Ecological_niche