1、Q1 群落、結構和穩定性 要 點群 落群落（community）是在相同時間聚集在同一地段上的許多物種種群（species populations）的集合。它的特性是由個體之間的相互作用如競爭（competition）和寄生（parasitism）決定的。群落也能夠從更廣闊的角度和物種多樣性（species diversity）、食物網（food-webs）、能量流（energy flow）和同資源種團（guilds）中種間的相互作用來觀察它的特性。Q1 群落、結構和穩定性 要 點群 落群落（coQ1群落、結構和穩定性課件The community is an assemblage of sp

2、ecies populations that occur together in the same place at the same place at the same time. It has properties determined by the imteractions among individuals such as competition and parasitism. The community can also be viewed from the broader perspective in terms of species diversity, food-webs, e

3、nergy flow and the interactions among guilds of species.Key NotesThe communityQ1 THE CPMMUNITY, STRUCTURE AND STABILITYThe community is an assemblage群落結構一個群落的物種多樣性取決于群落含有的不同種的數量即種豐富度（the species richness）和種多度的均勻性（the evenness of species abundance）。多樣性指數（diversity indices）可以通過這兩個因子計算出來。表達種豐富和種均勻度綜合的另

4、一種方式是通過種的相對多度對種的順序作圖。多樣性能夠在局域群落（local community）、地區（region）和最廣闊的地理尺度（geographic scale）（如大陸）三個不同的空間尺度上測算它。這樣就產生了a、和多樣性。 群落結構一個群落的物種多樣性取決于群落含有的不同種的數量即種The species diversity of a community depends on the number of different species it contains (the species richness) and the evenness of species abundanc

5、e across species. Diversity indices can be calculated to take into account both of these factors. Another way of representing species richness and evenness together is to plot the relative abundance of species against rank order of species abundance. Diversity can be measured over the three differen

6、t spatial scales of the local community, the region and the broadest geographic scale (e.g. the continent). This yields alpha ()-, beta ()-and gamma ()-diversity. Community structureThe species diversity of a com群落邊界群落不會突然中斷，而是逐漸的過渡到其他群落，因為各個物種是逐漸受到它們的環境耐受力限制的。這一點可以通過梯度分析來得到證明，梯率分析重點在于物種分布重疊區域。分類和排序

7、的統計方法允許群落的邊界在這個連續體上重疊。分類技術分出了生態學上不同的物種或地段，獲得了客觀等級。排序并不是企圖勾畫出邊界，而是根據它們在分布上的相似性而勾畫出物種集團或地段。群落邊界群落不會突然中斷，而是逐漸的過渡到其他群落，因為各個Communities do not end abruptly but grade into one another as individual species encounter the limits of their environmental tolerance. This can be demonstrated through gradient ana

8、lysis, which focuses on the overlapping distributions of individual species. The statistical methods of classification and ordination allow community boundaries to be superimposed on this continuum. Classification techniques separate ecologically different species or sites yielding objective classes

9、. Ordination does not attempt to draw boundaries but groups species or sites according to how similar they are in their distributions. Community boundariesCommunities do not end abruptl同資源種團同資源種團是許多占據相似生態位的物種組合的集團；如以闊葉樹為食物的許多昆蟲就形成一個同資源種團。一些研究已經表明，在一個群落內的某些同資源種團中的總物種的比例是不變的。這就表明也許有某一共同的“規則”在統治著群落結構。同

10、資源種團同資源種團是許多占據相似生態位的物種組合的集團；如Guilds are groups of species that occupy similar niches; for example, insects feeding on broad-leaved trees form one guild. Some studies have found constancy in the proportion of total species in certain guilds within a community. This indicates that there may be certain

11、 common rules governing community structure.GuildsGuilds are groups of species t群落的復雜性、多樣性和穩定性穩定性有兩個組成成分恢復力（resilience）和抵抗力（resistance）。這兩個指標描述了群落在受到干擾后的恢復能力和抵御變化的能力。復雜性被認為是決定群落恢復力和抵抗力的重要因素。然而群落越復雜并不意味著群落越穩定。復雜性增加已經顯示會導致不穩定。此外，群落的不同組分（如種豐富度和生物量）也許對干擾有不同反應。具有較低生產力的群落（如凍原）其恢復力是最低的。相反，較弱的競爭可以使許多的物種共存，從

12、而減少群落的不穩定性。群落的復雜性、多樣性和穩定性有兩個組成成分恢復力（res茫茫的北極凍原茫茫的北極凍原There are tow components to stability resilience and resistance, which describe the communitys ability to recover from disturbance and to resist change. Complexity is thought to be important in determining resilience and resistance, However, more

13、complex communities are not necessarily the most stable; increased complexity has been shown to lead to instability. In addition, different components of the communities (e.g. species richness and biomass) may respond differently to disturbance. Communities with a low productivity (e.g. tundra) to b

14、e the least resilient. In contrast, weak competition permits coexistence among species and reduces community instability.Community complexity, diversity and stabilityThere are tow components to st相關主題資源分配（見I3） 食物鏈（見P3）營養復雜性與穩定性食物鏈的長度也許能夠影響群落的恢復力。具有不同營養連接水平的許多群落模型，顯示復雜性導致恢復力和穩定性下降。然而，這樣的研究應該被謹慎地解釋，因為

15、真正的群落所具有的特性在零群落模型中并沒有被發現。穩定性也依賴于環境狀況一個脆弱的（復雜的或多樣的）群落也許能夠在一個穩定和可預知的環境中持續下去，而在一個多變的和不可預知的環境中，僅僅簡單的和生長旺盛的群落才能夠生存下去。相關主題資源分配（見I3） Related topicsResource partitioning (I3) Food chains (P3)Trophic complexity and stabilityFood chain length may influence the resilience of the community. Models of communitie

16、s with different levels of trophic connectance show that complexity reduces resilience and stability. However, such studies should be interpreted with caution, as real communities msy possess important attributes mot found in the communities of null models. Stability also depends on environmental co

17、nditions a fragile (complex or diverse) community may persist in a stable and predictable environment, while in a variable and unpredictable environment only simple and robust communities will survive.Related topicsResource partitiQ2 島嶼群落與移殖 要 點物種-面積關系島嶼上（或一個地區中）物種數目會隨著島嶼面積的增加而增加，最初增加十分迅速，當物種接近該生境所能

18、承受的最大數量時，增加將逐漸停止。物種數目的對數與面積對數的坐標圖顯示的是一個線性關系。對于海洋島嶼和生境島嶼來說，這些雙對數坐標圖直線的斜率，大多在0.240.34之間。對于連續生境內的亞區域，斜率接近0.1。隨著面積增加，物種多樣性增加的效果在島嶼上要比連續生境內明顯。Q2 島嶼群落與移殖 要 點物種-面積關系島嶼上（或一島嶼島嶼The number of species on an island (or in any area) will increase with the size of the island. The increase is initially rapid, tail

19、ing off at the maximum number of species for a given habitat. A plot of log species number against log area gives a linear relationship. For oceanic islands or islands of habitat, the slopes of these log-log plots mostly fall within the range 0.24-0.34. For subareas within continuous habitat, the sl

20、ope is around 0.1. The effect of increasing species diversity with increasing area is more pronounced on islands than within continuous habitat.Key NotesThe species-area relationshipQ2 ISLAND COMMUNITIES AND COLOMOZATIONThe number of species on an is島嶼生物地理學麥克阿瑟和威爾遜的島嶼生物地理學理論指出，島嶼上物種的數目是由新移殖來的物種和以前存在

21、物種的滅絕之間的動態平衡決定的。當移殖種的數目增加時，到達島嶼的移殖來的物種的數目會隨著時間的推移而減少。相反，當物種之間的競爭變得強烈時，滅絕的速率就會增加。當滅絕和移殖的速率達到相等時，物種的數目就處于平衡穩定狀態。模型研究也證明了物種的數目會隨著島嶼面積的增加而增加，和隨著距移殖者源距離的縮短而增加。對模型研究有利的證據，是由對除去動物的島嶼上物種的再移殖的觀察，和對最近隔離的島嶼物種的喪失結果所提供的。當與鄰近大陸對照的時候，滅絕和移殖過程說明了島嶼植物區系和動物區系的衰亡。島嶼生物麥克阿瑟和威爾遜的島嶼生物地理學理論指出，島嶼上物種MacArthur and Wilsons theo

22、ry of island biogeography states that the number of species found on an island is determined by a dynamic equilibrium between the immigration of new colonizing species and the extinction of previously established ones. As the number of colonizing species increases, the number of immigrants arriving

23、on the island decreases over time. In contrast, as competition among species becomes more intense, the extinction rate increases. The point at which extinction and colonization rates are equal gives the number of species at equilibrium. the model also accounts for the increase in species number with

24、 increasing island size and decreasing distance from a source of colonists. Extinction and colonization account for the depauperate flora and fauna of islands when compared to the adjacent mainland.Island biogeographyMacArthur and Wilsons theory 島嶼和異質種群異質種群理論已經替代了島嶼生物地理學來解釋片斷化生境的“島嶼”種群行為。異質種群含有許多種群，

25、這些種群之間通過遷入和遷出而交換個體。與島嶼不同，生境斑塊（patch）是在景觀鑲嵌板塊（landscape mosaic）之中的，景觀板塊能夠影響斑塊的性質和它所含的物種種類。相關主題種內競爭（見I2） 保育對策（見V2）稀有物種、生境損失和滅絕（見V1）島嶼和異質異質種群理論已經替代了島嶼生物地理學來解釋片斷化生Related topicsIntraspecific competition (I2) Conservation strategies (V2)Rare species, habitat loss and extinction (V1)Islands and metapopula

26、tionsMetapopulation theory has superseded island biogeography in explaining the behavior of populations in islands of fragmented habitat. A metapopulation consists of a number of populations that exchange individuals through immigration and emigration. Unlike islands, habitat patches are embedded in

27、 a landscape mosaic that can influence the quality of the patch and the species it will contain.Related topicsIntraspecific coQ3 群落格局、競爭和捕食 要 點群落集合集合規則（assembly rule）的概念企圖解釋自然群落是如何不同于來自物種庫中的物種而隨機裝配出來的群落。群落集合也許能被生境類型、物種移殖和定居，或者種內的相互關系，像捕食、寄生和競爭所影響。集合規則研究群落組成中的格局，將那些由“零(null)”群落模型所產生的格局與真實的群落格局相比較。Q3

28、群落格局、競爭和捕食 要 點群落集合集合規則（aThe concept of assembly rules attempts to explain how natural communities vary from random assemblages derived from the range of available species (the species pool). Community assembly may be influenced by habitat type, species colonization and establishment, and /or by inte

29、rspecific relationships such as predation, parasitism and competition, Assembly rule studies investigate patterns in community make- up, comparing real community patterns with those generated by null community models.Key NotesCommunity assemblyQ3 COMMUNITY PATTERNS, COMPETITION AND PREDATIONThe conc

30、ept of assembly rules競 爭競爭可能是形成群落結構的一個重要力量，但是在調查的時候，它又不一定是重要的。過去競爭的痕跡在群落中可以留下很深的烙印（像生態位的分化）。競爭的一些研究已經表明，生態學上相似物種組成的同資源種團當中，僅僅只有一個成員在群落中能夠生存，這就意味著其他相似物種被競爭排斥了。島嶼上超飄流的鳥類物種的分布也支持了該理論，即競爭導致了群落的結構化。競 爭競爭可能是形成群落結構的一個重要力量，但是在調查新西蘭島嶼新西蘭島嶼Competition can be an important force shaping community structure but

31、is not necessarily significant at the time of investigation. The ghost of competition past can leave a strong imprint on a community (e.g. as niche differentiation). Some studies of competition have shown that only one member of a guild of ecologically similar species tends to be present in the comm

32、unity, suggestive of competitive exclusion of other similar species. The distribution of supertramp bird species on islands also supports the theory that communities are structured by competition.CompetitionCompetition can be an importan食肉動物選擇捕食和轉換獵物能夠使稀有物種免遭捕殺。這種行為能夠導致許多相對稀少的物種在同一個群落中共存。食草動物食草動物對植物群落有兩個作用：（i）它們選擇攝食影響群落的物種多度。（ii）啃食抑制了競爭物種的生長，因此加速和維持了低競爭物種的多樣性。當啃食強度很強時，物種多樣性降低，物種會局部滅絕。食肉動物選擇捕食和轉換獵物能夠使稀有物種免遭捕殺。這種行為能Grazing animals have two effects on plant communities: (i) their selective feeding affects species abundance in the community, and (i