水域生态学：09 种群生态(modified)

1、Ch.2 种群生态Population EcologyOutlineProperties of populationDemographyPopulation growthIntraspecific interactionsLife historiesPopulation regulation1. Properties of Populations种群(population) 在一定时期内生活在特定地区的同一物种个体的集合种群基本特征：数量特征空间特征遗传特征：基因库(gene pool)种群生态学population ecology ：研究种群生长、波动、扩散及种内、种间相互关系的科学时空变化

2、spatial & temporal changes分布distribution多度abundance种群动态(Population dynamics)是研究核心: 研究种群生态之目的拯救濒危种Saving endangered species控制害虫种群Controlling pest populations管理鱼类和游猎种类种群game populations了解和控制流行病disease epidemics种群的群体特性(group characteristics)-统计量:初级特性primary characteristics: 密度Density改变种群密度的4个参数：出生natal

3、ity (births)死亡mortality (deaths)迁入immigration迁出 emigration次级特性 Secondary characteristics年龄分布age distribution性比sex ratio遗传组成genetic composition种群增长速率population growth rate 空间中个体分布式型pattern of distribution种群结构Population structure种群表现出动态行为，随时间而改变because of births, deaths, and movements of individuals.密

4、度和空间分布the density and spacing of individuals within suitable habitat年龄结构 the proportions of individuals in various age classes交配体系mating system遗传结构genetic structure2.种群参数Population Parameters密度Density 和 相对密度 Relative density出生率 Natality 和 死亡率 Mortality迁入 Immigration 和 迁出 Emigration年龄分布 Age distribut

5、ion性比 Sex ratio空间和时间分布 Spatial & Temporal distribution2.1 Population Density (abundance)单体生物 (unitary organism ) An organism, such as an arthropod or vertebrate, whose growth to adult form follows a determinate pathway, unlike modular organisms whose growth involves indeterminate repetition of units

6、 of structure.构件生物 (Modular organism ) A organism which grows by producing additional units of body construction that are very similar to the units of which it is already composed.侧枝构件的生长，示基株original genet及其无性系分株ramets。由于所有 ramets在基因上完全一致，因此 the ramets 一起构成 genet. 构件生物的例子: (i) duckweed, 随着生长分离出ramet

7、s; (ii) grasses, ramets以匍匐枝stolons或根茎rhizomes联系; (iii) trees, 以构件增加的方式生长特定(单位)面积或体积生境内的个体数种群密度Population density粗密度Crude density: The measurement of the number of individuals per unit area生态密度Ecological density: Density measured in terms of the amount of area available as living space (patch)种群密度的变化

8、特点：种群密度的估算对种群动态研究非常重要自然条件改变，密度也会发生变化种群密度随生物个体增大而下降种群大小随时间而变化长期记录反映出在短期内容易被忽视的波动密度反映种群与环境的关系。通常，资源最丰富的地方个体最多。Body size and population density of herbivorous mammalsAllee effect(阿利效应）: 最大种群增长出现在中等密度时 maximal population growth may occur at moderate density.密度过低(undercrowding): 配偶困难近亲交配导致近交衰退inbreeding密

9、度过高(overcrowding):食物减少 冲突(strife)增加 疾病传播加快容易被捕食根据密度可将物种分为：优势种 (dominant species)常见种 (common species) 稀有种 (rare species) 稀有性 Rarity受以下因素影响 稀有种类容易灭绝 rare species are vulnerable to extinctiongeographic rangehabitat tolerancepopulation sizeCommonness, rarity, and vulnerable to extinction袋獾辐射松三角叶杨厥短叶紫杉千岁

10、兰最小生存种群Minimum viable population (MVP)最小生存种群：种群在一个地区内得以维持繁衍的最少个体数，或者说种群能够维持存在一定年限（通常100或1000年）的最小数量 MVP取决于种群统计学特征demographics 种群内遗传多样性种群密度统计绝对密度统计全部计数法 total count :个体可明显标记的小种群通常用于濒危种类，特别是大型动物如哺乳类、鸟类等抽样调查法Sampling methods样方法Use of quadrats：the general procedure in this technique is to count all the

11、individuals on several quadrats of known size and then to extrapolate the average count to the whole标志重捕法Mark-recapture methods： the technique of capture, marking, release, and recapture is an important one for mobile animals, because it allows not only an estimate of density, but also estimates of

12、birth rate and death rate, migration route. Used mainly on larger forms, such as butterflies, snails, beetles, and many vertebrates, that can be readily marked.Petersen methodFor an initial marked sample of size M, a second sample of size n, containing x marked individuals, the population size N is:

13、 N = nM/xIf 20 fish are captured, marked, and returned to a small pond, and a second sample of 50 fish contains 6 marked fish, the population estimate is 50(20)/6 = 167.第二批样本中标记个体数 m第二批样本总个体数 n=标记数 M总样本大小 N标记重捕法的3个重要前提（假设）标记不影响被标记动物的行为被捕的可能性均等；标记与未标记动物的死亡率一样Petersen法假定在标记-重捕期间没有死亡率没有迁移相对密度Indices of

14、 Relative Density (多度指数Index of abundance)捕捉数 (Traps) 粪堆数 (Number of fecal pellets)鸣叫频率 (Vocalization frequency)毛皮收购记录 (Pelt records) 单位努力捕捞量 (catch per unit fishing effort, CPUE) 活动痕迹数 (Number of artifacts)调查问卷 (Questionnaires)盖度 (Cover)食量 (Feeding capacity)路旁计数 (Roadside counts)2.2 出生率和死亡率Natality

15、 & Mortality出生率Natality最大出生率Maximum natality种群处于理想条件下的出生率实际出生率Realized natality (ecological natality)在特定条件下种群实际上的出生率出生率取决于生物的特性性成熟速度、每次繁殖量、每年繁殖次数、一生繁殖次数等).出生率 Natality潜在繁殖力(Fecundity): 生理学概念, refers to an organisms potential reproductive capacity (potential fecundity)：怀卵量实际繁殖力(Fertility): 生态概念, is b

16、ased on the number of viable offspring produced during a period of time(realized fertility)：产卵量Fecundity 通常与亲本护幼负相关死亡率Mortality (存活率survival)寿命longevity:潜在寿命Potential longevity, 某一物种个体在理想条件下，由生理极限决定所能达到的最大寿命 (生理寿命physiological longevity )实际寿命Realized longevity ：现实环境条件下个体的实际寿命最小死亡率Minimum mortality生态

17、死亡率Ecological mortality死亡率测定:直接方法: 如标志重捕法间接方法: 如根据种群年龄组相对丰度变化的连续观测分析 the relative abundance of successive age groups in the population死亡率Mortality2.3迁入和迁出(Immigration & emigration)种群内的个体移动Movements within populations 称为扩散 (dispersal).亚种群之间的个体移动Movements between subpopulations 称为迁移(migrations), or mo

18、re specifically:迁出emigration (leaving a subpopulation，)迁入immigration (entering a subpopulation)，扩散Dispersal扩散(散布)-是大多数生物生活史的必要部分，是局域种群间产生基因流动gene flow,防止近交衰退inbreeding的生态过程。一些种群维持净迁出，总是输出个体，称为源种群(source populations);另一些种群依靠净迁入维持存在，称为汇种群 (sink populations) 散布用标志法确定在种群研究中很少测定迁入和迁出，大多数情况下假设两者相等种群分布种群分布

19、 (distribution of a population) 是指它的地理范围 geographic range. 这个范围内可能出现适合和不适合的生境片层(patches).根据种群分布范围可将物种分为特有种Endemic species:仅局限于某一地区或生境分布的物种广布种cosmopolitan species本地种native (indigenous) species外来种exotic (alien, non-native, non-indigenous) species2.4种群内个体分布型式Dispersion of Individuals within Populations

20、种群内个体分布型式描述个体相互之间的间隔，反映生境的异质性 (heterogeneity) 和种群社会作用可能的几种型式:成群分布、成团分布 (clumped, aggregated, clustered)均匀分布 (evenly spaced, regular, uniform)随机分布 (random)小尺度上，随机分布、均匀分布或成团分布均有可能；大尺度上, 表现为成团分布Dispersion of PopulationClumped dispersionUniform DispersionRandom DispersionCauses of DispersionEven spacing

21、 may arise from direct interactions among individuals:maintenance of minimum distance between individuals or direct competition for limited resources may cause this patternClumped distribution may arise from:social predisposition to form groupsclumped distributions of resourcestendencies of progeny

22、to remain in the vicinity of their parents确定分布型式的方法泊松分布（ Poisson distribution ）V(variance，方差)/M(mean，平均值)If V/M=1, random If V/M=0, even spacing If V/M1, clumpingWhere: x=样本中含有的个体数 f=出现频率（不同个体数样本的出现率） N=样本总数2.5 统计学方法-生命表Life tables生命表Life table：是一个种群根据个体存活年龄和繁殖力所作的归纳总结A life table combined with a fe

23、cundity schedules can be used to estimate净生殖率net reproductive rate (R0)几何级数增长率geometric rate of increase ()指数增长率per capital rate of increase (r)Life tables动态生命表 (dynamic life table cohort, a generation, age-specific or horizontal life table) 根据跟踪观察一群同一时间出生的(同龄群，cohort)生物的死亡或存活动态过程获得的数据来编制的生命表. 难于应用到

24、运动和（或）长寿的动物种群中cohort methodfollow group of individuals born at same time through all ages until death. In practice this is very difficult to do if organisms are long-lived.Assumptions:1) No emigration or immigration.2) Sample being followed is representative of entire population.Two procedures:1) Fo

25、llow survival, problem is it combines both deaths and emigration.2) Unlocated individuals counted as deaths.Life tables静态生命表( static life table, stationary, time-specific, current, or vertical life table,) 根据某一特定时间，对种群作一个年龄结构的调查，并根据其数据编制的生命表.要求具备确定个体年龄的一些方法。假定种群所经历的环境年复一年是没有变化的。综合生命表 (Composite life

26、 table )Life tables summarize demographic information (typically for females) in a convenient format, including:age (x)number alive at age x (nx)survival of newborn individuals to age x (age-specific survival rate lx): proportion of individuals of age x dying by age x+1 ( mx)proportion of individual

27、s of age x surviving to x+1 ( sx)fecundity at age x ( bx)expectation of further life of individuals of age x2.6 内禀增长率The Intrinsic Rate of Increase马尔萨斯参数 (Malthusian parameter )或内禀增长率 (能力)(intrinsic rate of increase, innate capacity for increase) (rm): 是一个具有稳定年龄结构的种群，在稳定条件下(理想条件下)的指数增长率。内禀增长率（能力）决定于

28、生殖能力、寿命和发育速度内禀增长率计算方法rm 通过在生命表上，从各年龄组净生殖率R0开始，经过几步计算获得近似值。净生殖率 (net reproductive rate, R0)是一个个体整个生命中后代总数的期望值R0=lxbxR0 = 1 表示种群稳定替代R0 1 表示种群增长内禀增长率计算方法种群世代时间 (generation time ) T = xlxbx /lxbx内禀增长率决定于净生殖率和世代时间:rm= loge R0/ TR0大、T小，导致种群增长最快2.7年龄结构 (Age Structure)一个种群中每一年龄级个体数的比例，称为该种群的年龄结构(age structu

29、re).种群的年龄分布反映存活、繁殖史和未来增长的潜力。Environmental factorsNatality ratesMortality ratesAge compositionRate of increase or decrease of the populationThe age distribution of a white oak, Quercus alba, population in Illinois (data from Miller 1923)The age distribution of a population of Rio Grande cottonwoods (

30、三叶杨), Populus deltoides subsp. wislizenii, near Belen, New Mexicon (data from Howe and Knopf 1991)出生率等于死亡率，数量达到稳定 (constant size)的种群，将保持一定的(fixed)年龄结构，称之为固定年龄分布 (stationary age distribution), 并维持这种分布。当特定年龄(age-specific)的出生率和死亡率固定不变，种群呈指数增长(grow exponentially)时，种群保持稳定的(constant)年龄结构，称之为稳定年龄分布(stable

31、age distribution)。Age distribution for human populations in countries with stable, declining, and growing populations (data from the U.S. Bureau of the Census, International Data Base)立陶宛(continued) Declining population匈牙利(continued) Growing population卢旺达2.8 存活曲线 (Survivorship Curves)存活曲线概括一个种群的存活型式

32、.当个体倾向于活到生理年龄时，在前期有高的存活率，接近生理年龄时死亡率急剧升高，存活率呈明显的凸形 convex, 是为型。典型的型曲线出现于人类、其他哺乳动物以及一些植物如果各龄死亡率稳定，存活曲线接近直线 straight，是为型号。II 型曲线是成年鸟类、啮齿类、爬行类以及多年生植物的典型特征如果在早期死亡率很高，则曲线呈凹形concave，是为III型。如牡蛎、鱼类、大多数无脊椎动物和一些植物Three types of survivorship curvesAge 2.9 性比 Sex Ratio种群中的性比显著影响繁殖潜力，在脊椎动物中也影响种群内的社会关系性比因繁殖方式而变 Re

33、productive modes:asexual reproduction: clone, gynogenesis(雌核生殖)bisexual: polygamy (polyandry, polygyny); monogamy; hermaphrodite (雌雄同体)sex reversal (性反转)性比 Sex Ratio环境因素Environmental cues影响性比温度：扬子鳄(the Yangzi alligator)29-32, 1:1at 34.5, all male26-27.5, most female. 生活条件：生活条件良好时增加雌性个体以增强种群的繁殖力；反之增加

34、雄性个体以降低繁殖力3. 种群增长Population growthPopulation sizeBirth (B)Death (D)Immigration (I)Emigration (E)+N t1 N t B D3.1 几何增长Geometric Growth起始种群数量t 时间时种群数量 时间间隔, in hours, days, years, etc 一个时间间隔内每个个体平均后代数量（周限生长率）离散种群discrete reproduction populations的生长：世代间不重叠，可用几何模型来描述种群生长N(t+1) = N (t)3.2 指数增长Exponential

35、 Growth 连续种群Continuous population的生长： 无环境条件限制下，指数增长（J型曲线, J-shape curve）Anatomy of equations for exponential population growtht 时间的数量 时间间隔：日、年等瞬时增长率起始数量dN/dt = r N(finite rate of increase, 周限增长率) = 后一时间种群数量与前一时间种群数量之比 = N(t+1)/N(t)r (instantaneous growth rate, 瞬时增长率，exponential growth rate, 指数增长率）两者

36、的关系： = e r loge = rA population is:growing when 1 or r 0constant when = 1 or r = 0declining when 0) or r 0种群倍增时间(Doubling time): 种群数量加倍所需的时间=0.6931/r3.3 逻辑斯谛增长 Logistic growth有限环境条件下连续种群增长方式可用逻辑斯谛增长方程描述(S型曲线,sigmoid curve)种群数量负载力(容纳量)内禀增长率数量变化时间变化Intrinsic rate of increase is the maximum per capita

37、rate of increase, achieved by a species under ideal environmental conditions种群增长的基本理论模型J-型增长S-型增长环境容纳量Carrying capacity：环境所能支持的某一特定种群的个体数。(1-N/K) 是种群继续增长的机会(the further opportunity for population growth)，也称剩余空间(residual space).种群增长率（种群潜在的最大增长）（最大增长的可实现程度）逻辑斯谛方程的积分式：逻辑斯谛曲线常被划为5个时期开始期(initial phase)，也

38、可称为潜伏期(latent phase)加速期(accelerating phase)转折期(inflecting phase)在 N=K/2时，加速度等于0，出现转折点(inflection point )。减速期(decelerating phase)饱和期(asymptotic phase)逻辑斯谛方程的应用最大持续产量 (maximum sustainable yield，MSY ) 在不减少种群数量，即种群补充量等于或超过采收量的前提下，可以从种群中采收的最大个体数量，MSY=rK /43.4 种群的时空动态Temporal and Spatial Dynamics of Popul

39、ations种群平衡Population equilibrium: 取决于种群的恢复力(resilience) 不规则波动Irregular fluctuation 混沌 (chaos)规则或周期性波动Regular or cyclic fluctuation, 振荡(oscillation)种群下降Population decline种群的时空动态种群爆发Population outbreak: 超越overshooting种群崩溃Population crash (collapse): 过渡补偿overcompensationPopulation cycles result from ti

40、me delays (time lag, 时滞): A delay in the response of a population (or other system) to conditions of the environment.Logistic growth curve and examples of fluctuations around K种群灭绝Population extinction：确定性灭绝deterministic extinction; 随机性灭绝stochastic extinction背景灭绝Background extinction 反映的是当生态系统变化，一些物

41、种消失，另一些物种取而代之的事实，其发生率相对较低，是自然世界的正常特性。大规模灭绝Mass extinction 指由于自然灾害natural catastrophes，如火山爆发volcanic eruptions、飓风hurricanes、干旱 droughts、或流星碰撞meteor impacts等所造成的大量物种的相继死亡.人类造成的灭绝Anthropogenic extinction 在受影响的物种数量、全球尺度和灾难性质上与大规模灭绝一样。4. 种内关系Intraspecific Interactions同种相残 (Cannibalism)：A intraspecific co

42、nsumer-resource interaction in which individuals consume other individuals of the same species. e.g., northern pike(狗鱼)利他行为 (Altruism) A social interaction that enhances the fitness of an unrelated recipient while reducing the fitness of the donor. e.g. rabbit 寄生 (Parasitism)：Individuals live in clo

43、se association, to cost of host. e.g. anglerfish(角鮟鱇)Female anglerfish (Edriolychnus schmidti) with two parasite males竞争 (Competition )：Use or defense of a resource by one individual that reduce the availability of that resource to other individuals.争夺竞争 (contest competition):Successful individuals

44、divide the resource and the unsuccessful are denied access to it. Contest competition is characteristic of species whose individuals are able to defend a resource from others.分摊竞争 (scramble competition ): All individuals have equal access to the resource, and each attempts to get a part of it. In ex

45、treme cases, scramble competition results in each individual obtaining insufficient amounts to survive or reproduce. 争夺竞争和分摊竞争竞争曲线示意图 (A) 和资源分配型式图(B)。实线表示争夺竞争，虚线表示分摊竞争，图B中点线表示存活所需最小资源量。Initial DensityNumber of SurvivorsALog Individual Resource Intake for SurvivorsInitial DensityMinimum Requirement f

46、or SurvivalB集群 (Schooling) 种群内个体由社会引力形成团体，集群的成员通常同种、同样大小和年龄，以同一方向沿着相似路径统一移动。Members of the school are usually of the same species, size, and age, and move in unison along parallel paths in the same direction.Advantages:提高繁殖成功率Improving breeding success有利于寻找食物Beneficial to searching food有助于防御被捕食Helpf

47、ul to defending from predation有益于迁徙（洄游）Conducive to migrationDisadvantages: 破坏食物资源Destroying food resources易招致捕食者攻击Prone to attack by predators 5. 生活史概述（Life History）出生、生长、分化、繁殖、衰老、死亡从出生到死亡所经历的全部过程。life history，life cycle为遗传物质所决定，一般不能改变，但具一定的可塑性(plasticity)e.g.种子数量、大小、个体大小（植株高矮）等相关性（某些遗传特性受另一些特性的限制，

48、e.g. 大小成熟期；大小寿命）生活史特性(Life History Traits)个体大小(Size)生长型式(Growth Pattern)性成熟年龄和大小(Age & Size at Maturity)后代数量、大小和性比(Number, Size and Sex-ratio of Offspring)特定年龄和大小繁殖投入 (Age- and Size-specific Reproductive investment)特定年龄和大小死亡进程(Age- & Size-specific Mortality Schedule)寿命(Length of Life)生活史理论 Life-hist

49、ory theoryBecause all organisms have access to limited energy and other resources, there are trade-offs (权衡)between the number and size of offspring (large, few eggs vs small, many eggs)Reproduction vs growth Current reproduction vs survivalcurrent reproduction vs future reproduction （Semelparity vs

50、 iteroparity） Life history theory predictionWhere adult mortality is higher, natural selection will favor early maturity and more reproductive effort; and where adult mortality is low, natural selection has been expected to favor delaying maturity and less reproductive effort. Reproductive effort is

51、 the allocation of energy, time, and other resources to the production and care of offspring.The great diversity of life histories may be classified on the basis of a few population characteristics, such as fecundity or number of offspring, survival, and age at maturity.r-selection(r-strategist): Selection on traits that determine fecundity and survival to favor rapid population growth (r) at low population densities. K-selection(K-strategist). Selection on traits that determine fecundity and survival to favor competitive ability at densities near the carrying capacity (K). r