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1.
Coulson T MacNulty DR Stahler DR vonHoldt B Wayne RK Smith DW 《Science (New York, N.Y.)》2011,334(6060):1275-1278
Environmental change has been observed to generate simultaneous responses in population dynamics, life history, gene frequencies, and morphology in a number of species. But how common are such eco-evolutionary responses to environmental change likely to be? Are they inevitable, or do they require a specific type of change? Can we accurately predict eco-evolutionary responses? We address these questions using theory and data from the study of Yellowstone wolves. We show that environmental change is expected to generate eco-evolutionary change, that changes in the average environment will affect wolves to a greater extent than changes in how variable it is, and that accurate prediction of the consequences of environmental change will probably prove elusive. 相似文献
2.
Both biotic interactions and abiotic random forcing are crucial influences on population dynamics. This frequently leads to roughly equal importance of deterministic and stochastic forces. The resulting tension between noise and determinism makes ecological dynamics unique, with conceptual and methodological challenges distinctive from those in other dynamical systems. The theory for stochastic, nonlinear ecological dynamics has been developed alongside methods to test models. A range of dynamical components has been considered-density dependence, environmental and demographic stochasticity, and climatic forcing-as well as their often complex interactions. We discuss recent advances in understanding ecological dynamics and testing theory using long-term data and review how dynamical forces interact to generate some central field and laboratory time series. 相似文献
3.
Henson SM Costantino RF Cushing JM Desharnais RA Dennis B King AA 《Science (New York, N.Y.)》2001,294(5542):602-605
Animals and many plants are counted in discrete units. The collection of possible values (state space) of population numbers is thus a nonnegative integer lattice. Despite this fact, many mathematical population models assume a continuum of system states. The complex dynamics, such as chaos, often displayed by such continuous-state models have stimulated much ecological research; yet discrete-state models with bounded population size can display only cyclic behavior. Motivated by data from a population experiment, we compared the predictions of discrete-state and continuous-state population models. Neither the discrete- nor continuous-state models completely account for the data. Rather, the observed dynamics are explained by a stochastic blending of the chaotic dynamics predicted by the continuous-state model and the cyclic dynamics predicted by the discrete-state models. We suggest that such lattice effects could be an important component of natural population fluctuations. 相似文献
4.
科学有效的渔业资源评估与管理是实现渔业资源可持续开发和利用的重要保障。传统的渔业资源评估与管理基于不变性假设,认为关键种群动力学过程不随时间发生变化。随着气候变化和人类活动的影响,种群的关键动力学过程可能随时间发生系统性的变化,形成非静态种群动力学过程,并在很大程度上颠覆了传统的不变性假设。本文结合近年来国际相关领域的研究成果,系统地阐述了非静态种群动力学过程的形成机制以及其对渔业资源评估模型、生物学参考点和渔业管理理念的影响。分析认为,在非静态种群动力学过程下,渔业资源评估模型和生物学参考点都需要考虑到关键种群动力学过程的时间变化,需要通过引入外部环境变量或者随时间变化的种群动力学参数,来应对非静态种群动力学过程对资源评估与管理带来的影响。研究建议,基于弹性的渔业管理是我们未来应对非静态种群动力学过程、维持渔业社会-生态系统稳定和健康的重要发展方向。 相似文献
5.
综合考虑地理空间因素,以STIRPAT模型作为基础,采用能源消费总量作为环境压力的指标,以人口密度、GDP和第二产业增加值比重分别代表人口、富裕度和技术项,估计人口、富裕度、技术指标的弹性系数。将能源消费的空间差异性纳入模型,采用地理加权回归模型,从市区的尺度估计北京市16个区各驱动力因素弹性变化的差异性,得到北京市区域内部能源消费变化在空间上的变化规律。结果显示,各驱动力因素在不同区的变化并不均衡,每种驱动力因素的变化也具有一定的空间规律。由此,可针对不同区经济发展和城市化进程的差异制定个性化的调控措施。 相似文献
6.
通过虫期生命表方法,对亚洲玉米螟自然种群数量变动进行了Var-ley-Gradwell K-图示分析和Morris-Watt相关回归分析。结果表明影响亚洲玉米螟自然种群数量变动的关键虫期,1代为低龄幼虫潜藏期,2代为卵期。影响亚洲玉米螟自然种群数量变动的主导致死因子,1代为低龄幼虫潜藏期的天敌捕食及自然死亡因子,2代为卵期的中华草龄捕食因子。 相似文献
7.
Pelletier F Clutton-Brock T Pemberton J Tuljapurkar S Coulson T 《Science (New York, N.Y.)》2007,315(5818):1571-1574
Population dynamics and evolutionary change are linked by the fundamental biological processes of birth and death. This means that population growth may correlate with the strength of selection, whereas evolutionary change can leave an ecological signature. We decompose population growth in an age-structured population into contributions from variation in a quantitative trait. We report that the distribution of body sizes within a population of Soay sheep can markedly influence population dynamics, accounting for up to one-fifth of observed population growth. Our results suggest that there is substantial opportunity for evolutionary dynamics to leave an ecological signature and visa versa. 相似文献
8.
Charmantier A McCleery RH Cole LR Perrins C Kruuk LE Sheldon BC 《Science (New York, N.Y.)》2008,320(5877):800-803
Rapid climate change has been implicated as a cause of evolution in poorly adapted populations. However, phenotypic plasticity provides the potential for organisms to respond rapidly and effectively to environmental change. Using a 47-year population study of the great tit (Parus major) in the United Kingdom, we show that individual adjustment of behavior in response to the environment has enabled the population to track a rapidly changing environment very closely. Individuals were markedly invariant in their response to environmental variation, suggesting that the current response may be fixed in this population. Phenotypic plasticity can thus play a central role in tracking environmental change; understanding the limits of plasticity is an important goal for future research. 相似文献
9.
油松毛虫种群动态的ARMA(p,q)模型 总被引：5，自引：0，他引：5
应用随机过程理论建立了油松毛虫上树后至化蛹阶段的ARMA(p,q)模型,并对该阶段的种群动态进行了模拟,其模拟值与实测值十分接近。 相似文献
10.
The spins of the terrestrial planets likely arose as the planets formed by the accretion of planetesimals. Depending on the masses of the impactors, the planet's final spin can either be imparted by many small bodies (ordered accretion), in which case the spin is determined by the mean angular momentum of the impactors, or by a few large bodies (stochastic accretion), in which case the spin is a random variable whose distribution is determined by the root-mean-square angular momentum of the impactors. In the case of ordered accretion, the planet's obliquity is expected to be near 0 degrees or 180 degrees , whereas, if accretion is stochastic, there should be a wide range of obliquities. Analytic arguments and extensive orbital integrations are used to calculate the expected distributions of spin rate and obliquity as a function of the planetesimal mass and velocity distributions. The results imply that the spins of the terrestrial planets are determined by stochastic accretion. 相似文献
11.
利用包括基因与环境互作的加性-显性遗传模型对6个花椰菜品种(系)完全双列杂交实验的2年观察资料进行花球球径不同发育阶段的遗传分析。结果表明:年份间的环境差异对亲本和F1的球径表现影响较小,球径在整个发育期主要受加性效应控制,不存在基因型×环境互作效应,选用瑞雪70天、c-3、c-5为亲本配置组合,能够使其后代在10月中下旬前在平均球径的基础上增大球径;而福州80天和c-8这2个亲本的表现恰好相反。进一步对不同发育阶段的平均球径进行条件遗传分析发现,加性主效应和显性主效应在球径增大的大部分时期都有新的表达,且不易受到年份等外部条件的影响,但这些新表达的效应在10月12日之前和之后表现为相反的方向。成熟期球径给定不同发育时期性状的条件遗传分析表明,在各个时期均检测到显著的条件加性方差(10月24日除外)和条件显性方差,10月6日之前的净加性表达效应的作用占最终球径表现变异的88.8%。 相似文献
12.
本文以时变延迟过程为基本模式,建立了油松毛虫种群动态的模拟模型.根据室内条件下饲养所得幼虫各龄期的有效积温,在模型中的温度为旬平均温度.模型中包括了自然死亡率,天敌捕食率对于种群变化的影响,反映了个体发育的差异对于群体结构的影响.模型模拟的结果与实际相符,显示了较强的预测功能. 相似文献
13.
Whereas case rates for some childhood diseases (chickenpox) often vary according to an almost regular annual cycle, the incidence of more efficiently transmitted infections such as measles is more variable. Three hypotheses have been proposed to account for such fluctuations. (i) Irregular dynamics result from random shocks to systems with stable equilibria. (ii) The intrinsic dynamics correspond to biennial cycles that are subject to stochastic forcing. (iii) Aperiodic fluctuations are intrinsic to the epidemiology. Comparison of real world data and epidemiological models suggests that measles epidemics are inherently chaotic. Conversely, the extent to which chickenpox outbreaks approximate a yearly cycle depends inversely on the population size. 相似文献
14.
西南山区乡村公共服务设施空间布局优化研究——以重庆市崇龛镇小学为例 总被引：2，自引：2，他引：0
在人口流失严重,居住相对分散的乡村地区,公共服务设施的空间配置及优化需要结合自身特点,超越现有的基于城市地区的优化方法。选取重庆市崇龛镇小学为研究对象,设置了模拟人口数量和空间分布动态变化的分析情景,探讨了人口空间非均衡减少对一般乡村公共服务设施空间布局的综合影响。结果表明:1)难以为继的规模与先天不足的可达性是一般乡村地区公共服务设施空间布局优化面临的主要矛盾;2)科学地预测人口变化,审慎地调整居民点空间结构,可在一定程度上引导需求集中,弥补"规模—可达性"矛盾;3)应重视供求关系、强化制度保障,以提升优化结果的现实意义和实施效果。给出了崇龛镇小学空间布局优化的操作方案和预期结果。提出了一般乡村地区公共服务设施空间布局优化的参考路径和操作步骤:1)核定人口空间变化情况;2)确定居民点调整基础与可行性;3)调整需求空间结构,引导公共服务设施布局优化;4)评估设施规模,强化制度保障。 相似文献
15.
将有限种群进化动力学的1/3定理推广到双倍体有限种群,并用Wright-Fisher过程描述.研究了这个种群的一个突变基因的固定概率,并且得到了3个进化定理:完全隐性突变基因的3/10定理、完全显性突变基因的2/5定理和4/5定理.最后,通过研究基本的随机过程解释了3/10定理. 相似文献
16.
东大河林区青海云杉种群结构与动态 总被引：2，自引：0，他引：2
以"空间代时间"的方法,用种群大小级结构代替年龄结构,采用静态生命表、生存分析方法,探讨了东大河林区青海云杉种群的结构和动态规律。结果表明,东大河林区青海云杉种群结构合理,为增长型种群;种群存活曲线属Deevey-Ⅱ型,在整个生活史中死亡率稳定;种群的死亡数、生命期望和消失率分别在幼苗、幼树胸径达到14cm和22cm出现波动,个体通过环境筛的压力增大,种群生命表和存活曲线从整体上反映了东大河林区青海云杉种群数量动态变化趋势;在胸径达到14cm和22cm时,4个生存函数均出现程度不同的波动,与种群静态生命表分析结果吻合。 相似文献
17.
植物组织中的稳定性碳同位素组成(δ13C)整合记录了气候因子和影响植物碳同化以及气孔导度的生理因子的相关信息。应用稳定碳同位素技术可以揭示环境变化中的一些相关信息。回顾了不同的环境因子和植物δ13C的关系,以及这些关系在气候变化研究中的应用,同时进一步讨论了这项技术在重建历史气候和预测未来气候变化中的作用。 相似文献
18.
环境保护与害虫持续控制 总被引：2，自引：0，他引：2
当前 ,全球面临的主要环境问题是 :(1)温室效应和空气污染 ;(2 )水资源严重匮乏 ;(3)水土流失和土地沙漠化 ;(4 )森林破坏和退化 .科学研究逐步证明 ,环境恶化可能对昆虫产生多方面的影响 .环境条件的变化可直接或间接地影响昆虫的种群数量变动、发育速率、发育历期、为害世代、繁殖力等生物学特性 ,植物 -害虫 -天敌之间的相互关系 ,昆虫的分布区域以及昆虫的生物多样性 .研究和实施害虫的持续控制 ,必须以生态系统为基础 ,揭示害虫发生发展的规律 ,保护生物多样性 ,最大限度地依靠系统的自我调控能力 ,把害虫的种群数量及危害程度控制在对人类造成经济损失的水平之下 ,谋求人类与自然的协调共存 相似文献
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20.
Aerial dispersal of pathogens on the global and continental scales and its impact on plant disease 总被引：2，自引：0，他引：2
Some of the most striking and extreme consequences of rapid, long-distance aerial dispersal involve pathogens of crop plants. Long-distance dispersal of fungal spores by the wind can spread plant diseases across and even between continents and reestablish diseases in areas where host plants are seasonally absent. For such epidemics to occur, hosts that are susceptible to the same pathogen genotypes must be grown over wide areas, as is the case with many modern crops. The strongly stochastic nature of long-distance dispersal causes founder effects in pathogen populations, such that the genotypes that cause epidemics in new territories or on cultivars with previously effective resistance genes may be atypical. Similar but less extreme population dynamics may arise from long-distance aerial dispersal of other organisms, including plants, viruses, and fungal pathogens of humans. 相似文献