【作者】 韩晓卓；

【导师】 李自珍；

【作者基本信息】 兰州大学 ， 生态学， 2006， 博士

【摘要】 当前,进化生态学是国际理论生态学与进化生物学相结合的重要前沿与热点之一。本文选题于该领域中的最新研究热点:物种的生态位构建及其进化动力学研究。所谓生态位构建是指有机体通过改变局部生存环境进而改变其自然选择的生物与非生物源的一种能力,其主要机制是有机体与环境在进化过程中产生反馈,从而使进化成为自然选择与生态位构建共同作用的过程。生态位构建理论的提出扩展和丰富了现有的进化思想,为物种适应性的研究提供了新颖的理论依据,也为解释不同尺度上的生态学现象提供了有效的机理模式。本文采用两种研究方法:一是构建微分动力系统模型,利用相平面分析以及数值模拟对系统的平衡点及其稳定性进行阐述:二是结合空间生态学中的元胞自动机模拟模型,运用Matlab和Mathematica数学软件实现空间模式、结构与动态的可视化。论文主体由五部分组成:第一章对生态位构建理论的基本内容及其研究现状与进展进行综述;第二章研究生态位构建在空间结构种群上的多态维持、空间分布、进化动态及环境恶化对多态的影响;第三章研究具有时滞生态位构建作用的集合种群动态与其空间分布模式,探讨了振荡与空间波、集合种群续存同时滞、生态位构建等关系;第四章考虑生态位构建对生境的修复作用,讨论生态位构建对集合种群动态、续存条件和阈值的影响;最后是对主要结论的总结和展望。其中对双位点种群遗传模型进行空间上的延伸和讨论时滞与生态位构建的双重作用对集合种群动态的影响以及破坏生境由于有机体的生态位构建作用而恢复的过程都属于创新性的工作;文中首次提出集合种群的侵占惯量和侵占动量概念。通过上述几个方面的研究,主要得出以下15条结论:(1)生态位构建可使空间结构种群,甚至是在没有杂合子优势的条件下,形成多种可能的稳定基因型分布模式;(2)随着环境的破坏与恶化,种群的生态位构建作用加速其较早形成稳定多态以阻碍环境对种群的不利影响,解释了有机体在不利环境下的一种生活史对策;(3)生态位构建作用通过基因型—环境反馈机制及有限的基因交流导致基因型多态的稳定共存;(4)有机体的生态位构建作用是一种积极的动力改变环境进而改变其自然选择的方向;(5)生态位构建的时滞作用对集合种群动态和空间分布产生深刻影响;(6)集合种群大小在时滞的崭新效应和等权重效应下达到一固定值,而在首位效应下达到统计稳定,表明首位效应的影响最显著;(7)首位效应下生态位构建相对权重的增量和时滞的长度是影响系统不稳定性动态的关键因素;(8)适中的生态位构建强度有利于集合种群的续存;(9)生态位宽度变窄会减少集合种群的数量从而增加其灭绝风险;(10)时滞和生态位构建的双重作用使系统产生周期振荡,并在异质性环境中产生稳定的螺旋波,破碎的螺旋波和环形波三种分布模式;(11)集合种群与资源含量的空间分布因为相滞而互补;(12)具有生态位构建的集合种群续存不仅取决于侵占率与灭绝率之间的平衡,而且依赖于生态位构建能力同其生境的自然消耗速率之间的妥协;(13)当生境中适合侵占的斑块比例小于其侵占率与灭绝率之比时,生态位构建作用促使集合种群在一定条件下续存:(14)生境斑块的状态从不适合到适合转变过程中存在生态位构建强度和系统初始条件这两个阈值;(15)集合种群的大小同正生态位构建能力正相关,意味着对环境具有较强正作用的有机体对维持有效生境起积极作用。综上,本文将生态位构建理论的研究从基因水平上扩展到具有空间结构性质的种群和集合种群水平上,探讨了其在不同空间模式下的进化及生态响应,对进化过程中生态位构建的理论模式及其空间动态模拟进行了创新性研究,从机理和方法上发展和丰富了生态位构建理论。更多还原

【Abstract】 Evolutionary ecology is one of the important frontiers and hotspots in recent international research of theoretical ecology and evolutionary biology. The subject of this dissertation is the new focus in this field: the research on species’s niche construction and its evolutionary dynamics. Niche construction refers to the capacity of organisms to modify its local important environments, consequently modifying their both biotic and abiotic sources of natural selection in their environment. The key of niche construction is the feedback between organism and environment in evolution. As a result, the evolution is the product of interacting processes of natural selection and niche construction. The classical evolutionary theory was extended with niche construction. It provides novel theoretical grounds for species adaptation and also offers the rational mechanism for explaining many ecological phenomena at different scales. Two approaches will be utilized in this dissertation. One is the differential dynamical system. I will use the phase plane analysis and numerical solution to illustrate the equilibriums and their stability of the system. The other is the simulated models in spatial ecology: cellular automaton. By the software Matlab and Mathematica, I can show the explicit graphic mode of the spatial pattern, structure and dynamics. The dissertation consists of five chapters. Chapter one summarizes the essential framework and the frontiers and development of niche construction. Chapter two discusses the effect of niche construction on polymorphism maintenance, spatial distribution and evolutionary dynamics for spatial structured population, as well as the influences of environments on polymorphism. Chapter three focus on the spatial dynamics and distribution pattern of metapopulation with time-lagged niche construction, exploring the relationships between oscillation and spatial wave, as well as time lag, niche construction and metapopulation persistence. Chapter four indicates the effects of niche construction on metapopulation dynamics, persistent condition and threshold by modifying the destroyed habitat. In the last chapter, I make the main conclusions and the perspectives about the niche construction development. Among of them, I extend the two-locus population genetics model with spatial scale, discuss the coupled function of time lag and niche construction on metapopulation dynamics and the modification of niche-constructing populations for destroyed habitat in a creative way. The terms of occupancy momentum and occupancy inertia in the metapopulation are also first coined in the thesis. Fifteen results and conclusions are obtained in this dissertation. (1)Niche construction can lead to stable coexistence of diverse genotypes in spatially structured population, which supports a stable polymorphism even without heterozygote superiority. (2)With habitat deterioration, niche construction accelerates the formation of steady polymorphism and hence impedes the harmful influences of environment on the population, which might embody a life-history strategy of organism under the unfavorable environment. (3)Niche construction results in the coexistence with alternative polymorphism through genotype-environment feedback and limited gene flow. (4)The niche-constructing organism is an active force to alter its environment and hence the direction of natural selection in order to better survival. (5)Spatial dynamics and distribution pattern of metapopulation are profoundly influenced by time-lagged niche construction. (6)Metapopulation size can reach a fixed level in the recency effect and equal weighting of time lag but is statistical stability in primacy effect, which implies the primacy effect is most remarkable. (7)The increment in the relative weightingof each generation’ niche construction and the length of time lag are significant factors for system destabilization. (8)Moderate capacity of positive niche construction benefits the metapopulation persistence. (9)The narrowing of niche breadth can decrease the metapopulation size and thereby increase the extinction risk. (10)The coupled function of time lag and niche construction make the system oscillation and generate the spiral wave, spiral-broken and circular wave in heterogeneous habitat. (ll)The spatial distributions of metapopulation and resource content are complementary due to a phase lag of their both frequencies. (12)Metapopulation persistence with niche construction depends not only on the balance between colonization and extinction, but also on the balance between the ability of niche construction and natural dissipation of habitat. (13)Metapopula-tion can survive under certain condition when the percent of suitable patches in habitat is lower than the ration of extinction to colonization. (14)Two thresholds exist in the process of transition of habitat quality dynamics from unsuitable to suitable, which include the intensity of niche construction and the initial condition of system. (15)Metapopulation size is positive correlated with the ability of positive niche construction, which means that organism or population who has strongly positive influences on their environment plays an important role to maintain the available habitat. In the dissertation, the researches on niche construction are expanded from gene level to the levels of population and metapopulation with an attribute of spatial structure and their evolutionary and ecological responses to differently spatial patterns are also discussed. We innovates in the theoretical patterns of niche construction in evolutionary process and its spatially dynamic simulation, the results of which develop theoretically and enrich methodologically the theory of niche construction.更多还原