Research On Dynamical Models And Mechanisms Of Spatially Structured Population Synchrony

Synchrony of spatial population refers to coincident in the population abundance in different location. Evidence for synchronous fluctuations of spatially separated population is ubiquitous in the literature. The presence, absence or degree of synchronization can be an important part of the function or malfunction of a biological system. At present, the search for mechanisms behind spatial population synchrony is currently a major issue in population ecology, and has attracted the interest of ecologists. Moreover, ecologists have recently recognized many environmental variables, including temperature, precipitation, humidity, river height, and some seasonal indices, have significantly reddened spectra, i.e. colored environmental noise. The subject of this dissertation is researching the mechanism of spatial synchrony; we discuss the relationship between colored environmental noise and population synchrony. In this research, we give a new method for generating sets of noise with a desired correlation and color. Using the time series analysis and numerical simulation, we analyze the influence of colored noise and dispersal on synchrony between population dynamics, and the complex interaction between the two synchronizing factors. We get some new conclusions as follows:1. The color of environmental noise has no influence on population synchrony with homogeneous linear dynamics, i.e. the classic Moran theorem still holds for colored environmental noise.2. Geographic variation may lead to qualitatively different population dynamics within a species and that interspecific synchrony occurs. AR₁ model describes environmental color intensifies the Moran effect when population dynamics are spatially heterogeneous.3. Simulation by nonlinear population model (Maynard Smith model) suggests whether red noise increases synchrony or not depends very much on how environment influences population renew process, i.e. the intrinsic rate of increase or the carrying capacity is influenced by environmental variation.4. If dispersal is valuable, the influence of noise color on population synchrony also depends on the pattern of dispersal between patches. 5. Local noise is known as a desynchronizing factor. Numerical simulation suggests that red local noise owns weaker desynchronizing capacity than white local noise.6. For multi-species spatial population the Moran effect needs not necessarily influence the focal species directly, synchrony is readily transferred through food webs or between age classes. Numerical simulation using host-parasitoid model suggests that indirect red noise can synchronize the population as same as direct red noise.7. Multi-factor regression analysis with linear variables is performed. This suggests that the noise color has limit synchronization comparing the dispersal and spatial correlation of noise.Overall, in this PhD paper, various aspects of environmental noise (such as intensity, extent, spatial correlation, color) and dispersal were discussed using linear and nonlinear population model from single species to multi-species spatial population. Moreover, the complex interaction between the two synchronizing factors was discussed. Therefore, our study not only enriches the theory of potential cause of spatial synchrony, but also enhances our understanding the phenomenon of widespread synchrony.Furthermore, those of theories and methods play an important role in endangered species protection, conservation corridors construction, controlling pests and eliminating human infectious diseases.