Variability across scales in coastal ecosystems

物种总数和相对丰度的剧烈波动仍然是种群和群落理论中尚未解决的问题。在海洋系统中，这些波动大多是假设由生境特性驱动的平衡动力学来研究的。然而，最近的研究表明，物种相互作用中涉及的生态和非线性反馈过程如何触发多重平衡的存在。我的研究项目的目标是了解这些生态过程，更具体地说，是那些与空间聚集和生态结构发展相关的生态过程，如何协同运作，以解释从个体到整个沿海地区的强烈波动和对环境的反应。例如，贻贝个体和贻贝床的发育是否与它们的空间连通性相互作用，从而在它们的先发制人能力和对松散空间的敏感性方面产生强烈的反馈？这些反馈能反过来推动整个景观的密度剧烈波动吗？最后，更大尺度的空间结构（如幼虫扩散和/或区域生境异质性）能否维持区域水平上的波动？为了实现这一目标，我将采用多学科方法，整合(1)互惠移植实验，(2)空间和个体发生的非平衡理论，以及(3)跨尺度监测。这里提出的研究将首先导致一个具有生态发展（即个体到生态系统水平的发展变化）和异质景观相关的跨尺度波动的空间结构生态系统理论（项目1.a）。当地反馈过程和预测波动都将在亚北极潮间带群落中进行测试。然后，景观层面的现象将被整合到异质海岸系统的非平衡理论中，该理论通过幼虫扩散耦合，将使用大规模数据进行验证。最后，我将把理论应用于海草生态系统的持久性。我们的努力旨在导致大规模海洋生态学的主要范式转变，并揭示新的区域特性，促进具有强环境异质性的复杂系统的可预测性和管理。

Strong fluctuations in the total and relative abundance of species remain an unresolved problem in population and community theories. In marine systems, these fluctuations have mostly been studied assuming equilibrium dynamics driven by habitat properties. However, recent work shows how ecological and non-linear feedback processes involved in species interactions could trigger the existence of multiple equilibriums. The goal of my research program is to understand how these ecological processes, and more specifically those associated with spatial aggregation and with the development of ecological structures, operate in synergy to explain strong fluctuations and responses to the environment, from the scale of individuals to that of entire coastal regions. For example, can the development of individual mussels and of mussel beds interact with their spatial connectivity to generate strong feedbacks in their ability to preempt and their susceptibility to loose space? Can these feedbacks in turn drive strong fluctuations of densities across whole landscapes? Finally, can spatial structure at larger scales such as larval dispersal and/or regional habitat heterogeneity maintain fluctuations at the regional level? Toward that goal, I will adopt a multidisciplinary approach integrating (1) reciprocal transplant experiments, (2) non-equilibrium theories of space and ontogeny, and (3) cross-scale monitoring. The research proposed here will first lead to a theory of spatially structured ecosystems with ecological development (i.e. individual to ecosystem level developmental changes) and associated cross-scale fluctuations in heterogeneous landscapes (Project 1.a). Both local feedback processes and predicted fluctuations will be tested in a sub-arctic intertidal community. Landscape level phenomena will then be integrated within a non-equilibrium theory of heterogeneous coastal systems coupled through larval dispersal that will be validated using large-scale data. Finally, I will apply theories to the persistence of seagrass ecosystems. Our effort is meant to lead to major paradigm shifts in large-scale marine ecology, and to reveal novel regional properties that foster predictability and management of complex systems with strong environmental heterogeneity.