RUI Collaborative Research: Spatial Realism in the Mussel Bed Disturbance Paradigm

我们对物理干扰如何塑造种群和群落结构的理解在很大程度上要归功于对贻贝床中波浪产生的缝隙形成的实地研究。先前的研究将贻贝床描述为一个非平衡系统，其中的干扰在空间上是不可预测的，产生随机拼凑的贻贝覆盖物和间隙。这个项目将测试另一种观点的假设和预测--干扰显示了可预测的地貌格局，不仅取决于外部强迫(波应力)的空间分布，还取决于决定聚集结构的生物过程。具体地说，贻贝生产力的空间变化(补充和生长)、生理压力和捕食相互作用，在贻贝覆盖的结构中产生景观图案。贻贝床的某些区域以单层的形式直接附着在岩石上，以抵抗干扰。其他区域以多层结构发展，当非常深的时候，迫使表层贻贝仅附着在邻近的贻贝上，而不是岩石表面，并导致内部贻贝仅微弱地附着在岩石或彼此之间，有利于传播扰动。因此，林隙形成和恢复的空间格局出现在一个统一的景观过程中。该项目的实地工作重点是建立一个详细的地理信息系统数据库，使用一些创新的采样方法，应用于不列颠哥伦比亚省巴克利海湾的10个贻贝床位。每个站点的地理信息系统数据层包括波浪力、地形(潮汐高度、坡度和坡向)、贻贝大小结构、贻贝床层厚度、分层的差异以及按层分层的特定大小的附着强度。将使用地理信息系统内插和回归分析首先检查假设的景观过程的假设，然后测试关于发生干扰和恢复的空间模式的具体预测。最后，受控野外实验将检验这一关键命题，即不同的贻贝床结构对干扰的抵抗力、程度和恢复能力都不同。智力上的优点：景观干扰假说包括几个不同于以前对该系统中干扰的概念化的过程：稳态(平衡)结构影响水动力应力引发干扰的可能性，以及一旦启动，干扰是否会传播。因此，平衡过程决定了扰动过程的基本特征。干扰在概率范围内是可预测的，干扰的景观格局在相当程度上反映了基础物种的生物学特征。这种干扰范式的重新构建可能适用于受干扰的不同层次的生态系统(如生物膜、珊瑚礁、森林)。广泛影响：该项目在少数群体服务机构(加州州立大学洛杉矶分校)、拥有独特海洋空间分析中心的综合性大学(加州州立蒙特利湾分校)和一级研究机构(加州大学洛杉矶分校)之间结成联盟。合作伙伴有相当多的指导和外展支持系统可供借鉴。该项目为加州州立大学洛杉矶分校的学生创建了一个共同指导计划，提供对海洋生态系统空间分析的深入介绍，无与伦比的实地研究经验，以及接触到博士授予机构的研究实验室，包括潜在的博士导师。计划在三个校区和实地场地班菲尔德海洋科学中心开展大量教育充实和培训活动。该项目将扩大代表不足的少数群体对西海岸生物海洋学的参与，并在这方面提供独特的资源。将通过COSEE-WEST向公众和K-12教师开展更多的外联活动。

Our understanding of how physical disturbance shapes the structure of populations and communities owes much to field studies of wave-generated gap formation in mussel beds. Prior studies depict mussel beds as a non-equilibrium system, in which disturbance is spatially unpredictable, generating a random patchwork of mussel cover and gaps. This project will test assumptions and predictions of an alternative view -- that disturbance shows predictable landscape patterns that depend not merely on spatial distribution of external forcing (wave stress) but also on biological processes determining the structure of the aggregation. Specifically, spatially varying mussel productivity (recruitment and growth), physiological stress, and predation interact to produce landscape patterns in the structure of the mussel cover. Certain regions of the mussel bed develop as mono-layers attached directly to the rock, resisting disturbance. Other regions develop in multi-layered configurations that when very deep force superficial mussels to attach solely to adjacent mussels instead of the rock surface, and cause interior mussels to only weakly attach to either rock or one another, favoring propagating disturbances. Therefore, spatial patterns of gap formation and recovery emerge from a unified landscape process.Field work for this project emphasizes construction of a detailed GIS database using some innovative sampling methods applied to 10 mussel bed sites in Barkley Sound, British Columbia. GIS data layers for each site include wave force, topography (tidal height, slope, and aspect), mussel size structure, mussel bed thickness, differentiation of layering, and size-specific attachment strengths stratified by layer. GIS interpolations and regression analyses will be used to first examine assumptions of the hypothetical landscape process and then test specific predictions regarding spatial patterns in the occurrence of disturbance and recovery. Finally, controlled field experiments will test the key proposition that different mussel bed structures cause different resistance to-, extent of-, and recovery from disturbance.Intellectual Merit: The landscape disturbance hypothesis includes several processes that differ from previous conceptualizations of disturbance in this system: steady state (equilibrium) structures influence the likelihood that hydrodynamic stresses initiate a disturbance and whether once initiated the disturbance will propagate. Thus, equilibrium processes condition essential features of the disturbance process. Disturbance is predictable within probabilistic limits, and the landscape patterns of disturbance reflect in considerable measure the biological characteristics of a foundation species. This reframing of the disturbance paradigm may apply to a diverse array of layered ecosystems subject to perturbations (e.g. biofilms, coral reefs, forests).Broader Impacts: The project forms an alliance among a Minority Serving Institution (Cal State LA), a comprehensive university with a unique center for marine spatial analysis (Cal State Monterey Bay) and a Tier 1 Research Institution (UCLA). The partners have considerable mentoring and outreach support systems to draw upon. The project creates a co- mentoring program for Cal State LA students, providing an intensive introduction to spatial analysis of marine ecosystems, an unmatched field research experience, and exposure to research labs of a PhD granting institution, including potential PhD advisors. Numerous educational enrichment and training activities are planned for the three campuses and the field venue, Bamfield Marine Sciences Centre. The project will broaden participation of underrepresented minorities in biological oceanography on the West Coast, and provide a unique resource in that regard. Additional outreach to the public and K-12 teachers will be done through COSEE-West.