Variability in Spore Dispersal and its Role in Kelp Population Dynamics

芦苇海带森林是全球潮下温带珊瑚礁的主要特征，经历了相对频繁和不可预测的局部灭绝和重新定居。这个项目是正在进行的调查的继续，调查的目的是在大面积海带丧失后使森林迅速恢复。该项目的目标是预测巨藻（Macrocystis pyrifera）中促进孢子扩展扩散的物理和生物条件的发生频率和相对重要性，并确定：(1)孢子迁移率在调节当地海藻种群动态中的作用；(2)有限扩散通过降低个体适合度而破坏种群稳定的可能性。研究方法是在广泛的物理和生物条件下，同时收集水运动和孢子释放和扩散的测量数据。这些信息将用于建立一个基于个体的模型，该模型将预测在不同条件下，水运动、植物繁殖力、植物间距、孢子释放和种群大小，在当地种群内部和外部的有效孢子传播。该模型的预测将用一个成年植物的实验种群进行检验。该模型还将用于预测不同水体运动、植物繁殖力、株距、孢子释放量和种群大小等条件下的自交受精频率和空间程度。自花受精对个体适应度的影响将在所有生命阶段通过实验确定。从该项目获得的资料将普遍适用于向近岸水域释放有能力的孢子或幼虫的大量无根海洋生物的扩散模式。这项工作的总体意义在于，它将为促进扩展繁殖体扩散的流体动力学条件以及繁殖体迁移对被认为具有相对封闭种群的物种动力学的影响程度提供急需的见解。此外，本研究的基于个体的方法将提供孢子从单个植物扩散的信息，这将用于评估巨藻自交受精的成本，巨藻是温带海洋藻类的优势群体，其生活史和扩散特征使它们面临自交受精不利影响的高风险。＊＊＊

9633329 REED Kelp forests, dominant features of subtidal temperate reefs worldwide, undergo relatively frequent and unpredictable local extinctions and recolonizations. This project is a continuation of ongoing investigations of the causal mechanisms that allow for rapid forest recovery following widespread kelp loss. The objective of the project is to predict the frequency of occurrence and relative importance of the physical and biological conditions that promote extended spore dispersal in giant kelp (Macrocystis pyrifera) and determine: (1) the role of spore immigration rates in regulating the dynamics of local kelp populations and (2) the potential for limited dispersal to destabilize populations by reducing individual fitness. The research approach is to collect measurements of water motion simultaneously with measurements of spore release and dispersal from isolated plants over a wide range of physical and biological conditions. This information will be used to build an individual-based model that will predict effective spore dispersal within and away from a local population for varying conditions of water motion, plant fecundity, plant spacing, spore release, and population size. Predictions from the model will be tested using an experimental population of adult plants. The model will also be used to predict the frequency and spatial extent of self-fertilization under different conditions of water motion, plant fecundity, plant spacing, spore release, and population size. The effects of self-fertilization on individual fitness will be experimentally determined for all life stages. The information obtained from the project will apply generally to dispersal patterns of a large number of sessile marine organisms that release competent spores or larvae into nearshore waters. The general significance of this work is that it will provide much needed insight into the hydrodynamic conditions that promote extended propagule dispersal and the degree to which propagule immigration influences t he dynamics of species perceived to have relatively closed populations. Additionally, the individual-based approach to this study will provide information on spore dispersal away from individual plants, which will be used to evaluate the costs of self-fertilization in giant kelp, a member of a dominant group of temperate marine algae whose life history and dispersal characteristics place them at high risk to the adverse effects of self-fertilization. ***