Variability in Spore Dispersal and its Role in Kelp Population Dynamics

9633329芦苇海带森林是世界各地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。该项目是对海藻大范围丧失后实现森林快速恢复的因果机制的持续调查。该项目的目的是预测促进巨藻(Macrocystis Pyrifera)孢子广泛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带种群动态中的作用；(2)通过降低个体适应度，有限扩散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，同时收集对水运动的测量和对孤立植物的孢子释放和扩散的测量。这些信息将被用来建立一个基于个体的模型，该模型将在不同的水分运动、植物繁殖力、植物间距、孢子释放和种群大小的条件下预测孢子在本地种群内和远离本地种群的有效传播。该模型的预测将使用成年植物的实验种群进行验证。该模型还将用于预测不同水分运动、植物繁殖力、植株间距、孢子释放和种群大小条件下的自花授粉频率和空间范围。自我受精对个体健康的影响将在所有生命阶段通过实验确定。从该项目获得的信息将普遍适用于大量固着海洋生物向近岸水域释放合格孢子或幼虫的扩散模式。这项工作的总体意义是，它将提供迫切需要的洞察，以促进扩大繁殖扩散的水动力学条件，以及繁殖迁移对被认为具有相对封闭种群的物种的动力学影响的程度。此外，这项研究的基于个体的方法将提供有关孢子从个体植物中扩散的信息，这些信息将被用来评估巨型海带的自受精成本，巨型海带是温带海藻中的一种，其生活史和扩散特性使其处于自受精不利影响的高风险中。***

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. ***