Effects of Hydrodynamic Forces, Sub-lethal Herbivory, and their Interaction, on the Mortality, Morphology and Composition of Kelps

埃克曼9314694海藻群落的物种组成和植物群落的丰富度受到两种主要类型的干扰--食草动物(如海胆)对植物的攻击，以及水流对植物施加的力，后者可能会将植物赶走或破坏。这两种形式的干扰可能会显著相互作用，因为食草动物对植物的亚致命性机械破坏(食草动物攻击较大的孢子体的典型结果)会削弱植物对流体作用力的抵抗力。这项研究将在华盛顿圣胡安群岛和不列颠哥伦比亚省巴克利海湾沿流动能量梯度的几个地点，对几个物种和形态的海藻进行广泛的现场测量和实验，以检验这些影响。这项研究将：(1)在一个地点内的一系列永久地点和微生境同时进行海流和波浪能量的长期测量，以表征海水施加的力；(2)测量海带死亡的概率和草食动物对植物亚致命损害的频率；(3)测量水流作用于海带的力；(4)测量海带破裂或移出所需的力、海带破坏的位置以及破碎力对植物大小和形状的功能(异速生长)依赖关系；(5)测量(2-4)中物种、地点和微生境之间的变异性，以及(6)进行实验以确定草食动物对破碎力和死亡概率的影响。***

Eckman 9314694 The species composition of kelp assemblages and the abundances of plants assemblages are influenced significantly by two major types of disturbance - attacks on plants by herbivores, such as urchins, and forces imposed on plants by moving water which may dislodge or break them. These two forms of disturbance may interact significantly, because sub-lethal mechanical damage of plants by herbivores (a typical result of herbivore attack on larger sporophytes) can weaken a plant's resistance to fluid forces. This study will examine these effects by carrying out an extensive series of measurements and experiments on kelps of several species and morphs in situ, working at several sites along a gradient of flow energy in both the San Juan Archipelago, Washington, and Barkley Sound, British Columbia. This study will: (1) make long-term measurements of current and wave energy simultaneously at a series of permanent sites and microhabitats within a site to characterize forces imposed by seawater; (2) measure probabilities of kelp mortality and frequencies of sub-lethal damage of plants by herbivores; (3) measure forces applied to kelps by flow; (4) measure forces required to break or dislodge kelps, the location of kelp failure, and the functional (allometric) dependence of breaking force on plant size and shape; (5) measure the variability in (2-4) among species, sites and microhabitats, and (6) conduct experiments to determine the impact of herbivores on breaking force and probability of mortality. ***