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

海带组合的种类组成和植物组合的丰度受到两种主要干扰的显著影响——食草动物（如海胆）对植物的攻击，以及流动的水对植物施加的可能使它们移位或断裂的力。这两种形式的干扰可能会显著地相互作用，因为食草动物对植物的亚致死机械损伤（食草动物攻击较大孢子体的典型结果）会削弱植物对流体力的抵抗力。本研究将在华盛顿圣胡安群岛和不列颠哥伦比亚省巴克利湾沿着水流能量梯度的几个地点，对几种物种和形态的海带进行一系列广泛的测量和实验，以检验这些影响。本研究将：(1)在一个地点内的一系列永久地点和微生境同时进行长期的海流和波浪能测量，以表征海水施加的力；(2)测定海带死亡概率和草食动物对植物亚致死伤害频率；(3)测量水流对海带的作用力；(4)测量破坏或移动海带所需的力，海带破坏的位置，以及破坏力对植物大小和形状的功能（异速）依赖性；(5)测量（2-4）在物种、地点和微生境之间的变异；(6)通过实验确定食草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. ***