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

Eckman 9314694海带组合的物种组成和植物组合的丰度受到两种主要类型的干扰的显著影响-草食动物对植物的攻击，如海胆，以及流动的水对植物施加的力，这可能会使它们移位或破碎。这两种形式的干扰可能相互作用显着，因为亚致命的机械损伤的植物草食动物（草食动物攻击较大的孢子体的典型结果）可以削弱植物的抵抗力流体的力量。本研究将检查这些影响进行了广泛的一系列测量和实验的几个物种和变形的海带原位，工作在几个站点沿着梯度的流能在圣胡安群岛，华盛顿，巴克利湾，不列颠哥伦比亚省。这项研究将：（1）在一系列永久性地点和地点内的微生境同时进行海流和波浪能的长期测量，以表征海水施加的力;（2）测量海藻死亡的概率和草食动物对植物造成亚致死损害的频率;（3）测量水流施加于海藻的力;（4）测量破碎或移走海带所需的力、海带破裂的位置以及海带的功能。（异速生长）植物的大小和形状的破碎力的依赖性;（5）测量（2-4）中的物种、地点和微生境之间的变异性;（6）进行实验以确定草食动物对断裂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. ***