Predicting Physical Disturbance in a Changing Environment: Field Test of a Biomechanical Approach

Denny扰动在群落结构的非平衡理论中起着核心作用，在该理论中，高物种多样性和物种共存是在异质扰动的斑块环境中随机招募的过程。岩石潮间带系统的扰动状态为研究提供了一个优势，因为它的特征是主要由单一因素引起的慢性高强度物理扰动-波浪作用施加的水动力。这种“波浪暴露”的控制性质是潮间带作为实验生态学模型系统的原因之一。丹尼博士的实验室最近已经能够将波浪统计和流体动力学方面的早期工作结果与潮间带生物强度的经验测量结合起来，采用定量的生物力学方法，预测作为时间和海洋“波浪”的函数的物理扰动。该方法的初步应用表明，其预测相当准确，但尚未对该方法进行严格的测试，这是该项目的动力。将对作为生物力学方法输入的参数进行广泛的实地测量，这些数据将用于预测沿岸一系列地点六种具有代表性的植物和动物中每一种的每周干扰率。然后将这些预测与在这些相同地点经经验测量的扰动率进行比较。然后可以计算预测和经验测量之间的拟合优度，为生物力学方法的整体预测能力提供证据。在这些研究中开发的廉价仪器将使潮间带生态学家有可能重复这种方法的基本步骤（测量最大波高，测量栖息地特有的最大水速），因此应该有助于在各种地点使用和测试生物力学方法。如果这些生物力学方法的测试证实了其预测物种特定干扰率的能力，该方法可以成为一个有价值的工具，用于理解波浪暴露的季节性和逐年变化的生态后果，并用于预测如果大规模气候变化导致海洋波浪度的长期变化，干扰率将如何变化。

9633070 Denny Disturbance plays a central role in non-equilibrium theories of community structure, in which high species diversity and species coexistence are attributed to processes of stochastic recruitment in a heterogeneously perturbed, patchy environment. The disturbance regime of the rocky intertidal system offers an advantage for study in that it is characterized by chronic high intensity physical disturbance due primarily to a single factor -- the hydrodynamic forces imposed by wave action. This controlling nature of "wave exposure" is one reason the intertidal zone serves as a model system in experimental ecology. Dr. Denny's lab has recently been able to combine the results of earlier work in wave statistics and hydrodynamics with empirical measurements of the strength of intertidal organisms in a quantitative, biomechanical method that predicts physical disturbance as a function of time and the "waviness" of the sea. Preliminary applications of this approach have shown that its predictions are reasonably accurate, but a rigorous test of the approach has not been conducted, which is the impetus for this project. Extensive field measurements will be conducted of the parameters that serve as inputs into the biomechanical approach, and these data will be used to predict the week-to-week rate of disturbance of each of six representative species of plants and animals at a series of sites along the shore. These predictions will then be compared to the rates of disturbance measured empirically at these same sites. The goodness of fit between prediction and empirical measurement can then be calculated to provide evidence of the overall predictive ability of the biomechanical approach. The inexpensive instruments developed in these studies will make it possible for intertidal ecologists to repeat the basic steps of this approach (measuring maximal wave height, measuring habitat-specific maximal water velocities), and thereby should facilitate the use and testing of the biomechanical method at a wide variety of sites. If these tests of the biomechanical approach confirm its ability to predict species-specific rates of disturbance, the method can be a valuable tool for understanding the ecological consequences of both seasonal and year-to-year variability in wave exposure, and for the prediction of how rates of disturbance will change if large-scale climatic change causes longterm shifts in the waviness of the ocean.