Interactive and Non-Linear Effects of Predation, Intraspeci-fic Competition and Environmental Variation Upon Species Persistence in Marine Soft-Bottom Communities

长期以来，海洋生态学领域的科学家一直试图了解自然群落中各种生物之间发生的复杂相互作用，以及它们环境的物理方面如何影响诸如生存、繁殖、引入新个体到种群中以及维持种群规模等重要的生态参数。关于一种生物对另一种生物种群的直接影响(例如，捕食者对被捕食物种的影响，或对共享同一栖息地的另一种生物的优势竞争对手)，人们已经了解了很多。更复杂的间接影响仍然不能很好地理解和预测，但这些类型的相互作用可以对自然种群的动态和维持产生戏剧性的控制影响。例如，依赖浮游幼体维持种群的河口动物可能会受到控制幼体丰度的捕食性鱼类近海变化的严重影响。利普修斯博士是一位年轻的生态学家，在他的研究中已经表现出了巨大的生产力和创新性，其中大部分都是关于重要的资源物种(龙虾和螃蟹)的。利普修斯博士提议对这种复杂的、更高级别的相互作用进行一项复杂的研究，这些相互作用有助于控制沿海河口的动物种群。他将研究的动物包括一些非常重要的商业物种；蓝蟹、软壳蚌和小翻领文蛤。这项研究不仅应该提供一些必要的数据来检验关于通过更高级别的相互作用来组织自然群落的新理论，而且它还将产生一些重要的生态信息，对宝贵的渔业资源的管理是有用的。

Scientists in the field of marine ecology have long sought to understand the complex interactions that occur between various organisms in a natural community, and how the physical aspects of their environment influence such important ecological parameters as survival, reproduction, the introduction of new individuals into a population, and the maintenance of population sizes. Much has been learned about the direct effects of one organisms on the population of another (e.g., a predator on a prey species, or a superior competitor on another living thing sharing the same habitat). More complex indirect effects are still not well understood nor predictable, yet these types of interactions can have dramatic controlling influences on the dynamics and maintenance of natural populations. For example, estuarine animals that rely on planktonic larvae to sustain populations can be drastically impacted by offshore changes in predatory fishes that control larval abundance. Dr. Lipcius is a young ecologist who has already exhibited great productivity and innovation in his research, much of it dealing with important resources species (lobsters and crabs). Dr. Lipcius has proposed a sophisticated investigation of such complex, higher-order interactions that work to control animal populations in coastal estuaries. The animals he will study include some very important commercial species; the blue crab, the soft-shelled clam, and the littleneck clam. This research should not only provide some needed data to test new theory on the organization of natural communities via higher- order interactions, but it will also yield some important ecological information useful in the management of valuable fisheries resources.