Collaborative Research: Kelp forest interaction webs in the Aleutian Archipelago: patterns and mechanism of change following the collapse of an apex predator.

过去35年来对海獭和海带森林生态系统进行的研究提供了一个更著名的大型脊椎动物捕食者自上而下强迫的例子。这些研究表明，1）海獭通过限制食草海胆间接维持海带森林，2）这种营养级联对许多其他物种和生态系统过程有很强的间接影响。这些见解主要是通过比较阿留申群岛的岛屿和没有海獭，海獭的空间异步人口恢复太平洋海上毛皮贸易后，他们的毁灭创造了一个机会。在超过35年的研究过程中，这些研究人员获得了大量关于海獭种群、海带森林群落以及许多阿留申群岛上有和没有海獭的相关海洋野生动物的数据。海獭的数量已经崩溃，整个地区的海獭物种现在已经生态灭绝。在这项研究中，Konar，Edwards和Estes博士将联合收割机与这一灭绝事件的几十年数据库相结合，记录海胆和肉质大型藻类（海带和其他物种）的分布和丰度的时空变化的模式和机制。 他们将通过重新访问20个岛屿来实现这一目标，他们拥有长期数据，并重新普查历史海带森林监测点的海胆丰度和人口结构，以及海带和其他肉质大型藻类的丰度和物种组成。结合起来，这些数据将提供一个帐户的水獭，海胆海带营养级联已经改变了海獭在阿留申群岛的崩溃的程度。现有的信息表明，海带森林非常迅速地崩溃海獭下降后，这种快速转变是由海胆从深水向上迁移，而不是在原地招聘和增长。这组海洋科学家将测试这一想法，方法是测量沿着从浅水和深水收集的动物海胆刺的生长增量的各种温度和营养敏感同位素模式。类似于海胆的深度避难所，来自其他地区的研究表明，大型藻类可能有一个空间避难所，从海胆放牧在浅水沃茨或非常密集的藻类站。他们将探索大型藻类的空间避难所，通过使用在海带森林监测点的再普查收集的数据，并通过扩大我们的调查，以较浅的沃茨和孤立的海带beds.This研究是一个机会，严格探索和记录的影响，一个大型脊椎动物捕食者的互动网络动态的相关生态系统。 该项目的智力价值强调了海洋岛屿和北极的近岸生态系统结构和过程研究的特殊性。该项目的更广泛影响包括对社会、教学和培训的益处。该项目将是非常有新闻价值的，因为它将描述一种迅速下降的海洋哺乳动物的现状，并将记录由于过去20多年来该物种丰度的波动而发生的变化。将向来自三所不同大学的研究生提供培训和教育机会。该项目将涉及阿拉斯加大学费尔班克斯，加州大学圣克鲁斯和圣地亚哥州立大学。

Research on sea otters and kelp forest ecosystems conducted over the past 35 years provides one of the better known examples of top-down forcing by a large vertebrate predator. These studies have shown that 1) sea otters indirectly maintain kelp forests by limiting herbivorous sea urchins, and 2) this trophic cascade has strong indirect effects on a number of other species and ecosystem processes. These insights were obtained largely through the comparison of islands in the Aleutian archipelago with and without sea otters, an opportunity created by the spatially asynchronous population recovery of sea otters following their decimation by the Pacific maritime fur trade. In the course of more than 35 years of studies, these researchers have obtained an extensive amount of data on sea otter populations, kelp forest communities, and an array of associated marine wildlife from numerous Aleutian Islands with and without sea otters. Sea otter populations have since collapsed and the species is now ecologically extinct across the entire region. In this study, Drs. Konar, Edwards and Estes will combine the multi-decadal database with this extinction event to chronicle the patterns and mechanisms of spatial and temporal change in distributions and abundances of sea urchins and fleshy macroalgae (kelps and other species). They will do this by revisiting 20 islands for which they have long-term data and re-censusing the historical kelp forest monitoring sites for the abundance and population structure of sea urchins, and for the abundance and species composition of kelps and other fleshy macroalgae. In combination, these data will provide an account of the degree to which the otter-urchin kelp trophic cascade has changed with the collapse of sea otters across the Aleutian archipelago.The available information indicates that kelp forests collapsed very rapidly following the sea otter decline, and that this rapid shift was facilitated by the upward migration of sea urchins from deep water as opposed to in situ recruitment and growth. This group of marine scientists will test this idea by measuring various temperature- and nutrient sensitive isotopic patterns along the growth increment of sea urchin spines of animals collected from shallow and deep water. Similar to a depth refuge for urchins, studies from other areas have suggested that macroalgae may have a spatial refuge from urchin grazing in shallow waters or amongst very dense algal stands. They will explore macroalgal spatial refuges by using data collected during the re-censusing of the kelp forest monitoring sites and by extending our surveys to shallower waters and isolated kelp beds.This research is an opportunity to rigorously explore and document the influences of a large vertebrate predator on the interaction web dynamics of its associated ecosystem. The intellectual merit of this project emphasizes the special character of oceanic islands and the Arctic for the study of near-shore ecosystem structure and processes.Broader impacts of this project include benefits to society, teaching, and training. The project will be very newsworthy because it will describe the current status of a rapidly declining marine mammal and will document changes that have occurred due to fluctuations in the abundance of this species over the last 20+ years. Training and educational opportunities will be offered to graduate students from three different universities. The project will involve the University of Alaska Fairbanks, University of California Santa Cruz, and San Diego State University.