Linking nearshore kelp forest dynamics to sandy beach ecosystems

初级生产者，如植物和藻类，构成大多数食物网的基础，其生产力和命运从根本上塑造生态系统。然而，食物和其他资源往往是从外部来源输送到食物网的，为接受者生态系统提供补贴。了解这些类型的营养连接和生态系统之间的交换是必要的预测食物网可能会对变化，无论是环境或人为的。尽管其潜在的重要性，跨生态系统的物质通量，这些通量在时间和空间上的变化，以及接收社区的生态响应的定量评价是缺乏的，特别是对海洋生态系统。通过调查源生态系统（海带森林）和受体生态系统（桑迪）之间的联系，该项目将扩大和改变我们对沿海海洋跨生态系统通量的理解。近岸海藻林是一种高生产力的海洋生态系统，其特征是净初级生产力（NPP）的季节和年际变化很大。 90%以上的海带森林NPP输出到邻近的生态系统，包括潮间带。海藻森林附近的桑迪海滩生态系统缺乏附着的植物和藻类，严重依赖进口的漂流海藻（wrack）来支持复杂多样的食物网。虽然桑迪是一个占主导地位的海岸线类型沿沿着美国海岸，提供栖息地和猎物的野生动物，包括濒危物种，并高度重视社会作为娱乐和文化资源，推动充满活力的沿海经济，他们收到生态研究相比，其他海岸线类型。这种知识的缺乏阻碍了海滩作为生态系统的养护和管理。海滩位于陆地和海洋之间的狭窄边缘，极易受到气候变化，特别是海平面上升的影响，并将受到气候变化的影响，海带森林也是如此。该项目综合了生物和物理方法，以了解出口海带的命运和运输，以及这种资源补贴的可变性如何塑造接受海滩生态系统的社区结构和功能。研究生和本科生将成为研究团队的成员，接受沿海海洋生态学和公共宣传和教育方面的科学培训和指导。培训当地居民和沿海管理人员并让他们参与定期对海滩上的海带植物进行的海岸线调查，将是这项研究的一个重要研究部分，并提高公众对科学研究、沿海生态以及海带森林与海滩生态系统之间联系的作用的认识。该项目的结果将为沿海海洋生态系统之间的连接动态提供新的见解，可应用于其保护和管理。该项目旨在了解捐赠生态系统（海带林）和接受生态系统（桑迪）之间的营养连接，主要目标有两个：1）评估海带藻体输入的变化如何影响海滩生态系统的模式和过程;通过海带森林到桑迪的漂流海带生物量的物理运输和输入，定量了解营养连接性。该项目将开始，在圣巴巴拉海峡、莫霍克礁和沿着10公里相邻海岸线的一个经过充分研究的海带森林进行为期两年的密集工作，研究小组将在那里测量随时间变化的潮间带群落结构，以应对海带输入的变化。为了评估沉船输入的变化对生态系统功能的影响，他们还将测量邻近海滩潮间带消费者的海带消费量和次级生产率。他们将使用以下辅助方法直接观察海带的命运和运输：1）使用带有全球定位系统的漂流器跟踪在莫霍克礁标记的海带植物; 2）在莫霍克礁用“漂流卡”标记大量海带植物（2000年），由项目小组和训练有素的志愿海滩清理者进行恢复。然后将计算沿海岸线沿着恢复的漂流卡和漂流者轨迹的结束分布。这些数据将用于为根据区域海洋模拟系统对沿海表层流的数值模拟建立的海带森林到海滩的海带迁移模型提供信息和验证该模型。利用该模型预测的海带搁浅率，研究人员将在加州南部海岸线100公里的一组更大的海滩上对群落结构和残骸生物量进行采样，以测试研究结果的普遍性。这种结合的命运和运输观测，海滩社区调查和过程测量，建模将使调查人员的特点，海带补贴投入的时间变化和这种变化的后果，为社区结构和功能的收件人海滩生态系统。

Primary producers, such as plants and algae, form the basis of most food webs and their productivity and fate fundamentally shape ecosystems. Often, however, food and other resources are delivered to a food web from an outside source, providing a subsidy to the recipient ecosystem. Understanding these types of trophic connections and exchanges between ecosystems is necessary for predicting how food webs may respond to change, whether environmental or anthropogenic. Despite their potential importance, quantitative evaluations of cross-ecosystem material fluxes, variation of these fluxes in time and space, and ecological responses of recipient communities are lacking, particularly for marine ecosystems. By investigating links between a source ecosystem, kelp forests, and a recipient ecosystem, sandy beaches, this project will expand and transform our understanding of cross-ecosystem fluxes in the coastal ocean. Nearshore kelp forests are highly productive marine ecosystems characterized by large seasonal and interannual variations in net primary production (NPP). More than 90% of kelp forest NPP is exported to adjacent ecosystems including the intertidal zone. Lacking attached plants and algae, sandy beach ecosystems near kelp forests depend heavily on imported drift kelp (wrack) to support complex and diverse food webs. Although sandy beaches are a dominant shoreline type along all U.S. coasts, provide habitat and prey for wildlife, including endangered species, and are highly valued by society as recreational and cultural resources that drive vibrant coastal economies, they receive little ecological study compared to other shoreline types. This lack of knowledge hinders the conservation and management of beaches as ecosystems. Perched on the narrow rim between land and sea, beaches are highly vulnerable to climate change, particularly sea level rise, and will be impacted by changes in climate, as will kelp forests. This project integrates biological and physical approaches to achieve an understanding of the fate and transport of exported kelp, and how variability in this resource subsidy shapes the community structure and function of recipient beach ecosystems. Graduate and undergraduate students will be integral members of the research team, receiving scientific training and mentoring in coastal marine ecology and in public outreach and education. The training and participation of local residents and coastal managers in regular shoreline surveys for beached kelp plants will provide an essential research component of the study and enhance public awareness of scientific research, coastal ecology and the role of links between kelp forest and beach ecosystems. The results of this project will provide new insights into the dynamics of connectivity between coastal marine ecosystems that can be applied to their conservation and management.The project seeks to understand trophic connectivity between a donor ecosystem, kelp forests, and a recipient ecosystem, sandy beaches, with two primary goals: 1) an evaluation of how variation in kelp wrack input affects patterns and processes in beach ecosystems and 2) a quantitative understanding of trophic connectivity through physical transport and input of drift kelp biomass from kelp forests to sandy beaches. The project will begin with two years of intensive work at a well-studied kelp forest in the Santa Barbara Channel, Mohawk Reef, and along 10 km of adjacent coastline, where the research team will measure intertidal community structure over time in response to variability in kelp inputs. To assess effects of variation in wrack input on ecosystem function, they will also measure kelp consumption and secondary production rates of intertidal consumers on adjacent beaches. They will directly observe fate and transport of kelp using complimentary approaches: 1) tracking kelp plants tagged at Mohawk Reef using drifters with GPS; and 2) tagging large numbers of kelp plants (2000) with "drift cards" at Mohawk Reef for recovery by the project team and trained volunteer beachcombers. Ending distributions of recovered drift cards and drifter tracks along the shoreline will then be computed. These data will be used to inform and validate a kelp forest-to-beach kelp transport model based on numerical simulations of coastal surface currents from the Regional Oceanic Modeling System (ROMS). Using predicted kelp beaching rates from this model run regionally, the investigators will then sample community structure and wrack biomass at a larger set of beaches spanning 100 km of the southern California shoreline to test the generality of research findings. This combination of fate and transport observations, beach community surveys and process measurements, and modeling will allow the investigators to characterize temporal variability in kelp subsidy inputs and the consequences of this variability for community structure and function of recipient beach ecosystems.