Ecosystem engineers and coastal sedimentary communities

海底沉积物覆盖了绝大多数海洋区域。然而，我们对形成其生物多样性和功能的过程的理解仍然是零碎的。在过去，大多数理论预测，在当地规模的捕食和物理因素将发挥最重要的作用，调节沉积群落。然而，随后的许多研究也表明，栖息地形成物种的建立对于这些系统中的多样性和功能的形成至关重要。这些基础物种，更一般地称为（自生）生态系统工程师，有能力创造或改变栖息地的属性，促进新的，更复杂的社区的发展。生态系统工程师的作用已经在岩石海岸，海带森林，红树林，珊瑚礁，甚至盐沼系统中得到了很好的研究。然而，在非结构化沉积海底，特别是在加拿大大西洋地区，仍有许多有待探索和测试。越来越多的证据表明，生态系统工程师在沉积环境中的社区属性和服务可能发挥关键作用，但没有足够的信息是他们的作用，推动物种之间的相互作用发生在不同的营养级。这是相关的时候，我们目睹了非本地物种的持续蔓延，有能力利用，消耗或破坏当地的生态系统工程师，并打开有关他们的相互作用，并最终，这些工程师对沉积系统的实际作用的相关问题。 这项研究计划的重点是几个突出的生态系统工程师目前和分散沿着加拿大大西洋沉积海岸线：蓝贻贝，东部牡蛎，鳗草和岩藻。该计划的主要目标是测试这些生态系统工程师对周围沉积物底栖动物的组装和物种相互作用的影响，以及非本土物种对其的潜在改变。六个假设是解决工作的三个主要研究方案：生态系统工程师作为驱动程序的底栖动物的结构和功能，他们的作用作为介质的自上而下的相互作用，和他们的作用作为介质的本地入侵物种的相互作用。在大西洋区域的沉积区，特别是沿海的爱德华王子岛，已经进行了大量的勘探工作，为提出和检验这些假设提供了基础。这项研究计划的成果将有助于我们对生态系统工程师及其在推动生物相互作用方面的作用的了解。这一结果也将对群落调控、营养复杂性和海岸带保护理论产生影响。

Sedimentary bottoms encompass a vast majority of the marine realm. Yet, our understanding of the processes that shape their biodiversity and function remains fragmentary. In the past, most theory predicted that at the local scale predation and physical factors would play a paramount role regulating sedimentary communities. However, numerous subsequent studies have also showed that the establishment of habitat-forming species is as critical to shape diversity and function in these systems. These foundation species, more generically known as (autogenic) ecosystem engineers, have the ability to create or alter the properties of a habitat, promoting the development of new, more complex communities. The role of ecosystem engineers has been well studied in rocky shores, kelp forests, mangroves, coral reefs, and even saltmarsh systems. However, in unstructured sedimentary bottoms, in particular those in Atlantic Canada, much remain to be explored and tested. Mounting evidence suggests that ecosystem engineers may play key roles on community attributes and services in sedimentary settings, but not enough information is available on their role driving the species interactions occurring within and among different trophic levels. This is relevant at a time when we witness the ongoing spread of non-indigenous species that have the ability to exploit, consume or disrupt local ecosystem engineers, and opens relevant questions about their interactions and, ultimately, about the actual role of these engineers on sedimentary systems. This research program focuses on several prominent ecosystem engineers present and scattered along sedimentary shorelines of Atlantic Canada: blue mussels, eastern oysters, eelgrass, and rockweeds. The main goal of this program is testing the effects of these ecosystem engineers on the assembly and species interactions of surrounding sedimentary infauna and their potential alteration by non-indigenous species. Six hypotheses are addressed by working on three main research scenarios: Ecosystem engineers as drivers of infaunal structure and function, their role as mediators of top-down interactions, and their role as mediators of native-invader species interactions. A considerable amount of exploratory work already conducted in sedimentary areas in the Atlantic region, and coastal Prince Edward Island in particular, provides the basis to propose and test each of these hypotheses. The outcome of this research program will contribute to our knowledge on ecosystem engineers and their role driving biological interactions. Such outcome will also have implications for theory on community regulation, trophic complexity, and coastal conservation.