Climate change-driven range expansion of an invasive marine invertebrate

沿海海洋系统是发展和检验生态学理论的理想场所。然而，作为陆地和水生生物群落之间的重要界面，它们受到当地人为影响（例如污染、沿海开发）的严重影响。气候变化尤其影响了潮间带环境，其中空气和水温的变化可能改变潮间带生物生活的环境。沿海生态系统也不成比例地受到生物入侵的影响，因为港口往往是引入非本地物种的门户。qu<s:1>圣劳伦斯海相河口（SLME）的潮间带群落是由每年的冬季冰冲刷扰动构成的，物理异质性（如裂缝、岩石之间的空间）在为固结物种（如贻贝、海藻）和流动物种（如蜗牛、螃蟹）提供避难所方面起着关键作用。除了19世纪中期被引入加拿大东部的一种草食性蜗牛——长尾蜗牛（periwinkle Littorina littorea）外，大多数常见物种都是这个生态系统的本土物种。此后，它遍布加拿大沿海地区和美国东北部，成为许多海岸的主要消费者。然而，它在SLME中的传播在历史上是有限的，但在过去的几十年里，它的丰度急剧增加。本提案的总体目标是研究最近范围扩大对SLME潮间带群落的影响，以及与cc相关的环境变量如何调节这些影响。采用基于现场和实验室的方法，将通过解决三个主要目标，评估空气和水温对这种入侵者的丰度、分布和行为的相对影响，包括其对食物资源（底栖微藻）、竞争对手和其他底栖无脊椎动物的影响。首先，完成对SLME中蜗牛数量和分布的栖息地（如海湾与岩石点）和微栖息地（如裂缝与暴露的岩石表面）的综合调查。同时，将评估生境和微生境特有的热环境，并记录生境/微生境利用的年际变化。第二，实地和实验室对空气和水温的中尺度操纵将评估微生境偏好的行为基础和人口后果（例如，生长、生存）。第三，评估群落影响（与本地沙氏L. saxatilis对微藻食物和庇护所的竞争以及对固结物种的影响）。总的来说，这种综合方法研究了这种入侵的后果，将为解决气候变化介导的非本地物种范围扩张的问题提供一个概念框架，并为这一沿海生态系统关键要素的动态提供实用知识。

Coastal marine systems are ideal for developing and testing ecological theory. However, as an important interface between terrestrial and aquatic biomes, they are heavily affected by local anthropogenic influences (e.g. pollution, coastal development). Climate change (CC) in particular has influenced intertidal environments where changes in both air and water temperatures may alter the environment in which intertidal organisms live. Coastal ecosystems are also disproportionally affected by biological invasions as ports are often gateways for the introduction of non-indigenous species. Intertidal communities in the Québec St. Lawrence maritime estuary (SLME) are structured by annual winter ice scour disturbance and physical heterogeneity (e.g., crevices, spaces between boulders) plays a key role in providing refuges for sessile (e.g. mussels, seaweeds) and mobile (e.g. snails, crabs) species. Most common species are indigenous to this ecosystem, with the exception of the periwinkle Littorina littorea, an herbivorous snail that was introduced into eastern Canada in the mid-1800s. It has since spread throughout the Canadian Maritimes and the northeastern USA, becoming a dominant consumer on many shores. Its spread into the SLME has, however, been historically limited, but its abundance has increased dramatically in the last decades.The general objective of this proposal is to examine the impacts of this recent range expansion on SLME intertidal communities and how CC-related environmental variables modulate these impacts. Using field- and laboratory-based approaches, the relative influence of air and water temperature on the abundance, distribution and behaviour of this invader will be assessed, including its effects on food resources (benthic microalgae), competitors, and other benthic invertebrates by addressing three major objectives. First, completing a habitat- (e.g., bays vs. rocky points) and microhabitat-specific (e.g., crevices vs. exposed rock surfaces) synoptic survey of the snail's current abundance and distribution in the SLME. In parallel, the habitat- and microhabitat-specific thermal environment will be assessed and inter-annual shifts in habitat/microhabitat use documented. Second, field and laboratory mesocosm manipulations of air and water temperature will assess the behavioural basis of microhabitat preferences and demographic consequences (e.g., growth, survival). Third, community impacts (competition for microalgal food and shelter with the native L. saxatilis and impacts on sessile species) will be evaluated. Overall, this integrated approach examining the consequences of this invasion will provide both a conceptual framework for addressing concerns of climate change-mediated range expansion of non-indigenous species and practical knowledge on the dynamics of key elements of this coastal ecosystem.