Effects of temperature on locomotion rate of the introduced slug Deroceras panormitanum (Gastropoda: Limacidae) on Marion Island: Impacts of global climate change

Many of the Southern Ocean Islands are experiencing rapid climate change. These islands have been invaded by a wide variety of species, which are having substantial effects on ecosystem functioning. Temperatures have increased by c. 1.2°C and rainfall has declined by 500 mm in the past half century on Marion Island. The slug, Deroceras panormitanum is an important invasive on Marion Island. Its distribution is largely restricted to moist, lowland areas below 200 m a. s. l. What the influence of temperature is on other aspects of performance that might be significant in determining the range limits of this species, such as locomotion ability, is not known. The primary aim of this study was to determine the effects of temperature on locomotion performance by investigating three aspects of performance curves: optimum temperature (Topt), performance breadth (Tbr) and maximum velocity (Umax). The responses of optimum temperature and performance breadth showed reverse acclimation. Individuals acclimated to the colder temperature (0°C) showed a higher optimum temperature and a wider performance breadth over all the groups. Field fresh individuals performed poorly overall. There were no significant acclimation effects on maximum velocity (Umax). The slugs seem to prefer temperatures between 5°C and 10°C, even though they perform poorly at these temperatures. If temperatures increase as predicted for the Southern Ocean Islands, slugs are likely to have increasing impacts on ecosystem functioning. The Dataset was used for the completion of an honours thesis.

南大洋诸岛正经历着快速的气候变化。这些岛屿已被众多外来物种入侵，对当地生态系统功能造成了显著影响。在过去半个世纪里，马里恩岛（Marion Island）的气温上升了约1.2℃，降雨量减少了500毫米。地中海拟蛞蝓（Deroceras panormitanum）是马里恩岛的重要入侵物种，其分布范围主要局限于海拔200米以下的湿润低地区域。目前尚不明确温度对该物种其他可能影响其分布范围限制的生理表现维度（如运动能力）的影响。本研究的核心目标为，通过探究运动表现曲线的三个核心指标——最适温度（optimum temperature, Topt）、表现广度（performance breadth, Tbr）与最大运动速度（maximum velocity, Umax），明确温度对该蛞蝓运动表现的影响。最适温度与表现广度的响应呈现反向驯化效应。在所有组别中，适应低温（0℃）环境的个体展现出更高的最适温度与更宽的表现广度。野外新鲜捕获的个体整体表现不佳。温度驯化对最大运动速度（Umax）无显著影响。尽管该蛞蝓在5℃至10℃的温度区间内表现不佳，但其似乎更偏好该温区。若如南大洋诸岛的气候预测那般气温持续上升，该蛞蝓对当地生态系统功能的影响可能会进一步加剧。本数据集用于完成一篇荣誉学士学位毕业论文。