DISSERTATION RESEARCH: Effects of multiple invasive species on nutrient cycling in Lake Seminole: effects of warmer winters on ecosystem dynamics

人类活动正在引起全球物种分布的重大变化。这些变化导致了植物和动物新组合的发展，因为新物种侵入了广泛的生态系统。在许多情况下，多个物种入侵同一地区，它们对生态系统过程的相互作用尚未得到很好的理解。该项目的总体目标是调查多种入侵者对位于佐治亚州和佛罗里达州边界的塞米诺尔湖营养循环的相互作用。实验将记录来自亚洲的高产水生植物水螅（Hydrilla verticillata）与丰富的亚洲蛤（Corbicula fluminea）以及两种新发现的蜗牛（来自南美洲的Pomacea maculata和来自佛罗里达州的Pomacea paludosa）共同生活的影响。这些实验旨在模拟光和温度的自然条件，并确定有和没有Corbicula和两种Pomacea的水螅对营养物质的吸收、储存和释放速率的差异。为了确定由于其他非本地物种的存在而导致的水生植被丰度和分布的更大规模变化，将开发用于跟踪非本地水生植被快速变化的遥感方法。中生态实验和遥感分析的结果将整合到一个一般的概念模型中，以预测这些入侵物种向北迁移到其他湖泊和河流时可能对养分循环产生的影响。最近的气候变化和人类增加的生物运动使许多物种分散到新的地点，在许多生态系统中产生了新的物种组合。了解非本地水生植物和动物如何相互作用，可以预测它们对特定生态系统服务的影响，如养分循环、高质量饮用水的可持续供应以及休闲划船和钓鱼。最近Pomacea对塞米诺尔湖的入侵提供了一个独特的机会来研究早期的多物种入侵，并调查对生态系统服务的影响，特别是对水质的影响。在塞米诺尔湖，另外两种丰富的入侵物种（水螅和Corbicula）已经建立。塞米诺尔湖目前在营养物质和污染物储存以及向下游社区提供高质量水方面发挥着关键作用。然而，人们对湖泊内入侵物种的相互作用或综合影响知之甚少，也不知道最近引入的物种将如何影响湖泊生产和营养循环。该项目将有助于填补这些知识空白，并告知当地和区域利益相关者入侵物种对湖泊生态系统的影响。我们将举办工作坊，促进与持份者就入侵物种的影响进行沟通。这个概念模型将有助于建立一个早期预警网络，告知居民如何减少入侵物种的传播、潜在的毒性风险和野生动物疾病。本地学生将从直接参与研究和研讨会中受益。

Human activities are causing major changes in species distributions globally. These changes have led to the development of new combinations of plants and animals as new species have invaded a wide range of ecosystems. In many cases, multiple species have invaded the same areas, and their interactive effects on ecosystem processes are not well understood. The overarching objective of this project is to investigate the interactive effects of multiple invaders on nutrient cycling in Lake Seminole, on the border of Georgia and Florida. Experiments will document the effects of a highly productive species of aquatic plant from Asia, Hydrilla verticillata, living together with an abundant Asian clam, Corbicula fluminea, and two newly established snail species (Pomacea maculata, from South America and Pomacea paludosa from Florida). These experiments are designed to simulate natural conditions of light and temperature and determine differences in rates of nutrient uptake, storage, and release by Hydrilla with and without Corbicula and the two Pomacea species. To determine larger scale changes in abundance and distribution of aquatic vegetation due to the presence of the other non-native species, remote sensing methods will be developed for tracking rapid changes among non-native aquatic vegetation. Results from mesocosm experiments and remote sensing analyses will be integrated into a general conceptual model to forecast likely future impacts on nutrient cycling as these invasive species move northward to other lakes and rivers. Recent climate change and increased organism movement by humans are dispersing many species into new locations, resulting in novel species combinations in many ecosystems. Understanding how non-native aquatic plants and animals interact allows for projection of their effects on specific ecosystem services, such as nutrient cycling, provision of sustainable supplies of high-quality drinking water, and recreational boating and fishing. The recent invasion of Lake Seminole by Pomacea, where two other abundant invasive species (Hydrilla and Corbicula) were already established, provides a unique opportunity to study multi-species invasions at an early stage and to investigate effects on ecosystem services, specifically their impact on water quality. Lake Seminole currently plays a critical role in nutrient and contaminant storage as well as in providing high-quality water to downstream communities. However, little is known about the interactions or combined effects of invasive species within the lake, nor how recent introductions will affect lake production and nutrient cycling. This project will help to fill these knowledge gaps and to inform local and regional stakeholders of the effects of invasive species on lake ecosystems. A workshop will be organized to facilitate communication with stakeholders on the effects of invasive species. The conceptual model will help to create an early warning network to inform residents on how to reduce the spread of invasive species, the potential risks of toxicity, and wildlife diseases. Local students will benefit from direct participation in research and workshops.