The effect of contaminants on mechanisms underlying invasive species impact

淡水生物多样性正受到一些全球变化驱动因素的威胁，包括水生污染造成的栖息地退化和入侵物种的扩散。众所周知，栖息地退化会增加入侵物种的成功，但其发生的机制尚不清楚。这项研究的主要目的是为了更好地了解物种入侵的非生物决定因素。这将通过比较一组本地和入侵伽玛科物种对潜在有毒元素（PTE）暴露的反应来完成。该项目的第一部分涉及确定合适的PTE浓度及其生物利用度。对欧洲各地淡水监测点的环境数据进行了分析，以开发一种符合环境实际的pte混合物，供今后的研究使用。PTE混合物是通过从PTE列表中找到最普遍的污染物来确定的，与它们最相关的其他污染物以及它们在一起的浓度比例。这些符合环境实际的混合物将用于观察不同伽玛科物种的生物积累反应。Gammaridae将暴露在与环境相关的高浓度混合物中，并通过ICP-MS分析确认摄取。下一个实验将观察伽玛蝶科对pte的生理生态反应。将像以前一样，监测暴露于PTE混合物的gamma类的代谢率（即耗氧量）、血淋巴浓度和临界热最大值/最小值。跨物种调查将确定入侵物种和本地物种的反应。接下来，我们将比较PTE暴露在入侵和本地伽玛尼科动物中的行为变化和长期健康后果。Gammaridae将通过长期（即4-6个月）暴露于pte来进行检查，重点关注它们的活动模式和长期健康影响（生存、生长、繁殖力）。与繁殖力有关的配偶配对和对繁殖机会的竞争的影响也将被调查。最后，我们将研究暴露于pte的入侵和本地伽玛蝶科通过种群间和种群内捕食对群落的影响。观察PTE暴露的伽玛蛾对低营养级“猎物”物种和同营养级“行间猎物”物种的捕食行为。捕食者的功能反应决定了猎物的消耗率作为密度的函数，将被建模，以便对接触污染物的捕食行为进行比较（项目团队先前已经表明，这可能与入侵物种的影响有关）。

Freshwater biodiversity is under threat from a number of drivers of global change including habitat degradation by aquatic contamination and the spread of invasive species. Habitat degradation is known to increase the success of invasive species, however the mechanisms by which this occurs remain unclear. The broad aim of this study is to develop a better understanding of the abiotic determinants of species invasions. This will be done by comparing the responses of a suite of native to invasive Gammaridae species to potentially toxic element (PTE) exposure. The first part of this project involved determining suitable PTE concentrations and their bioavailability. Environmental data from freshwater monitoring sites across Europe were analysed to develop an environmentally realistic mixture of PTEs for use in future studies. The PTE mixture was determined by finding the most prevalent contaminants from the list of PTE's, which other contaminants they're most correlated with and the ratios at which their concentrations are found together.These environmentally realistic mixtures will be used to look at the bioaccumulation response of different Gammaridae species. Gammaridae will be exposed to the mixtures at environmentally relevant and elevated concentrations, with uptake confirmed via ICP-MS analysis. The next experiment will look at ecophysiological responses of Gammaridae to PTEs. Metabolic rate (i.e. oxygen consumption), haemolymph asmolarity and critical thermal maximum/minimums will be monitored in Gammaridae exposed to PTE mixtures as before. Investigation across the suite of species will determine responses in invasive and native species. Next we will compare the behavioural changes and longer-term fitness consequences of PTE exposure in invasive and native Gammaridae. Gammaridae will be examined through chronic (i.e. 4-6 months) exposure to PTEs with a focus on their activity patterns and longer-term fitness impacts (survival, growth, fecundity). Linked to fecundity, the effects of mate-pairing and competition for reproductive opportunities will also be investigated. Finally, we'll investigate community impacts via inter- and intraguild predation by invasive and native Gammaridae exposed to PTEs. The predatory behaviour of PTE exposed gammaridae towards lower trophic level 'prey' species and same trophic level 'interguild prey' species will be observed. Predator functional responses determining rates of prey consumption as a function of density will be modelled allowing for comparisons of predatory behaviour (which the project team have previously shown can be linked with invasive species impact) with respect to contaminant exposure.