DISSERTATION RESEARCH: An empirical test of species range limit evolution using the world's largest amphibian invasion

入侵物种是全球生物多样性丧失的主要驱动力之一。甘蔗蟾蜍（Rhinella marina）被列入国际自然保护联盟（www.issg.org）维护的100种世界上最严重的外来入侵物种名单。这种大型的新热带蟾蜍已经入侵了全球40多个国家，并在许多方面对当地生态系统产生了负面影响。最大的，也可以说是最具破坏性的，甘蔗蟾蜍入侵地点在澳大利亚。 在那里，甘蔗蟾蜍通过其作为新型有毒猎物、无脊椎动物和小型脊椎动物的捕食者以及与本地青蛙的竞争对手的影响，危及许多本地野生动物物种。 这项研究将揭示哪些环境因素和进化过程有助于甘蔗蟾蜍非常成功地入侵澳大利亚。这些知识将有助于土地管理人员实施控制措施，以保护本地物种免受甘蔗蟾蜍的侵害，并可能限制入侵的总体范围。 此外，物种的入侵也提供了独特的，虽然不幸的，自然实验，以阐明控制物种的地理范围限制的过程。了解物种活动范围限制的机制是生态学和进化领域的一个长期目标。鉴于全球气候变化可能需要改变世界许多地区的地理分布范围，这一问题已变得紧迫。的物种。甘蔗蟾蜍非常适合调查物种的范围限制，因为自从1935年被故意引入澳大利亚以来，它们的入侵历史记录非常丰富。反过来，这使得预测模型的未来入侵的基础上，扩散的关系，以验证历史数据的实际入侵。甘蔗蟾蜍在澳大利亚也有稳定和积极扩大范围的优势，提供了一个独特的机会，比较范围限制与扩大在地理上复制的地区。 甘蔗蟾蜍的入侵澳大利亚将使用景观遗传和基因组分析与控制实验室饲养实验相结合的调查。甘蔗蟾蜍的传播模式将与关键的景观因素，以确定栖息地限制和/或提高甘蔗蟾蜍在澳大利亚各地的运动。一项基因组研究还将揭示基因组中可能有助于甘蔗蟾蜍成功入侵的pupestival适应区域。 结合实验室饲养实验，这项工作将提供一个主要的地理范围扩展的适应作用的基因型和表型测试。 总的来说，这项工作将提供一个罕见的经验测试的领先生态和进化理论的物种的范围限制，除了有用的信息，以帮助控制一个臭名昭著的世界各地的入侵者。

Invasive species are one of the key drivers behind the global loss of biodiversity. The cane toad (Rhinella marina) is on the 100 World's Worst Invasive Alien Species list maintained by the International Union for the Conservation of Nature (www.issg.org). This large, Neotropical toad has invaded over 40 countries worldwide and has detrimentally impacted native ecosystems in many ways. The largest, and arguably most damaging, cane toad invasion site is in Australia. There, cane toads have imperiled numerous native wildlife species through their effects as novel toxic prey items, predators of invertebrates and small vertebrates, and competitors with native frogs. This study will reveal which environmental factors and evolutionary processes are contributing to the cane toad's extraordinarily successful invasion of Australia. This knowledge will help land managers implement control measures to protect native species from cane toads, as well as potentially limit the overall extent of the invasion. Moreover, species' invasions also provide unique, albeit unfortunate, natural experiments for elucidating the processes that control species' geographic range limits. Understanding the mechanisms underlying species' range limits is a longstanding goal in the fields of ecology and evolution. It has become urgent in light of the fact that global climate change may necessitate geographic range shifts for many of the world?s species. Cane toads are ideally-suited to investigate species' range limits because have an extraordinarily well-documented history of invasion since their deliberate introduction to Australia in 1935. In turn, this allows predictive models of their future invasion based on landscape-dispersal relationships to be validated with historical data from the actual invasion. Cane toads also have both stable and actively-expanding range edges across Australia, providing a unique opportunity to compare range limits versus expansion in geographically-replicated areas. The cane toad's invasion of Australia will be investigated using a combination of landscape genetic and genomic analyses with controlled laboratory rearing experiments. Cane toad dispersal patterns will be correlated with key landscape factors to determine which habitats restrict and/or enhance cane toad movement throughout Australia. A genomic study will also reveal putatively adaptive regions of the genome that may be contributing to the cane toad's invasion success. In combination with laboratory rearing experiments, this work will provide genotypic and phenotypic tests of the role of adaptation in a major geographic range expansion. Overall this work will provide a rare empirical test of the leading ecological and evolutionary theories for species' range limits, in addition to useful information to help control a notorious worldwide invader.