Collaborative Research: Ecological Correlates of Introgressive Hybridization Between Native and Introduced Populations of Salmonid Fishes

本文研究了外来虹鳟鱼（Oncorhynchus mykiss）的引入对黄石地区濒危赤喉鳟鱼（O. clarki bouvieri）本地基因库的生态和遗传影响。除了竞争、捕食和引进物种引入致病生物外，对一些本地鱼类来说，一个主要威胁是与引进物种杂交。杂交品种，如果是可育的，可以传播并导致亲本基因被引进物种的基因完全取代。本研究旨在确定黄石赤喉鳟鱼和虹鳟鱼之间的杂交程度，以及在本地基因库中发生的遗传稀释程度。此外，该研究还将测试环境的特定特征（温度、海拔、水流等）是否与纯物种或杂交物种的存在或缺失相关。通过这种方式，这项研究将确定特定的环境是有利于杂交鱼类的传播，还是为黄石国家公园的纯切喉鳟鱼提供了优势。本研究将首次提供虹鳟鱼遗传入侵模式的文献资料，并开始探索这种模式的生态机制。如果发现环境因素能预测黄石原生切喉鳟鱼比杂交鳟鱼更成功，那么这些栖息地就可以得到优先保护。只有通过综合了解影响入侵物种成功的生态和遗传因素，我们才有希望阻止它们的传播，拯救本地基因库

This proposal focuses on the ecological and genetic impacts of the introduction of non-native rainbow trout (Oncorhynchus mykiss) on native gene pools of threatened Yellowstone cutthroat trout (O. clarki bouvieri). In addition to competition, predation and the introduction of disease organisms by introduced species, for some native fish species, a major threat is that of hybridization with the introduced species. Hybrids, if fertile, can spread and cause the complete replacement of parental genes with those of the introduced species. This study is designed to determine the extent of hybridization between Yellowstone cutthroat trout and rainbow trout as well as the degree of genetic dilution that has occurred in native gene pools. In addition, the study will also test whether particular features of the environment (temperature, elevation, stream flow, etc.) are correlated with the presence or absence of pure species or hybrids. In this manner, the study will determine if particular environments favor the spread of hybrid fishes, or provide an advantage to the remaining pure populations of Yellowstone cutthroat trout.This study will provide the first documentation of the pattern of genetic invasion of rainbow trout and begin to explore the ecological mechanisms that are responsible for this pattern. If environmental correlates are found which predict the success of native Yellowstone cutthroat trout over hybrids, such habitats can be given top priority for conservation. Only through a combined approach of understanding both the ecological and genetic factors that influence the success of invasive species, can we ever hope to deter their spread and save native gene pools