Complex genetic patterns and distribution limits mediated by native congeners of the worldwide invasive red‐eared slider turtle

<p>Non-native (invasive) species offer a unique opportunity to study the geographic distribution and range limits of species, wherein the evolutionary change driven by interspecific interactions between native and non-native closely related species is a key component. The red-eared slider turtle, <i>Trachemys scripta elegans</i> (TSE), has been introduced and successfully established worldwide. It can coexist with its native congeners <i>T. cataspila</i>, <i>T. venusta</i> and <i>T. taylori</i> in Mexico. We performed comprehensive fieldwork, executed a battery of genetic analyses and applied a novel species distribution modeling approach to evaluate their historical lineage relationships and contemporary population genetic patterns. Our findings support the historical common ancestry between native TSE and non-native (TSE_alien), while also <span>highlighting the genetic differentiation of the exotic lineage. G</span>enetic patterns are associated with their range size/endemism gradient, the microendemic <i>T. taylori</i> showed significant reduced genetic diversity and high differentiation, whereas TSE_alien<span> showed </span>the highest diversity and signals of population size expansion. Counter to our expectations, <span>lower naturally occurring distribution overlap and little admixture patterns </span>were found<span> between TSE and its congeners, exhibiting reduced gene flow and clear genetic separation across neighboring species despite having zones of contact. We demonstrate that</span> these native <i>Trachemys</i> species have distinct climatic niche suitability, likely preventing establishment of and displacement by the TSE_alien. Moreover, we <span>found </span>major niche overlap between TSE_alienand native species worldwide, supporting our prediction that sites with closer ecological optima to the invasive species have higher establishment risk than those that are closer to the niche-center of the native species.</p>