Abstract：
Natural hybrid zones have provided important insights into the evolutionary process, and their geographic dynamics over time can help to disentangle the underlying biological processes that maintain them. Here, we leverage replicated sampling of an identical transect across the hybrid zone between yellow-shafted and red-shafted flickers in the Great Plains to assess its stability over ∼60 years (1955-1957 to 2016-2018). We identify a ∼73-km westward shift in the hybrid zone center toward the range of the red-shafted flicker, but find no associated changes in width over our sampling period. In fact, the hybrid zone remains remarkably narrow, suggesting some kind of selective pressure maintains the zone. By comparing to previous work in the same geographic region, it appears likely that the movement in the hybrid zone has occurred in the years since the early 1980s. This recent movement may be related to changes in climate or land management practices that have allowed westward movement of yellow-shafted flickers into the Great Plains.
摘要：
自然混合带提供了对进化过程的重要见解，随着时间的推移，它们的地理动态可以帮助解开维持它们的潜在生物过程。这里,我们利用大平原黄轴和红轴闪烁之间的混合带的相同样带的重复采样来评估其60年（1955-1957年至2016-2018年）的稳定性。我们发现混合带中心向西向红轴闪烁范围移动了73公里，但在我们的采样周期内没有发现宽度的相关变化。事实上,混合区仍然非常狭窄，表明某种选择性压力维持该区域。通过与同一地理区域的先前工作进行比较，混合地带的运动似乎很可能发生在1980年代初以来的几年中。最近的运动可能与气候或土地管理实践的变化有关，这些变化使黄轴闪烁的向西移动进入大平原。
