Human-impacted landscapes facilitate hybridization between a native and an introduced tree.

摘要: Spatial and temporal dynamics of hybridization, in particular the influence local environmental conditions, are well studied for sympatric species but less is known native-introduced systems, especially long-lived species. We used microsatellite chloroplast DNA markers to characterize anthropogenic landscapes on extent, direction, spatial distribution hybridization between a native North American tree Juglans cinerea (butternut) an introduced ailantifolia (Japanese walnut) 1363 trees at 48 locations across range butternut. Remarkably, admixture sites reached nearly 70%, while fragmented continuous forests showed minimal (<8%). Furthermore, more hybrids had J. seed parents (95%) than (69% 59%, respectively). Our results show strong landscape type rate direction realized gene flow. While common landscapes, our suggest that even small forested serve as substantial barriers hybrid establishment, key consideration butternut conservation planning, already exhibiting severe decline, other forest hybridize with congeners.