Abstract Background The invasive Chondrostoma nasus nasus has colonized part of the distribution area of the protected endemic species Chondrostoma toxostoma toxostoma. This hybrid zone is a complex system where multiple effects such as inter-species competition. bi-directional introgression. strong environmental pressure and so on are combined. https://www.alarecre.com/American-Flag-Color-Block-iPhone-14-Waterproof-Case-p12619/