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.chiggate.com/jerome-brown-philadelphia-eagles-mitchell-ness-1990-legacy-jersey-discount/