Authors: Galbusera, Peter; Ball, Alex;Bertola, Laura;Bishop von Wettberg, Eric;Fienieg, Elmar;Helsen, Philippe;Kopatz, Alexander;Russo, Isa-Rita;Senn, Helen;Stronen, Astrid Vik;

The IUCN currently considers hybrids as a threat to biodiversity conservation. Hybridization with an invasive or feral population/species can negatively affect resident taxa by genetic swamping and homogenization. Moreover, population viability can be compounded by outbreeding depression (also in later generations) and/or lead to the loss of genetic diversity. Yet hybridization is omni-present and can play an important role in evolutionary processes such as speciation. Furthermore, interspecific genetic exchange is a natural process and may be essential for adaptation. Hence, we need to consider and manage hybrids in a more nuanced way. Here, under the initiative of the IUCN SSC Conservation Genetics Specialist Group, we discuss different aspects of hybridization, taking into account risks and benefits of hybrids, including the specifics of taxa, the level of threat, the population size, the distinction between human induced versus natural hybrids, besides legal, welfare and functional ecological aspects. We argue that genetic analyses increase our ability to discover introgression and identify hybrids, allowing us to better assess, monitor and manage genetic diversity, which is critically important for the resilience of populations and ecosystems. If introgression can ensure or improve retention of unique genetic components without reducing population viability, hybrids may warrant preservation.