A contextual approach to hybridization in the twenty-first century: purity, endangered species, and red wolves

Abstract Hybridization and genetic admixture between species have long generated controversy in conservation biology. While some conservationists regard hybridization as a major threat to biodiversity, recent genomic research suggests that gene flow between species is widespread in evolutionary history and may enhance adaptive capacity in rapidly changing environments. Despite this growing recognition, conservation policy—particularly under the U.S. Endangered Species Act—remains ambiguous regarding the status and management of admixed populations. This paper examines whether conservationists have general reasons to prevent hybridization and admixture. I argue that there is no prima facie justification for a blanket commitment to preventing interspecies genetic mixing. After introducing the stakes of this issue through the historical Red Wolf Recovery Program, I analyze two prominent arguments commonly invoked to justify anti-hybridization positions: appeals to genetic purity and concerns about ‘extinction through introgression.’ I argue that genetic purity lacks intrinsic conservation value and that worries about introgressive extinction are often overstated and misapply arguments for the intrinsic value of species. Furthermore, efforts to prevent hybridization can undermine other conservation goals, including maintaining genetic diversity and ecological connectivity. In place of general prohibitions, I defend a contextual approach to hybridization, according to which the value or harm of admixture must be evaluated on a case-by-case basis, considering its ecological, evolutionary, and cultural consequences.