Perspectives on the conservation of wild hybrids

Abstract

Hybridization processes are widespread throughout the taxonomic range and require conservation recognition. Science can help us understand hybridization processes but not whether and when we ought to conserve hybrids. Important questions include the role of humans in hybridization and the value we place on natural and human-induced hybrids concerning their ecological function. Certain hybrids resulting from human actions have replaced the ecological role of extirpated or extinct parent taxa and this ecological role should be preserved. Conservation policies must increasingly recognize populations of wild organisms that hybridize naturally within the context of their historical ecological role. Natural selection acts on individual organisms and the range of characteristics displayed by individual hybrids constitute raw material for evolution. Guidelines must consider the conservation value of individuals and the ethical aspects of removing hybrids for the purpose of conserving population genetic integrity. Conservation policies should focus on protecting the ecological role of taxa affected by hybridization. An informative example is North American canids (Canis), where body size, prey availability, and human landscape modifications may interact and impose local selective pressures. Gray wolves (Canis lupus) and eastern wolves (Canis lycaon or Canis lupus lycaon) or Great Lakes wolves appear to hybridize naturally within the context of their historical ecological role. In contrast, eastern coyotes (C. latrans) exhibit wolf ancestry and have partly replaced the ecological role of an extirpated parent taxa in parts of northeastern North America. The need for advancing conservation policies that reflect our current understanding of ecology and evolution is urgent.