Gene flow and endangered species translocations: a topic revisited

Understanding the evolutionary role of gene flow is pivotal to the conservation of endangered populations. Gene flow can be enhanced through population translocations that are conducted to maintain genetic variation and combat the negative consequences of inbreeding depression (two of the major concerns in the conservation of subdivided or isolated populations). While researchers have given extensive consideration to the idea that gene flow can act as a creative evolutionary force by maintaining genetic variation or spreading adaptive gene complexes, the focus of this paper is to investigate gene flow as a force that constrains local adaptation. I briefly review the theoretical basis of and summarize empirical studies that indicate gene flow can constrain local adaptation, and may thereby lower short-term population fitness. This review suggests that knowledge of gene flow rates and understanding ecological differences among populations is necessary before embarking on a program to artificially enhance gene flow. (C) 1998 Elsevier Science Ltd. All rights reserved.