The Role of Hybrid Vigor in the Replacement of Pecos Pupfish by Its Hybrids with Sheepshead Minnow

摘要: Many species are jeopardized by hybridization and genetic introgression with closely related species. Unfortunately, the mechanisms that promote or retard gene flow between divergent populations little stud- ied poorly understood. Like many imperiled fish species, Pecos pupfish (Cyprinodon pecosensis )i s threatened replacement its hybrids a close congener. We examined swimming performance growth rate of hybrid to determine role vigor in homogenization C. pecosen- sis sheepshead minnow (C. variegatus). The F1 hybrids, backcross purebred variegatus displayed greater endurance than .I naddition, grew more rapidly .T he ecological superiority probably promoted their rapid spread through beyond historic range hese results indicate eradication restoration native is unlikely. Extinction unique via can result from human activities increase historically fragmented populations; conservation managers must weigh potential for such catastrophe against presumed benefits increased interpopulation flow. This example illustrates how, after has occurred, conflict may arise formerly complementary goals.