Recent work has suggested that species extinctions in ecological systems can occur as a consequence of deterministic transient chaos even in the absence of external disturbances. We argue and present a practical method to demonstrate that species extinctions due to transient chaos can be effectively prevented by applying small, ecologically feasible perturbations to the populations at appropriate but rare times. This may be of significant importance to the challenging environmental problems of species preservations. (C) 1999 Elsevier Science B.V. All. rights reserved.