C. B. Kepler N.F.R. Snyder S.R. Derrickson F. J. Dein J. W. Wiley J.M. Wunderle Jr. A.E. Lugo D.L. Graham W.D. Toone David Ehrenfeld M.H. Wilson 1995 application/pdf en Society for Conservation Biology and Blackwell Science, Inc. Puerto Rican parrots and potential limitations of the metapopulation approach to species conservation chapter