About Issues in Ecology Issues in Ecology is designed to report,in language understandable by non-scientists,the consensus of a panel of scientific experts on issues relevant to the environment./ssues in before publication.No responsibility for the views expressed by authors in ESA publica- tions is assumed by the editors or the publisher,the Ecological Society of America. leading professi responsible application of ecological principles to the solution of environmental problems For more information,contact the Ecological Society of America,1707 H Street.NW Suite 400,Washington,DC,20006.ISSN 1092-8987 esa About Issues in Ecology About Issues in Ecology Issues in Ecology is designed to report, in language understandable by non-scientists, the consensus of a panel of scientific experts on issues relevant to the environment. Issues in Ecology is supported by the Pew Scholars in Conservation Biology program and by the Ecological Society of America. It is published at irregular intervals, as reports are com￾pleted. All reports undergo peer review and must be approved by the Editorial Board before publication. No responsibility for the views expressed by authors in ESA publica￾tions is assumed by the editors or the publisher, the Ecological Society of America. Issues in Ecology is an official publication of the Ecological Society of America, the nation’s leading professional society of ecologists. Founded in 1915, ESA seeks to promote the responsible application of ecological principles to the solution of environmental problems. For more information, contact the Ecological Society of America, 1707 H Street, NW, Suite 400, Washington, DC, 20006. ISSN 1092-8987