Research ReproductiveBlackwell Publishing Ltd and physiological responses to simulated climate warming for four subalpine species Susan C. Lambrecht1,5, Michael E. Loik2,5, David W. Inouye3,5 and John Harte4,5 1Department of Biological Sciences, San José State University, San José, CA 95192, USA; 2Department of Environmental Studies, University of California, Santa Cruz, CA 95064, USA; 3Department of Biology, University of Maryland, College Park, MD 20742, USA; 4Energy and Resources Group, University of California, Berkeley, CA 94720, USA; 5Rocky Mountain Biological Laboratory, PO Box 519, Crested Butte, CO 81224, USA Summary Author for correspondence: • The carbon costs of reproduction were examined in four subalpine herbaceous S. C. Lambrecht plant species for which number and size of flowers respond differently under a long- Tel: 408-924-4838 term infrared warming experiment. Fax: 408-924-4840 Email:
[email protected] • Instantaneous measurements of gas exchange and an integrative model were used to calculate whole-plant carbon budgets and reproductive effort (RE). Received: 6 June 2006 • Of the two species for which flowering was reduced, only one (Delphinium Accepted: 18 August 2006 nuttallianum) exhibited higher RE under warming. The other species (Erythronium grandiflorum) flowers earlier when freezing events under warming treatment could have damaged floral buds. Of the two species for which flowering rates were not reduced, one (Helianthella quinquenervis) had higher RE, while RE was unaffected for the other (Erigeron speciosus). Each of these different responses was the result of a different combination of changes in organ size and physiological rates in each of the species. • Results show that the magnitude and direction of responses to warming differ greatly among species.