Shefferson, Kull, and Tali 2005

		Shefferson, R.P., T. Kull, and K. Tali. 2005. Adult whole-plant dormancy
		induced by stress in long-lived orchids. Ecology 86:3099-3104

Abstract Dormancy is a condition in which an herbaceous perennial does not
sprout for one or more growing seasons. To test whether dormancy is an adaptive
response to environmental stress, we defoliated and shaded individuals of two rare
geophytic orchids, Cypripedium calceolus and Cephalanthera longifolia, in five
Estonian populations early in the growing season in 2002 and 2003. We also
censused plants at the same time, and conducted one more census in 2004. Mark-
recapture models were used to estimate the probabilities of dormancy (d, the
complement to resighting, (p), and apparent survival (phi). Apparent survival varied
little by treatment, with Cypripedium and Cephalanthera surviving at 0.986 ± 0.014
and 0.974 ± 0.021 (mean ± SE), respectively. In contrast, treatment impacted
dormancy dramatically. For both Cephalanthera and Cypripedium, defoliated plants
were most dormant (0.320 ± 0.055 and 0.095 ± 0.036, respectively). However, while
both control and shaded plants were roughly equally least dormant in Cypripedium
(d(control) = 0.048 ± 0.020 vs. d(shaded) = 0.045 ± 0.021), the least dormant
Cephlanthera had been shaded (0.182 ± 0.040 vs. d(control) = 0.206 ± 0.050). We
conclude that dormancy may allow the plant to buffer stress in the short-term without
increasing mortality risk.

Article copyright notice: © 2005 by the Ecological Society of America

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Shefferson, Kull, and Tali 2005