Using rainout shelters to evaluate climate change effects on the demography of Cryptantha flava

摘要: Summary 1 Precipitation in arid regions is temporally variable with much of it arriving discrete, unpredictable pulses. Climate change models predict an increase the variation precipitation, longer droughts and larger rainfall events, addition to increased temperatures. 2 A life table response experiment (LTRE) was conducted herbaceous arid-land perennial Cryptantha flava (Boraginaceae) from 1997 2000, order determine how precipitation affects asymptotic population growth (l) vital rates. Variation took two forms, through rainout shelters erected just before during 1999 spring growing season, naturally occurring over 4 years. 3 An unexpected effect on l observed that could not be attributed drought. The value decreased greatly control census plots 1998–99 transition but did decrease sheltered plots. spring, when were place, unusually cold, resulting frost damage unsheltered plants. Plants under experienced elevated nighttime temperatures escaped damage. greater attributable almost entirely contributions survival, stasis. 4 There residual effects drought treatment 1999–2000 as populations while populations. Compared controls, there large negative growth, stasis a positive retrogression droughted plots. 5 Natural fecundity contributed considerably inter-annual Annual strongly paralleled annual seedling establishment. relative other rates varied among transitions. 6 Synthesis. study illustrates sensitivity this species early season events precipitation. It suggests importance considering seasonal timing projecting population-level consequences global climate change, particular attention given triggers germination Researchers using create treatments should consider their warming effects.