Effect of predation and solar exposure on the emergence and survival of desert seedlings of contrasting life-forms

We evaluated the effect of solar exposure and predation on seedlings of six species of three life-forms. Columnar succulents and arborescent semi-succulents emerged faster under shrubs (24 and 55 days) than in open places (44 and 60 days). Succulents had a longer survival time (138 days) without predators and under shrubs. Predator exclusion led to a longer survival in semi-succulents under shrubs (237 days) and in open places (198 days). Predation did not affect the survival time of shrubs. Our results extend to the seedling stage, the hypothesis that in desert environments, each life-form adopts different strategies for survival and growth. (C) 2003 Elsevier Ltd. All rights reserved.