Effects of timing of emergence and microhabitat conditions on the seedling performance of a coastal Mediterranean plant

摘要

Seedling emergence is a critical stage in the life cycle of annual plants, especially in arid and semiarid Mediterranean ecosystems characterized by high environmental unpredictability. We examined whether the timing of seedling emergence is related to plant survival and fitness for Anchusa littorea (Boraginaceae), an annual plant growing in a Mediterranean coastal sand dune ecosystem of southwest Sardinia (Italy). Seedling emergence, survival, and fruit set was monitored during 4 y (2008-2011) in 25 plots distributed in 2 contrasting microhabitats. Emergence concentrated in late winter (February-March), with few plants emerging thereafter. Early emergence time increased plant life length and fitness. Microhabitat conditions did not influence seedling emergence, although higher survival and fitness occurred in more favourable habitats. Our study enabled us to characterize the patterns of recruitment in A. littorea by analyzing the most critical stages in its life cycle.