EMERGENCE AND SURVIVAL OF BROMUS SETIFOLIUS SEEDLINGS IN DIFFERENT MICROSITES OF A PATAGONIAN ARID STEPPE

Abstract

ABSTRACT In a plant community of the arid steppe, structurally characterized by shrubs encircled by grasses and scattered tussocks with bare soil patches interspersed, the hypothesis of differential seedling survival in differentially protected microsites was tested. Seeds of Bromus setifolius were placed in the soil at two different depths and in two different microhabitats: leeward of a shrub and bare soil patch. No changes were recorded in the germination rate treatments. However, seadling survival under shrub protection was lower than in bare soil patches. Higher soil water potential in bare soil patches—probably due to smaller root biomass of established grasses—appeared to be the major determinant of the higher survival rate observed. A model based on seed density and seedling survival is proposed for seedling recruitment in relation to distance from the mother plant. The promotion of seedling establishment in the best suited microhabitats is visualized as a possible means of enhancing recovery of v...