Woody Plant Effects on Soil Seed Banks in a Central Texas Savanna

Abstract

Abstract We studied germinable seed banks in soil associated with grasslands, relatively young (<40 years) Juniperus ashei (Ashe juniper), and long-established Quercus virginiana var. fusiformis (plateau live oak) patches of woody plants in a central-Texas savanna to ascertain the degree to which Ashe juniper alters the seed bank of sites previously inhabited by grassland vegetation, and to assess how seed banks differ beneath two common types of patches associated with woody plants in this savanna ecosystem. Across all habitats and over an annual growth cycle, 3,364 seedlings representing 116 species emerged from these seed banks. Annual forbs were the dominant life form in all habitats (62% of seedlings). The fraction of perennial forb and graminoid seedlings was comparable (19 versus 18%, respectively), and seedlings of woody plants were rare. Density, diversity, and species composition of seed banks varied significantly among the three habitats. Seed banks in grassland and live oak were most dissimila...