Microsite Requirements for Germination and Establishment of Three Grass Species

Abstract

The safe sites, i. e., microsite requirements for germination and establishment, were partially characterized for three of the dominant grass species of the Edwards Plateau of central Texas, Aristida longiseta, Bouteloua rigidiseta and Stipa leucotricha. Seeds were germinated and grown in field-collected soil in a greenhouse under different watering regimes and in soil-filled benches with various soil surfaces and with adult plants. Both watering regime and microsite type strongly affected germination and establishment. Litter and rocks, but not the proximity of an adult plant, increased germination, survival and growth. A safe site for these species appears to be a microsite that prevents desiccation. Differences among the species in the relative favorableness of different types of microsites were slight. Species differed more in the timing of germination. Since the timing of rainfall and of temperature fluctuations varies considerably between years in central Texas, different cohorts of seedlings, and hence different species, may be successful in different years.