Vegetation Dynamics: Recruitment and Regeneration in Two-Phase Mosaics

Abstract

Banded landscapes are characterized by bands of dense perennial vegetation oriented parallel to the contour, separated by bare soil (Figures 1.1, 1.10, 1.12, this volume). They are widely distributed globally and have been studied in arid and semiarid climates of Sahelian Africa and the Middle East (White 1971; Wickens and Collier 1971), South Africa (van der Meulen and Morris 1979), Australia (Mabbutt and Fanning 1987; Tongway and Ludwig 1990), and North America (Cornet et al. 1992). (1971) defined the common characteristics apparently necessary for the existence of a banded vegetation spatial structure. These characteristics are now well known and include a semiarid climate and rainfall runoff as sheet-flow on gently inclined surfaces (chapter 1, this volume). Commonly, the band and interband zones have a similar soil type and texture but not always. For example, some banded landscapes are located on soils with swell/shrink gilgai patterns and dynamics (Dunkerley and Brown 1995; Macdonald, Melville, and White 1999). The most common vegetation association in the bands is a mixture of grass and shrubs and/or trees (Slatyer 1961; Montana, Lopez-Portillo, and Mauchamp 1990; Seghieri et al. 1997) but can be dominated by grass (Worral 1959), trees alone (Worral 1960), or chenopod shrubs (Macdonald, Melville, and White 1999).