The Effect of Landscape Structure on Primary Productivity in Source-Sink Systems

The objective of this study was to understand how landscape structure influences primary productivity in arid shrublands. We propose that analyzing spatial arrangement of shrub patches can help to restore degraded landscapes by indicating limiting factors to landscape productivity.Based on field data from a shrub land in the Northern Negev Desert, Israel, a computer model was developed to simulate the process of surface runoff generation and redistribution by two functional units: shrub patches acting as sinks and a matrix of crusted soil acting as source. Response variables are landscape productivity and water leakage. The model shows two different kinds of ecosystem behaviour: one where water availability limits productivity and one where productivity is not affected by water availability. Spatial arrangement of patches affects landscape productivity only in a water-limited system. We propose that analysis of spatial arrangement of shrub patches in arid shrublands can indicate whether the system is limited by water availability.