Stripes, strands or stipples: modelling the influence of three landscape banding patterns on resource capture and productivity in semi-arid woodlands, Australia

In the semi-arid open woodlands or savannas of eastern Australia banded veg etation is a common form of landscape patchiness. This banding can form rel atively long strands or shorter stripes across the landscape, or small patc hes can occur in a stippled pattern. In degraded areas these patches can be completely removed from the landscape. This study addresses two related qu estions: does the type of patchiness (strands, stripes, or stipples) signif icantly influence how efficiently these semi-arid landscapes capture and st ore scarce soil resources; and how does this efficiency compare with landsc apes that have lost all their patches? Results from a landscape simulation model, validated for a semi-arid woodland study site, demonstrated that the loss of landscape patchiness had the greatest influence on the capacity of the landscape to capture rainfall as soil water-reduced by about 25% compa red to banded landscapes. This 25% loss of soil water reduced annual net pr imary productivity in these systems by about 40%. Banded patterns (stripes or strands) captured about 8% more rainfall as soil water than a stippled p attern; this increased their plant production by about 10%. However, these differences between banding patterns were relatively small compared to the impact of totally eliminating patchiness, which can occur with severe land degradation. This implies that preventing the loss of landscape patchiness is very important for managing savannas for production and conservation goa ls. (C) 1999 Elsevier Science B,V. All rights reserved.