Do variations on a model of landscape function assist in interpreting the growth response of vegetation to rainfall in arid environments

Across nearly 100 sampling locations widely distributed within the and shrub-land of Western Australia, we demonstrated a general relationship between landscape function, primary productivity and rainfall-use efficiency. Sampling locations included landscapes that had been severely 'degraded' by more than 100 years of grazing, mainly by sheep. There was generally less phytomass and poorer rainfall-use efficiency on dysfunctional or degraded landscapes than on functional or non-degraded landscapes. Relationships were stronger at broader spatial scales of patch-mosaics than at the scale of individual patches and are likely to be more readily interpreted over decadal rather than yearly time-scales. A-priori assessment of landscape 'resilience' provided few insights into the capacity of landscapes to respond to rainfall. Contrary to expectations, herb mass increased on both resilient and non-resilient landscapes as proportional areas occupied by vegetated patches declined. (C) 2002 Academic Press.