A null model for assessing the cover-independent role of bare soil connectivity as indicator of dryland functioning and dynamics

•We provide null-model expressions for the bare-soil connectivity index, Flowlength.•Bare-soil connectivity exhibits a non-linear inverse dependence on vegetation cover.•The models provided allow disentangling vegetation cover and pattern functional roles.•Deviations from the null-models may serve as early warning of dryland degradation.