Experimental evidence for potential beneficial effects of fallen timber in forests

Reductions in habitat complexity have been linked with declines of numerous species around the world. In forests and woodlands, fallen timber has been systematically and in many places completely stripped, leaving forest floors bereft of an important structural element. While there are many correlative studies linking woody debris to species richness and the occurrence of certain taxa, there are few compelling experimental data to provide support for the causality of these relationships. We report on the rapid response of a near-threatened, wood-dependent species of Australian bird, the Brown Treecreeper Climacteris picumnus, to a meso-scale experiment conducted in a floodplain forest of the Murray River in southeastern Australia. Some 1000 Mg of wood were redistributed after one year's prior monitoring to effect eight treatments in 34 1-ha plots. We show that Brown Treecreeper densities increased substantially in all treatments with wood loads ≥40 Mg/ha, which is about twice the basin-wide average for floodplains of the southern Murray-Darling Basin. While we have no related information on reproductive performance of the birds, we contend that these results provide important management guidance for restoring wood loads for these floodplain forests.