“Branching” with woody debris as a multipurpose restoration tool in an overgrazed arid landscape

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The restoration of arid landscapes impacted by historical overgrazing can be complex and may require active, multifaceted interventions, particularly where an ecosystem has shifted to an alternate state. Woody debris is naturally present in many ecosystems, enhancing ecosystem function, and its addition is used as a restoration intervention in overgrazed landscapes to restore ecological function. We applied 13,500 m2 of structurally complex coarse woody debris made up of leaves, branches, and twigs (known as “branching”) across 15 sites within three different vegetation communities of varying degradation (erosion scalds, chenopod shrublands, and black box woodlands) in a semiarid floodplain in southern Australia. Using a Before/After, Control/Impact design, we quantified the impact of branching on vegetation cover and composition and small reptile and mammal abundance and richness for 4 years after treatment application. We found that branching facilitated the recovery of vegetation, most effectively on erosion scalds, the most degraded vegetation community, with a 20% increase in cover and more than triple the plant species richness. In black box woodlands, plant species richness more than doubled in branched plots. Reptile abundance and richness increased in branched plots but only 4 years after application, and mammals were not strongly associated with the addition of woody debris. Our study provides experimental evidence for the use of complex woody debris as a multipurpose restoration tool to facilitate vegetation recovery and provide habitat for small vertebrates. This technique is effective in drylands, where active restoration interventions are risky and prone to failure.