Canebrake and Associated Forest Structure Influence Avifauna Occurrence

Past restoration of hardwood forests prioritized planting of woody vegetation cover, particularly oaks (Quercus spp.). This restoration regime often did not consider other microhabitat components, which failed to restore habitat complexity. Giant cane (Arundinaria gigantea (Walter) Muhl.) was an important microhabitat feature for creating a dense understory structure within the hardwood forest landscape. Many bird species are associated with stands of giant cane (canebrakes) for food, cover, and nesting ground. The decline of canebrakes may reduce nesting and foraging habitat, negatively impacting bird communities. Here, we used a hierarchical multi-species occupancy model to assess how giant cane and its associated overstory forest structure influenced breeding bird occupancy in southern Illinois. Bird surveys were conducted from May to July 2022–2024 at 100 site-years using passive acoustic monitoring. Responses to the vegetation structure (tree density and size) and canebrakes varied among species and nesting guilds (overstory, understory, and ground). Occurrence probabilities of 54% of the bird species increased with the presence of canebrake. We did not find any significant relationships between bird occupancy and vegetation structure and canebrake characteristics. Overall, maintaining a hardwood forest stand with a heterogeneous canopy cover would create variations in light environments, allowing canebrakes to benefit bird species across nesting guilds.