Response of Shrubland Birds to Regenerating Clearcut Area and Shape

Conservation of birds that breed in early-successional forests will require an understanding of their response to patch size and shape during the early seral stages following disturbance. We modeled the effects of patch area, patch shape, and time period following harvest on territory densities of 5 shrubland bird species and bird community composition in 36 clearcuts from 1997 to 2014 in the Missouri Ozarks, USA. Our best-supported models indicated that densities of indigo bunting (Passerina cyanea), yellow-breasted chat (Icteria virens), and prairie warbler (Setophaga discolor) declined from the early time period (1–7 years post-harvest) to the late time period (12–18 years post-harvest), regardless of clearcut area or shape. Yellow-breasted chat density and bird species richness were positively related to clearcut shape complexity. Bird species richness increased, and bird species density decreased with clearcut area during both time periods. Non-metric multidimensional scaling indicated that bird community composition was strongly related to time since harvest. Within the spatial scale of our study, successional stage is more influential than clearcut size and shape, and some bird species may benefit from relatively small or irregularly shaped clearcuts.