The impact of natural disturbances on bird assemblages in Białowieża Primeval Forest disappears within 35–45 years

Forest disturbances that create canopy openings play a crucial role in shaping the dynamics of European forests. Disturbance legacies are often thought to affect forest communities for decades or even centuries, but these predictions are rarely based on empirical evidence.

We assessed changes in bird assemblages in 50 wind‐created canopy gaps (0.06–14 ha; median = 0.8 ha) and 50 control sites in Białowieża Primeval Forest, Poland, one of the best‐preserved lowland temperate forests in Europe and an important reference for natural forest processes. The same locations were surveyed in 1988 (0–10 years since gap formation) and again in 2023 (35–45 years since formation).

In 1988, canopy gaps hosted bird assemblages distinct from controls (i.e. increased abundance of dunnock ( Prunella modularis ), Eurasian blackcap ( Sylvia atricapilla ) and common chiffchaff ( Phylloscopus collybita ) and reduced abundance of red‐breasted flycatcher ( Ficedula parva ) and wood warbler ( Phylloscopus sibilatrix )), with gap area strongly shaping these differences. By 2023, canopy cover had recovered in gaps, bird assemblages no longer differed between treatments, and initial gap size had no detectable effect. Some differences in forest structure between treatments persisted (e.g. tree species composition, canopy height).

Synthesis and applications . Our results indicate that some of the effects of natural disturbance events in primeval forest ecosystems may disappear faster than previously thought. This study highlights the resilience of the Białowieża Primeval Forest and suggests the inherent resilience of highly productive temperate forests shaped by natural disturbances. In addition, our results suggest that natural forests do not require human intervention to recover their canopy cover as well as their old‐growth‐associated bird diversity within several decades after a localized disturbance event. Although this recovery has been documented only for the forest canopy and a single taxon, it provides important support for efforts to restore natural processes in temperate forests, particularly through rewilding approaches with minimal human intervention.