Historical natural disturbances shape spruce primary forest structure and indirectly influence bird assemblage composition

Understanding the processes shaping composition of assemblages in response to disturbance events is crucial for preventing ongoing biodiversity loss forest ecosystems. However, studies responses typically analyze immediate or short-term impacts only, while relating long-term history assemblage dynamics are rare. To address this important knowledge gap, we used a dendroecological approach link natural 250 years (1750–2000) structural habitat elements and, turn, breeding bird assemblages. We data collected 2017 and 2018 from 58 permanent study plots within 10 primary spruce stands distributed across Western Carpathian Mountains Europe. This dataset contained counts environmental variables describing density, tree diameter distribution, height, microhabitats, deadwood quantity quality, regeneration. Bird were significantly influenced by structure which was turn shaped (disturbance frequency, time since last its severity). Early successional species associated with more open habitats positively disturbance-related (i.e. deadwood-related variables, canopy cover), some responded negatively. At same time, overall abundance, richness Shannon diversity remained unchanged under variable histories. Our results support view forests as highly dynamic ecosystem, harbouring populations at all stages succession despite significant changes shifting patch mosaics over due disturbances.