Trait-based mechanisms of understory fine-scalespecies persistence in Tilio-Carpinetum stands of the Bialowieza Forest under differentmanagement regimes.

Plant communities are characterized by continuous fine-scale dynamics, and traitbased approaches can help us explore ecological mechanisms behind such dynamics. The issue of species persistence is of crucial importance to understand the complexity of vegetation dynamics in forest ecosystems and to predict future shifts in species composition and functional relationships of understory communities as a result of climate changes and management activities. This study aims at exploring which functional traits are correlated with the fine-scale species persistence in the understory of Tilio-Carpinteum stands of the Białowieża Forest along a timespan of twenty years. The vegetation surveys were performed both in and outside the Białowieża National Park, in ten 20x10 m plots representing three types of management regimes: (1) long-lasting preservation of natural forest, (2) preservation of pioneering stands spontaneously emerged on the abandoned clearcuts, (3) growth of planted stands. The sampled stands were subject to four surveys over the period 1997−2018. Each plot was divided into 200 pixels 1x1 m, for each of which abundance of vascular plant species, pH of the uppermost soil layer and the canopy influence index were calculated. We selected a set of above- and belowground traits (e.g. specific leaf area, seed mass, clonal traits) reflecting different plant functions and we assigned to each species the relative attributes. Conditional inference trees were used to evaluate if specific traits are correlated with patterns of species persistence at a fine scale and if such correlations change across different site conditions depending on the degree of management. The results of this study will help us assess the effects of different management regimes on trait-based mechanisms of species persistence in the understory layer.