The impact of shifts in precipitation and temperature during seed ripening on the germination dynamics of 23 meadow species

Weather fluctuations can influence germination dynamics and pose a threat to the conservation of lowland hay meadow species. This study aims to assess the effects of temperature and precipitation changes on the germination performance of 23 studied species, divided into two harvest periods (July and late September/early October) of a two-year collection (2022-2023). The study classifies these species based on shared germination characteristics and identifies key parameters influencing germination performance. Germination tests were conducted in Petri dishes at 20 °C for 16 hours (dark) and 30 °C for 8 hours (light), with a light intensity of 1000 lux. Quantitative (GC - germination capacity, FUS - fresh ungerminated seeds, and DS - dead seeds) and qualitative (t50 – the half of germination time, T. Index - Timson index) aspects were analysed using two-way ANOVA. Results revealed significant interactions between species and weather conditions across both collection periods. Wetter conditions increased GC and shortened t50 associated with reduced germination velocity in most species, while warmer and drier conditions prolonged t50 and increased DS share. Heatmap clustering revealed that several species, including Tragopogon pratensis, Dianthus deltoides, and Centaurea jacea, demonstrated stable germination performance, making these species promising candidates for restoration. The decision tree analysis identified the Timson index as the most influential parameter explaining GC. These findings demonstrate that understanding germination dynamics altered by climate change may aid conservation-oriented restoration efforts for local species, enabling the implementation of seed mixtures of introduced species and informed decisions on the optimal time for seed recruitment.