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Question: Temperate grasslands are known for their high plant diversity and distinct seasonality. However, their intra‐annual community dynamics are still largely overlooked by ecologists. Therefore, we explored the seasonal alpha‐ and beta‐diversity patterns of vascular plants and their relationships to above‐ground biomass in a rocky steppe (Festucion valesiacae). Location: Pavlov Hills, SE Czech Republic. Methods: For one year, we monitored the plant community of the rocky steppe at monthly intervals in 42 permanent plots of 0.25 m2. We examined seasonal changes in above‐ground biomass (estimated from the cover and height of living plant parts) and seasonal beta‐diversity, which we partitioned into turnover and nestedness components and their quantitative counterparts: balanced changes and abundance gradients. Results: We identified a pronounced seasonal pattern of above‐ground biomass, species richness and composition. Total above‐ground biomass was highest in June (summer), with a peak representing only 60% of total annual production (sum of individual species' maxima). However, the observed peak in species richness occurred in March (early spring), with 80% of the total species number recorded throughout the year. Accordingly, nestedness and abundance gradient patterns differed in the spring months, while seasonal turnover and balanced changes in abundance were generally congruent. Annual, short‐lived, and perennial species exhibited different seasonal patterns of species richness and biomass production, although a sharp increase in biomass and a peak in species richness in spring were universal across the community. Conclusions: Seasonal climatic constraints on plant growth are key determinants of primary production dynamics. Plants adapt to these constraints by adjusting their life cycles in different ways. In dry grasslands, the complexity of plant responses to climatic seasonality can result in seasonal beta‐diversity patterns with divergent peaks in biomass and species richness. [ABSTRACT FROM AUTHOR]

Question: Infrequent events of extreme drought or extreme temperatures may considerably affect the structure and functioning of vegetation. Here we investigate how fluctuations in precipitation and temperature shape year‐to‐year dynamics and plant species composition in a dry grassland community, and how this variation affects plants with different life histories. Location: Dry grassland (Festucion valesiacae) in the Pavlov Hills, SE Czech Republic. Methods: Long‐term trends in vegetation change in the grassland studied were assessed by the ordination of plot records from vegetation surveys performed between 1930 and 2019. In addition, year‐to‐year changes in vegetation were studied in seven permanent plots of 16 m2 surveyed annually from 1993 to 2018. Variation in species composition and abundances was related to temperature and precipitation in the preceeding two springs, summers, autumns and winters using ordinations and mixed‐effect linear models. Results: There were no remarkable directional changes in the grassland community over the period 1930–2019. However, during the last 25 years, the community exhibited pronounced year‐to‐year fluctuations, which depended on weather conditions in the previous two years. Species with different life histories (e.g. perennials vs. annuals) and different ecology (e.g. ruderal vs. dry‐grassland species) responded differently to specific weather patterns. Perennials were sustained by wet summers, annuals benefitted from wet springs and autumns and moderately warm and wet winters, and covers of ruderals of mixed life histories increased after dry summers. Conclusions: Plant species composition in a Central European dry grassland shows remarkable year‐to‐year dynamics in response to weather patterns over the previous two years. These community changes are non‐directional and contribute to the stability of this grassland, which has not changed considerably over the past 90 years. However, increasing frequency of drought events because of ongoing climate change can result in a directional change with an expansion of ruderal species. [ABSTRACT FROM AUTHOR]