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Abstract

Warming and increased frequency of droughts caused by climate change can have significant impact on vegetation and restoration efforts. This study focuses on long-term climate (1995-2020) and vegetation data (1995-2019) from a sand grassland restoration experiment in Kiskunság National Park, Hungary, to investigate the effect of droughts on vegetation composition. Restoration interventions involved the removal of black locust stands (1994/1995) and regular mowing (1995-2001) at three sites. Vegetation data were analyzed according to two categorical types (role in restoration and carbon fixation pathway), focusing on four distinct groups: target, invasive, C3 and C4 plants. The findings of the study indicate that increasing temperatures and more frequent droughts can be expected at the sites and summer months can be severely affected by drought. Droughts lead to shifts in vegetation composition, promoting the dominance of invasive species indirectly and favoring C4 species directly over target and C3 species. Target species suffered indirect negative effects due to the invasion of alien plants that can better recover after drought events. Mowing generally favored target and C4 plants; however, mowed areas were more susceptible to invasion of alien species than control after drought. These findings shed light on the complex interactions between climate change, restoration intervention, and community dynamics of sand grasslands, emphasizing the need for further studies to find effective management strategies in the face of changing climatic conditions.