Drivers of genetic diversity in plant populations differ between semi-natural grassland types Authors and addresses of institutions

The conservation of genetic diversity requires a deeper understanding of the processes shaping intraspecific variation. In recent decades, numerous studies identified various drivers of genetic diversity. However, the interpretation of these drivers remains inconsistent, since their strength and balance may differ between species and habitats. Therefore, we analyzed potential drivers of genetic diversity in a comparative multispecies approach across different semi-natural grassland types. We used molecular markers to detect genetic diversity in populations of nine typical grassland plant species from dry calcareous grasslands, mesic hay meadows, and wet litter meadows in Central Europe. Additionally, we collected data on potential drivers of genetic diversity, which were assigned to four categories describing habitat age, landscape structure, habitat quality, and population size. Subsequently, we applied multiple linear regression models and variation partitioning analyses to identify the most influential drivers of genetic diversity in semi-natural grassland plant populations. Our study revealed clear differences in drivers of genetic diversity between grassland types. In calcareous grasslands genetic diversity depended almost completely on landscape structure. However, we identified habitat age and habitat quality as additional drivers in hay meadows, while population size was another driver in litter meadows. The strong variation in drivers of genetic diversity in hay and litter meadows can be ascribed to higher levels of environmental variation among these sites and due to their more recent origin than calcareous grassland sites. We conclude that different drivers of genetic diversity must be considered to maintain high levels of intraspecific diversity in different grassland types.

Automated summary

This study investigated the potential drivers of genetic diversity in different semi-natural grassland types, revealing clear differences in genetic diversity drivers between calcareous grasslands, hay meadows, and litter meadows. The results showed that landscape structure was the primary driver of genetic diversity in calcareous grasslands, while habitat age, habitat quality, and population size were additional drivers in hay meadows and litter meadows. The study concludes that maintaining high levels of intraspecific diversity in different grassland types requires considering different drivers of genetic diversity.