Genetic monitoring of an endangered species : associations between population characteristics and environmental factors in a dioecious perennial plant

Understanding the genetic and ecological factors influencing population decline is essential for the conservation of threatened species. Our study species Antennaria dioica (L.) Gaertn. is a dioecious perennial with frequent clonal growth and has undergone significant population decline across much of Europe, making it a suitable model for studying genetic diversity and ecological interactions in declining species. This study combines over a decade of genetic monitoring with environmental data and herbarium specimens spanning up to 200 years. Field surveys in 2010 and 2022/2023 recorded population size, sex ratio, seedling percentage, vegetation height, bare soil cover, and soil depth. We analyzed genetic diversity and population structure using ddRAD sequencing on contemporary and historical samples and examined associations between population characteristics and environmental conditions. While overall genetic diversity in central Germany remained moderate, populations showed clear differentiation without strong large-scale spatial genetic structure. Populations sampled in 2010 and later classified as ‘potentially extinct’ or ‘still extant’ in 2022/2023 differed significantly in their genetic cluster composition, indicating long-term demographic and genetic shifts. Herbarium specimens revealed a male-biased sex ratio under drought conditions and a phenological shift likely driven by habitat loss rather than climate change. Our findings highlight the importance of population size and balanced sex ratios for the persistence of dioecious, partially clonal species and demonstrate the value of integrating genetic, historical, and ecological data for potential conservation.