Cultural Landscape as Both a Threat and an Opportunity to Preserve a High Conservation Value of Vascular Flora: A Case Study

This study aimed to show the influence of cultural landscape structure on species richnessand the conservation value of vascular flora.The analyses are based on 3201 original floristic lists (relevés) and 83,875 floristic data collected since 1994 within Gopło Millennium Park (Nadgoplański Park Tysiąclecia) in a rural area in central Poland. Descriptions of landscape composition in grid cells (0.5 km × 0.5 km) include land use structure, mean deviation of uneven proportions of various land use types, and Shannon index of diversity (H’). Vascular plant diversity was described using total species richness and contributions of groups of native and alien species. Assessment of floristic conservation value was based on qualitative and quantitative floristic index (<i>Wfj</i> and <i>Wfi</i>), mean coefficient of conservatism (<i>C</i>), and floristic quality index (<i>FQI</i>). Floristic analyses were conducted in relation to the whole study area and within grid cells, basing on numbers of species and number of floristic data. The results suggest that species richness in grid cells depends more strongly on diversity and evenness of contributions of land use types, irrespective of which land use types were present. Species richness is strongly dependent on land use structure. Larger contributions of arable fields and built-up areas are linked with a decrease in species richness of nonsynanthropic native plants and species of floristic conservation value. Regularity in this respect is very well illustrated by indices excluding the influence of species richness on floristic value (quantitative floristic index <i>Wfi</i> and mean coefficient of conservatism <i>C</i>). According to the algorithm of <i>FQI,</i> the most valuable floras are characterized by a large number of species with a high contribution of conservative ones. In the study area, this condition was met by floras of surface waters and wetlands.