Citation: Chmiel, J. Cultural Landscape as Both a Threat and an Opportunity to Preserve a High Conservation Value of Vascular Flora: A Case Study. Diversity 2023, 15, 211. https://doi.org/10.3390/d15020211 Academic Editors: Raúl Romero-Calcerrada and Mario A. Pagnotta Received: 30 November 2022 Revised: 30 January 2023 Accepted: 31 January 2023 Published: 2 February 2023 Copyright: © 2023 by the author. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). diversity Article Cultural Landscape as Both a Threat and an Opportunity to Preserve a High Conservation Value of Vascular Flora: A Case Study Julian Chmiel Department of Systematic and Environmental Botany, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Pozna ´ nskiego 6, 61-614 Pozna ´ n, Poland; chmielju@amu.edu.pl Abstract: This study aimed to show the influence of cultural landscape structure on species richnes- sand 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 Goplo Millennium Park (Nadgopla ´ nski Park Tysi ˛ aclecia) 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 (Wfj and Wfi), mean coefficient of conservatism (C), and floristic quality index (FQI). 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 Wfi and mean coefficient of conservatism C). According to the algorithm of FQI, 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. Keywords: cultural landscape; land cover structure; land use structure; flora; species richness; biodiversity; conservation value; natural resource management 1. Introduction At early stages of civilization, all forms of human impact on the natural environment were selective, spatially limited, and did not affect its potential for regeneration. Currently, however, the use of natural resources is a decisive factor influencing landscape structure and determining the possibility of existence of plant species and communities [1]. Changes in land use structure, generating transformations of landscape elements, will be key factors of global biodiversity change by the year 2100 [2]. Relations concerning landscape structure, habitat preferences, and species richness have been studied by many researchers [3]. So far, studies have concerned, primarily, effects of farming on patterns of plant species richness in relation to a broad spectrum of patchy rural cultural landscape [4–8] or some of its elements, e.g., meadows and pastures [9–12], linear marginal habitats or forest islands in the agricultural landscape [13–16], and aquatic habitats located between fields [17]. The spatial scope of analyses varies widely: from the continental scale [18] to a local one, limited to small areas [19–21]. In some studies, special attention was paid to relations between alien species richness and structure of land use Diversity 2023, 15, 211. https://doi.org/10.3390/d15020211 https://www.mdpi.com/journal/diversity