National Park or Cultural Landscape Preservation? What the Soil Seed Bank Reveals for Plant Diversity Conservation

National parks play an important role in the conservation of biodiversity, mainly excluding human influence following the IUCN approach. However, in Europe, they are often characterized by a high percentage of traditional cultural landscape elements, which require active management. This calls into question whether the national park protection strategy is always appropriate. Here, we follow this question by taking the soil seed bank of various habitats of the Asinara National Park (Sardinia, Italy) as an example. Asinara is a suitable model region, as the island mainly consists of traditional cultural landscape elements, but the main conservation goals include afforestation plans and nature development promotion, which creates a trade-off between the conservation of forest vs. cultural landscapes. We investigated the soil seed bank, standing vegetation, and environmental factors in different cultural and natural habitats. Since the highest species richness and diversity were revealed for cultural vegetation units, they need to be of primary concern regarding the preservation of the island’s phytodiversity. Given the main objective of the conservation of biodiversity in the Asinara National Park, we conclude that a biosphere reserve with an adapted sustainable land-use management might be more suitable than a national park to account for both natural and cultural landscape preservation. This conclusion applies to many other European national parks.