Gardens as drivers of native plant species dispersal and conservation

Abstract

Gardens hold untapped potential for participatory biodiversity conservation. Conservation gardening has recently emerged as a way to foster declining native plant species in urban and rural green spaces. But the impact of cultivating these species on population trends in the broader landscape remains underexplored. This study examines the effects of cultivating herbaceous native plants on their long‐term population trends and endangerment, using Rothmaler's ‘Herbaceous Ornamental and Crop Plants’ in Germany, along with the German Red List of 1998 and 2018. It investigates whether native plants under cultivation are less endangered, examines the long‐term population trends relative to cultivation frequency and assesses the potential role of cultivation in improving Red List status. The findings reveal that cultivated species, especially those commonly grown in gardens, were less likely to be endangered. Moreover, commonly cultivated species had fewer declining and more positive long‐term population trends compared to non‐cultivated species. Some evidence suggests that commonly cultivated plants recorded on the 1998 Red List as threatened are more likely to improve their status, yet still a considerable proportion is in decline. These findings hint at a promising role of gardens as a means to support native species populations, but they also underscore the need for a nuanced understanding of which species are most likely to benefit from cultivation. Read the free Plain Language Summary for this article on the Journal blog.