Ecological restoration of an urban demolition site through introduction of native forb species

• Published in: Urban forestry & urban greening Vol. 47; p. 126509
• Main Authors: Schröder, Roland, Kiehl, Kathrin
• Format: Journal Article
• Language: English
• Published: Elsevier GmbH 01.01.2020
• Subjects: Invasive species; Novel ecosystems; Robina pseudoacacia; Urban green infrastructure; Urban restoration; Wasteland; Wasteland; Novel ecosystems; Invasive species; Urban green infrastructure; Robina pseudoacacia; Urban restoration
• ISSN: 1618-8667; 1610-8167
• DOI: 10.1016/j.ufug.2019.126509

•Introduction of two native forb seed mixtures resulted in high establishment rates.•We found ten spontaneously occurring plant species of conservation value, which were not affected by seeding.•Introduction of native forb species led to suppression of woody species and reduced dominance of perennial grasses.•Seeding reduced the frequency of an invasive non-native species. Urban brownfields can provide habitats for endangered native plant species but may also support invasive non-native species. The aim of our study was to develop and test different measures for the ecological restoration of an urban brownfield. We aimed to enhance native plant species richness by seeding two native forb seed mixtures containing 25 (HD-mixture) and 13 species (LD-mixture), respectively, without affecting spontaneously colonizing plant species of nature conservation value. Additionally, we tested the effects of species introduction and mowing on the establishment of invasive non-native plant species, woody species development, and perennial grass dominance. With establishment rates of 84% (HD) and 92% (LD) in the first study year and about 60% for both seed mixtures in the fourth year, species introduction was successful and led to rapid re-vegetation of the formerly bare brownfield. Although seeding did not result in increased species richness using either seed mixture, the dominance of perennial grasses was significantly reduced by the establishment of forb species from the HD-mixture. Overall, we observed the spontaneous establishment of ten plant species of conservation value; seeding affected these species only temporarily, in the second year. Seeding (with either seed mixture) and mowing both resulted in reduced cover of woody species and a lower frequency of the invasive non-native Robinia pseudoacacia. Our study demonstrated the high nature conservation value of dry and nutrient-poor urban brownfields for spontaneously occurring threatened plant species. Further studies have to evaluate if the reduced cover of grasses and woody species through introduction of site-specific native forb species might increase these sites’ aesthetic value and broader acceptance of brownfields by urban residents.