Erstaunliche Vielfalt in einem unscheinbaren Lebensraum: die Pflasterfugen-Flora der Stadt Zürich
Krüsi, B.O.; (2012). Erstaunliche Vielfalt in einem unscheinbaren Lebensraum: die Pflasterfugen-Flora der Stadt Zürich. Vierteljahrsschrift der Naturforschenden Gesellschaft in Zürich, 157,, (3/4). 59-72. Peer reviewed.
Surprising diversity in an inconspicuous habitat: the flora of pavement gaps in the city of Zurich, Switzerland
On city streets, plants growing in pavement gaps usually remain unnoticed or are considered "weeds". On public places in the City of Zürich, we studied 100 plots, each 1 m2 in size, and discovered an astonishing floristic diversity. On the whole, we found 213 vascular plant species, 173 on the 100 plots themselves. Out of the 213 species 28 are on the Red List for the Eastern Central Plateau, two as "endangered (EN)", 15 as "vulnerable (VU)" and 11 as “near threatened (NT)”. 27 of the 100 plots studied contained at least one Red List species. On average, we recorded 7.5 vascular plant species per square meter. With 13.6 species per square meter (maximum 15) the greatest floristic diversity was found on areas covered with grass pavers. Regarding invasive neophytes, five species from the Black List and three from the Watch List were found. Since they were present on 11% of the plots only and with low cover they do not present any major hazard. In conclusion, the spontaneous flora of pavement gaps is surprisingly rich and encompasses a considerable number of rare and endangered species. And, it is both easy and cheap to foster this flora, for instance, by (i) reducing cleaning, (ii) refraining from filling cobble stone gaps with concrete and (iii) using grass pavers instead of asphalt e.g. on parking lots and tramway tracks.