One year after the first reintroduction of the Malinverni’s quillwort in the Ticino River Natural Park, Italy

Summary

Malinverni's quillwort is an aquatic fern relative confined to a small area of Italy's western Po Valley, where it depends on clean, low-nutrient lowland streams that have been degraded by fertilizer and herbicide runoff from surrounding rice farming and by mechanized channel maintenance. Surveys in 2007 to 2009 found the species surviving at just nine sites, and starting in 2008 researchers at the University of Pavia studied its population genetics, ecological needs and reproductive timing to inform what became the species' first ever reintroduction attempt. Genetic analysis of the nine wild populations found low variation between them, so plants raised for reintroduction deliberately crossed spores from different sites to maximize diversity. A spring-fed artificial channel inside the Ticino River Natural Park was restored and reshaped as the release site, and 20 individuals were planted there in spring 2016, followed by 20 more in spring 2017. Monthly monitoring found 18 percent mortality after the first year, mostly from sediment build-up on the plants, and while mature spores were confirmed ready for dispersal by autumn 2016, a survey the following spring found no second-generation sporelings downstream. A further 20 plants were added in early 2018 after the sediment problem was addressed. The project rates itself partially successful: the population survives and is being actively managed, but natural recruitment has not yet been confirmed.