Oenothera or not Oenothera? Managing sandy coastal systems is the secret

Invasive alien plant species are considered a major cause of global biodiversity loss, especially when interacting with other global drivers of change such as habitat loss and climate change.

Predicting the likelihood of establishment and invasion of alien species, identifying the factors responsible for spatiotemporal patterns of invasion and quantifying their relative importance are essential elements for risk assessment and adaptive management of invasive alien plant species.

The work carried out by the University Cà Foscari, REDUNE partner, aimed at predicting the probability of establishment and successful invasion of Oenothera stucchii Soldano, a neophyte invasive species belonging to the Oenothera subsection. Oenothera, in xerophilous grasslands of grey dunes.

Three sampling sites on the Venetian coast were chosen for this study: Vallevecchia, the Laguna del Mort and the Cavallino Peninsula. At the sampling sites, xerophilous grey dune grasslands develop inland of the shifting dunes and occupy the portion of the coastal zone ranging from approximately 20 to 80 m from the sea.

Based on fine-scale field data, the authors described the mechanisms determining the spatial patterns of occurrence and abundance of O. stucchii in coastal dunes and provided a quantitative estimate of the most susceptible areas of grey dune habitats prone to invasion by O. stucchii, combining proximity to beach accesses (less than 50 m), low resident vegetation cover (<40%), high number of annual species (10 species) and low embryonic and mobile dune crests (<5.5 m).

These results provide useful suggestions that can be used to plan appropriate measures to prevent the establishment and spread of O. stucchii in sandy coastal systems. These should include the regulation of beach accesses, which should be planned at a distance of at least 200 m from each other, to secure areas sufficiently distant from beach accesses with a high probability of O. stucchii absence, and the closure of unauthorised paths that jeopardise the regulation of beach access. Measures limiting human trampling in dune systems need to be supported by stakeholders, but have proven effective in allowing the plant community to recover even in a short period of time. The resilience of xerophilous grasslands in the grey dunes could also be improved by filling vegetation gaps with new plantations of native perennial species to increase biotic resilience. Perennial species permanently occupy the site and form stable communities over time, thus reducing niche vacancies.

This developed model can also be applied to closely related congeners species included in the subsection. Oenothera, which shares similar biological and ecological traits.




Using fine-scale field data modelling for planning the management of invasions of Oenothera stucchii in coastal dune systems.

Gabriella Buffa, Carlo Gaetan , Stefano Piccoli , Silvia Del Vecchio , Edy Fantinato

Ecological Indicators 125 (2021) 107564