How do ephemeral factors shape recreation along the urban river? A social media perspective.

• We implement the landscape mosaic model to describe UBS recreation diversity. • We investigate seasonal patterns of riverine activity among Instagram users. • Both ecological and social ephemerals explain recreational demand for UBS. • The social-ecological mosaic shapes seasonal patterns of use intensity. • Intensity of visits to more natural areas does not depend on ephemeral phenomena. Urban Blue Spaces provide multiple benefits to city dwellers and, therefore, are a key element in the social-ecological system. To responsibly maximise these benefits, it is necessary to link data and knowledge on the social and ecological functions of the urban ecosystem. This paper aims to identify recreational use intensity patterns of urban riverfronts along the Vistula river in Warsaw, Poland. The landscape mosaic model was used to identify differences along the urban core–periphery axis, and explore disparities induced by the variety of riverfront functions. Recreational demand for the river was assessed by measuring the daily activity of Instagram users in 2019. The short-term perspective we applied allowed us to examine the role of several ephemeral factors on the variability of use intensity. Our results indicate that both the position along the core–periphery axis, and the social-ecological characteristics of urban riverfronts can shape seasonal patterns of use intensity. Overall, Instagram users concentrate their activity in the city centre. Seasonal fluctuations are found across the mosaic of Warsaw's riverscape, due to both its ecological (level of naturalness) and social (recreation versus 'entertainment machine') functions. Ephemeral factors shape recreational patterns in various ways: (1) fine weather attracts Instagram users more than unfavourable conditions discourage them; (2) demand for 'pure' riverine nature is independent of all of the proposed factors; and (3) the relationship between air quality and use intensity is weak. [ABSTRACT FROM AUTHOR]