Quantifying human pressure
We quantified human pressure using the human footprint index (HFP),
calculated for each year in each river site
(https://wcshumanfootprint.org/map/; Venter et al. 2016). Due to
insufficient available data, the 2020 and 2021 HFP was not used. The HFP
incorporates into a cumulative index eight single human pressures: (1)
built environments, (2) crop land, (3) pasture land, (4) human density,
(5) nighttime lights, (6) railways, (7) roads and (8) navigable
waterways (Venter et al. 2016). This index ranges between 0 and 50 (the
cumulative sum of all eight individual human pressures), and the higher
the HFP, the higher the human pressure. A full explanation of the HFP
calculation is provided in the Supplementary Material .