Supplementary material 1 from: Henle K, Klenke RA, Barth MB, Grimm-Seyfarth A, Bowler DE (2025) Challenges and opportunities for assessing trends of amphibians with heterogeneous data – a call for better metadata reporting. Nature Conservation 58: 31-60. https://doi.org/10.3897/natureconservation.58.137848

Clustering of sites