Landscape drivers and spatial scale predict epiphyte biodiversity across human-modified landscapes.

The study was located in the departments of Cundinamarca, Boyacá, Meta, and Santander, in the Colombian eastern cordillera (Fig. 1 and Fig. S1). We sampled 23 landscapes of Andean forests across a wide elevational range (1163-3415 m) with mean cloud cover of 82% (25-90%; Wilson &amp; Jetz 2016), temperature ranging 7-28 ℃ and annual precipitation of 891-3711 mm per year. Landscapes were composed of Andean forests (Andino and Altoandino; Etter et al. 2021) with discrete boundaries surrounded by a predominantly pastureland matrix. Forests were selected to ensure that we sampled the full range of the elevational gradient in the study region. <br> Surveys were conducted from January to November 2019. Within each local landscape, we sampled between two and 18 sampling plots of 10 X 30 m (n= 167 plots in total). Sampling plots were located between 150 and 600 m apart. We recorded all individuals on standing tree trunks, fallen tree trunks and branches, vines, lianas, leaves on standing trees or herbaceous plants, palm trees, tree ferns, and cycads in the understory (50-200 cm above-ground without soil contact). Forest structure was highly variable with average tree density of 38.8 trees per plot (8-100 trees per plot) and basal area of average 14.1 cm2 (5 - 52 cm2), and we also detected recent events of selective logging. The number of species and adult individuals (i.e., ramets) were recorded, whilst younger stages were not included due to a large uncertainty in species identification. Ramets usually comprised various individual stems, but for our purpose, a ramet only counts as one single individual spatially separated from another set of stems of the same or another species or an empty space (Sanford, 1968). Adult plants were defined as all large individuals (within the observed variation in the local population) with evidence of developed floral or reproductive structure, large ramets, many stems per stand, and a prominent root system. Identification to species or morphospecies was conducted following specialized literature and consultancy with local experts at the Herbarium VALLE!. Orchid species with no flowers were taken to nurseries in the vicinity of the sampled plots, and later visited for identification. All dubious individuals and juveniles were ignored due to uncertainty in their taxonomical rank.