The fate of páramo plant assemblages in the sky islands of the northern Andes - Appendix S1. Vegetation and occurrence data used in this study

Aims: Assessing climate change impacts on biodiversity is a main
scientific challenge, especially in the tropics, therefore, we predicted
the future of plant species and communities on the unique páramo sky
islands. We implemented the Spatially Explicit Species Assemblage
Modelling framework, by i) calculating species’ maximum dispersal
distance, ii) modelling species distributions at present up to 2100, iii)
assembling models into communities. Finally, we assessed the vulnerability
of sky islands based on richness and composition changes. Location:
Ecuadorian super-páramo (>4200 m) Methods: Using species trait
data, the maximum dispersal distance of 435 species was calculated.
Species distribution models (SDM) were fitted to obtain current and future
distribution predictions based on dispersal and bioclimatic factors. The
final assemblages for present and 2100 were achieved by stacking all
probabilistic SDMs and applying the probability ranking rule. The
vulnerability of each sky island was evaluated by quantifying richness and
composition changes. Results: Maximum dispersal distances ranged between
0.008-6027 m/year, and across all scenarios, 70% of models showed a net
loss in species distribution while 9% of all species were predicted to
undergo extinction by 2100. Local richness was estimated to decrease by
56.63% on average, and composition changes in each sky island suggested a
mean loss of 64.74% of their original species pool against a 12.97% gain.
Finally, 5% of the sky island floras reconverted from high-elevation to
low-elevation species. These numbers were usually more important for
high-elevation species and the mountains Pichincha, Ilinizas and Antisana.
Conclusions: Our study is methodologically pioneer and provides novel
insight on the future of páramo biodiversity. Significant losses in
species distribution and changes in community richness and composition
suggest drastic impacts and call for further study considering additional
factors, such as land-use. Finally, we recommend focusing monitoring and
conservation strategies on the northern sky islands in priority.