DOI: 10.5061/dryad.b2rbnzsk7
title: Compositional shifts of alpine plant communities across the High Andes

description: Aim: Climate change is transforming mountain summit plant communities
 worldwide, but we know little about such changes in the High Andes.
 Understanding large-scale patterns of vegetation changes across the Andes,
 and the factors driving these changes, is fundamental to predicting the
 effects of global warming. We assessed trends in vegetation cover, species
 richness (SR) and community-level thermal niches (CTN) and tested whether
 they are explained by summits’ climatic conditions and soil temperature
 trends. Location: High Andes Time period: Between 2011/2012 and 2017/2019
 Major taxa studied: Vascular plants Methods: Using permanent vegetation
 plots placed on 45 mountain summits and soil temperature loggers situated
 along a ~6,800 km N-S gradient, we measured species and their percentage
 cover and estimated CTN in two surveys (intervals between 5-8 years). We
 then estimated the annual rate of changes for the three variables and used
 generalized linear models to assess their relationship with rates of
 change in the locally recorded soil temperatures, annual precipitation,
 and the minimum air temperatures of each summit. Results: Over time, there
 was an average loss of vegetation cover (mean = -0.26 %/yr), and a gain in
 SR across summits (mean = 0.38 species m2/yr), but most summits had
 significant increases in SR and vegetation cover. Changes in SR were
 positively related to minimum air temperature and soil temperature rate of
 change. Most plant communities experienced shifts in their composition by
 including greater abundances of species with broader thermal niches and
 higher optima. However, the measured changes in soil temperature did not
 explain the observed changes in CTN. Main conclusions: High-Andean
 vegetation is changing in cover and SR and is shifting towards species
 with wider thermal niche breadths. The weak relationship with soil
 temperature trends could have resulted from the short study period that
 only marginally captures changes in vegetation through time.
description: The information reported here comes from two main sources: (1)
 Data collected on the field during vegetation surveys (between 2011/2012
 and 2017/2019) on permanent vegetation plots plus soil temperature
 collected in dataloggers installed on each research site across the Andes.
 (2) Species records obtained from GBIF, TROPICOS, La Paz herbarium (LPB)
 and ULA -Merida herbarium. These records represent species in the
 permanent plots during the first and second surveys.
description: (1) R-studio; (2) QGis For further
 information, users are advised to refer to the README document
 ("README_Dataset-compositional-changes_Andes.md") and the
 accompanying published article: Cuesta, F., Carilla, J., LLambí, L.D.,
 Muriel, P., Lencinas, M. V., Meneses R.I., Feeley, K., Pauli, H., Aguirre,
 N., Beck, S., Bernardi, A., Cuello, Duchicela, S. A., Eguiguren, P.,
 Gamez, L.E., Halloy, S., Hudson, L., Jaramillo, R., Peri, P.L., Ramírez,
 L. A., Rosero-Añazco, P., Thompson N., Yager, K., Tovar, C.  Compositional
 shifts of alpine plant communities across the high Andes. Global Ecology
 and Biogeography. Accepted. DOI: 10.1111/geb.13721