Latitudinal and altitudinal patterns of plant community diversity on mountain summits across the tropical Andes

BECERRA, MARÍA T.; TUPAYACHI, ALFREDO; SAMANIEGO, NATALIA; JÁCOME, JORGE; GRAU, ALFREDO; CARILLA, JULIETA; HALLOY, STEPHAN; CUESTA, FRANCISCO; PAULI, HARALD; VIÑAS, PAUL; SUÁREZ-DUQUE, DAVID; JARAMILLO, RICARDO; GÁMEZ, LUIS E.; MENESES, ROSA ISELA; AGUIRRE, NIKOLAY; MURIEL, PRISCILLA; GOSLING, WILLIAM D.; YAGER, KARINA; THOMPSON, NATALI; RAMÍREZ, LIREY; IRAZÁBAL, JAVIER; CUELLO, SOLEDAD; BECK, STEPHAN; LLAMBÍ, LUIS DANIEL

ECOGRAPHY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2017 vol. 40 p. 1381 - 1394

0906-7590

Te high tropical Andes host one of the richest alpine floras of the world, with exceptionally high levels of endemismand turnover rates. Yet, little is known about the patterns and processes that structure altitudinal and latitudinal variationin plant community diversity. Herein we present the first continental-scale comparative study of plant communitydiversity on summits of the tropical Andes. Data were obtained from 792 permanent vegetation plots (1 m2) within50 summits, distributed along a 4200 km transect; summit elevations ranged between 3220 and 5498 m a.s.l. We analyzedthe plant community data to assess: 1) differences in species abundance patterns in summits across the region, 2) the roleof geographic distance in explaining floristic similarity and 3) the importance of altitudinal and latitudinal environmentalgradients in explaining plant community composition and richness. On the basis of species abundance patterns, our summitcommunities were separated into two major groups: Puna and Páramo. Floristic similarity declined with increasinggeographic distance between study-sites, the correlation being stronger in the more insular Páramo than in the Puna (correspondingto higher species turnover rates within the Páramo). Ordination analysis (CCA) showed that precipitation, maximumtemperature and rock cover were the strongest predictors of community similarity across all summits. Generalizedlinear model (GLM) quasi-Poisson regression indicated that across all summits species richness increased with maximumair temperature and above-ground necromass and decreased on summits where scree was the dominant substrate. Ourresults point to different environmental variables as key factors for explaining vertical and latitudinal species turnover andspecies richness patterns on high Andean summits, offering a powerful tool to detect contrasting latitudinal and altitudinaleffects of climate change across the tropical Andes.