INVESTIGADORES
GAVINI Sabrina
capítulos de libros
Título:
Alpine plant diversity in temperate mountains of South America
Autor/es:
EZCURRA, CECILIA; GAVINI, SABRINA S.
Libro:
Encyclopedia of the World's Biomes
Editorial:
Elsevier
Referencias:
Lugar: Amsterdam; Año: 2020; p. 323 - 334
Resumen:
The temperate Andes are climatically, topographically and floristically very diverse. The dry temperate Andes (30°37°S) reach elevations > 5000 m and are arid or semiarid. The wet temperate Andes (37°55°S) rarely reach 3000 m elevation and receive higher annual precipitation. Although alpine vegetation of the temperate Andes is generally found in areas with growing season temperatures below 9°C, the effect of latitude and the north-to-south and east-to-west precipitation gradients result in differences in species composition and treeline elevation. Alpine areas of the dry temperate Andes are generally found above 3000 m and are bounded by xeric woods, matorral, and steppe. In contrast, the alpine areas of the wet temperate Andes are surrounded by Nothofagus forest or krummholz, and in this region, the treeline descends with latitude from ca. 2000 m in the north to ca. 500 m in the south. At the local scale, abiotic factors such as precipitation, elevation, aspect, and related temperature differences are the major determinants of floristic variation and species richness in alpine regions of the temperate Andes. On a larger scale, at different latitudes with different precipitation, species richness increases in the southernmost wettest sites. In all sites, the number of species is higher at intermediate elevations, with decreasing species richness toward the extremes. The higher levels of plant diversity at middle elevations are related principally to the effects of positive plant-plant interactions. Therefore, patterns of diversity in the high temperate Andes can be attributed to abiotic (mostly climatic) variables, but also to biotic interactions, for instance, owed to nursing cushion plants. Biotic interactions can play an important role as evolutionary drivers of alpine plant diversity, challenging the assumption that only large-scale abiotic phenomena such as climate, geomorphology and historical processes regulate alpine plant diversity.