Microclimatic modifications of cushion plants and their consequences for seedling survival of native and non-native herbaceous species in the high andes of central Chile

Abstract

Cushion plants are one of the most common growth forms in alpine habitats. Their low stature, dense canopy, and compact form allow them to decouple their microclimate from the surrounding environment, mitigating the effect of low temperatures and drought, enhancing the survival of other species. In this study, we evaluated the modifications on soil temperature and moisture over an entire growing season by two cushion species (Laretia acaulis and Azorella monantha) in alpine communities located at two different elevations in the central Chilean Andes. Additionally, we performed seedling survival experiments with two native herbaceous species (Hordeum comosum and Erigeron andicola) and the non-native forb Cerastium arvense to assess if seedling survival is higher within cushions than outside them. Our results indicated that cushions ameliorated extreme low and high substrate temperatures, improved soil moisture, and enhanced seedling survival of the three herbaceous plant species evaluated. Our results suggest that microclimatic modifications associated with cushion plants could be important for the establishment and survival of other plant species, both native and non-native, in the high alpine communities of central Chile.