PARENT SESSION
Tuesday, August 8, 5:00-6:30 pm
Poster Session 12 - Plant population and reproductive ecology
Exhibit Hall, Ballroom Level, Cook Convention Center

Facilitation via seed germination on alpine plant species of the high Andes of central Chile.

Chacón, Paulina^{*,1, 2}, Cavieres, Lohengrin^{1, 2}, ¹ Universidad de Concepción, Concepción² Instituo de Ecología y Biodiversidad, Santiago

ABSTRACT- It has been reported that nurse plant species are important for the maintenance of diversity in stressful environments such as high mountains. We have observed many alpine plant species growing on high elevation cushion plants in the Andes of central Chile (33°S). Nevertheless, it is not clear if this pattern is determined by differential seed germination. We predict that some species will germinate better within cushions due to the favourable microhabitat conditions provided by these plant species. At two elevations (2800 and 3200 m.a.s.l.) in the Andes of central Chile, we registered seed germination using seeds of different alpine species that were sowed on two cushions species, Laretia acaulis (Apiaceae) and Azorella monantha (Apiaceae), and in open areas adjacent to the cushions. At 2800 m where only the species L. acaulis grows, we found that some species only germinated within this cushion plant (e.g., Madia sativa) while others germinated only or preferment in open areas (e.g., Phacelia secunda and Chaetanthera euphrasioides). Although, we did not found significant differences, a greater proportion of total seeds germinated in the soil. At 3200 m where the two cushions plants exist, we found the most of the species studied germinated in greater number on A. monantha, while few seeds did on L. acaulis and open areas adjacent to the cushions plants. In synthesis, cushion nurse species provide a favourable habitat for seed germination of some alpine species in the physiologically stressful environments of the semi-arid Mediterranean-type climate Andes of central Chile through facilitation during the first phases of the plant life cycle.

Key words: cushion plants, Andes of Central Chile, facilitation