Azorella compacta: survival champions in extreme, high‐elevation environments

• Main Authors: Francisco I. Pugnaire, José A. Morillo, Cristina Armas, Susana Rodríguez‐Echeverría, Aurora Gaxiola
• Format: Article
• Language: English
• Published: Wiley 2020-02-01
• Series: Ecosphere
• Subjects: cushion plants; high‐elevation ecosystems; long‐lived plants; plant‐microbe interactions; Puna
• Online Access: https://doi.org/10.1002/ecs2.3031

Abstract Cushion plants are life forms with a hemispherical or mat‐like, prostrate canopy well adapted to the extreme conditions of cold regions that have appealed to scientists for their ability to cope with extreme environments in most mountains, arctic, and subantarctic regions of the world. They can buffer the effects of low temperature and drought and improve soil conditions, which makes them notable facilitator species. Living at the edge in the Atacama Desert is one such species, Azorella compacta (yareta or llareta), in the Apiaceae family that can reach much over 6 m (~20 ft) in diameter with a mat‐like shape that tends to hemispherical growth form. Azorella compacta can be found in the dry Puna system, which spreads from northern Chile and Argentina to southern Peru and western Bolivia, between 3800 and 5200 m elevation, making it one of the woody plant species occurring at highest elevations in the world. In this deserted edge of the Atacama, nutrient limitation adds to other stressors such as water scarcity and high UV radiation. A compact canopy and the fact that they are embedded in resin prevent beneficiary species from growing within the cushion and condition how senesced leaves decompose inside the canopy. They can reach 3000 yr old and have to deal with episodic disturbance and herbivory events. Plants in such environments may potentially act as microbial refuges, and it could be expected that bacterial endophytes and mycorrhizal fungi have a main role in the functioning of these survival champions.