THE NURSE OBJECTS AS SHELTER AND NUTRIENTS SOURCE: REFLECTIONS ON CACTACEAE ESTABLISHMENT AND RESTORATION IN ARID ZONES BELONGING TO THE ANDEAN WESTERN SLOPES

In this scientific note I analyze two new paradigms in the Cactaceae recruitment and establishment. The first one is related to the facilitation effect given by nurse objects (rocks) compared with nurse plants, which could be enhanced in places where fog deposition and dew formation are highly frequent phenomena. The trophic biology of the rock-colonizing cactus is the second paradigm. Recent studies have discovered and isolated bacteria living into (endophytic) and outside (in the rhizoplane) cactus roots which are responsible for rock weathering and nutrients release. Research on the hidden water gains driven by rocks and bacteria isolation and inoculation to cactus seedlings are very important topics in the endemic cactus populations' restoration and recovering plans in arid environments of the Andean western slopes.