Recovery of Basalt Substrate for Xeric Scrub Restoration in a Lava Field in Mexico City

Abstract

The alteration of biophysical conditions in cities limits restoration and management of ecosystems in urban areas. The Pedregal de San Angel Ecological Reserve (PSAER) protects important remnants of a unique type of xeric scrub in a lava field embedded in Mexico City. Unearthing and replacing basalt rock have been carried out in PSAER to recover rocky basalt substrate, a physical feature in this type of location, in areas where it has been removed or buried and invading species have become predominant. To obtain an overview of the recovery of the plant community following restoration actions, we sampled and compared vegetation structure in terms of species richness, composition, relative coverage and diversity in 12 sites of PSAER: five conserved areas, three restored areas, and four disturbed areas. Restored areas presented intermediate values with respect to those in conserved and disturbed areas for total and non-ruderal native species richness, Simpson dominance index, and relative cover of non-ruderal and exotic species. Our results show that replacing and unearthing rock are still insufficient but are promising methods to promote restoration of this xeric scrub and similar plant communities that develop on lava fields.