Table 1 General characteristics of the study sites within the PSAER, Mexico City, accordingly with data of Estañol-Tecuatl & Cano-Santana [38], and Antonio-Garcés et al. [28]
Site | Years managed | Area | Disturbances | Restoration practices | Vegetation summary |
|---|---|---|---|---|---|
Conserved sites | Does not apply | Does not apply | Does noy apply | Does not apply | Plant community is characterized by native species, like Pittocaulon praecox, Echeveria gibbiflora, Dahlia coccinea and Muhlenbergia robusta. The mean plant richness is 48 spp. and, regarding to the relative coverage, only the 1.4% is characterized by exotic plants |
R1 | 8 | 0.225 ha | The area was affected during 2004 and 2005 by the partial construction of a parking lot, which included the elimination of the original vegetation and the basaltic rock, as well as the filling with sand and flattened of the exposed surface. The construction of the parking lot was later cancelled | The recovery of the original substrate by i) the extraction of the foreign material with a bulldozer, and ii) the addition of fragmented basalt rock, creating a gradient accordingly with their diameter (at the bottom, rocks of ≥ 1 m, then rocks of 50 cm and smaller rocks conformed the upper layer). iii) The removal of inorganic wastes. iv) The extraction of 13.8 m3 of different exotic plant species (C. clandestinus, Ricinus communis and Eucalyptus spp.) | Buddleja cordata (native) canopy with a coverture of 90%. Cissus verticillata (native) as dominant schrub in 34% of the area, and a herbaceous layer consistent mainly of Cenchrus clandestinus (exotic) with 55% of coverture, and D. coccinea (native) with 21% of coverture |
R2 | 8 | 0.52 ha | Accumulation of inorganic garbage and gardening debris from an adjacent soccer field from 1974 to 2005 The edges of this zone present leftovers of rubble originated from the maintenance of the buildings in the campus | i) The extraction by hand of 183.7 m3 of organic wastes, inorganic garbage and rubble. ii) The removal of the 83.7% of the eucalypt population by cutting them and leaving only the tree stump iii) The introduction of 1,079 seedlings of 10 native species, and approximately 53,000 seeds of Muhlenbergia robusta, a native species. iv) The control of the Mirabilis jalapa population by the extraction of their shoot and root systems by hand | B. cordata (native) and Schinus molle (exotic) canopy present in less of the 30% of the area. Montanoa tomentosa (native) as dominant schrub, but only in around 25% of the area. Herbaceous layer mainly of C. clandestinus (exotic) with around 60% of coverture |
R3 | 6 | 0.35 ha | Before this site was considered as a protected area, it was divided in two parts to allow the vehicle transit | i) To promote the natural growth of the native vegetation, the flattened area was covered by a 3 m thick layer of basalt rock | Canopy of B. cordata (native) with around 9% of coverture. Absence of dominant shrubs. Herbaceous layer consistent mainly of Wigandia urens (native) with around 40% of coverture and C. clandestinus with around 12% of coverture |
Disturbed sites | Does not apply | Does not apply | Extraction of basalt rock, accumulation of garbage and invasion of exotic species | Does not apply | The mean plant richness in these sites is 24 spp. On average, the 65.8% of their relative coverage is dominated by exotic species, mainly Eucalyptus camaldulensis and C. clandestinus, as well as the native species Tripogandra purpurascens |