Vertebrate Fauna Evaluation After Habitat Restoration in a Reserve within Mexico City

Little is known about how animals respond to restoration activities (Majer 2009). The presence of vertebrates has beneficial effects on restoration because they participate in processes that accelerate or influence the success of the restoration (Majer 1989, Tucker 2000). It is important to implement animal monitoring programs in order to effectively assess restoration outcomes.

The Pedregal de San Ángel ecological reserve (PSA), Mexico City, protects the xeric scrub community dominated by Pittocaulon praecox growing on a lava field. The PSA supports 32 protected species and 54 species endemic to Mexico (Lot and Cano-Santana 2009). However, the reserve is embedded within the city and suffers disturbances such as: fire, garbage, and introduced exotic species, both plants and animals (MacGregor-Fors et al. 2010). Since 2005, two sites located within buffer zones of the PSA have been subject to ecological restoration (A8 and A11). A8 (0.51 ha), is surrounded by buildings and soccer fields, and since 1974 to 2005 it had a steady accumulation of yard waste and garbage. The vegetation was dominated by Eucalyptus camaldulensis and Montanoa tomentosa. In 2005, eucalyptus plants were removed and native plants were introduced. During 21 restoration working days, done every two to three months since April 2005, volunteers dug up the basalt substrate and other exotic plants were removed. Also, two areas with piles of rocks (diameter of 2-3 m and 1.2 m height) were created as shelter. During this study, the vegetation height was on average 2.5 m, with 12 trees of E. camaldulensis reaching 10 to 20 m in height. At the other site, A11 (0.31 ha), removal of original vegetation occurred in January 2005, and basaltic substrate was covered for a parking lot; but, eventually the construction was canceled (Antonio-Garcés et al. 2009). For restoration at this site, a considerable amount of foreign material was removed and the zone was covered again with basaltic rocks. Dominant exotic plants were then removed by hand during 13 restoration working days, done every one to four months since October 2006 (Antonio-Garcés et al. 2009). During this study, the vegetation height was on average 2.0 m, with trees of Buddleia cordata reaching 2 to 4 m in height, which was the dominant plant. The reference zone (RZ; 0.29 ha) was located 15 m north of the A11 plot. The area had a diverse topography, with large cracks and areas with exposed large flat slabs of basaltic rock. This area was dominated by P. praecox, B. cordata, and E. camaldulensis (Antonio-Garcés et al. 2009, Villeda-Hernández 2010). At RZ, E. camaldulensis trees were 7 to 19 m height.

Table 1.

Similarity indices (IS_J) between vertebrate communities from two sites under ecological restoration (A8 and A11) and one reference zone (RZ) in the Pedregal de San Ángel ecological reserve, Mexico City, Mexico. Data from February 2009 to May 2010.

To assess the status of vertebrate fauna, we recorded species richness, composition, abundance, and diversity of vertebrate fauna (amphibians, reptiles, diurnal birds, and non-flying mammals) at A8 and A11 after five years of restoration activities, and compared these variables with those from RZ. We looked for amphibian and reptile species during slow random walks through and around the sites from 10:00 AM to 12:00 PM (which corresponded to the peak hours of diurnal bird activity; Gill 2007), between May 2009 and May 2010. Sampling occurred throughout the year with eight days of observations per site. We recorded the frequency of sightings during each visit. To determine the composition of bird species, we sampled from June 2009 to May 2010, once every 15 days through direct observations at each site. We recorded the frequency of sightings observed within each site. Small mammals were sampled every three months, from February 2009 to May 2010, to determine presence and abundance. We placed 16 Sherman traps on the ground at each site. We sampled during two consecutive nights each time near the...