The study was conducted at Sector 1 of the Serra da. Mesa reservoir, located in the upper Tocantins river basin, north of the state of Goias, in midwestern Brazil ...
Supporting Information Eloy de Amorim et al. 10.1073/pnas.1709080114 SI Methods Study Area. The study was conducted at Sector 1 of the Serra da Mesa reservoir, located in the upper Tocantins river basin, north of the state of Goias, in midwestern Brazil (13°50′S, 48°20′W) (Fig. S1). In October 1996, the dam was closed, flooding an area of ∼178,000 ha in a filling process that lasted for ∼2 y, creating the largest reservoir by water volume in Brazil. The area has an irregular topography, composed of several valleys that were flooded, leaving only the tops of hills above the water, which became isolated islands. The vegetation of these islands consists of cerrado sensu stricto and some patches of rocky cerrado. Herpetofaunal monitoring (Table S1) has been conducted since 1996 in the area (14). Over a 5-y monitoring period, lizard richness decreased due to the rapid extinction of one species, Ameiva ameiva. Ten years after the complete filling of the reservoir, five other species become apparently extirpated from the islands of Serra da Mesa—Cercosaura ocellata, Colobosaura modesta, Norops meridionalis, Norops brasiliensis, and Tropidurus montanus — and two of these species—C. ocellata and C. modesta—were also not found on the sampled mainland sites (16). Except for C. ocellata (a known spider eater; ref. 41) and C. modesta (feeding largely on spiders and orthopterans; ref. 42), all of the extinct species from the islands are larger than the study subject, G. amarali, and have termites in their diet: A. ameiva ranges from 34.2 to 126.0 mm SVL, and 75.41% of its diet is composed by Isoptera (43); N. meridionalis maximum SVL is 56.0 mm (44), and 16.83% of its diet was composed of Isoptera, with an importance value index (IVI) of 11.64 (45); N. brasiliensis maximum SVL is 69.0 mm, and 16.81% of its diet is Isoptera, with an IVI of 7.76 (46); T. montanus ranges from 30.5 to 98.0 mm in size (47), and 4.8% of its diet is Isoptera, present in 34.8% of the stomachs analyzed in the study (48). It is probable that these large lizards consumed larger termites, so their extinction may have increased the availability of such termites.
Eloy de Amorim et al. www.pnas.org/cgi/content/short/1709080114
Study Subjects. G. amarali is a Cerrado endemic gecko, charac-
teristic of rocky fields, but often found in termite nests, because termites comprise most of their diet (49). Individuals range from 20 to 55 mm in size. They are thermoconformers (49) and breed in the dry season, perhaps because it is the period of greatest termite availability (17). Field Procedures. We sampled five islands, as well as five mainland areas (Fig. S1), to test our hypotheses. Sampling was carried out for a total of 2 mo spread throughout July–October 2011. All sites had similar structural and microhabitat features for lizards— vegetation, termite nests, burrows, and other typical shelters. For lizard collection, we used the “exhaustive sampling squares” methodology, developed and described by R.A.B. In each of the 10 sites, we sampled a 2,500-m2 plot. The plot perimeters were enclosed by vertical barriers of plastic sheeting to prevent lizard escape and was surrounded by firebreaks. After enclosure, the area inside the plot was burned to remove the undergrowth and facilitate the search for lizards. All precautions were taken to prevent fire from spreading to areas outside the plot. It is important to note that the flora and fauna of the Cerrado biome are adapted to the natural regime of fires (50). In previous situations in which this method was used (15, 16), no animal was found burned, and fire did not spread to other areas. The study area was inspected thoroughly in search of lizards just after fire, and all shelters were carefully checked. All lizards found were handcaught, counted, weighed, and measured before being euthanized. After 2 h of inspection without finding additional lizards, we assumed that all individuals in the area were captured, and the enclosure was taken down. All of the animals collected were deposited in the Herpetological Collection of the University of Brasília, Department of Zoology.
1 of 2
Fig. S1. Serra da Mesa hydroelectric power plant reservoir study sites. M1, M2, M3, M4, and M5 are the mainland sites, and I34, I35, I37, I38, and IX are the island sites.
Table S1. Lizard species sampled in 1996, 2001, and 2011 at Sector 1 of the Serra da Mesa reservoir, municipality of Minacu, Goias, Brazil
Taxa Teiidae A. ameiva Ameivulla ocellifera Salvator merianae Tupinambis quadrilineatus Gymnophthalmidae C. ocellata C. modesta Micrablepharus maximiliani Tropiduridae Tropidurus cf. montanus Tropidurus oreadicus Tropidurus torquatus* Hoplocercidae Hoplocercus spinosus* Iguanidae Iguana iguana Polychrotidae N. meridionalis N. brasiliensis* Polychrus acutirostris* Mabuyidae Copeoglossum nigropunctatum Notomabuya frenata Phyllodactylidae G. amarali Sphaerodactylidae Coleodactylus brachystoma Total richness
I34 I35 I37 I38 Mean size, mm 1996 2001 2011 1996 2001 2011 1996 2001 2011 1996 2001 2011 148.1 50.2 284.2 204.3 40.7 42 31.6 58.8 60.2 101 88.6 352.9 46 61 102 84.5 65.7 48.5 2.22 8
9
2
9
7
4
6
8
6
6
8
6
*Species that were not registered on the islands, but were found at Sector 1 of the Serra da Mesa reservoir area.
Eloy de Amorim et al. www.pnas.org/cgi/content/short/1709080114
2 of 2
