ABSTRACT It is generally assumed that lizards are active whenever climatic conditions are favorable. Homonota uruguayensis (Vaz-Ferreira & Sierra de Soriano, 1961) is the only native gecko - and nocturnal lizard - living in the northern Pampa biome, and its ecology is poorly known. This study aimed at describing this species’ pattern of daily and annual activity and its relation with environmental temperatures. The study was conducted in the extreme south of Brazil (Rosário do Sul, State of Rio Grande do Sul), between May 2010 and January 2011 at a rocky outcrop located in the Pampa biome. The study was carried out in a total of four seasonal field trips, totalizing 1185 hours of field work. The data were collected, both during the day and the night in 6-hour shifts (duration of the sampling period). The area was randomly covered at each shift to record activity and microhabitat use by the lizards. In total 1541 specimens were recorded throughout the study. Homonota uruguayensis showed diurnal and nocturnal activity in the four seasons, with periods of daily activity varying significantly between all seasons in a cyclic and multimodal pattern, with no significant relation with environmental temperatures. There was no difference in activity related to sex and age classes. Most active lizards were found when air temperatures ranged from 14 °C to 32.9 °C (82% of active lizards) and substrate temperatures ranged from 10 °C to 32.9 °C (87% of active lizards).

RESUMEN La suposición general ha sido que los lagartos son activos cuando las condiciones climáticas son favorables. Homonota uruguayensis (Vaz-Ferreira & Sierra de Soriano, 1961) es la única lagartija nativa - y la lagartija nocturna - que vive en el norte de bioma Pampa. La ecología de esta especie es poco conocida y este estudio tuvo como objetivo describir su patrón de actividad diaria y anual y su relación con las temperaturas ambientales. El estudio se llevó a cabo en el extremo sur de Brasil (Rosário do Sul, Rio Grande do Sul), a partir de mayo 2010 - enero 2011, en un afloramiento rocoso situado en el bioma Pampa. El estudio totalizó cuatro excursiones de campo estacionales y 1185 horas. Los datos fueron recogidos a lo largo de los turnos de 6 horas durante el día y la noche. El área fue recorrida aleatoriamente en cada turno siempre registrandose la actividad y el microhabitat utilizado por los lagartos. A lo largo del estudio, 1541 especímenes se registraron. Homonota uruguayensis presentó hábito diurno y nocturno en las cuatro estaciones, con períodos de actividad diaria variando significativamente entre todas las estaciones en forma cíclica y multimodal, no se observó relación significativa con las temperaturas ambientales. No fue constatada diferencia entre los sexos con relación a la actividad y las clases de edad. La mayoría de los lagartos activos fue encontrada a temperaturas del aire que variaron de 14 °C a 32,9 °C (82% de lagartos activos) y a temperaturas del sustrato entre 10 °C y 32,9 °C (87% de lagartos activos).

ABSTRACT The use of traps is extremely important in several types of ecological studies, and may assist in the capture of individuals in areas that are difficult to access. In the present study, we compared the effectiveness of wooden (Schramm) versus "Tomahawk" traps to capture Salvator merianae (Duméril & Bibron, 1839) lizards. The study was conducted in Eldorado do Sul, Rio Grande do Sul, Brazil. Field data were collected from August 2013 to March 2015, during the reproductive period of the species. The study involved two types of baited traps: i) "Tomahawk", made of galvanized steel; and ii) Schramm, a wooden trap. The capture rate of the Schramm wooden traps was 1.63 individuals/day, and of the "Tomahawk" was 0.36 individuals/day. These results are important for researchers working with large lizards and may help to increase sampling efficiency for these organisms.

Microhabitat use by Cnemidophorus vacariensis Feltrim & Lema, 2000 as studied between October 2006 and September 2007 in two rocky formations in the municipality of Bom Jesus. The area was searched randomly between 8:00 am and 6:00 pm and the microhabitat used by the lizards was recorded. Our observations revealed that C. vacariensis has terrestrial habits and prefers open areas. Burrows are the main microhabitat used by the species (56.38%). When in activity, 54.76% of the individuals were observed under rocks, and 38.1% on the ground where herbaceous vegetation was present. The rocks under which they constructed their burrows were on average significantly thicker during warmer seasons temperatures (x¯ = 13,45cm) with respect to colder seasons (x¯ = 9,85cm). The rocks selected by the adults (x¯ = 12.94 cm) were on average significantly thicker than those selected by the juveniles (x¯ = 9.86cm). There were no statistically significant differences between sexes with respect to rock thickness.