Full length paper

Temporal variation and size class distribution in a hepertological assemblage from Córdoba, Argentina

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Cuadernos de Herpetología 19 (1): 35-52, 2005 rmartori@exa.unrc.edu.ar

Abstract

From a conservationist perspective, knowledge of the abundance, diversity, and activity patterns of a herpetological assemblage is essential to understand community dynamics and habitat utilization. We proposed four null hypotheses regarding the dynamics of an assemblage of amphibians and reptiles from Argentina: 1) The capture frequency of each species studied is similar during the two years; 2) The capture frequency of each species is similar in every month of each period; 3) The activity of each species is similar to that of every other species and 4) The proportion of each size class for each species is similar throughout the year. During the study, nineteen species were collected: ten species of Amphibia belonging to four families, and nine species of Squamata, distributed among seven families. In relatively complex habitats, with dense vegetation and very irregular herpetological activity, the pitfall method is one of the few efficient ways to evaluate terrestrial animal activity. Pitfall traps are an effective method to perform herpetological inventories, but results must be reported with caution because traps capture some species more easily than others. The main results of this study were: Hypothesis 1 was rejected for all species except Mabuya dosivittata, which showed similar frequencies during both years. Hypothesis 2 was rejected, as all species showed significant seasonal differences. The most variable species were Bufo fernandezae and Odontophrynus americanus; the most constant was Pantodactylus schreibersi. Hypothesis 3 was rejected for all species; except Elachistochleis bicolor that showed a similar activity pattern as the assemblage. Hypothesis 4 was rejected, size groups of each species showed temporal variation due to recruitment and recruitment period varied in and between species. During the first period, the highest diversity index was registered in April 1999 (5.46). During the second year the highest diversity index recorded (6.85) was in January 2000. This study shows the importance of long-term studies for conservation purposes. It also emphasizes the importance of understanding variation of the phenologies of individual species and the variation of activity and diversity within assemblages between years.

Key words:

Amphibia; Squamata; Argentina; ensamble; clases etarias

Received: Nov. 04, 2004 ▪ Accepted: May. 11, 2005

Associate Editor: F. Cruz
Martori, R.; Aun, L.; Gallego, F. & Rozzi Giménez, C. 2005. Temporal variation and size class distribution in a hepertological assemblage from Córdoba, Argentina. Cuadernos de Herpetología 19: 35-52.