Variación espacial y temporal de la herpetofauna en ecosistemas de sabanas inundables de la Orinoquía-Colombia

Abstract

EcologíaVariación espacial y temporal de la herpetofauna en ecosistemas de sabanas inundables de la Orinoquía-Colombia RESUMENSe comparó la diversidad de anfibios y reptiles en bosques de vega, de galería y sabanas y entre las épocas seca y de lluvias en ecosistemas de sabanas inundables. Se realizó un muestreo en tres sitios en cada época climática, mediante los métodos de encuentro visual y trampas de caída con barreras de interceptación. El esfuerzo de muestreo para cada cobertura fue de 252 horas de recorridos y 504 horas de trampas de caída. Se registraron 23 especies de anuros y 37 especies de reptiles: 10 serpientes, 13 lagartos, un anfisbénido, cuatro tortugas, y un cocodrilo. La mayoría son nuevos registros para la zona nororiental del departamento de Casanare. La mayor riqueza y abundancia se reportó en las sabanas. El clima no es una variable determinante en la riqueza, pero si en la abundancia de la herpetofauna. Las sabanas son de gran importancia para el mantenimiento de la estructura de los ensamblajes de herpetofauna a lo largo del ciclo anual, los bosques son zonas de refugios de diversidad durante el periodo de inundación.Palabras clave. Anfibios, bosques de ribera, diversidad, reptiles, sabanas neotropicales. ABSTRACTWe compared the diversity of amphibians and reptiles in forest of vega, gallery forest and savannas in flooded savannas ecosystems. One sampling was conducted at three sites in each climatic season, using visual methods and encounter barriers of interception with pitfall traps. Sampling effort for each type of vegetation was 252 hours, and 504 hours of pitfall traps. A total of 23 species of anurans and 37 species of reptiles (ten snakes, thirteen lizards, one worm lizard, four turtles and one crocodilian) were recorded. Most are new records for the northeastern region of Casanare department. The greatest richness and abundance of herpetofauna were found in savannas. The weather is not a determining variable in the richness but in the abundance of the herpetofauna. Savannas are very important for maintaining the structure of herpetofauna assemblages throughout the annual cycle, forests are areas of maintenance of diversity during the flood period.

Biotic Assessment Index Based on Anuran Species to Evaluate the Biotic Integrity of the Flooded Savannas Ecosystem From Pauto River Basin (Casanare-Colombia)

“…This climatic condition has acted as a strong selective pressure to the anuran ensembles that inhabit the flooded savannas. It has caused great changes of its richness, composition, and abundance between dry and wet seasons (Montoya et al, 2011;Angarita-Sierra, 2014;Blanco-Torres, 2017). For example, three out of five frog families present in this ecosystem (Leptodactylidae, Bufonidae and Microhylidae) contain the highest species abundance and are composed by species with opportunistic life traits, semi-fossorial habits, low water dependence, and wide habitat preference such as Leptodactylus fuscus (Schneider, 1799), Leptodactylus fragilis (Brocchi, 1877), Rhinella beebei (Gallardo, 1965;Dixon & Staton, 1976;Duellman & Trueb, 1994;Tárano, 2010).…”

“…The main assumption that supports the IBIA is the closed ecological relationship between the anuran assemblage and the natural vegetation of the flooded savannas (Angarita-Sierra, 2014, Pedroza-Banda et al, 2014, Blanco-Torres et al, 2017. The IBIA has been developed in a similar way as Shulse et al (2009) and Waringer et al (2005) as follows.…”

“…Currently, the amphibian diversity of the flooded savannas is represented by 26 species of anurans and one caecilian Siphonops annulatus (Mikan, 1820), but the knowledge of their distributions is still limited (Pedroza-Banda et al, 2014, Rangel-Ch, 2014. According with Angarita-Sierra (2014) and Blanco-Torres et al (2017) about 75% to 96.8% of the anuran assemblage biomass during dry and wet season is allocated at natural savannas and forests, as well as that the anuran assemblage inhabiting savannas are unlike from those that harbors the pastures areas or transformed grasslands for extensive livestock farming (Appendix, Table 8). In fact, during the dry season, the forests are keystone for the establishment and maintenance of anuran assemblages because they work as shelter that safeguards 96.8% of the anuran assemblage biomass (Cortés-Duque & Sánchez-Palomino, 2011, Angarita-Sierra, 2014Blanco-Torres et al, 2017).…”

“…According with Angarita-Sierra (2014) and Blanco-Torres et al (2017) about 75% to 96.8% of the anuran assemblage biomass during dry and wet season is allocated at natural savannas and forests, as well as that the anuran assemblage inhabiting savannas are unlike from those that harbors the pastures areas or transformed grasslands for extensive livestock farming (Appendix, Table 8). In fact, during the dry season, the forests are keystone for the establishment and maintenance of anuran assemblages because they work as shelter that safeguards 96.8% of the anuran assemblage biomass (Cortés-Duque & Sánchez-Palomino, 2011, Angarita-Sierra, 2014Blanco-Torres et al, 2017). Additionally, 70% of the species prefer the natural savanna and forest over any transformed vegetation (Angarita-Sierra, 2014).…”

Tadpoles Inhabiting Natural and Anthropogenic Temporary Water Bodies: Which Are the Environmental Factors that Affect the Diversity of the Assemblages?

“…In our study area (in the department of Casanare) 46 species of anurans have been reported, of which 28 breeds in lentic bodies of water (Pedroza-Banda et al, 2014). Also, the natural savannas have the greatest abundance and richness of anurans in the region (Blanco-Torres et al, 2017), but they are highly transformed by land-use changes for cattle ranching (Etter et al, 2008;Angarita-Sierra, 2014;Angarita-Sierra, 2021). We evaluated larval stage anuran assemblages inhabiting different bodies of water with the following objectives: 1) to determine the variation in species diversity between natural ponds (immersed in savannas or gallery forest) and anthropogenic puddles (immersed on roads or pastures); 2) to characterize temporal changes in environmental variables between bodies of water shaped by aquatic physicochemical variables, vegetation structure, land use management practices, and distance to landscape elements; and 3) to determine the relationship between changes in species diversity and the environmental variables.…”