The role of bromeliad architecture and abiotic factors in occupation by anurans

Abstract

Bromeliads are excellent models for the study of biological communities, as their structural complexity simulates highly heterogeneous environments. The present study explored the effect of the structural complexity of terrestrial bromeliads as a refuge site, as well as the influence of macro-spatial variables on the abundance of anurans in the Caatinga biome. This study was carried out in the municipality of Paulo Afonso, state of Bahia, northeast of Brazil, where two sites with a high abundance of bromeliads of the species Aechmea aquilega were selected. The sites were visited twice a month, in a total of 15 visits. The survey of the presence and abundance of anurans in the interior of the plants was performed visually. Bromeliads with anurans inside had their height, leaf number and internal temperature (intrinsic variables) measured. Air temperature, air humidity and precipitation (extrinsic variables) were also measured. Principal Component Analysis and Multiple Regression Model were used to identify the influence of these variables on the abundance of anurans in the interior of the plants. A total of 147 anurans, distributed among the Bufonidae and Hylidae families, were found, with an average of 1.3 individuals per bromeliad and 9.8 individuals per visit. The internal temperature of the bromeliads was 1.6ºC lower than air temperature, however, the intrinsic and extrinsic variables did not have an effect on the abundance of anurans. Anurans preferably used large bromeliads, with 78.2% of individuals using bromeliads taller than 60 cm. The results suggested that the biotic and abiotic factors discussed did not significantly influence the use of bromeliads by anurans. Additional studies addressing other aspects of the structural complexity of bromeliads and environmental factors are necessary to better understand the use of these plants by anurans in the Caatinga biome.

Key words: amphibians, community structure, refuge site, semi-arid, intrinsic and extrinsic variables, hydric stress.