Uso y selección de microhábitat en un ensamble de anuros del Chaco Serrano de Argentina

Abstract

Introduction: Research on spatial resource usage and partition strategies is important to understand the mechanisms of coexistence in sympatric amphibian species, even more when there are temporal variations in habitat availability. Objective: To learn about the patterns of microhabitat use, its seasonal variations and the possible influence of phylogeny on an anuran assembly of the Chaco Serrano in Argentina. Methods: Samplings were carried out in the Valle Fértil Natural Park protected area, Valle Fértil Department, San Juan, between 2012 and 2017. In the field, we recorded the microhabitat where each specimen was found, and we also measured site variables. In addition, microhabitats availability was determined. Data were analyzed using Manly’s selectivity index. Generalized linear models (GLM) were used to assess temporal variations in microhabitat use. Results: The species evaluated were: Rhinella arenarum arenarum, Leptodactylus latrans, Pleurodema tucumanum and Odontophrynus occidentalis. All species showed differences in usage frequencies: R. a. arenarum showed preferences for rocky and aquatic sites, P. tucumanum showed preferences towards bare soil and rocky sites, L. latrans and O. occidentalis showed greater preferences for rocky and aquatic sites. All species but Odontophrynus exhibited seasonal variations in microhabitat selection and usage. Odontophrynus occidentalis showed differences in usage proportions among microhabitats. Conclusions: This study shows plasticity in microhabitat usage as an important determinant of anuran spatial distribution, without apparent restrictions imposed by space competition or phylogeny. When species activity is coincident, the space resource may be distributed in a way that species overlap is reduced.

Composition, Microhabitat and Conservation of the Anurans Community in Lower Basin Temascatio River, Guanajuato

“…Although the species present varied adaptations to the environment, specifically to particular microhabitats in their ecological distribution, differentiation and plant heterogeneity are decisive in the selection of microhabitats by making them more varied, thus avoiding overlap between species (Urbina-Cardona, 2008;Luria-Manzo et al, 2019;Nieva-Cocilio et al, 2020). However, this did not occur in the present study, given the high overlap that occurred in several species, which shows that factors such as temperature also influence the selection of microhabitat and the distribution and association between species.…”

“…Given their physiological characteristics and moisture requirements, most of these species are limited to wet environments and seasons where food, optimum environmental conditions, and mating partners are available (Santos et al, 2008;Martínez-Baños et al, 2011;Leyte-Manrique et al, 2018;Luria-Manzano et al, 2019). Consequently, an understanding of ecological aspects that influence the distribution of anurans is important when it comes to their conservation, especially when species are found in seasonal habitats that drastically affect their characteristics such as abundance, sex proportion, and age classes (Conte and Machado, 2005;Cortés-Suárez, 2014;Vitt and Caldwell, 2014;Nieva-Cocilio et al, 2020).…”

Estructura de un ensamble de anuros del Chaco Serrano de Argentina

“…Además, se ha registrado que esta especie ocupa cuerpos de agua de manera oportunista para reproducirse, pero refleja una preferencia específica por sitios con suelo desnudo, que presentan menor inercia térmica que otros sustratos y por consiguiente su temperatura desciende con mayor rapidez durante la noche (Nieva Cocilio et al 2020). Por otro lado, Zug et al (2001) propusieron que individuos de pequeño tamaño o en estadios tempranos de desarrollo deben tener una temperatura corporal mayor que individuos más grandes, otra explicación congruente con nuestros resultados ya que P. tucumanum es la especie más pequeña del ensamble y los adultos poseen un tamaño corporal que no supera los 45 mm (Nieva Cocilio et al 2020). Los resultados de nuestro estudio concuerdan con Hamann y Kehr La influencia de las precipitaciones sobre P. tucumanum coincide con su aumento significativo de abundancia durante la estación de lluvias.…”

“…En este sentido, las variaciones detectadas en nuestro estudio podrían relacionarse con los eventos climatológicos sucedidos en febrero de 2014 (estación lluviosa), que presentaron altas precipitaciones (185,9 mm mensuales) y consecuentemente crecidas del caudal del río que arrasaron y modificaron considerablemente el hábitat. Este hecho, en consecuencia, afectó la abundancia y distribución de los anuros del ensamble, sobre todo a L. luctator que utiliza mayormente ambientes acuáticos (Nieva Cocilio et al 2020) y luego de estos eventos solo se hallaron siete individuos. No obstante, también es posible que las disminuciones en abundancia entre dos periodos sólo se deban a fluctuaciones corrientes de las poblaciones, sin implicar necesariamente una declinación poblacional a futuro (Pechmann y Wilbur 1994, Bustamante et al 2005).…”

Protozoa and Nematodes Infecting Odontophrynus occidentalis (Anura, Odontophrynidae) from the Monte Desert of Argentina

“…Odontophrynus occidentalis (Berg, 1896) is found in the provinces of Catamarca, La Rioja, San Juan, Mendoza, San Luis, Neuquén, La Pampa and Buenos Aires (Turazzini et al, 2016). Regarding the biology of the species, the advertisement call was studied by Salas & di Tada (1988), the diet is preferably composed of arthropods (Cocilio et al, 2020), and the thermal biology was studied by Sanabria et al (2012;. O. occidentalis is classifi ed as Least Concern (LC) by the IUCN (2023) and as Not Th reatened in the latest classifi cation of the conservation status of amphibians and reptiles of Argentina (Vaira et al, 2012).…”