Occupancy and probability of detection of the introduced population of Eleutherodactylus coqui in Turrialba, Costa Rica

From Firenze University Press Journal: Acta Herpetologica

Jimmy Barrantes-Madrigal, Instituto Internacional en Conservación y Manejo de Vida Silvestre, Universidad Nacional

Manuel Spínola Parallada, Instituto Internacional en Conservación y Manejo de Vida Silvestre, Universidad Nacional

Gilbert Alvarado, Laboratorio de Patología Experimental y Comparada (LAPECOM), Escuela de Biología, Universidad de Costa Rica

Víctor J. Acosta-Chaves, Sede del Atlántico, Universidad de Costa Rica Sede Atlántico

The study of the factors that determine the establishment and dynamics of an exotic species in a new ecosystem is not only a vital component in the develop-ment of biological invasion management strategies, but it also provides important information for understand-ing the processes that take place in natural ecosystems (Jiménez-Valverde et al., 2011; Wan et al., 2019). In most scenarios the introduced species fail to establish or advance beyond the first stages of invasion (Zenni and Núñez, 2013). However, under the right conditions, these species can colonize and spread over large areas and ecosystems causing severe alterations (Mačić, 2018). Additionally, in some cases rapid evolutionary processes may occur that favor their adaptation to new conditions (Whitney and Gabler, 2008; Carneiro and Lyko, 2020), where characteristics such as behavior, morphological and reproductive traits, and genetic variability of populations of introduced species may differ considerably with respect to the populations in their native range (O’Neill et al., 2018).

The Common coqui frog (Eleutherodactylus coqui, Thomas 1966) is a species native from Puerto Rico with a long history as an invasive species (Lowe et al., 2004). In its native habitat E. coqui is one of the most abundant amphibians, and it can be found from the forest floor to the canopy, inhabiting almost all environments (Joglar, 1998). It breeds throughout the year (Townsend and Stewart, 1994). Neonates take 8 to 9 months to become sexually mature (Towsend and Steward, 1994) and lays on average 4–6 clutches of eggs per year, each containing 16–41 eggs per clutch (Towsend and Stewart, 1994). Eggs are generally deposited in covered sites that pro-vide protection from rain and environmental conditions (Townsend, 1989; Beard and Pitt, 2012). Egg develop-ment is direct (Towsend and Steward, 1985) and hatch after 14–17 days (Towsend and Steward, 1994). This anuran was introduced to the Hawaiian archi-pelago in the late 1980s, where in less than 10 years it had spread throughout an extensive area of the archipelago (Kraus and Campbell, 2002). As in Puerto Rico, E. coqui populations in Hawaii are abundant; it has been reported population densities of up to 91000 individuals per hectare at the archipelago, a number three times higher than the estimates reported in Puerto Rico (Beard et al., 2008). These extreme densities have caused not only ecosystem alterations such as changes in the inver-tebrate community (Choi and Beard, 2012), alteration in the nutrient cycle and herbivory regimes (Sin et al., 2008), but also social and economic effects due to noise pollution produced by their constant vocalizations and the measures required for its control (Beard et al., 2009).In Costa Rica, the Common coqui frog was intro-duced around 1998 into the city of Turrialba (García-Rod-ríguez et al., 2010; Barrantes-Madrigal et al., 2019). Unlike its invasion process in Hawaii, in the Cartago Province it has been kept restricted to a few localities for almost two decades: Turrialba and Juan Viñas (Barrantes-Madrigal et al., 2019). Although Barrantes-Madrigal et al. (2019) provided an update of the invasion status of the species in Costa Rica, since then have been observed few individu-als in San Antonio de Escazú (San José Province) (https://www.inaturalist.org/observations/48536340). To continue research on this topic is relevant to understand why this population survived in Turrialba, and what implications could it has with the years across the country.Although there is much information in the literature about the ecology of E. coqui, this information comes mainly from islands (Puerto Rico and Hawaii) where the ecological conditions are different from the continental neotropical context found in Costa Rica. The objective of this work is to determine the habitat selection of the Common coqui frog (Eleutherodactylus coqui) population introduced in the town of Turrialba to identify habitat variables that favor its occupation. We predicted that the vegetation structure and the availability of breeding sites would play a relevant role in the selection of the micro-habitat of this frog as it has been in its native (Townsend, 1989) and exotic range (Beard et al., 2003). This research is relevant to understand why this population survived in Turrialba, and what implications could it has with the years across the country.

DOI: https://doi.org/10.36253/a_h-13209

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