ANURANS FROM BARRA DE LA LAGUNA DE ROCHA

— We present a list of amphibian species from the protected area Barra de la Laguna de Rocha (BLR), Uruguay. Fifteen monthly three-day field trips were conducted between September 2011 and March 2013. During each field trip, active searches of individuals and auditive samplings were performed at seven selected sites. We recorded 19 species of amphibians belonging to five families: Bufonidae (4 especies), Hylidae (5), Leptodactylidae (7), Microhylidae (1) and Odontophrynidae (2). Comparing these data with historical records (obtained from cientific collections and literature), eight species represented new records for the study site. The species richness in the area represents 39.6% of the total richness recorded for Uruguay. We highlight the presence of Melanophryniscus montevidensis (Philippi, 1902), a Critically Endangered (CR) species at national level, and globally Vulnerable (V). Information on BLR's amphibian species composition could help in the implementation of the management plan for this conservation unit, as well as to stimulate future studies in the area.


INTRODUCTION
Inventory and wildlife monitoring studies are basic and essential for planning conservation strategies in natural areas (Heyer et al., 1994;Maneyro & Carreira, 2006). Information on species richness is useful for directing conservation efforts, as it allows to define the current status of local populations through comparison with historical records (Bardier & Maneyro, 2015). Additionally, an inventory of species can be employed to establish conservation priorities within a specific area (Heyer et al., 1994).
Amphibian populations have suffered widespread declines and extinctions in recent decades. Currently, amphibians are the most threatened vertebrate group worldwide (Stuart et al., 2004(Stuart et al., , 2008Collins & Crump, 2009;IUCN, 2018). Due to their biological and physiological characteristics (e.g., ectotherm condition, permeable skin, biphasic life cycles; Wells, 2007), these animals are particularly vulnerable to habitat loss, changes in water and soil quality, and to potential impacts of climate change (Stuart et al., 2004(Stuart et al., , 2008Collins & Crump, 2009). Paisaje Protegido Laguna de Rocha is a protected area located in Southern Uruguay, being Barra de la Laguna de Rocha one of its conservation focal objects. Currently, there is no official inventory of the amphibian species from this area based on systematic samples. Previous reports (e.g., Maneyro et al., 1995;Núñez et al., 2004), mention records of some species for this locality and nearby areas. However, these data are scarce and do not come from systematized studies. Long-term field samplings become essential, in order to provide a complete and updated characterization of the amphibian fauna composition.
The aims of this study were to obtain the inventory of amphibian species occurring in the southern sector of this conservation unit (Rocha, Uruguay); to compare this inventory with the historical records available in scientific collections and literature; and to suggest which species may be priorities for conservation in the area. This study aims to contribute to the implementation of the management plan for this protected area, as well as to stimulate further studies in the BLR.

MATERIALS AND METHODS
The study was carried out at sites surrounding the southern coast of Laguna de Rocha, locally known as Barra de la Laguna de Rocha (BLR) (Rocha, Uruguay) (34°40'02"S; 54°14'00"W) (Fig.  1). Since 1976, this area is part of the biosphere reserve Bañados del Este, included in the UNESCO Man and Biosphere Program (MAB), due to its great biodiversity (Pezzani, 2007). The lagoon has a great touristic activity and its sandy environments represent really important habitats for amphibians (Maneyro    al., 1995). At moment, this area is part of Paisaje Protegido Laguna de Rocha (34°37′59″S,54°17′40″W), an area that belongs to the National System of Protected Areas (SNAP) (DINAMA, 2010). It exhibits a coastal sand dune system, located at the southern portion of the lagoon, these areas are the most critically endangered within the protected area, and require strict conservation measures. The dunes have associated flood prone meadows, with shallow temporary ponds (<30 cm deep) of variable sizes and sandy substrata. Amphibians use these ponds during the breeding activity. The high concentration of salt in the environment determines a halophyte vegetation cover (Trimble et al., 2003). The climate is subtropical, with an average annual temperature of 16.4 °C and an average annual accumulated rainfall of 1058.7 mm (Tutiempo Network, 2019).
In order to obtain the list of species in BLR, fifteen monthly three-day field trips were performed in September 2011, November 2011 and between March 2012 and February 2013. Seven sampling sites were selected (Fig. 1). These sites comprise the breeding water bodies and their surroundings. Individuals were sought at the selected sites through active visual search (Heyer et al., 1994), with a sampling effort of at least 3 hours per day. In addition, fifteen-minute acoustic samplings (Heyer et al., 1994) were performed at all sites throughout three monitoring shifts (morning: 08:00-13:00 h, afternoon: 14:00-19:00 h, evening: 20:00-24:00 h). Additionally, historical records of species for the study site were obtained from the literature (Maneyro et al., 1995;Núñez et al., 2004), and were complemented with those obtained from the review of the Colección Científica de la Facultad de Ciencias of the Universidad de la República (ZVCB). For taxonomical determination of observed specimens were used local field guides (Maneyro & Carreira, 2012), and acoustic records of known species were employed for comparisons.
Finally, the list of species obtained was compared with the historical records. The conservation status of the species was determined using as a main reference the national Red List (Carreira & Maneyro, 2015). Some specimens were photographed, and the photo vouchers were deposited at the Colección Fotográfica de la Facultad de Ciencias -Anfibios (CF-B). Also, some voucher specimens were collected and stored at Colección Científica de la Facultad de Ciencias of the Universidad de la República, for which, a collection license was issued by the national authority (División Fauna de la Dirección de Recursos Naturales Renovables of the Ministerio de Ganadería, Agricultura y Pesca). The specimens were euthanized in the field following the protocols approved by the Comisión Honoraria de Experimentación Animal associated with the project ANII FCE 2514.
Within the total recorded species, only Melanophryniscus montevidensis (Philippi, 1902) is threatened in Uruguay (Carreira and Maneyro, 2015). This species is cataloged as Vulnerable (VU) at global scale (Langone, 2004), whereas at the national level it is considered Critically Endangered (CR) (Carreira & Maneyro, 2015). It was observed in the study area during the diurnal and nocturnal samplings, associated with temporary ponds during different breeding events. Another species, Odontophrynus maisuma, is locally Near Threatened (NT) (Carreira & Maneyro, 2015), but due to its recent description, its conservation status has not been globally evaluated (IUCN, 2018). The remaining 17 species are considered as Least Concern (LC) for their conservation status, both locally and globally (IUCN, 2018, Carreira and (Table 1).

DISCUSSION
Currently there are 49 amphibian species inhabiting Uruguay (Maneyro & Carreira, 2012); and a large number are distributed throughout the coastal areas of the country (Maneyro and Carreira, 2006). The Rocha Department is known for its high diversity of amphibians (Maneyro et al., 1995), and it has the highest species richness in Uruguay (26 species) (Núñez et al., 2004). The amphibian richness found during this study (19 species) was similar in comparison to some localities within the Rocha Department. In the coastal locality of Aguas Dulces 20 species were recorded (González & Gambarotta, 2001), while from La Coronilla, Nuñez et al. (2004) reported 16 species, and more recently, Bardier and Maneyro (2015) enlisted 23 species in Cerro Verde (historical records of the area were included). Moreover, the number of species in the BLR exceeded the species richness found in Cabo Polonio (11 species) (López, 2006), and Laguna de Castillos (13 species) (Gambarotta et al., 1999). The amphibian species richness in BLR represents 39.6% of the total richness recorded for Uruguay, and 73.1% of the total species richness recorded for Rocha. Consequently, the study site could be considered as an area with a high diversity of amphibian species.
This study allows to expand the historical record of species for the area, since eight new species were found during the sampling period. These new records reflect an optimal sampling effort, since in this study the monitoring was carried out in the Tabla 1. Lista de especies de anuros de Barra de la Laguna de Rocha, Uruguay. A: registro auditivo; V: registro visual; Estatus en la UICN: estado de conservación de la UICN (UICN, 2018); Estado de NC: estado de conservación nacional (Carreira & Maneyro, 2015): CR: en peligro crítico; LC: Menor preocupación; NE: no evaluado; NT: Casi amenazado; VU: Vulnerable. * La especie no se puede distinguir de otros taxones simpátricos a través del registro auditivo. ** Los asteriscos indican posibles especies prioritarias para la conservación en Barra de la Laguna de Rocha.  (Carreira & Maneyro, 2015): CR: Critically endangered; LC: Least concern; NE: Not evaluated; NT: Near threatened; VU: Vulnerable. * The species cannot be distinguished from other sympatric taxa through the auditive record. ** Asterisks indicate potential prioritary species for conservation in Barra de la Laguna de Rocha.

Family/Species
Voucher number Recording method IUCN status NC status

Family Bufonidae
Melanophryniscus montevidensis (Philippi, 1902 long-term, covering all the seasons of the year, as well as the different times of the day, and combining acoustic and visual sampling. These two sampling methods were complementary and contributed to make the data collection more precise. This permitted us to differentiate between species that are often confused using only the auditive record, as is the case of Rhinella dorbignyi (Duméril & Bibron, 1841) and R. fernandezae (Gallardo, 1957); Physalaemus biligonigerus (Cope, 1861) and P. gracilis; Odontophrynus americanus (Duméril & Bibron, 1841) and O. maisuma.
Another aspect to be highlighted is that some samplings included periods with high levels of rainfall, which allowed us to register the presence of explosive-breeder species, whose reproductive activity is brief and occurs after heavy rainfalls (Wells, 2007). Some species with these characteristics in the study area are: Melanophryniscus montevidensis, Elachistocleis bicolor and Odontophrynus americanus. During the sampling period Pleurodema bibroni (Tschudi, 1838) was not recorded in BLR. This draws our attention as within the study area there are well preserved sites and geographically close records for this species (Kolenc et al., 2009(Kolenc et al., , 2012. Pleurodema bibroni is nationally  listed as near threatened (NT) (Carreira & Maneyro, 2015), and its populations have declined in recent years (Kolenc et al., 2009(Kolenc et al., , 2012, which leads us to think they may have disappeared from the study site. Melanophryniscus montevidensis should be considered  as a priority species for conservation in BLR. This species is restricted to the Uruguayan coasts and Brazil (Bernardo-Silva et al., 2012). It is critically endangered in Uruguay (Carreira & Maneyro, 2015), due to its drastic population decline, small extension of occurrence (less than 10 km2), habitat deterioration and the growing urbanization of the coastal areas, among others (Langone, 2004;Arrieta et al., 2013).
Additionally, the species is threatened by the consequences of climate change (Toranza & Maneyro, 2013;Zank et al., 2014). In the BLR the breeding activity of M. montevidensis occurs in shallow temporary water bodies with abundant emergent hydrophilic vegetation (Pereira & Maneyro, 2016a). This species also presents high fidelity to both breeding and shelter sites (mainly rushes and caraguatales near the breeding ponds) (Pereira & Maneyro, 2016b). This information is essential and should be considered in the implementation of the management plan for the area, given that the increasing urbanization of the coastal area and the habitat fragmentation are two of the main causes considered for the decrease in their populations (Carreira & Maneyro, 2015). This is the first inventory of amphibians from BLR and represents a new contribution for a better knowledge of the local herpetofauna. The study area proved to be of great potential importance for the preservation of amphibian populations because it has a great diversity, comparable with other localities of greater area within the Rocha department. It also highlights the presence of a threatened species at local and global scale. Paisaje Protegido Laguna de Rocha belongs to SNAP since 2010, and the management plan is being recently implemented. Considering this aspect, the information about the richness and species distribution is fundamental to propose long-term conservation measures with the aim of protecting the amphibian biodiversity in BLR.