Browsing by Author "Lobos, Gabriel"

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    A hybrid zone of two toad sister species, Rhinella atacamensis and R-arunco (Anura: Bufonidae), defined by a consistent altitudinal segregation in watersheds
    (2013) Correa, Claudio; Mendez, Marco A.; Araya, Sergio; Lobos, Gabriel; Eduardo Palma, R.
    Delimiting the spatial extension of a hybrid zone is essential to understand its historical origin and to identify the geographical and/or environmental factors which delimit it. Rhinella atacamensis and R. arunco are two sister species which together inhabit Chile between 25 degrees and 38 degrees S. Their distribution limits coincide at about 32 degrees S, where recently it was reported that they hybridize in a small watershed (Pupio creek). Although the genetic evidence suggests that these two species form a hybrid swarm, they are not mixed homogeneously in the entire watershed, but rather are spatially segregated: R. arunco is found in the lower part of the creek and R. atacamensis in the higher part. An extensive exploration north and south of 32 degrees S revealed other instances of hybridization, with the same pattern of spatial segregation within other watersheds. This study describes the hybrid zone combining mitochondrial sequences and nuclear AFLP markers. In the northern part, the hybrid zone is a narrow strip which crosses several watersheds and extends more than 130 km from NW-SE, so that R. atacamensis is found at higher altitudes towards the south. However, two points south of this strip show that the hybrid zone is more extensive and complex, and probably extends along the entire border of the mountain chains which form the watershed of the Aconcagua River (32 degrees 30' - 33 degrees S). We propose an explanation for the origin of this hybrid zone considering paleoclimatic and orographic information, and briefly discuss the taxonomic implications of these results.
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    Current threats faced by amphibian populations in the southern cone of South America
    (2022) Pablo Kacoliris, Federico; Berkunsky, Igor; Carlos Acosta, Juan; Acosta, Rodrigo; Gabriela Agostini, Maria; Sebastian Akmentins, Mauricio; Luz Arellano, Maria; Azat, Claudio; Carla Bach, Nadia; Mirta Blanco, Graciela; Calvo, Rodrigo; Charrier, Andres; Corbalan, Valeria; Correa, Claudio; Elena Cuello, Maria; Deutsch, Camila; Di-Pietro, Diego; Soledad Gaston, Maria; Gomez-Ales, Rodrigo; Kass, Camila; Kass, Nicolas; Lobos, Gabriel; Agustin Martinez, Tomas; Martinez-Aguirre, Tomas; Mora, Marta; Nieva-Cocilio, Rodrigo; Pastore, Hernan; Manuel Perez-Iglesias, Juan; Piaggio-Kokot, Lia; Rabanal, Felipe; Jesus Rodriguez-Munoz, Melina; Cecilia Sanchez, Laura; Tala, Charif; Ubeda, Carmen; Vaira, Marcos; Alicia Velasco, Melina; Vidal, Marcela; Daniel Williams, Jorge
    In this work, we update and increase knowledge on the severity and extent of threats affecting 57 populations of 46 amphibian species from Chile and Argentina in southern South America. We analyzed the intrinsic conser-vation problems that directly impact these populations. We shared a questionnaire among specialists on threats affecting target amphibian populations with information on i) range, ii) historical occurrence and abundance, iii) population trends, iv) local extinctions, v) threats, and vi) ongoing and necessary conservation/research. We assessed association patterns between reported threats and population trends using multiple correspondence analysis. Since 2010, 25 of 57 populations have declined, while 16 experienced local extinctions. These pop-ulations were affected by 81% of the threat categories analyzed, with those related to agricultural activities and/ or habitat modifications being the most frequently reported. Invasive species, emerging diseases, and activities related to grazing, ranching, or farming were the threats most associated with population declines. Low con-nectivity was the most frequent intrinsic conservation problem affecting 68% of the target populations, followed by low population numbers, affecting 60%. Ongoing monitoring activity was conducted in 32 (56%) populations and was the most frequent research activity. Threat mitigation was reported in 27 (47%) populations and was the most frequent ongoing management activity. We found that habitat management is ongoing in 5 (9%) pop-ulations. At least 44% of the amphibian populations surveyed in Chile and Argentina are declining. More in-formation related to the effect of management actions to restore habitats, recover populations, and eliminate threats such as invasive species is urgently needed to reverse the conservation crisis facing amphibians in this Neotropical region.
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    Invasive Pleurodema thaul from Robinson Crusoe Island: molecular identification of its geographic origin and comments on the phylogeographic structure of this species in mainland Chile
    (2008) Correa, Claudio; Lobos, Gabriel; Pastenes, Luis; Mendez, Marco A.
    Robinson Crusoe Island, located 670 kin west of the coast of central Chile, is characterized by a high number of endemic and introduced species of plants and animals. This island lacks native amphibians or reptiles, but Somewhat more than 30 years ago the toad Pleurodema thaul, native to continental Chile, was introduced. The coast of central Chile was identified as the geographic Source of the introduced population of Robinson Crusoe by means of phylogenetic analyses of mitochondrial sequences. These analyses also suggest a high degree of phylogeographic structure for this species in continental Chile.
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    Invasive African clawed frog Xenopus laevis in southern South America: key factors and predictions
    (2013) Lobos, Gabriel; Cattan, Pedro; Estades, Cristian; Jaksic, Fabian M.
    The African clawed frog Xenopus laevis is one of the most widely distributed amphibians in the world. It has invaded an area of approximately 21,200 km(2) since its naturalization in Chile in the early 1980s. Currently, there is scant knowledge on the factors and processes underlying its distributional pattern. We constructed a bioclimatic niche model considering areas susceptible to be invaded (coarse model). At a local scale, we explored topographic, ecological, and anthropic variables, to identify which of these have the greatest predictive power for the expansion of this African species in southern South America. Not surprisingly, the projection of the distribution of Xenopus laevis laevis in southern Africa had the highest probabilities associated with the mediterranean area of the Cape region. From the habitat projection on southern South America, we predict high habitat suitability for this species in the mediterranean region of Chile. Nonetheless, the coastal desert of northern Chile, the Atlantic coasts of Argentina (32 degrees to 54 degrees S), Uruguay, southern Brazil, the north-central part of Argentina (22 degrees to 35 degrees S) and the central-southern region of Bolivia, are potentially suitable as well. At a local scale, we confirm that lentic aquatic environments, with slow drainage and murky waters, highly connected, human-disturbed, and part of an irrigation system of small streams and canals, account for the highest probabilities of successful establishment of X. laevis within the area of invasion. Based on our habitat suitability models, we expect the African clawed frog to invade farther north and farther south in Chile. We warn that the pet trade and subsequent release of African clawed frog to the wild pose a serious invasion risk to other countries of the southern cone of South America.
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    Natural history notes of Telmatobius dankoi (Anura, Telmatobiidae), a critically endangered species from northern Chile
    (TAYLOR & FRANCIS LTD, 2016) Lobos, Gabriel; Rebolledo, Nicolas; Charrier, Andres; Rojas, Osvaldo
    Telmatobius dankoi is a species described from only one locality in the Atacama Desert in northern Chile and therefore is considered to be critically endangered. There has been no information on its biology or ecology since its original description in 1999. Here we provide information on its distribution, habitat, density, diet and threats. The habitat of this species is restricted to a single stream, where it is submitted to strong anthropic pressure. Its density suggests that it forms only a small population. The diet consisted mainly of benthic invertebrates. Telmatobius dankoi is thus one of the most threatened vertebrates of Chile.
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    Natural history of the Mocha Island ground frog Eupsophus insularis, a critically endangered species
    (2021) Lobos, Gabriel; Rebolledo, Nicolas; Charrier, Andres; Correa, Claudio; Rabanal, Felipe; Vidal, Marcela
    Eupsophus insularis inhabits a small island in the southeast Pacific, and its natural history is unknown. The species is listed as Critically Endangered based on its restricted distribution, i.e., an island under ongoing habitat deterioration. We assessed the distribution, habitat requirements, density, diet, and threats of the species with the aim of proposing strategies for its conservation. The species is restricted to a terrestrial strip 24-205 m above sea level associated with pristine temperate humid forests located in areas of low slope. A capture-recapture study indicated that its density was 15-66 individuals/ha of optimal habitat. Its diet is composed mainly of invertebrates of the humid forest floor. The high prevalence of chytrid fungus and habitat loss are important threats to the species. Herein, we present data to help with the management of the species on the island and that might help in designing more robust strategies to mitigate present and future threats.