Browsing by Autor "Noelia Gobel"

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A new species of the Phalloceros harpagos species complex (Cyprinodontiformes: Poeciliidae) from the middle and lower Uruguay River floodplains
(Fundación Miguel Lillo, 2025) Wilson S. Serra; Fabrizio Scarabino; Noelia Gobel; Gabriel Laufer
Phalloceros mimbi sp. nov. is described from specimens collected in the floodplains of the middle and lower Uruguay River in Uruguay (Río Negro and Salto Departments) and Argentina (Entre Ríos Province). This species belongs to the P. harpagos species complex and is diagnosed by the following unique combination of characters: 1) presence of a symmetric hood-like structure located immediately anterior to the urogenital papilla in females, 2) absence of large papillae at the mandibular symphysis of large adult females, 3) possession of well-developed hooks positioned in distal portion of gonopodial appendices of males and4) lateral spot usually present in both sexes. To date, P. mimbi has not been found coexisting in sympatry with other Phalloceros species. The geographically closest species is P. caudimaculatus, who differs from P. mimbi by the absence of hooks in gonopodial appendix in males. Two of the three known populations of P. mimbi are relatively protected from the main threats to the species. However, conservation initiatives should consider its presence and ensure that it receives the necessary attention; considering that its global distribution occupies less than 200.000 km2 and its occurrence area represents less than 10% of the national territory it must be considered a priority for conservation and an Threatened Species for the species list of Sistema Nacional de Áreas Protegidas (SNAP) of Uruguay.
Data from: Long-term monitoring reveals how pondscape connectivity shapes the early spread of a biological invasion
(2026) Noelia Gobel; Matías Arim; Iván González-Bergonzoni; Sofía Cortizas; Nadia Kacevas; Johan Sebastian Soto Duque; Gabriel Laufer Laufer
Biological invasions lead to loss of biodiversity and ecosystem degradation, and a better understanding of their drivers is urgently needed. This is particularly true in the initial stages of an invasion, when the transition from local establishments to regional advancing fronts occurs. The abundances of the local population, demographic rates, and spatial conditions for dispersal have been proposed to interact in determining invasive species expansion, but little empirical evidence has been accumulated. This study examines the population dynamics of the American bullfrog (Aquarana catesbeiana), a globally invasive aquatic anuran, during the initial stages of its invasion process in a pond landscape within the Pampas grasslands of Uruguay. We evaluated how the spatial spread of the invasion was influenced by connectivity between invaded and uninvaded ponds, bullfrog abundance in invaded ponds, elevation gradients, and pond area. This analysis was based on an 11-year monitoring program (2012-2022) that captured the onset and initial stage of spatial expansion. Throughout the study period, the number of invaded ponds increased at a rate of 7.7 % per year. A model of invasion probability revealed that connectivity to invaded ponds and the population status of those ponds were key determinants of spread. Connectivity to previously invaded ponds interacted with bullfrog abundance to determine invasion probability. Ponds connected to invaded locations with intermediate bullfrog abundances showed the highest invasion likelihood, with colonization odds more than twice those associated with connections to ponds with low bullfrog abundances, whereas connections to ponds with high abundances had more moderate effects. Our results highlighted how ponds with intermediate bullfrog abundance play a crucial role in facilitating the invasion spread, this is most likely due to higher propagule release. Ponds with high bullfrog abundance were likely constrained by density-dependent effects, reducing the survival and dispersal of metamorphs. Our study highlights that prioritizing bullfrog eradication in systems with intermediate abundances may be more effective to prevent the expansion of the invasion. We note that landscape features and population demography within invaded areas could be more interrelated than commonly assumed and should be jointly considered in invasive species management strategies.