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American Bullfrog (Lithobates Catesbeianus) Diet In Uruguay Compared With Other Invasive Populations In Southern South America, Gabriel Laufer, Noelia Gobel, Mauro Berazategui, Matías Zarucki, Sofía Cortizas, Alvaro Soutullo, Claudio Martinez Debat, Rafael O. De Sá Dec 2021

American Bullfrog (Lithobates Catesbeianus) Diet In Uruguay Compared With Other Invasive Populations In Southern South America, Gabriel Laufer, Noelia Gobel, Mauro Berazategui, Matías Zarucki, Sofía Cortizas, Alvaro Soutullo, Claudio Martinez Debat, Rafael O. De Sá

Biology Faculty Publications

Between 2000-2020, more than ten new populations of the invasive American bullfrog (Lithobates catesbeianus) have been reported in the southern cone of South America. We studied the stomach contents of 126 bullfrogs from a population at an early invasion stage in Uruguay (Acegua, Cerro Largo Department). We observed a rich diet, with extensive prey volume range (1 mm3 to more than 7 000 mm(3)); the most frequent items were Hymenoptera (19.6%), Coleoptera (16.4%), Amphipoda (13.3%), Anura (8.9%) and Heteroptera (8.7%). Despite some overlap, differences were observed in volume (chi(2) = 54.6, p <0.001, d.f. = 2) and prey quantity (F = 8.1, p <0.001, d.f. = 79) between males, females, and juveniles. Juveniles showed significantly higher consumption of terrestrial prey by count (82% of their total ingestion) than adults (29% for males and 32% for females) (chi(2) = 28.5, p <0.001, d.f. = 2). Adults, especially females, showed a high frequency of cannibalism (33% of their total ingestion; chi(2) = 20.9, p <0.001, d.f. = 2). Comparing our data with other bullfrog regional studies, we found great plasticity in trophic habits and differences in the incidence of cannibalism (higher incidence in the populations of Acegua, Uruguay, and Buenos Aires, Argentina). These differences could be related to local biodiversity, but also could be affected by the invasion phase. Cannibalism frequency was higher in small bullfrog populations, where it could be favoring the establishment success. This shift in foraging strategies during the invasion process had been insufficiently evaluated in amphibians. Knowing the ecological determinants for the invasion by bullfrogs can be useful to the development of management strategies.


The Identity Of Rana Margaritifera Laurenti, 1768 (Anura, Bufonidae), Esteban O. Lavilla, Ulisses Caramaschi, José A. Langone, José P. Pombal Jr., Rafael O. De Sá May 2013

The Identity Of Rana Margaritifera Laurenti, 1768 (Anura, Bufonidae), Esteban O. Lavilla, Ulisses Caramaschi, José A. Langone, José P. Pombal Jr., Rafael O. De Sá

Biology Faculty Publications

Rana margaritifera was described by Laurenti in 1768 and currently is associated to the genus Rhinella, under the combination Rhinella margaritifera. Currently, the R. margaritifera species group consists of 16 recognized species. Further-more, many additional species have been suggested to exist in this group which highlights the ambiguity surrounding the identity of Rhinella margaritifera and impend further description of the species in this group. After an exhaustive bibliographic review, we concluded that the recent designation of a lectotype for R. margaritifera is invalid according with Art. 73, ICZN, 1999. Herein, we designate and provide the description of a …


The Identity Of Zachaenus Roseus Cope, 1890 (Anura: Species Inquirenda), Esteban O. Lavilla, J. J. Nuñez, F. E. Rabanal, José A. Langone, Rafael O. De Sá Aug 2010

The Identity Of Zachaenus Roseus Cope, 1890 (Anura: Species Inquirenda), Esteban O. Lavilla, J. J. Nuñez, F. E. Rabanal, José A. Langone, Rafael O. De Sá

Biology Faculty Publications

Zachaenus roseus Cope, 1890, has puzzled systematists working in southern South America. A single individual, the holotype, has ever been collected and this specimen is in extremely poor preservation condition. Herein, the precise location of the type locality of Z. roseus is determined based on a historical review of the literature. Furthermore, following a careful comparison with all species that inhabit the southern austral forest, and that could potentially correspond to Zachaenus roseus, we conclude that this taxon is placed in the synonymy of Eupsophus calcaratus (Günther, 1881)


Altered Ecological Flows Blur Boundaries In Urbanizing Watersheds, Todd R. Lookingbill, Sujay S. Kaushal, Andrew J. Elmore, Robert Gardner, Keith N. Eshleman, Robert H. Hilderbrand, Raymond P. Morgan, Walter R. Boynton, Margaret A. Palmer, William C. Dennison Jan 2009

Altered Ecological Flows Blur Boundaries In Urbanizing Watersheds, Todd R. Lookingbill, Sujay S. Kaushal, Andrew J. Elmore, Robert Gardner, Keith N. Eshleman, Robert H. Hilderbrand, Raymond P. Morgan, Walter R. Boynton, Margaret A. Palmer, William C. Dennison

Geography and the Environment Faculty Publications

The relevance of the boundary concept to ecological processes has been recently questioned. Humans in the post-industrial era have created novel lateral transport fluxes that have not been sufficiently considered in watershed studies. We describe patterns of land-use change within the Potomac River basin and demonstrate how these changes have blurred traditional ecosystem boundaries by increasing the movement of people, materials, and energy into and within the basin. We argue that this expansion of ecological commerce requires new science, monitoring, and management strategies focused on large rivers and suggest that traditional geopolitical and economic boundaries for environmental decision making be …