Montane Frog Research Articles

Frogs of the Eleutherodactylus biporcatus Group (Leptodactylidae) of Central America and Northern South America, Including Rediscovered, Resurrected, and New Taxa

Abstract A revision of the broad-headed frogs of the biporcatus species group of Eleutherodactylus s.l. has a wholly unexpected nomenclatural consequence. Eleutherodactylus biporcatus (W. Peters, 1863) is not from “Veragua” (western Panama) as originally thought, but is the proper name for the Venezuelan frog heretofore known as E. maussi (Boettger, 1893). Three names are resurrected from synonymy for Central American species currently masquerading under the misapplied name biporcatus, and a fourth species is described as new: (1) The rediscovery of Eleutherodactylus gulosus (Cope, 1875) shows it to be a large montane frog occupying an apparently small range in the borderland of Costa Rica and Panama. (2) Eleutherodactylus rugosus (W. Peters, 1863) is a smaller species occurring on the Pacific versant of southwestern Costa Rica and western Panama; Lithodytes pelviculus Cope and L. florulentus Cope are synonyms of E. rugosus. (3) Eleutherodactylus megacephalus (Cope, 1875), an intermediate-sized frog rangi...

Catastrophic declines of Australian rainforest frogs: Is unusual weather responsible?

In the montane rainforests of eastern Australia, at least 14 species of frogs that breed in, and live near, streams have declined dramatically during the past 15 years. I explored the hypothesis that atypical weather was wholly or partly responsible for these declines, using a computerized weather analysis package and data on 10 rainfall and temperature parameters gathered from 17 strategically located weather stations. Most weather stations exhibited a moderate (≤25%) reduction in annual rainfall in the five years immediately preceding frog declines, usually due to a decline in wet season rainfall, and within-year rainfall variability declined consistently. During the same period nearly half of all stations exhibited a significant increase in the frequency of ‘major drought’ months. There also was an excessive number of months with atypically high average temperatures, especially in summer, although other temperature parameters did not deviate significantly from long-term weather averages. In general, however, the moderate deviations of rainfall and temperature measures from long-term averages at each site appear to be an inadequate explanation for the dramatic declines of montane frogs in Queensland. Other possible factors, especially epidemic disease, should be explored in further detail.

Declining Amphibian Populations

W T tORLDWIDE DECLINES IN AMPHIBIAN POPULATIONS ATtracted wide attention following a workshop sponsored by the National Research Council (NRC) (1, 2). The declines seem to be general, but some regions and many taxa are apparently unaffected (1). Are the declines due to normal climatic fluctuations, which produce droughts and frosts that can severely reduce population size locally, or are there other, more insidious causes? The report of census data for four amphibians (three salamanders and a frog) gathered during a 12-year period of continuous (daily) monitoring at the Savannah River Site in South Carolina contributes importantly to this question (3). Substantial variation was found in breeding population sizes and juvenile recruitment. Population declines were found in some years, but these were coupled with increases; there is a complex dynamic associated with many factors, especially local moisture regimen. The new data, the most extensive available, raise the possibility that declines are the coincidental effect of population fluctuations. If so, the consequences will vary greatly from place to place. The southeastern United States is a veritable carpet of amphibians, from the abundant salamanders of the highest Appalachian peaks to dense lowland populations of both frogs and salamanders. Should populations decline to local extinction in this area, chances of recovery are high. However, local extinctions have more profound implications in other parts of the world, where species are specialists for habitats that are localized or badly fragmented; under such circumstances, opportunities for recolonization are low to nonexistent (4). It is significant that participants at the NRC workshop, who heard a brief summary of the new data, considered it unlikely that global declines were coincidental, because of the number and widespread distribution of the reports, but population fluctuations clearly must be taken into account. Concern about declines arises because amphibians are abundant, integral components ofmany diverse ecosystems. They are local top carnivores that are major consumers of invertebrates, especially insects. General declines would have widespread consequences and might indicate more general environmental problems (5). Some declines have been dramatic. Ranid frogs have all but disappeared from southern California (6). By the late 1980s a montane frog (Rana muscosa) had disappeared from 98% of the ponds in which it had been studied in the mid-1970s in SequoiaKings Canyon National Park (1, 4). In Oregon, populations ofRana cascadae, monitored since the mid-1970s, have suffered about an 80% disappearance (1, 7). The golden toad (Bufo periglenes), endemic to the Monteverde Cloud Forest Preserve in Costa Rica, has not bred in its traditional breeding sites since 1987; many other frog taxa in the region have experienced declines and local disappearance during this period (1, 8). The gastric-brooding frog (Rheobatrachus silus), which lived in rivers in relatively undisturbed regions of Queensland, Australia, has not been seen since 1979, and several other sympatric species offrogs also are thought to be extinct (9). Sometime after 1981, 8 of 13 species of frogs that had been present in Reserva Atlantica, Brazil, disappeared, including unusual diurnal hylodine frogs, whose birdlike calls were distinctive features

Montane and piedmont chorus frogs (Paeudacris triseriata): metabolic rate as a function of temperature.

Die Stoffwechselraten von Froschen (Pseudacris triseriata) aus Tiefland- und Bergpopulationen wurden bei 10 ‡C und 20 ‡C bestimmt. Die beiden Populationen unterschieden sich nicht signifikant in der Stoffwechselrate bei den 2 Testtemperaturen.