Adrián García-Rodríguez

Rediscovery of the critically endangered streamside frog, Craugastor taurus (Craugastoridae), in Costa Rica

In 1987 the amphibian decline crisis reached its apex in Costa Rica when at least 17 species experienced population crashes and subsequently went undetected for decades. The amphibian declines in Costa Rica were relatively well documented and came to exemplify the current global amphibian decline crisis. The Mesoamerica endemic frog clade, the Craugastor punctariolus species group, is one of most severely affected anuran clades, experiencing a loss of 26 out of 33 species throughout Mesoamerica. Eight species of C. punctariolus group frogs occur in Costa Rica, and all declined following the 1987 die-off; despite intensive surveys over the last 14 years, most remain undetected. To date, only one species in this group, the stream-breeding frog C. ranoides, in known to have a stable population, and only in the Santa Elena Peninsula. Here we document the rediscovery of another species, the South Pacific streamside frog C. taurus, in southeastern Costa Rica, representing the first sighting after fifteen years of searching. We discovered two previously unknown populations in Punta Banco, the driest section within the historical range, in an area representing only 4% of the historical distribution. Our findings add to the short but growing list of recently rediscovered amphibian species in Costa Rica and provide encouraging news in an otherwise discouraging situation for amphibian conservation. Additional research and monitoring are urgently needed to develop long-term management plans for this and other Critically Endangered species

Too wet for frogs: changes in a tropical leaf litter community coincide with La Nina

Extreme climatic events such as the El Nino Southern Oscillation profoundly affect many plants and animals, including amphibians, which are strongly negatively affected by drought conditions. How amphibians respond to exceptionally high precipitation as observed in La Nina events, however, remains unclear. We document the correlation between the exceedingly wet 2010-2012 La Nina and community-level changes in a leaf litter frog assemblage in Costa Rica. Relative abundances of species shifted, diversity and plot occupancy decreased, and community composition became homogenized with the onset of La Nina. These aspects remained altered for over 20 months but rebounded to pre-La Nina levels after approximately 12 months. We hypothesize that complex ecological cascades associated with excess moisture caused short-term declines in abundances of species and associated changes in community structure. If additional stressors such as disease or habitat loss are not co-occurring, frog communities can rapidly recover to pre-disturbance levels following severe climatic events.

Automatic detection of vocalizations of the frog Diasporus hylaeformis in audio recordings

A method for the automatic detection of calls of the frog Diasporus hylaeformis (Eleutherodactylidae) in audio recordings is proposed. The method uses the loudness, timber, and pitch of the vocalizations to identify the calls of the most prevalent individual in a recording. The first step consists in calculating the loudness of the signal to recognize the sections where the focal individuals vocalizations are. The second step consists in using the timber of the signal to recognize vocalizations. Finally, we use two principles we observed in the sounds produced by this species to discriminate between the calls of the most prevalent individual and other calls: individuals tend to vocalize using an almost constant pitch and different individuals use different pitches. Results show that the method is resistant to background noise (including calls of individuals of the same species), microphone-manipulation-induced noise, and human voice, and also that it adapts well to variations in the microphone level prod...

Range expansion and noteworthy records of Costa Rican birds (Aves)

We present new distribution information for 19 species of Costa Rican birds. Thirteen species show changes in altitudinal distribution, 9 are recorded at higher elevations such as Egretta rufescens (Gmelin, 1789), Heliomaster constantii (Delattre, 1843), Myiozetetes cayanensis (Linnaeus, 1766), and Lonchura malacca (Linnaeus, 1766), and 4 are recorded at lower elevations, Panterpe insignis Cabanis & Heine, 1860, Empidonax albigularis Sclater & Salvin, 1859, Sayornis nigricans (Swainson, 1827), and Dacnis venusta (Lawrence, 1862). We recorded 2 forest understory species, Geotrygon montana (Linnaeus, 1758), and Grallaria guatimalensis Prévost & Des Murs, 1842, inside the area of the county with the most urban development. Finally, Saltator grossus (Linnaeus, 1766), which was restricted to Caribbean forest, was recorded at the South Pacific rainforest for the first time.

Multiple lines of evidence support the species status of the poorly known Diasporus tigrillo and the recently described Diasporus citrinobapheus (Anura: Eleutherodactylidae)

The genus of direct-developing frogs Diasporus is currently composed of 11 species ranging from Honduras to Ecuador. Body size variability, advertisement call divergence, and polychromatism have all been reported at the interpopulation level, suggesting that the existence of some species may be masked within the current nomenclature of this group. This pattern highlights the need for integrative approaches to resolve the taxonomy of the genus and provide a robust delimitation of the species it contains. Here, we provide novel data on morphology, genetics, habitat use, and bioacoustics for D. tigrillo, the least known species in the genus. Then we use an integrative approach to assess the divergence between this species and D. citrinobapheus a recently described species. D. tigrillo was indicated as the most similar species to D. citrinobapheus by its authors; however, given the lack of available information for D. tigrillo this conclusion was based only on morphological data obtained from a few deteriorated specimens collected and preserved five decades ago. With our morphological redescription, molecular inference, ecological observations, and acoustic analysis, we found important differences between these two taxonomic entities. Our data, in addition to improving the knowledge of D. tigrillo, therefore provides robust evidence to support the validity of both species. Molecular sequence data. GenBank Accession numbers are detailed in the text. Phylogenetic data. Information related can be reviewed at this URL: http://purl.org/phylo/treebase/phylows/study/TB2:S18102

A checklist of the amphibians and reptiles of Río Macho Biological Station, Provincia de Cartago, Costa Rica

We provide a checklist of the amphibians and reptiles of Rio Macho Biological Station (RMBS), Costa Rica. During a period of a year (2012–2013) we conducted visual and acoustic surveys in a natural mature forest plot (>50 years old) (MF), secondary forest plot (~17 years old) (SF), in open areas and riparian forest at RMBS. We found a total of 11 species of amphibians and 15 species of reptiles belonging to 11 taxonomic families. We also compared the diversity of the MF against the SF. The MF contained 10 species (five amphibians and five reptiles) and the SF seven (three amphibians and four reptiles), with similar dominance between sites. Unfortunately, some forest and riparian species have vanished at this elevation after an enigmatic decline; according to historical literature pristine areas should contain higher species richness. Perhaps, the secondary forest will provide an available habitat for an important percentage of the remaining forest species.