RIQUEZA, DIVERSIDAD Y ABUNDANCIA DE ANFIBIOS EN EL BOSQUE NUBOSO DE CERRO AZUL, SECTOR ALTO CHAGRES, PARQUE NACIONAL CHAGRES, PANAMÁ

The aim of this study was to determine the conservation status of the cloud forest of Cerro Azul, considering the wealth of prevailing amphibian species. Sampling was done over a period of six months, from February 2009 until July of that year. Samplings were carried out using transect as search technique day and night raiding along natural water sources (rivers and streams), located at the three sites were selected for monitoring. Amphibian abundance was 661 individuals, subdivided into two orders (Anura and Caudata), 9 families, 15 genera and 26 species. A richness of 26 species of amphibians was obtained, which showed a seasonal pattern, with the months with lower precipitation those with the greatest number of species The Cerro Azul area had the highest diversity index during the transition period between the dry season and the rainy season. Applying ecological feasibility analysis (AVE) it was determined that the state of conservation of Cerro Azul cloud forest, based on species richness of amphibians, is in a poor condition. Abundance ranges indicated that more than half of all amphibian species recorded (62%) decreased their abundance since the last inventory made 15 years ago.    El objetivo de este estudio fue determinar el estado de conservación del bosque nuboso de Cerro Azul, considerando la riqueza de especies de anfibios existentes. El muestreo se realizó por un periodo de seis meses, desde febrero de 2009 hasta julio del mismo año. Los muestreos fueron llevados a cabo mediante la técnica de búsqueda por transectos, realizando incursiones diurnas y nocturnas a lo largo de fuentes naturales de agua (ríos y quebradas), ubicadas en los tres sitios que fueron seleccionados para monitorear. La abundancia registrada de anfibios fue de 661 individuos, agrupados en dos órdenes (Anura y Caudata), 9 familias, 15 géneros y 26 especies. Se obtuvo una riqueza de 26 especies de anfibios, la cual presentó un patrón estacional, siendo los meses con menor precipitación los que aportaron el mayor número de especies. El área de Cerro Azul presentó el mayor índice de diversidad durante el período de transición, entre la estación seca y la estación lluviosa. Al aplicar el análisis de viabilidad ecológica (AVE) se determinó que el estado de conservación del bosque nuboso para Cerro Azul, basado en la riqueza de especies de anfibios, se encuentra en una condición de Pobre. Los rangos de abundancia indicaron que más de la mitad de las especies de anfibios registradas (62%) disminuyeron su abundancia desde el último inventario realizado hace 15 años.&nbsp

Spindly leg syndrome in Atelopus varius is linked to environmental calcium and phosphate availability.

Spindly leg syndrome (SLS) is a relatively common musculoskeletal abnormality associated with captive-rearing of amphibians with aquatic larvae. We conducted an experiment to investigate the role of environmental calcium and phosphate in causing SLS in tadpoles. Our 600-tadpole experiment used a fully-factorial design, rearing Atelopus varius tadpoles in water with either high (80mg/l CaCO3), medium (50mg/l CaCO3), or low calcium hardness (20mg/l CaCO3), each was combined with high (1.74 mg/l PO4) or low (0.36 mg/l PO4) phosphate levels. We found that calcium supplementation significantly improved tadpole survival from 19% to 49% and that low calcium treatments had 60% SLS that was reduced to about 15% at the medium and high calcium treatments. Phosphate supplementation significantly reduced SLS prevalence in low calcium treatments. This experimental research clearly links SLS to the calcium: phosphate homeostatic system, but we were unable to completely eliminate the issue, suggesting an interactive role of other unidentified factors

The relationship between spindly leg syndrome incidence and water composition, overfeeding, and diet in newly metamorphosed harlequin frogs (Atelopus spp.)

Spindly Leg Syndrome (SLS) is a persistent animal welfare issue associated with the rearing of amphibians in captivity. We conducted two experiments to investigate the effects of diet, water composition and overfeeding on prevalence of SLS in newly metamorphosed harlequin frogs ( Atelopus spp.). In our first experiment, we offered 400 full-sibling tadpoles of Atelopus certus isocaloric diets in treatments of 31%, 37%, 42% and 48% crude protein respectively. Tadpoles fed higher protein diets metamorphosed faster, but the incidence of SLS exceeded 80% in all treatments leading to the conclusion that variation in dietary protein was not responsible for causing SLS. We used 720 full-sibling Atelopus glyphus tadpoles in a second experiment to examine the effects of diet type, water composition and diet ration on SLS. We found that an overall incidence of 58% spindly leg in tadpoles reared in tap water, but reduced to about 10% in water treated by reverse osmosis and then reconstituted. It is possible that the reverse osmosis treatment removed some factor that caused the SLS, or that the reconstitution may have added a mineral lacking in the original tap water. Within tap water treatments, overfeeding tadpoles in tanks increased the incidence of SLS. We recommend further experimental research into this condition to identify the causative factors in the water. Additional research into the nutritional composition of food available to wild tadpoles would be useful in formulating captive diets, that have to date been solely based on surrogate species

Repeated measures ANOVA testing the effects of time (weeks 0–4) and group size on fecal glucocorticoid levels in <i>Atelopus</i> housed together (groups of 8 vs 2).

<p><i>(</i><b><i>a</i></b><i>). We omitted group size n = 1 from the analysis because there were too many missing values to run statistical comparisons. Repeated measures ANOVA testing the effects of time (weeks 1–4) and group size (8 vs 2) on aggressive interactions in Atelopus housed together (</i><b><i>b</i></b><i>).</i></p

Ethogram describing different types of aggressive interactions observed for <i>Atelopus</i>.

<p><b>Fight</b>: Combat involving mouth or front limbs, often flipping of opponent; <b>Mount</b>: >50% of initiators body covers the victim for >5 seconds; <b>Release call</b>: High pitched, weak, peep like call; maximum tally of one per individual; <b>Physical contact</b>: Any remaining forms of physical contact; <b>Stalk</b>: One individual actively follows/chases another for >5 seconds; <b>Wave</b>: Circular movements in front limbs.</p

Cortisol EIA profile (black, diamond marks) and Corticosterone RIA profile (grey, triangle marks), in <i>Atelopus</i> feces following an ACTH challenge (0.2 IU, IM).

<p>Cortisol EIA profile (black, diamond marks) and Corticosterone RIA profile (grey, triangle marks), in <i>Atelopus</i> feces following an ACTH challenge (0.2 IU, IM).</p

Evaluating group housing strategies for the ex-situ conservation of harlequin frogs (Atelopus spp.) using behavioral and physiological indicators

We have established ex situ assurance colonies of two endangered Panamanian harlequin frogs, Atelopus certus and Atelopus glyphus, but observed that males fought with each other when housed as a group. Housing frogs individually eliminated this problem, but created space constraints. To evaluate the potential stress effects from aggressive interactions when grouping frogs, we housed male frogs in replicated groups of one, two, and eight. We measured aggressive behavioral interactions and fecal glucocorticoid metabolite (GC) concentrations as indicators of stress in each tank. In both small and large groups, frogs initially interacted aggressively, but aggressive interactions and fecal GCs declined significantly after the first 2 weeks of being housed together, reaching the lowest levels by week 4. We conclude that aggressive interactions in same-sex groups of captive Atelopus may initially cause stress, but the frogs become habituated within a few weeks and they can safely be housed in same-sex groups for longer periods of time

Fecal glucocorticoid concentrations immediately before and after male <i>Atelopus</i> were grouped together at week 1 (ng cortisol/g ± SEM) changed significantly over time (p = 0.04*), but there were no significant differences between groups sizes (A).

<p>Frogs housed singly (mean  = 44.2 ng cortisol/g±7.4 SEM) could not be included in this analysis because of too many missing values. Aggressive interactions changed significantly over time (p<0.001***), but there were no significant differences between group sizes.</p

Ongoing harlequin toad declines suggest the amphibian extinction crisis is still an emergency

Biodiversity loss is extreme in amphibians. Despite ongoing conservation action, it is difficult to determine where we stand in overcoming their extinction crisis. Among the most threatened amphibians are the 131 Neotropical harlequin toads. Many of them declined since the 1980s with several considered possibly extinct. Recently, more than 30 species have been rediscovered, raising hope for a reversing trend in the amphibian extinction crisis. We use past and present data available for harlequin toads (Atelopus), to examine whether the amphibian extinction crisis is still in an emergency state. Since 2004 no species has improved its population status, suggesting that recovery efforts have not been successful. Threats include habitat change, pathogen spread and climate change. More mitigation strategies need implementation, especially habitat protection and disease management, combined with captive conservation breeding. With harlequin toads serving as a model, it is clear that the amphibian extinction crisis is still underway. The status of the harlequin toads has not improved since 2004 despite species rediscoveries accompanied by increasing conservation efforts, and habitat destruction and degradation continue to threaten them today, according to an analysis of population status records over the period 2004-2022