The new paper, titled "After the epizootic: Host–pathogen dynamics in montane tropical amphibian communities with high prevalence of chytridiomycosis" appeared today in Biotropica. In the cloud forests of the Kosñipata Valley of Manu National Park, where chytrid infection (Bd) is highly prevalent, we have monitored frog communities since 1996. An epizootic of chytridiomycosis caused the disappearance of 35% of species richness in the early 2000s.
In this study authored by former Ms student Brandon LaBumbard (now PhD student at UMass), and coauthored by current PhD candidate Alex Shepack, we investigated the post‐epizootic Bd prevalence and infection intensity within the remnant amphibian community from 2008 to 2015, and modeled Bd dynamics as a function of species, season, reproductive mode, life stage, and elevation. Prevalence was higher in 2012–2015 than in 2008–2009, but overall prevalence has remained fairly constant (~50%) post‐epizootic. We found that while prevalence decreased with elevation during the wet season, it increased with elevation during the dry season, potentially due to seasonal changes in temperature and precipitation.
Our data suggest that the few stream‐breeding species that survived epizootics, such as Boana gladiator (see picture here), might facilitate Bd infection in sympatric susceptible hosts (most of which are terrestrial‐breeding species) by helping keep Bd in the environment, and by acting as reservoir hosts. Reservoirs thereby lead to continual declines of susceptible species long after initial Bd emergence, warranting the need for long‐term monitoring to understand population and species extinction risks in remnant populations in areas where Bd is still present and causing disease.
We would like to give special thanks to Peru Verde and the staff at Gallito de las Rocas lodge for their support and for allowing us to work at the San Pedro biological station.
The lab has been awarded an NSF grant, part of the collaborative proposal "Linking Host Life History, Movement Ecology, and Climate to Predict Epizootics in Megadiverse Tropical Amphibian Communities", with collaborators Gui Becker (University of Alabama) and Rayna Bell (California Academy of Sciences). Field sites include frog communities in Brazil, Peru, and Cameroon
The funded collaborative project will include 1) field surveys spanning the old world and new world tropics to assess infection patterns in diverse amphibian communities across space and time, 2) a field experiment to isolate the effects of climatic variability on amphibian community structure and disease risk, and 3) novel methods of disease modelling that integrate observational and experimental data to forecast disease dynamics and population demographics at the community scale. A cornerstone of this integrative approach is to examine the disease dynamics of fully terrestrial amphibians. This guild of tropical frogs has been experiencing cryptic population declines and extinctions ostensibly linked to disease, droughts, shifts in host behavior, spatial aggregation, and pathogen spillover. The field survey component will compare spatiotemporal disease dynamics among co-occurring terrestrial-breeding and aquatic-breeding amphibian species, focusing on divergent host movement patterns and responses to climatic variability.
Meet the newest addition to the high-Andean genus Phrynopus: Phrynopus remotum. The new species was discovered by collaborators and coauthors Germán Chávez and Luis García Ayachi, and is known from a single locality in the central Andes of Peru (Departamento de Huánuco) at 3,730 meters of elevation. The description appeared today in the journal PeerJ. The new species is morphologically distinguishable by the presence of small tubercles on upper eyelids and heels, an areolate venter, and the absence of dorsolateral folds or ridges. Similar to most species in this genus, P. remotum lacks the tympanic membrane and annulus, i.e. there is no external tympanum. It also shares an overall compact body shape and short limbs, traits that are associated with life in high-Andean grasslands and cloud forests just below the treeline in several genera of strabomantid frogs, such as Bryophryne, Phrynopus and several species of Pristimantis.
Along with collaborators Luis Mamani, Edgar Lehr and Rudolf von May, we named a new genus for three species of terrestrial-breeding frogs previously described as Bryophryne. The new name, Qosqophryne, is dedicated to the city and region of Cusco in southern Peru, where these frogs live. As far as we know the three species only occur in the Vilcabamba mountain ridge. The paper is published as part of a special issue on Neotropical herpetofauna.
On the basis of molecular phylogenies, the genus is the sister genus to Microkayla, a larger group of similar frogs distributed in Bolivia and extreme southern Peru (Department Puno). These two genera (Qosqophryne and Microkayla) are more closely related to species of Noblella and Psychrophrynella than to species of Bryophryne. Although there are no known morphological synapomorphies for either Microkayla or Qosqophryne, the high endemism of their species, and the disjoint geographic distribution of the two genera, with a gap region of ~310 km by airline where both genera are absent, provide further support for Qosqophryne having long diverged from Microkayla. The exploration of high elevation moss and leaf litter habitats in the tropical Andes will contribute to increase knowledge of the diversity and phylogenetic relationships within Terrarana.
PhD student and lab member Anne Sabol published one of the chapters of her master thesis in Animal Behavior, titled "How does individual variation in sociality influence fitness in prairie voles?". Prairie voles vary substantially in their social behaviour, and this variation may carry consequences for individual fitness. Anne and her collaborators found that voles with an intermediate level of sociality had the highest mating success, and voles with intermediate sociality with all voles had higher reproductive success. Furthermore, males with an intermediate number of social connections had higher mean body mass. Therefore, it seems that intermediate levels of sociality was most favorable for fitness. Anne conducted this work during her master program at the University of Michigan, in the lab of Dr. Ben Dantzer. The paper was available online on 29 March (https://doi.org/10.1016/j.anbehav.2020.02.009). Congrats Anne!
During the last weeks of February we conducted field work in the high Andes, at the transition of cloud forest and grasslands, near Manu National Park. We are continuing an experiment with leaf litter frogs that we started last December. We are studying the ecosystem roles of leaf litter frogs, in collaboration with Dr. Sparkle Malone, Dr. Sarah Kupferberg and Isabel Diaz.
Leaf litter frogs belong to the family of terrestrial-breeding frogs Strabomantidae. Most of these highly terrestrial frogs are small with short and compact bodies, especially at high elevations. We set up enclosures to compare the effects of frog presence (using the abundant Psychrophrynella usurpator) on ecosystem functioning in grasslands and cloud forest environments. We will measure these effects throughout the wet season (until June). Stay tuned for preliminary results!
Rachel and Kenny will present at our annual Biosymposium at Biscayne Bay Campus next Saturday, 8 February starting at 9 am. Both talks are lighting talks in the afternoon session ( 3:30 pm):
Interactions between disease and consumer driven nutrient recycling in Andean tadpoles
The effects of Bd recognition and avoidance on marsupial frog offspring deposition decisions
Rachel Kaitlin Prokopius
For the month of October the lab traveled back to the high elevation grasslands at Pampas Galeras National Reserve in Peru to conduct research on Telmatobius tadpoles. As part of his doctoral thesis Kenneth Anderson is expanding on the work done here by Andrew Rubio investigating the ecosystem role of Telmatobius, and how that role is changing due to chytridiomycosis.
While the Pampas Galeras National Reserve was founded to protect the vicuñas (a species of camelid prized for its extremely fine wool), it also protects native Telmatobius frogs which live in the streams throughout the reserve. Multiple species of Telmatobius frogs have suffered from major declines due to chytrid but the frogs at Pampas Galeras seems to be co-existing with the disease without massive declines. The effects of chytrid as an enzootic disease have been largely unstudied, so the goal of research on these frogs is to learn how chytrid changes the ecosystem function of these frogs.
Telmatobius tadpoles are specifically useful for looking at this relationship because tadpoles do not die from chytrid. The fungus only grows on their mouthparts and at high levels of infection causes deformations. This is very useful for estimating infection levels in the field and it’s likely that the change to the mouthparts causes a change in diet for the tadpoles as well. We suspect that this change in diet, along with changes in energy and nutrient needs caused by disease will change how tadpoles cycle nutrients with their streams.
To do this Kenneth, along with his dauntless field tech Yasmani Larota Calla, swabbed frogs for disease, and collected urine and feces of tadpoles for nutrient readings. Tadpole urine is easily collected by putting a tadpole in a bag and waiting for about an hour, the water is then filtered to separate the feces and brought back to the field station for ammonium chemistry in the field (using a Turner fluorometer). We’ll come back with another update once or data has been analyzed but we expect that chytrid will change the nutrient ratios in tadpole urine, and we expect that the amount of urine produced plays an important role in the nutrient cycling of these unique high elevation streams.
Alessandro and Alex are just back from the first meeting of the Atelopus Survival Initiative in Medellin, Colombia. More than 80% of this symbolic genus of frogs are threatened by extinction. Together with biologists and conservationists from across the range of this genus, we worked to come up with concrete plans for research and management - focusing on developing capacity in countries of need and improving research across the region. While only the first step, we hope this meeting and the ASI will catalyze cooperation and lead to successful conservation of this incredible group.
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