scholarly journals Endemic Infection of Batrachochytrium dendrobatidis in Costa Rica: Implications for Amphibian Conservation at Regional and Species Level

Diversity ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 129 ◽  
Author(s):  
Héctor Zumbado-Ulate ◽  
Kiersten N. Nelson ◽  
Adrián García-Rodríguez ◽  
Gerardo Chaves ◽  
Erick Arias ◽  
...  
Keyword(s):  
Costa Rica ◽  
Batrachochytrium Dendrobatidis ◽  
Infection Intensity ◽  
Amphibian Conservation ◽  
Conservation Strategies ◽  
Amphibian Species ◽  
Current Impact ◽  
Taxonomic Groups ◽  
Species Descriptions ◽  
Effective Conservation

Batrachochytrium dendrobatidis (Bd) has been associated with the severe declines and extinctions of amphibians in Costa Rica that primarily occurred during the 1980s and 1990s. However, the current impact of Bd infection on amphibian species in Costa Rica is unknown. We aimed to update the list of amphibian species in Costa Rica and evaluate the prevalence and infection intensity of Bd infection across the country to aid in the development of effective conservation strategies for amphibians. We reviewed taxonomic lists and included new species descriptions and records for a total of 215 amphibian species in Costa Rica. We also sampled for Bd at nine localities from 2015–2018 and combined these data with additional Bd occurrence data from multiple studies conducted in amphibian communities across Costa Rica from 2005–2018. With this combined dataset, we found that Bd was common (overall infection rate of 23%) across regions and elevations, but infection intensity was below theoretical thresholds associated with mortality. Bd was also more prevalent in Caribbean lowlands and in terrestrial amphibians with an aquatic larval stage; meanwhile, infection load was the highest in direct-developing species (forest and stream-dwellers). Our findings can be used to prioritize regions and taxonomic groups for conservation strategies.

scholarly journals Fungal infection, decline and persistence in the only obligate troglodytic Neotropical salamander

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9763
Author(s):  
Mizraim Olivares-Miranda ◽  
Vance T. Vredenburg ◽  
Julio C. García-Sánchez ◽  
Allison Q. Byrne ◽  
Erica B. Rosenblum ◽  
...  
Keyword(s):  
Batrachochytrium Dendrobatidis ◽  
Infection Intensity ◽  
Sampling Technique ◽  
Sympatric Species ◽  
Amphibian Declines ◽  
Small Range ◽  
Museum Specimens ◽  
Amphibian Species ◽  
Extant Population ◽  
Epidemic Wave

The fungal pathogen Batrachochytrium dendrobatidis (Bd) is implicated in global mass die-offs and declines in amphibians. In Mesoamerica, the Bd epidemic wave hypothesis is supported by detection of Bd in historic museum specimens collected over the last century, yet the timing and impact of the early stages of the wave remain poorly understood. Chiropterotriton magnipes, the only obligate troglodytic Neotropical salamander, was abundant in its small range in the decade following its description in 1965, but subsequently disappeared from known localities and was not seen for 34 years. Its decline is roughly coincident with that of other populations of Neotropical salamanders associated with the invasion and spread of Bd. To determine the presence and infection intensity of Bd on C. magnipes and sympatric amphibian species (which are also Bd hosts), we used a noninvasive sampling technique and qPCR assay to detect Bd on museum specimens of C. magnipes collected from 1952 to 2012, and from extant populations of C. magnipes and sympatric species of amphibians. We also tested for the presence of the recently discovered Batrachochytrium salamandivorans (Bsal), another fungal chytridiomycete pathogen of salamanders, using a similar technique specific for Bsal. We did not detect Bd in populations of C. magnipes before 1969, while Bd was detected at low to moderate prevalence just prior to and during declines. This pattern is consistent with Bd-caused epizootics followed by host declines and extirpations described in other hosts. We did not detect Bsal in any extant population of C. magnipes. We obtained one of the earliest positive records of the fungus to date in Latin America, providing additional historical evidence consistent with the Bd epidemic wave hypothesis. Genotyping results show that at least one population is currently infected with the Global Panzootic Lineage of Bd, but our genotyping of the historical positive samples was unsuccessful. The lack of large samples from some years and the difficulty in genotyping historical Bd samples illustrate some of the difficulties inherent in assigning causality to historical amphibian declines. These data also provide an important historical baseline for actions to preserve the few known remaining populations of C. magnipes.

scholarly journals Prevalence of the fungal pathogen Batrachochytrium dendrobatidis in amphibians of Costa Rica predated first-known epizootic

2018 ◽  
Author(s):  
Marina E. De León ◽  
Héctor Zumbado-Ulate ◽  
Adrián García-Rodríguez ◽  
Gilbert Alvarado ◽  
Hasan Sulaeman ◽  
...  
Keyword(s):  
Costa Rica ◽  
Fungal Pathogen ◽  
Batrachochytrium Dendrobatidis ◽  
Emerging Infectious Diseases ◽  
Infection Prevalence ◽  
Pcr Assay ◽  
Local Data ◽  
Amphibian Species ◽  
Genetic Lineages ◽  
Quantitative Pcr Assay

AbstractEmerging infectious diseases are a growing threat to biodiversity worldwide. Outbreaks of the infectious disease chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), have caused the decline and extinction of numerous amphibian species. In Costa Rica, a major decline event occurred in 1987, more than two decades before this pathogen was discovered. The loss of many species in Costa Rica is assumed to be due to Bd-epizootics, but there are few studies that provide data from amphibians in the time leading up to the proposed epizootics. In this study, we provide new data on Bd infection rates of amphibians collected throughout Costa Rica, in the decades prior to the epizootics. We used a quantitative PCR assay to test for Bd infection in 1016 specimens collected throughout Costa Rica. We found Bd-infected hosts collected as early as 1964, and a infection prevalence average per decade of just 4%. The infection prevalence remained relatively low and geographically constrained until the 1980s when epizootics are hypothesized to have occurred. After that time, infection prevalence increased three-fold and Bd-infected hosts we collected throughout the entire country. Our results, suggest that Bd may either have invaded Costa Rica earlier than previously known, and spread more slowly than previously reported, or that an endemic lineage of the pathogen may exists. To help visualize areas where future studies should take place, we provide a Bd habitat suitability model trained with local data. Studies that provide information on genetic lineages of Bd are needed to determine whether an endemic lineage of Bd or the Global Panzootic Lineage (identified from mass die off sites globally) was present in Costa Rica and responsible for the epizootics that caused amphibian communities to collapse.

scholarly journals Infectious disease threats to amphibian conservation

2018 ◽  
Vol 27 (Supplement) ◽  
pp. 81-90
Author(s):  
A.A. Cunningham
Keyword(s):  
Infectious Disease ◽  
Batrachochytrium Dendrobatidis ◽  
Biodiversity Loss ◽  
Amphibian Conservation ◽  
Disease Spread ◽  
Population Declines ◽  
Amphibian Species ◽  
Late 20Th Century ◽  
Amphibian Population ◽  
In The Wild

The unexplained decline of amphibian populations across the world was first recognised in the late 20th century. When investigated, most of these “enigmatic” declines have been shown to be due to one of two types of infectious disease: ranavirosis caused by infection with FV3-like ranavirus or with common midwife toad virus, or chytridiomycosis caused by infection with Batrachochytrium dendrobatidis or B. salamandrivorans. In all cases examined, infection has been via the human-mediated introduction of the pathogen to a species or population in which it has not naturally co-evolved. While ranaviruses and B. salamandrivorans have caused regionally localised amphibian population declines in Europe, the chytrid fungus, B. dendrobatidis, has caused catastrophic multi-species amphibian population declines and species extinctions globally. These diseases have already caused the loss of amphibian biodiversity, and over 40% of known amphibian species are threatened with extinction. If this biodiversity loss is to be halted, it is imperative that regulations are put in place – and enforced – to prevent the spread of known and yet-to-be discovered amphibian pathogens. Also, it is incumbent on those who keep or study amphibians to take measures to minimise the risk of disease spread, including from captive animals to those in the wild.

scholarly journals Novel findings on the impact of chytridiomycosis on the cardiac function of anurans: sensitive vs. tolerant species

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5891 ◽  
Author(s):  
Raquel F. Salla ◽  
Gisele M. Rizzi-Possignolo ◽  
Cristiane R. Oliveira ◽  
Carolina Lambertini ◽  
Lilian Franco-Belussi ◽  
...  
Keyword(s):  
Cardiac Function ◽  
Batrachochytrium Dendrobatidis ◽  
Electrolyte Imbalance ◽  
Amphibian Conservation ◽  
Amphibian Species ◽  
Cardiac Pumping ◽  
Negative Effect ◽  
Cardiac Relaxation ◽  
The Impact

Background Understanding of the physiological effects of chytridiomycosis is crucial to worldwide amphibian conservation. Therefore, we analyzed the cardiac function of two anuran species (Xenopus laevis and Physalaemus albonotatus) with different susceptibilities to infection by the causative agent of chytridiomycosis, Batrachochytrium dendrobatidis (hereafter Bd). Methods We analyzed the in situ heart rate (fH - bpm), relative ventricular mass (RVM -%), and Ca2+ handling in heart of Bd infected animals compared to uninfected controls of both study species. Results Bd infection resulted in a 78% decrease in contraction force values in P. albonotatus when compared to the less susceptible X. laevis. This negative effect was even more evident (82%) for the cardiac pumping capacity. The time to reach peak tension was 125% longer in P. albonotatus than in X. laevis, and cardiac relaxation was 57% longer. Discussion These results indicate a delay in the cardiac cycle of P. albonotatus on a beat-to-beat basis, which was corroborated by the bradycardia observed in situ. In summary, Bd-sensitive species present impaired cardiac function, which could be a factor in mortality risk. The more pronounced effects of Bd in P. albonotatus may not only result from electrolyte imbalance, as previously reported, but also could be an effect of toxins produced by Bd. For X. laevis, the ability to promote cardiac adjustments seems to be an important homeostatic feature that allows greater tolerance to chytridiomycosis. This study provides new physiological mechanisms underlying the tolerance or susceptibility of amphibian species to chytridiomycosis, which determine their adaptability to survive in the affected environments.

scholarly journals Urban Amphibians of the Texas Panhandle

2012 ◽  
Vol 19 (4) ◽  
pp. 243-253
Author(s):  
Rasika Ramesh ◽  
Kerry Griffis-Kyle ◽  
Gad Perry ◽  
Michael Farmer
Keyword(s):  
Species Richness ◽  
Habitat Preferences ◽  
Amphibian Declines ◽  
Amphibian Conservation ◽  
Conservation Strategies ◽  
High Plains ◽  
Severe Drought ◽  
Negative Effects ◽  
Road Density ◽  
Amphibian Species

Habitat loss, degradation, and fragmentation due to urbanization are implicated in amphibian declines worldwide. Conservation efforts require information on resident species and their habitat interactions, but amphibian ecology is largely  unstudied in urban centers of the Southern High Plains. Here, we gathered baseline data on amphibian presence, species richness, and habitat preferences at site-specific and landscape scales during a severe drought year in the city of Lubbock, in northwestern Texas. Ephemeral playa wetlands are characteristic of this landscape. During urbanization, these have been extensively modifiied for stormwater drainage,  agriculture, and construction of roads, buildings and neighborhoods. A semi-arid climate with frequent droughts, together with urbanization, could have an adverse effect on resident amphibians. In 2011, we sampled 23 urban lakes for amphibian presence, using a combination of audio, visual, and larval surveys. We detected five amphibian species at seven lakes; Texas Toads (Anaxyrus speciosus) and Spotted Chorus Frogs (Pseudacris clarkii) were the most frequently encountered species. We found significant negative effects of nearby road density on amphibian species presence and richness. We also detected significant negative effects of basic pH on amphibian species richness. These data can be used for prioritizing lakes for amphibian conservation strategies, to monitor ecosystem function in urban wetlands, and to guide future development and restoration efforts.

scholarly journals Significant reductions of host abundance weakly impact infection intensity of Batrachochytrium dendrobatidis

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242913
Author(s):  
Jaime Bosch ◽  
Luis M. Carrascal ◽  
Andrea Manica ◽  
Trenton W. J. Garner
Keyword(s):  
Batrachochytrium Dendrobatidis ◽  
Infection Intensity ◽  
Natural World ◽  
Natural Habitats ◽  
Amphibian Species ◽  
Host Abundance ◽  
Amphibian Larvae ◽  
Severity Of The Disease ◽  
The Impact ◽  
Salamander Larvae

Infectious diseases are considered major threats to biodiversity, however strategies to mitigate their impacts in the natural world are scarce and largely unsuccessful. Chytridiomycosis is responsible for the decline of hundreds of amphibian species worldwide, but an effective disease management strategy that could be applied across natural habitats is still lacking. In general amphibian larvae can be easily captured, offering opportunities to ascertain the impact of altering the abundance of hosts, considered to be a key parameter affecting the severity of the disease. Here, we report the results of two experiments to investigate how altering host abundance affects infection intensity in amphibian populations of a montane area of Central Spain suffering from lethal amphibian chytridiomycosis. Our laboratory-based experiment supported the conclusion that varying density had a significant effect on infection intensity when salamander larvae were housed at low densities. Our field experiment showed that reducing the abundance of salamander larvae in the field also had a significant, but weak, impact on infection the following year, but only when removals were extreme. While this suggests adjusting host abundance as a mitigation strategy to reduce infection intensity could be useful, our evidence suggests only heavy culling efforts will succeed, which may run contrary to objectives for conservation.

Locality, time and heterozygosity affect chytrid infection in yellow-bellied toads

2020 ◽  
Vol 142 ◽  
pp. 225-237
Author(s):  
P Oswald ◽  
A Rodríguez ◽  
J Bourke ◽  
N Wagner ◽  
N de Buhr ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Breeding Season ◽  
Batrachochytrium Dendrobatidis ◽  
Infection Intensity ◽  
Sampling Period ◽  
Infection Prevalence ◽  
Infection Status ◽  
Population Declines ◽  
Amphibian Species ◽  
High Genetic Diversity

The chytrid fungus Batrachochytrium dendrobatidis (Bd) infects numerous amphibian species worldwide and is suggested to drive population declines and extinction events. We report a study of Bd infection at the northernmost distribution of the European yellow-bellied toad Bombina variegata. A total of 577 individuals from ponds in 16 study sites were sampled for DNA and Bd throughout the breeding season. Microsatellite genotyping revealed 3 genetic clusters for the host B. variegata with an overall low genetic diversity. One of the clusters displayed a low microsatellite heterozygosity, a high inbreeding coefficient as well as high Bd infection prevalence and intensities. Multi-model estimates identified site, time of sampling, and heterozygosity to be important predictors of an individual’s Bd infection status, and identified a strong effect of site on individual Bd infection intensity. The study site effects are suggestive of localized infection peaks, and the increase of individual Bd infection probabilities towards the end of the sampling period suggests cumulative infection during the breeding season. This study highlights the need for regular monitoring of Bd infection variables at multiple localities and times to gain insights into Bd dynamics. Due to the detected relationship between individual Bd infection status and heterozygosity, conservation measures should focus on the maintenance of high genetic diversity and connectivity within and among amphibian populations.

scholarly journals Diversity patterns, research trends and mismatches of the investigative efforts to amphibian conservation in Brazil

2014 ◽  
Vol 86 (4) ◽  
pp. 1873-1886 ◽  
Author(s):  
FELIPE S. CAMPOS ◽  
DANIEL BRITO ◽  
MIRCO SOLÉ
Keyword(s):  
Spatial Scales ◽  
Research Trends ◽  
Amphibian Conservation ◽  
Research Topics ◽  
Amphibian Species ◽  
Diversity Patterns ◽  
Main Research ◽  
The Status ◽  
Geographic Regions ◽  
Taxonomic Groups

The number of papers on biology of amphibians has increased in the recent years. A detailed overview of the publications on amphibians can be very useful in assessing the status of our knowledge about this taxonomic group. Due to the large number of articles published, we aimed to assess the scientific contribution of herpetological researches carried out between the years 2001 and 2010 on Brazilian amphibians, considering the diversity patterns, the threats and the research topics that have been published most often. We applied scientometric attention indexes in the reviewed studies from seven scientific databases. To examine the relationship between the numbers of species recorded locally and regionally at different spatial scales, we used an additive partitioning of diversity in three hierarchical levels (i.e., states, geographic regions and biomes). We evaluated 892 articles and 914 species, which showed that 65 % of the total diversity of Brazilian amphibian species was represented by the beta diversity among the biomes. We identified many differences in the allocation of research efforts for taxonomic groups, threats categories, geographic regions, and research topics, highlighting the main research trends conducted and the priority themes for investigation of further papers on Brazilian amphibians.

scholarly journals Local Community Knowledge and Perceptions towards Amphibians in Urban and Rural Settings: Tools for Biological Conservation

2020 ◽  
Author(s):  
Danny Vergara-Ríos ◽  
Andrés Camilo Montes-Correa ◽  
J. Nicolás Urbina-Cardona ◽  
Miguel Antonio De Luque-Villa ◽  
Pedro E. Cattan ◽  
...  
Keyword(s):  
Young Adults ◽  
Educational Level ◽  
Native Species ◽  
Local Community ◽  
Age Groups ◽  
Amphibian Conservation ◽  
Conservation Strategies ◽  
Negative Beliefs ◽  
Taxonomic Groups ◽  
Rural Locality

Abstract Background Human perceptions determine the degree to which people can coexist with biodiversity. It is, therefore, important to identify the sociodemographic factors that determine these local perceptions to adjust amphibian conservation strategies. In this research, the effect of the urban or rural location where people live, as well as their gender, age and educational level, concerning the knowledge and perceptions about amphibians was determined.Methods The data were collected through individual semi-structured surveys, which sought to evaluate changes in the perceptions, of 401 participants, about amphibians. We measured seven response variables through the Likert scale, which ranges from 1 (totally disagree) to 5 (totally agree): composition of taxonomic groups, number of known taxonomic groups, species composition of anurans, number of species of anurans, level of importance of amphibians in nature, positive perceptions about amphibians and negative beliefs about amphibians. For each response variable, a Bray-Curtis matrix was generated and multivariate analysis of variance (PERMANOVA).Results Ninety-two percent of people correctly recognized frogs and toads as amphibians, but there was confusion in classifying caecilians and salamanders within this group, or including reptiles (lizards, turtles and snakes) within the group of amphibians. This confusion was more evident for women from urban locality. No one recognized the five native species shown in the study, although the inhabitants of the rural locality recognized more species than those of the urban locality. Positive perceptions of amphibians varied between urban and rural locality for young adults, people with a high school education level, and people without formal education. Negative beliefs varied between urban and rural locations for women, adolescents, young adults, and professionals with undergraduate studies. Half of the people accepted information on the conservation of amphibians.Conclusion Positive perceptions of people about amphibians should be used as a flag to strengthen environmental educational strategies that seek to change negative attitudes about this group. Field activities are crucial to consolidating the positive perceptions of people about amphibians, mainly in urban locations. The results suggest that amphibian conservation plans that aim to inform and educate the public should be focused differently for age groups, genders, and educational level for people in urban and rural locations.

scholarly journals Assessing Suitable Habitats for Treefrog Species after Previous Declines in Costa Rica

Diversity ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 577
Author(s):  
Héctor Zumbado-Ulate ◽  
Catherine L. Searle ◽  
Gerardo Chaves ◽  
Víctor Acosta-Chaves ◽  
Alex Shepack ◽  
...  
Keyword(s):  
Costa Rica ◽  
Sympatric Species ◽  
Costa Rican ◽  
Suitable Habitat ◽  
Minimum Convex Polygon ◽  
Amphibian Species ◽  
Environmental Threats ◽  
The Status ◽  
Suitable Habitats ◽  
Iucn Assessment

Treefrogs represent 22% of amphibian species in Costa Rica, but gaps in the knowledge about this group of amphibians can impede conservation efforts. In this study, we first updated the status of Costa Rican treefrogs and found that a total of 38% of treefrog species are threatened according to the most recent IUCN assessment in 2019. Additionally, 21% of Costa Rican treefrog species have a high vulnerability to extinction according to environmental vulnerability scores. Then, we predicted the historical climatic suitability of eight target species that we expected to have exhibited changes in their ranges in the last 20 years. We assessed the location of new occurrence records since 2000 to identify recovery, range expansion, or previously underestimated ranges due to methodological limitations. We also estimated the area of each species’ suitable habitat with two metrics: extent of suitable habitat (ESH) and area of minimum convex polygon (AMCP). Six declined species exhibited recovery (i.e., new occurrences across historical range after 2000), with the widest recovery found in Agalychnis annae. We also found that Isthmohyla pseudopuma appears to have spread after the decline of sympatric species and that the range of I. sukia was originally underestimated due to inadequate detection. We found that the ESH was 32–49% smaller than the AMCP for species that are slowly recovering; however, the ESH is similar or greater than the AMCP for species that are recovering in most of their ranges, as well as rare species with widespread ranges. Results of this work can be used to evaluate the risk of environmental threats and prioritize regions for conservation purposes.

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