scholarly journals Observations on the intensity and prevalence of Batrachochytridium dendrobatidis in sympatric and allopatric Epidalea calamita (native) and Discoglossus pictus (invasive) populations

Author(s):  
Albert Montori ◽  
Olatz San Sebastián ◽  
Marc Franch ◽  
Eudald Pujol-Buxó ◽  
Gustavo A. Llorente ◽  
...  

We analyse if the presence of the invasive Discoglossus pictus and the native Epidalea calamita in the same geographic area can shape the dynamics of infection by Batrachochytridium dendrobatidis (Bd). Both amphibian species share breeding habitat preferences in the area (i.e. ephemeral and temporary ponds) and are common syntopic competitors. We sampled adults of either species in a total of nine breeding localities in Catalonia (NE Iberian Peninsula): six localities within sympatric geographic areas, two localities outside the current invasion range of D. pictus, and one locality comprising solely D. pictus due to its recent introduction and the ancient extinction of E. calamita. We analysed the prevalence and intensity of infection by Bd in 183 individuals (81 D. pictus and 101 E. calamita). The presence of Bd was detected in eight of the localities, all of which had not been yet confirmed as positive for the fungus. Only in one locality, with presence of D. pictus, Bd presence was not detected. Mean prevalence was slightly but non-significantly higher in E. calamita (46.5%) than in D. pictus (36.6%). Allopatric populations of E. calamita showed significantly lower prevalence of Bd infection than sympatric ones, but similar differences were not found for infection intensity. Likewise, no significant differences were found in infection intensity between allopatric and sympatric D. pictus populations. The presence of abundant Bd outside the invasion range of D. pictus supports the assertion that Bd has not been introduced in the studied area because of D. pictus invasion. However, the presence of the two species in sympatry may enhance the infection rates and therefore the prevalence of Bd in the native species.    

2019 ◽  
Vol 40 (4) ◽  
pp. 425-435 ◽  
Author(s):  
Eudald Pujol-Buxó ◽  
Gabriel M. Riaño ◽  
Gustavo A. Llorente

Abstract The choice of breeding sites by pond-breeding anurans has notable consequences for the fitness of larvae. Hence, beyond pond typology and phenology, adults can also discriminate according to several other features, for instance to favour allotopy with potential competitors. However, the lack of shared evolutionary history might impede proper ecological differentiation with alien species during the first stages of invasions. Here, we studied several possible sources of ecological segregation between the invasive Discoglossus pictus and the native Epidalea calamita in ephemeral ponds, where the native toad hardly had competition before the arrival of the invasive frog. During spring of 2016, we periodically surveyed 69 ephemeral ponds in three areas with different invasion histories to detect the presence/absence of eggs and tadpoles of these species. Invasive D. pictus started breeding earlier than E. calamita, but differences were not significant. Similarly, there were not clear differences among areas with different invasion histories. However, we found for both species a mutual tendency to directly avoid larval syntopy at the end of the reproductive season. We also found interspecific differences in the features that both species use for pond choice, preferring the native species shallower and less vegetated ephemeral ponds. Globally however, co-occurrence was high, pointing at other processes as key to the coexistence between both species in these habitats.


2013 ◽  
Vol 34 (1) ◽  
pp. 63-73 ◽  
Author(s):  
Balázs Vági ◽  
Tibor Kovács ◽  
Raluca Băncilă ◽  
Tibor Hartel ◽  
Brandon P. Anthony

Temporary ponds are characterized as being in natural or close to natural states in Central and Eastern Europe, especially those located in forested landscapes. As these ponds function as breeding sites for many amphibians, they represent an ideal target to explore the terrestrial and aquatic habitat preferences of different species. We surveyed 133 small ponds in a forested, hilly region of North-Central Hungary. The occurrence of ten amphibian species and amphibian species richness were compared to six pond-related habitat variables and the extent of four terrestrial habitat types in the area surrounding the ponds. Our results suggest that most species’ occurrence and species richness are chiefly related to pond characteristics, although terrestrial habitat variables could also be a determining factor in particular species. Whereas the majority of amphibian species prefer larger, hence more permanent water bodies with abundant aquatic vegetation, the common frog (Rana temporaria) chooses small, shallow wallow pits for breeding and has special requirements concerning terrestrial habitat composition. This could explain its restricted distribution in the area. Our results suggest that maintaining a diverse set of ponds and forestry management which facilitates habitats’ structural heterogeneity are both important factors for the preservation of the rich amphibian fauna in Central Europe.


Author(s):  
Selene Babini ◽  
Luciana Cibils Martina ◽  
Elisa Luque ◽  
Noemi Gari ◽  
Nancy Salas ◽  
...  

<p>Agriculture is considered an important factor for the decline of amphibians recorded in the last decades. Intensive agriculture requires the application of great amounts of pesticides and fertilizers, consequently many aquatic habitats have been altered. The over-enrichment of waters with nutrients from agriculture causes growth of algae and cyanobacteria and the shift of the community composition toward the dominance of tolerant taxa. The aim of this study was to analyze the diet of tadpoles and the size of larvae and metamorphs of the native species <em>Rhinella arenarum </em>in agroecosystems of central Argentina. Four sampling sites with different degree of human disturbance were selected, three temporary ponds from agroecosystems (A1, A2, A3), and a pond in a semi-modified landscape, not affected by agriculture or cattle. The sites were visited once a week from October 2013 to January 2014. Tadpoles and metamorphs were captured, anesthetize and preserved. Morphometric parameters were measured on tadpoles and metamorphs and for 20 tadpoles the complete intestine was removed and their contents analyzed. Phosphate values were higher in agroecosystem ponds. Body size and mass of tadpoles and metamorphs were different between sites, being smaller in agricultural ponds. Diet analysis revealed that all larvae mainly consumed microalgae. Larval diets allowed differentiating the sites, larvae from A1 and A3 sites showed a diet with a similar composition and structure (with a predominance of <em>Nitzschia palea</em>), meanwhile larvae from A2 and SM showed different diets. In SM, the larvae mainly consumed <em>Trachelomonas </em>sp. Analysis of structural variables revealed a higher algal abundance in the diet of larvae from A3, a lower richness in SM and that there were no differences between sites in diversity and evenness of diets. Our hypothesis was support in part, given that resistant algae taxa were found in agroecosystem ponds and tadpoles and metamorphs were smaller, but larval diets showed higher abundance and richness. The analysis of the diet of aquatic stages of <em>R. arenarum</em> allowed us to know the trophic availability and environmental quality of temporary ponds from agroecosystems. </p>


2017 ◽  
Vol 17 (2) ◽  
Author(s):  
Janaina Reis Ferreira Lima ◽  
Jucivaldo Dias Lima ◽  
Soraia Dias Lima ◽  
Raullyan Borja Lima Silva ◽  
Gilda Vasconcellos de Andrade

Abstract Amphibian research has grown steadily in recent years in the Amazon region, especially in the Brazilian states of Amazonas, Pará, Rondônia, and Amapá, and neighboring areas of the Guiana Shield. Even so, few data are available for the Amazonian savannas of Brazil. To contribute to the understanding of the diversity of the amphibians of these savannas, we surveyed 15 temporary ponds, six located in open areas, seven on the edge of savanna forest, and two within the forest, in the savanna of the Rio Curiaú Environmental Protection Area (EPA) in Macapá, in the state of Amapá, northern Brazil. Sampling occurred from May 2013 to August 2014 during periods when the ponds contained water. Amphibians were sampled through visual and auditory surveys conducted during both the day- and the nighttime periods on seven days each month over a total of 84 days. A total of 1574 individuals belonging to four families, 12 genera, and 28 species were recorded during the surveys. The cumulative species curve reached the asymptote, indicating that sampling effort was adequate. The number of species was 25% higher than that reported in other studies in Amazonian savannas. Twelve species were recorded for the first time in the savanna of Amapá. Lysapsus boliviana was the most common species (n = 332 of the individuals recorded). The greatest amphibian species richness found in the Rio Curiaú EPA was associated with the savanna mosaic, forest patches, lowland swamp, and temporary ponds. The results of this study contribute to the understanding of the diversity of amphibian species in the Guianan area of endemism in northern Brazil, and also the Amazonian savannas.


PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9763
Author(s):  
Mizraim Olivares-Miranda ◽  
Vance T. Vredenburg ◽  
Julio C. García-Sánchez ◽  
Allison Q. Byrne ◽  
Erica B. Rosenblum ◽  
...  

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.


2018 ◽  
Vol 409 ◽  
pp. 817-825 ◽  
Author(s):  
G. García-Salgado ◽  
S. Rebollo ◽  
L. Pérez-Camacho ◽  
S. Martínez-Hesterkamp ◽  
E. De la Montaña ◽  
...  

2020 ◽  
Vol 57 (6) ◽  
pp. 1700-1711
Author(s):  
X Acosta ◽  
A X González-Reyes ◽  
N D Centeno ◽  
J A Corronca

Abstract This study determined the spatial and temporal dynamics of two native neotropical species flies of forensic interest, belonging to the Lucilia (Robineau-Desvoidy) genus. The study focused on their abundance and reproductive behaviors associated with different habitats and phenological parameters. In the Province of Salta, Argentina, monthly samplings were performed over 1 yr in urban, rural, and native habitats, at morning, mid-day, and afternoon periods, controlling the oviposition of captured specimens. Environmental variables were also assessed: cloudiness, precipitation, relative humidity, temperature, and tree cover. Lucilia purpurascens (Walker) appeared to be associated with native habitats, whereas Lucilia ochricornis (Wiedemann) was mainly associated with rural habitats, exhibiting distinct habitat preferences. Two ecotones were also identified: rural–urban and rural–native, suggesting rural habitats promoted habitable conditions at its margins. Both species were recorded at the end of winter to the middle of autumn, with an initial peak in early spring, and a second peak at late summer. These peaks were associated with the highest numbers of laid eggs. Lucilia purpurascens preferred high tree coverings, whereas L. ochricornis resisted areas with intermediate sun, suggesting limited sun exposure was important. The latter was also associated with daily flight activities; during the warm season, the densest catches occurred at morning and afternoon periods, whereas during the cold season, they occurred at mid-day. Climatic variables explained 77% of variability in terms of abundance and oviposition. Synergistic effects were observed between these variables, suggesting that these variables conditioned insect distribution and reproduction, and not just temperature per se.


2009 ◽  
Vol 55 (6) ◽  
pp. 597-602 ◽  
Author(s):  
D. E. Bakaloudis ◽  
C. G. Vlachos ◽  
E. Chatzinikos ◽  
V. Bontzorlos ◽  
M. Papakosta

Biology ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 821
Author(s):  
Sara Roje ◽  
Bořek Drozd ◽  
Luise Richter ◽  
Jan Kubec ◽  
Zdeněk Polívka ◽  
...  

The round goby is an invasive fish in Europe and North America that threatens native species by predation and competition. Its habitat preferences are similar to those of the European bullhead, which it displaces from shelters and out-competes for available resources. We assessed the microhabitat preferences, shelter use, and activity of the round goby and European bullhead in single-species experiments in habitat simulator systems to investigate their behavior in a novel environment. Fish were video-recorded for 28 h in the presence of shelter and feed with water velocity ranging from 0.00 to 0.96 m s−1. The two species showed similar behavior under given conditions. A primary difference was in stress-induced behavior in the initial phases of observation. The round goby spent more time in movement when outside the shelter and a longer time in the escape zone in the exploration period during light. Our results confirmed a significant preference of round goby for low velocity areas and a preference for higher velocities in the European bullhead. Both species were able to cope with velocities > 0.7 m s−1. Therefore, the reported invasion success of round goby is probably not driven by space use or activity patterns, but rather by higher adaptability.


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