Composition of amphibian assemblages in agroecosystems from the central region of Argentina (original) (raw)
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Interciencia, 2008
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Daniel Lara-Tufiño, Luis. M. Badillo-Saldaña,Raquel Hernández-Austria & Aurelio Ramírez-Bautista. PeerJ :e6390 DOI 10.7717/peerj.6390, 2019
Habitat loss or degradation due to land cover change is regarded as one of the main drivers of amphibian decline; therefore, it is imperative to assess the effects of land-cover change on this group of vertebrates. In this study, we analyze changes in alpha and beta diversity of amphibian communities found in five land-cover types: mountain cloud forest, tropical evergreen forest, shade coffee, milpa huasteca, and grazing areas; six samples sites were established for each land-cover type, separated at least one km away. The study was conducted in the northwest part of the state of Hidalgo, in a transition zone between the Sierra Madre Oriental and the Gulf of Mexico, which is a region rich in amphibian species. The results indicate that alpha diversity decreases with loss of canopy cover, this being high in mountain cloud forest, tropical evergreen forest, and Shade coffee, and low in milpa huasteca and grazing areas. The land-cover type with the highest species evenness was found in milpa huasteca and the lowest in. The highest beta diversity was observed among tropical evergreen forest and grazing areas. Mountain cloud forest contains both exclusive species and the highest number of species currently regarded as threatened by national and international conservation assessment systems. In order to preserve amphibian diversity in the study area it is vital to protect the last remnants of native vegetation, especially mountain cloud forest, but also including Shade coffee, since the latter habitat harbors amphibian diversity similar to that found in native forests. Finally, implementation of policies that both reduce Grazing areas and increase their productivity is also necessary, since these highly modified areas turn out to be the ones that affect amphibian diversity the most.
Biodiversity and Conservation, 2002
The species composition, reproductive ecology, and patterns of activitywere determined for an anuran assemblage of an area of subtropical montaneforest in northwest Argentina. Twenty-four species were recorded at ParqueNacional Calilegua, Province of Jujuy. This study reflects a 75% increase in thenumber of species reported in previous surveys. Most species inhabiting the parkare mainly from adjacent Chacoan regions and only six taxa are known to beendemic from montane forest areas. Most species are aquatic breeders, and theabsence of many forest reproductive modes is noticeable. Although baselineinformation to compare former community composition was lacking, comparisonsbased on museum specimens revealed no evidence of local population extinctions.Immediate intensive monitoring is needed to quantitatively address amphibianpopulation fluctuations and to examine the effectiveness of present-day montaneforest protection. Although long-term population monitoring and documentation ofspecies declines is lacking, I propose a list of seven species of conservationconcern in order to assist and promote future monitoring programs.
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The occurrence of abnormalities in amphibians has been reported in many populations, and its increase could be related to environmental pollution and habitat degradation. We evaluated the type and prevalence of abnormalities in 5 amphibian populations from agroecosystems with different degrees of agricultural disturbance (cultivated and reference areas). We detected 9 types of abnormalities, of which the most frequent were those occurring in limbs. The observed prevalence of abnormality in assessed populations from cultivated and reference areas was as follows: Rhinella fernandezae (37.1 and 10.2%, respectively), Leptodactylus latrans adults (28.1 and 9.2%) and juveniles (32.9 and 15.3%), and Hypsiboas pulchellus (11.6 and 2.8%). Scinax granulatus populations did not show abnormalities. Pseudis minuta, which was only detected in the reference area, exhibited a prevalence of 13.3%. For R. fernandezae, L. latrans, and H. pulchellus, generalized linear mixed models showed that prevalence of abnormalities was significantly higher (p < 0.05) in cultivated than in reference areas. L. latrans juveniles were more vulnerable to abnormalities than adults (p < 0.05). The presence of abnormalities in some species inhabiting different agroecosystems suggests that environmental stress factors might be responsible for their occurrence. While we detected pesticides (endosulfan, cypermethrin, and chlorpyrifos) and lower dissolved oxygen levels in ponds of the cultivated area, no data are currently available on how other factors, such as injuries from predators and parasite infections, vary by land use. Further research will be necessary to evaluate possible causes of abnormalities detected in the present study mainly in the context of factor interactions.
Conservation status of Amphibians of Argentina: An update and evaluation of national assessments
—We present a review on the conservation status of the 177 species and subspecies of amphibians of Argentina and compare the first national assessment, conducted in 2000, with the most recent one, from 2012, to determine changes in conservation status over time. We also evaluate the degree of taxonomic and geographic non-randomness in extinction risk among these taxa. The present study shows an improvement in the knowledge of amphibian diversity in Argentina, but also increasing evidence of population declines and species absences. Twenty-two species showed a genuine increase in threat status between national assessments, and habitat loss and/or degradation, chytrid fungus infection, and introduction of invasive species have been reported as the main threats. Randomization tests showed families Telmatobiidae and Batrachylidae to be over-threatened and Hylidae and Leptodactylidae to be significantly under-threatened. Also, four ecoregions were shown to be significantly over-threatened (Patagonian Steepe, Patagonian Woodlands, Puna, and Yungas Forests). This evaluation help to identify groups of species that face similar suites and intensities of threat as a result of their overlapping geographical distributions and shared biological susceptibility as a result of their evolutionary history. We consider that our results highlight patterns and trends to alert policymakers and to guide priority actions. Citation: Vaira M, Pereyra LC, Akmentins MS, Bielby J. 2017. Conservation status of amphibians of Argentina: An update and evaluation of national assessments. Amphibian & Reptile Conservation 11(1) [General Section]: 36–44 (e135).
Anuran amphibians' diversity in a northwestern area of the Brazilian Pantanal
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In the Pantanal, the largest continuous floodplain in the world, the diversity and distribution of anuran amphibians vary in and across distinct subregions and distinct habitats occurring along inundation gradients. Permanent and natural aquatic habitats are relatively scarce in the Pantanal, and occurrence of temporary aquatic habitats varies seasonally, depending on rains. We here present results of evaluations of anuran's species richness and abundance in a seasonally flooded area in the northwestern section of the Pantanal (Fazenda Baía de Pedra, Cáceres municipality, state of Mato Grosso, Brazil), comparing values obtained in 10 plots systematically distributed over 5 km 2 with those obtained in additional aquatic plots in the study area. Data were obtained in five field trips, from February 2008 to March 2009. In addition to the plots, 36 water bodies (20 permanent and 16 temporary) were also sampled for the presence of anurans. In total, 3,983 individuals from 34 anuran species distributed in five families were recorded: Hylidae (14 species), Leptodactylidae (8), Leiuperidae (6), Microhylidae (4), and Bufonidae (2). Local richness represents 77.3% of the anuran diversity already recorded for the Brazilian Pantanal. The number of species recorded exclusively in systematically distributed terrestrial plots and in water bodies was 28 and 32, respectively. Sampling methods used at Fazenda Baía da Pedra were efficient in determining anuran richness, abundance, composition and distribution. Evaluations of anuran richness and abundance by using permanent sampling plots in the Pantanal may benefit from additional sampling sites, particularly permanent and temporary water bodies. PANSONATO, A., MOTT, T. & STRÜSSMANN, C. Diversidade de anfíbios anuros em uma area na porção noroeste do Pantanal brasileiro. Biota Neotrop. 11(4): http://www.biotaneotropica.org.br/v11n4/pt/ abstract?article+bn01711042011
Morphological Abnormalities in Amphibian Populations from the Mid-Eastern Region of Argentina
Herpetological Conservation and Biology, 2011
We present the first compilation and analysis of cases of morphologically abnormal anurans from the mideastern region of Argentina (Córdoba, Santa Fe, and Entre Ríos Provinces). We sampled for abnormal individuals at 51 sites in agricultural, suburban, and forest settings between January 2000 and December 2009. We recorded 71 abnormal individuals, including 16 types of abnormalities in 15 anuran species. In agricultural sites, we found 12 types of abnormalities, with ectromelia being the most abundant. In suburban sites, we recorded seven types of abnormalities, with brachygnathia and ectromelia being the most common. In forest sites, we found three types of abnormalities, with ectromelia again being the most abundant. This study is the first catalog of anurans with morphological abnormalities in Argentina, thus expanding the geographic range of observed abnormalities in amphibians and illustrating the ubiquity of this phenomenon.
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Land use in Mexico has dramatically changed in recent decades since deforested lands have been repurposed for agriculture. We evaluated the amphibian taxonomic and functional diversity of a heterogeneous landscape with ten land cover/use types in west-central Mexico. Taxonomic diversity was evaluated with q-order indices, and functional diversity was calculated with three multivariate functional diversity indices by land cover/use. The relationship between amphibian diversity, habitat structure, and environmental variables was analyzed using multidimensional distance-based analyses. Our results showed that most native land cover types exhibited a similar species richness (low values) among the studied crops, except for the riparian habitat surrounded by tropical dry forest (high richness) and secondary vegetation (intermediate richness). Regarding functional diversity, the riparian habitat surrounded by tropical dry forest, sugar cane field, and secondary vegetation had the highest ...