ABSTRACT
The amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) causes chytridiomycosis, a disease among the main causes of amphibian declines worldwide. However, Bd studies on Neotropical amphibians from temperate areas are scarce. We present a comprehensive survey of Bd in Uruguay, in temperate central eastern South America, carried out between 2006 and 2014. Skin swabs of 535 specimens of 21 native and exotic frogs were tested by PCR. We used individual-level data to examine the relationship between infection, climatic variables, and their effects on body condition and the number of prey items found in stomach contents. Infection was widespread in free-ranging anurans with an overall prevalence of 41.9%, detected in 15 native species, wild American bullfrogs Aquarana catesbeiana, and captive specimens of Ceratophrys ornata and Xenopus laevis. Three haplotypes of the Bd ITS region were identified in native amphibians, all belonging to the global panzootic lineage (BdGPL), of which only one was present in exotic hosts. Despite high infection frequencies in different anurans, we found no evidence of morbidity or mortality attributable to chytridiomycosis, and we observed no discernible impact on body condition or consumed prey. Climatic conditions at the time of our surveys suggested that the chance of infection is associated with monthly mean temperature, mean humidity, and total precipitation. Temperatures below 21°C combined with moderate humidity and pronounced rainfall may increase the likelihood of infection. Multiple haplotypes of BdGPL combined with high frequencies of infection suggest an enzootic pattern in native species, underscoring the need for continued monitoring.
Subject(s)
Climate , Mycoses , Animals , Mycoses/veterinary , Mycoses/epidemiology , Mycoses/microbiology , Uruguay/epidemiology , Batrachochytrium/genetics , Anura/microbiology , Chytridiomycota/isolation & purificationABSTRACT
Standardised terminology in science is important for clarity of interpretation and communication. In invasion science - a dynamic and rapidly evolving discipline - the proliferation of technical terminology has lacked a standardised framework for its development. The result is a convoluted and inconsistent usage of terminology, with various discrepancies in descriptions of damage and interventions. A standardised framework is therefore needed for a clear, universally applicable, and consistent terminology to promote more effective communication across researchers, stakeholders, and policymakers. Inconsistencies in terminology stem from the exponential increase in scientific publications on the patterns and processes of biological invasions authored by experts from various disciplines and countries since the 1990s, as well as publications by legislators and policymakers focusing on practical applications, regulations, and management of resources. Aligning and standardising terminology across stakeholders remains a challenge in invasion science. Here, we review and evaluate the multiple terms used in invasion science (e.g. 'non-native', 'alien', 'invasive' or 'invader', 'exotic', 'non-indigenous', 'naturalised', 'pest') to propose a more simplified and standardised terminology. The streamlined framework we propose and translate into 28 other languages is based on the terms (i) 'non-native', denoting species transported beyond their natural biogeographic range, (ii) 'established non-native', i.e. those non-native species that have established self-sustaining populations in their new location(s) in the wild, and (iii) 'invasive non-native' - populations of established non-native species that have recently spread or are spreading rapidly in their invaded range actively or passively with or without human mediation. We also highlight the importance of conceptualising 'spread' for classifying invasiveness and 'impact' for management. Finally, we propose a protocol for classifying populations based on (i) dispersal mechanism, (ii) species origin, (iii) population status, and (iv) impact. Collectively and without introducing new terminology, the framework that we present aims to facilitate effective communication and collaboration in invasion science and management of non-native species.
Subject(s)
Introduced Species , Terminology as Topic , AnimalsABSTRACT
The uneven spatial distribution of biodiversity is a defining feature of nature. In fact, the implementation of conservation actions both locally and globally has progressively been guided by the identification of biodiversity 'hotspots' (areas with exceptional biodiversity). However, different regions of the world differ drastically in the availability of fine-scale data on the diversity and distribution of species, thus limiting the potential to assess their local environmental priorities. Within South America-a megadiverse continent-Uruguay represents a peculiar area where multiple tropical and non-tropical eco-regions converge, creating highly heterogeneous ecosystems, but where the systematic quantification of biodiversity remains largely anecdotal. To investigate the constraints posed by the limited access to biodiversity data, we employ the most comprehensive database for tetrapod vertebrates in Uruguay (spanning 664 species) assembled to date, to identify hotspots of species-richness, endemism and threatened species for the first time. Our results reveal negligible spatial congruence among biodiversity hotspots, and that tetrapod sampling has historically concentrated in only a few areas. Collectively, our study provides a detailed account of the areas where urgent biodiversity monitoring efforts are needed to develop more accurate knowledge on biodiversity patterns, offering government and environmental bodies a critical scientific resource for future planning.
Subject(s)
Biodiversity , Conservation of Natural Resources , Endangered Species , Vertebrates/physiology , Animals , UruguayABSTRACT
BACKGROUND: The continental and marine territories of Uruguay are characterised by a rich convergence of multiple biogeographic ecoregions of the Neotropics, making this country a peculiar biodiversity spot. However, despite the biological significance of Uruguay for the South American subcontinent, the distribution of biodiversity patterns in this country remain poorly understood, given the severe gaps in available records of geographic species distributions. Currently, national biodiversity datasets are not openly available and, thus, a dominant proportion of the primary biodiversity data produced by researchers and institutions across Uruguay remains highly dispersed and difficult to access for the wider scientific and environmental community. In this paper, we aim to fill this gap by developing the first comprehensive, open-access database of biodiversity records for Uruguay (Biodiversidata), which is the result of a large-scale collaboration involving experts working across the entire range of taxonomic diversity found in the country. NEW INFORMATION: As part of the first phase of Biodiversidata, we here present a comprehensive database of tetrapod occurrence records native from Uruguay, with the latest taxonomic updates. The database provides primary biodiversity data on extant Amphibia, Reptilia, Aves and Mammalia species recorded within the country. The total number of records collated is 69,380, spanning 673 species and it is available at the Zenodo repository: https://doi.org/10.5281/zenodo.2650169. This is the largest and most geographically and taxonomically comprehensive database of Uruguayan tetrapod species available to date and it represents the first open repository for the country.
ABSTRACT
Elachistocleis haroi sp. nov. is described from El Algarrobal, Jujuy province, north-western Argentina. The new species is diagnosed by the dorsal pattern of mid-longitudinal bright yellow stripe from the intraocular zone, surpassing the post-cephalic transverse skin fold, to vent; dorsum grayish brown mottled with a paravertebral symmetric pattern of dark spots resembling a pine tree; and a thin regular yellow line on the posterior surface of the thighs and tibiae. The advertisement call is a long trill with an average duration of 3.18 seconds, multipulsed with a mean dominant frequency of 4.56 kHz. The tadpole is characterized by the oral dermal flaps with papillae-like edges.
Subject(s)
Anura/classification , Animal Structures/anatomy & histology , Animal Structures/growth & development , Animals , Anura/anatomy & histology , Anura/growth & development , Anura/physiology , Argentina , Body Size , Female , Larva/anatomy & histology , Larva/classification , Larva/growth & development , Male , Organ Size , Pinus , Vocalization, AnimalABSTRACT
Scinax aromothyella is a recently described hylid frog. Its distribution is not well known. There are records for Misiones, Argentina and for southeastern Uruguay. Here we report a new record of S. aromothyella from Aceguá, Cerro Largo Department, Uruguay (31º 53' 39" S and 54º 9' 17" W), based in tadpoles collected on the 15 of August, 2007. This new record extends the distribution of S. aromothyella in approximately 100 km north from previous reports in Uruguay. The samples were collected in a site located 2 km away from the border line with Brazil, reinforcing the idea that S. aromothyella might occur in Rio Grande do Sul.
Scinax aromothyella es un anfibio hilido recientemente descripto y con distribución poco conocida. Existen registros de Misiones, Argentina, y del sureste de Uruguay. Reportamos en este trabajo un nuevo registro de S. aromothyella para el Departamento de Cerro Largo, Uruguay, localidad Aceguá (31º 53' 39" S y 54º 9' 17" W) basado en renacuajos colectados el 15 de agosto de 2007. Este registro extiende la distribución de S. aromothyella más de 100 km al norte de los registros previos en Uruguay. La cercanía a la frontera (2 km) refuerza la idea de la ocurrencia de esta especie en el sur de Brasil.
Subject(s)
Amphibians , Anura/classification , Ecosystem , Ecosystem/analysis , Ecosystem/classification , Ecosystem/adverse effects , LarvaABSTRACT
We examined the diet of 4 annual fishes, Austrolebias viarius, Austrolebias cheradophilus, Austrolebias luteoflammulatus and Cynopoecilus melanotaenia inhabiting temporal ponds of southeastern Uruguay, by analysis of stomach contents. Fishes were captured from fifty ephemeral ponds of Castillos Lagoon basin, in the region of the Humedales del Este. We identified 13099 individual prey items extracted from 669 stomachs of the four captured species. In the studied system, annual killifishes represents the most abundant and conspicuous top predators. Killifishes are generalist key predators at the ephemeral ponds of the studied system, consuming mostly aquatic items. Zooplancton represented the bulk of the diet in the four analyzed species, followed by eggs, algae and diatoms. Insects are the next group in prey number, as follows: Diptera larvae (especially Chironomidae and Cullicidae), Ephemeroptera (especially Betidae), and coleopteran larvae (especially Dytiscidae). Acari are also important prey in number. The four fish species differ in diet composition and in diet richness. A general pattern of differences in diet richness among killifish species and demographic groups could be related to variations in body sizes. As top predators annual killifishes are an important component of the temporal pond ecosystems. Understanding the natural history of this species and their communities is necessary in order to conserve them.(AU)
Nós examinamos a dieta de 4 peixes anuais, Austrolebias viarius, Austrolebias cheradophilus, Austrolebias luteoflammulatus e Cynopoecilus melanotaenia, que habitam poças temporárias do sudeste do Uruguai, através da análise de conteúdo estomacal. Os peixes foram capturados em cinco poças temporárias da bacia da lagoa Castillos, na região de Humedales del Este. Nós identificamos 13099 itens de presas estraídos de 669 estômagos das quatro espécies. No sistema estudado, peixes anuais representam os predadores de topo mais abundantes e conspícuos. Os rivulídeos são predadores generalistas nas poças temporaries estudadas, consumindo principalmente itens aquáticos. Zooplâncton representou o item principal da dieta para as quatro espécies, seguido de ovos, algas e diatomáceas. Insetos compoem o próximo grupo em número de presas, como segue: larvas de Diptera (especialmente Chironomidae e Cullicidae), Ephemeroptera (especialmente Betidae), e larvas de Coleoptera (especialmente Dytiscidae). Ácaros foram também presas importantes em número. As quatro espécies de peixes diferem na composição e riqueza das dietas. O padrão geral de diferenciação da dieta entre espécies e grupos demográficos de rivulídeos pode ser relacionado à variação do tamanho corporal. Como predadores de topo, os rivulídeos anuais são um componente importante dos ecossistemas de poças temporárias. A compreensão da história natural destas espécies e de suas comunidades é necessária a sua conservação.(AU)
Subject(s)
Animals , Cyprinodontiformes/metabolism , Food Chain , Fishes , Behavior , Gene Transfer, HorizontalABSTRACT
Intraspecific competition is predicted to strongly influence species abundance and dynamics through two main mechanisms: consumption and interference of resources. Tadpoles were used in experiments in which we tried to elucidate the relative importance of each mechanism. Our goal was to apply this experimental procedure to Leptodactylus ocellatus, a common South American anuran, a species whose larvae exhibit aggregative behavior and receive parental care. Previous work suggests that tadpole schools should present lower levels of intraspecific competition. Tadpoles from a single nest were reared in the laboratory in three densities (1, 2, and 4 individuals/container) and three food levels (1, 2, and 4 ration multiples) in a randomized three-block design for a factorial analysis of variance, up to day eight. Contrary to previous work with other species, our results show both the absence of interference competition effects, and that larval growth depends only on per capita food availability. The differences between species in intraspecific competition mechanisms are probably related to strong differences in ecology and life history. Leptodactylus ocellatus tadpoles could be directing interference competition away from their kin, reducing schooling costs. Further studies (including kinship as a factor) would give more information about these larvae, allowing a better understanding of the evolutionary and ecological mechanisms behind the biological patterns observed in Leptodactylus species.
Subject(s)
Anura/physiology , Behavior, Animal/physiology , Ecosystem , Animals , Food Supply , Larva , Population Density , Species SpecificityABSTRACT
Passive remote sensing of airborne chemicals at infrared wavelengths may be limited by temporal fluctuations in atmospheric brightness temperatures deltaT(t). Brightness temperatures in two infrared spectral bands were simultaneously measured on clear and cloudy days along three lines of sights. For time windows t < 3-5 s, deltaT(t) remained constant at the sensor noise level and rapidly increased as t increased. The fluctuation time scale for the cloudy day was longer than for the clear day. The long correlation time for T(t) limits the utility of signal averaging in improving detection signal-to-noise ratio (SNR). The simultaneous outputs of the two spectral channels during the clear day exhibited no spectral coherence at t < 3 s and limited coherence at t > 30 s. Measurements during the cloudy day were largely coherent. Consequently, band-by-band subtraction may have limited benefits.
ABSTRACT
A differential absorption radiometer sensor that was optimized for near-perfect (to approximately 2%) correction of the absorption by ambient atmospheric species (e.g., water) is described. A target gas is detected remotely by its IR signature viewed through a bandpass filter centered at one of its strongest lines. A second radiometric measurement obtained through a bandpass filter centered at a frequency optimized to match the absorption by an atmospheric trace species (e.g., water vapor) at the sample filter frequency provides near-perfect correction for dominant background absorption effects. The net absorption (emission) by the target gas was obtained through subtraction of the reference signal of the second measurement from that of the target gas measurement. For multiple species detection, additional sample and reference filter pairs can be configured. Predictions show that detection of strong absorbers such as dimethyl methylphosphonate at an optical density below 100 mg/m2 is possible from distances of < 6 km.