Spatial Distribution Of Activity Research Articles

Spatial distribution of neural activity in the anterior olfactory nucleus evoked by odor and electrical stimulation

Several lines of evidence indicate that complex odorant stimuli are parsed into separate data streams in the glomeruli of the olfactory bulb, yielding a combinatorial "odotopic map." However, this pattern does not appear to be maintained in the piriform cortex, where stimuli appear to be coded in a distributed fashion. The anterior olfactory nucleus (AON) is intermediate and reciprocally interconnected between these two structures, and also provides a route for the interhemispheric transfer of olfactory information. The present study examined potential coding strategies used by the AON. Rats were exposed to either caproic acid, butyric acid, limonene, or purified air and the spatial distribution of Fos-immunolabeled cells was quantified. The two major subregions of the AON exhibited different results. Distinct odor-specific spatial patterns of activity were observed in pars externa, suggesting that it employs a topographic strategy for odor representation similar to the olfactory bulb. A spatially distributed pattern that did not appear to depend on odor identity was observed in pars principalis, suggesting that it employs a distributed representation of odors more similar to that seen in the piriform cortex.

Convergência espacial do PIB <i>per capita</i> no estado do Ceará

Políticas públicas regionais no Estado do Ceará têm sido implementadascom o objetivo de descentralizar a atividade econômica da Região Metropolitana deFortaleza. O que se espera dessas políticas é uma redução da concentração do PIBper capita entre os municípios com convergência de renda e a formação de clustersde atividades no interior do Estado. Este trabalho tem como objetivo principalidentificar as mudanças ocorridas na distribuição espacial da atividade econômicano Estado do Ceará no período de 1996 a 2003. Para tanto, utilizou-se técnicas deeconometria espacial para verificar a evolução dos clusters e estimar a convergênciaabsoluta do PIB per capita ao longo do período analisado. Os resultados indicarama presença de efeitos espaciais relevantes e relacionamento entre os municípios e aformação de clusters importantes no interior do Estado. Além disso, conclui-se quehouve convergência absoluta do PIB per capita com consequente diminuição dasdisparidades regionais no Estado no período analisado.

Erratum

Acta PhysiologicaVolume 200, Issue 3 p. 289-289 Free Access Erratum This article corrects the following: On functional motor adaptations: from the quantification of motor strategies to the prevention of musculoskeletal disorders in the neck–shoulder region P. Madeleine, Volume 199Issue s679Acta Physiologica pages: 1-46 First Published online: June 23, 2010 First published: 11 October 2010 https://doi.org/10.1111/j.1748-1716.2010.02185.xAboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat In the article by Madeleine (2010), a list of references was not published. The missing list is published below. This supplement is based on the following peer-reviewed articles referred to by their Roman number in the text. I. Madeleine, P., Lundager, B., Voigt, M. & Arendt-Nielsen, L. 1999. Shoulder muscle coordination under chronic and experimental neck-shoulder pain. An occupational pain study. Eur J Appl Physiol79, 127–140. II. Madeleine, P., Lundager, B., Voigt, M. & Arendt-Nielsen, L. 2003. Standardised low repetitive work: evidence of different motor control strategies between experienced and a reference group. Appl Ergon34, 533–542. III. Madeleine, P., Lundager, B., Voigt, M. & Arendt-Nielsen, L. 2003. The effects of neck-shoulder pain development on sensory-motor interactions among female workers in poultry and fish industry. A prospective study. Int Arch Occup Environ Health76, 39–49. IV. Madeleine, P., Vedsted, P., Blangsted, A.K., Sjøgaard, G. & Søgaard, K. 2006. Effectiveness of audio and visual biofeedback from the upper trapezius electromyographic and mechanomyographic activity during standardized computer work. Ergonomics49, 921–933. V. Madeleine, P., Leclerc, F., Arendt-Nielsen, L., Ravier, P. & Farina, D. 2006. Experimental muscle pain changes the spatial distribution of upper trapezius muscle activity during sustained contraction. Clin Neurophysiol11, 2446–2455. VI. Madeleine, P. & Farina, D. 2008. Time to task failure in shoulder elevation is associated to increase in amplitude and to spatial heterogeneity of upper trapezius mechanomyographic signals. Eur J Appl Physiol102, 325–333. VII. Madeleine, P., Mathiassen, S.E. & Arendt-Nielsen, L. 2008. Change in the degree of motor variability associated with experimental and chronic neck-shoulder pain during a standardized repetitive arm movement. Exp Brain Res185, 689–698. VIII. Madeleine, P., Voigt, M. & Mathiassen, S.E. 2008. Cycle to cycle variability in biomechanical exposure among butchers performing a standardized cutting task. Ergonomics51, 1078–1095. IX. Madeleine, P. & Madsen, T.M.T. 2009. Changes in the amount and structure of motor variability during a deboning process: effects of work experience and neck-shoulder discomfort. Appl Ergon40, 887–894. We apologise for missing this reference list. Reference Madeleine, P. 2010. On functional motor adaptations: from the quantification of motor strategies to the prevention of musculo-skeletal disorders in the neck–shoulder region. Acta Physiol 199(Suppl. 679), 1– 46. Wiley Online LibraryWeb of Science®Google Scholar Volume200, Issue3November 2010Pages 289-289 ReferencesRelatedInformation

Quantitative accuracy of the closed-form least-squares solution for targeted SPECT

The aim of this study is to investigate the quantitative accuracy of the closed-form least-squares solution (LSS) for single photon emission computed tomography (SPECT). The main limitation for employing this method in actual clinical reconstructions is the computational cost related to operations with a large-sized system matrix. However, in some clinical situations, the size of the system matrix can be decreased using targeted reconstruction. For example, some oncology SPECT studies are characterized by intense tracer uptakes that are localized in relatively small areas, while the remaining parts of the patient body have only a low activity background. Conventional procedures reconstruct the activity distribution in the whole object, which leads to relatively poor image accuracy/resolution for tumors while computer resources are wasted, trying to rebuild diagnostically useless background. In this study, we apply a concept of targeted reconstruction to SPECT phantom experiments imitating such oncology scans. Our approach includes two major components: (i) disconnection of the entire imaging system of equations and extraction of only those parts that correspond to the targets, i.e., regions of interest (ROI) encompassing active containers/tumors and (ii) generation of the closed-form LSS for each target ROI. We compared these ROI-based LSS with those reconstructed by the conventional MLEM approach. The analysis of the five processed cases from two phantom experiments demonstrated that the LSS approach outperformed MLEM in terms of the noise level inside ROI. On the other hand, MLEM better recovered total activity if the number of iterations was large enough. For the experiment without background activity, the ROI-based LSS led to noticeably better spatial activity distribution inside ROI. However, the distributions pertaining to both approaches were practically identical for the experiment with the concentration ratio 7:1 between the containers and the background.

STATISTICAL MODELS OF CRIMINAL BEHAVIOR: THE EFFECTS OF LAW ENFORCEMENT ACTIONS

We extend an agent-based model of crime-pattern formation initiated in Short et al. by incorporating the effects of law enforcement agents. We investigate the effect that these agents have on the spatial distribution and overall level of criminal activity in a simulated urban setting. Our focus is on a two-dimensional lattice model of residential burglaries, where each site (target) is characterized by a dynamic attractiveness to burglary and where criminal and law enforcement agents are represented by random walkers. The dynamics of the criminal agents and the target-attractiveness field are, with certain modifications, as described in Short et al. Here the dynamics of enforcement agents are affected by the attractiveness field via a biasing of the walk, the detailed rules of which define a deployment strategy. We observe that law enforcement agents, if properly deployed, will in fact reduce the total amount of crime, but their relative effectiveness depends on the number of agents deployed, the deployment strategy used, and spatial distribution of criminal activity. For certain policing strategies, continuum PDE models can be derived from the discrete systems. The continuum models are qualitatively similar to the discrete systems at large system sizes.

Technological Enclaves and Industrial Districts: An Analysis of the Regional Distribution of Innovative Activity in Europe

This paper explores the spatial distribution of innovative and productive activity across 109 regions of the European Union, thanks to an original databank on regional patents statistics. The main results worth highlighting are as follows. The technological activity in the EU appears to be highly concentrated, although concentration tends to decline over the eighties. This results from the huge differences between southern and northern Europe. As expected, there is a positive association between the regional distribution of innovative activity and labor productivity. Further, contrary to previous evidence on the United States, our data show a significant link between the specialization in innovation and in production both at the country and at the industry level. This suggests that localized knowledge spillovers and agglomeration economies foster a local economic system towards a specialization in both production and technology. More surprisingly there appears a negative correlation between technological concentration and aggregate productivity, that is the European regions which enjoy a more homogeneous distribution of their technological capability across different industrial sectors appear to be also characterized by a higher productivity level. This outcome may suggest the presence of positive inter-industry externalities that favor those regions which succeed in covering a broader range of technological activities.

Productive public input, integration and agglomeration

This paper analyzes, within a regional growth model, the impact of a productive governmental input and integration on the spatial distribution of economic activity. In doing so, two benchmark cases (i) equal distribution, and (ii) agglomeration in the sense of a core–periphery structure as well as the corresponding transition processes are discussed. Integration is understood as enhancing inter-territorial cooperation and it describes the extent to which one region may benefit from the other region's public input. Both integration and the characteristics of the public input crucially affect whether or not agglomeration arises and hence to which extent economic activity is concentrated. Key results are: Intensifying integration reduces the strengths of agglomeration forces and the corresponding degree of concentration will be lower. Relative congestion leads to an overestimation of capital returns and capital growth in the core region is faster due to congestion thereby leading to suboptimally high concentration.

Locating nonvolcanic tremors beneath the San Andreas Fault using a station‐pair double‐difference location method

It has been a challenging task to locate nonvolcanic tremors because of the lack of impulsive wave arrivals. A station‐pair double‐difference (DD) location method is developed to determine absolute tremor locations by directly using the station‐pair travel time differences measured from cross‐correlating tremor waveform envelopes. Multiple tremors are located together for inverting for station corrections to take into account velocity model inaccuracy. The new method is applied to tremors in the Parkfield region of central California between 27 July 2001 and 21 February 2009. Compared to the tremor catalog locations determined from a grid search location method, most of the newly located tremors are located at depths between 20 and 35 km, well below the seismogenic zone in the area. The tremors beneath Cholame, CA are more clearly separated into two zones laterally distributed across the San Andreas Fault, with most tremors occurring to the southwest and exhibiting a periodic pattern of occurrence. The new tremor locations help better delineate the spatial and temporal distribution of tremor activity and therefore are helpful for better understanding tremor origin and process.

Active biofeedback changes the spatial distribution of upper trapezius muscle activity during computer work

The aim of this study was to investigate the spatio-temporal effects of advanced biofeedback by inducing active and passive pauses on the trapezius activity pattern using high-density surface electromyography (HD-EMG). Thirteen healthy male subjects performed computer work with superimposed feedback either eliciting passive (rest) or active (approximately 30% MVC) pauses based on fuzzy logic design and a control session with no feedback. HD-EMG signals of upper trapezius were recorded using a 5 x 13 multichannel electrode grid. From the HD-EMG recordings, two-dimensional maps of root mean square (RMS), relative rest time (RRT) and permuted sample entropy (PeSaEn) were obtained. The centre of gravity (CoG) and entropy of maps were used to quantify changes in the spatial distribution of muscle activity. PeSaEn as a measure of temporal heterogeneity for each channel, decreased over the whole map in response to active pause (P < 0.05) underlining a more homogenous activation pattern. Concomitantly, the CoG of RRT maps moved in caudal direction and the entropy of RMS maps as a measure of spatial heterogeneity over the whole recording grid, increased in response to active pause session compared with control session (no feedback) (P < 0.05). Active pause compared with control resulted in more heterogeneous coordination of trapezius compared with no feedback implying a more uneven spatial distribution of the biomechanical load. The study introduced new aspects in relation to the potential benefit of superimposed muscle contraction in relation to the spatial organization of muscle activity during computer work.

Estimation of Cortical Connectivity From EEG Using State-Space Models

A state-space formulation is introduced for estimating multivariate autoregressive (MVAR) models of cortical connectivity from noisy, scalp-recorded EEG. A state equation represents the MVAR model of cortical dynamics, while an observation equation describes the physics relating the cortical signals to the measured EEG and the presence of spatially correlated noise. We assume that the cortical signals originate from known regions of cortex, but the spatial distribution of activity within each region is unknown. An expectation-maximization algorithm is developed to directly estimate the MVAR model parameters, the spatial activity distribution components, and the spatial covariance matrix of the noise from the measured EEG. Simulation and analysis demonstrate that this integrated approach is less sensitive to noise than two-stage approaches in which the cortical signals are first estimated from EEG measurements, and next, an MVAR model is fit to the estimated cortical signals. The method is further demonstrated by estimating conditional Granger causality using EEG data collected while subjects passively watch a movie.

The economic impact of future increase in tropical cyclones in Japan

This article estimates the non-first-order economic loss in Japan due to a future increase in tropical cyclones. One possible effect of global warming could be the increase in intensity of tropical cyclones. Using historical storm tracks between the years 1978 and 2007 and altering their intensities due to this potential increase in their intensity, this paper calculates the future potential regional GDP loss in a certain area that is affected by tropical cyclones. Most of the literature is concerned with physical damage and the loss of lives due to tropical cyclones. However, there are additional economic costs when sustained wind speeds are higher than 30 knots (55.56 km/h), a level that generally will lead to a precautionary cessation of many human activities. Using a Monte Carlo simulation, the paper calculates the potential economic costs for the year 2085 under a climate change scenario with a linear one-per cent yearly increase in CO2. Using a spatial distribution of economic activity in Japan, it is possible to forecast which parts of the country are likely to experience the highest loss risk.

Advanced methods and applications in regional science

The spatial distribution of economic activity is a central and general issue in regional economic theory and policy. Accordingly, methods andmodels play (and have played) an important role in understanding economic activity’s spatial distribution. Agglomeration of firms in the same industrial sector gives rise to technological externalities by pointing to localisation economies. Externalities are also found, from knowledge spillovers within industries, and furthermore in agglomerations of firms belonging to different industries as a result from a variety of business services and knowledge spillovers across industries. How to understand and to analyse these economic processes depends upon the accessibility of appropriate quantitative methods. All these germane topics called the attention of researchers that attended to theThird Jean Paelinck Seminar held in Cartagena (Spain) in 2008. In this meeting advanced methods and models with applications in regional science were presented. The papers of this special issue, entitledAdvanced Methods and Applications in Regional Science, have its origin on this biannual international meeting. The special issue therefore focuses on methods and applications with a direct and clear relevance in regional science’s frontier of knowledge. For that reason, the reader can find two types of papers. First type are openly related with advanced methods that help in analysing some interesting regional topics as industry concentration in large

Microseismic activity analysis for the study of the rupture mechanisms in unstable rock masses

Abstract. Rockfalls are common instabilities in alpine areas and can cause significant damage. Since high mountains have been affected by an increasing number of these phenomena in the last years, a possible correlation with permafrost degradation induced by climate change has been hypothesized. To investigate this topic, a monitoring system, made of 5 triaxial geophones and 1 thermometer, was installed in 2007 at the Carrel hut (3829 m a.s.l., Matterhorn, North-western Alps), in the frame of the Interreg IIIA Alcotra project n. 196 "Permadataroc". The preliminary data processing relates to the classification of recorded signals, the identification of the significant microseismic events and the analysis of their distribution in time and space. The first results indicated a possible correlation between clusters of events and temperature trend, and a concentration of events in specific sectors of the rock mass. Research is still in progress. The recording of data for a longer period is planned to fully understand seasonal trends and spatial distribution of microseismic activity, and possible relations with permafrost degradation. Nevertheless, the preliminary observations prove that the monitoring system can detect noises generated by rock slope deformation. Once fully developed, this technique could become a helpful tool for early warning and preliminary stability assessments.

Focal Adhesion Kinase Dynamics under Shear Stress in Live Endothelial Cells Studied with a FRET Biosensor

Focal adhesion kinase (FAK) plays an important role in integrin‐mediated mechanotransduction signaling events. We transfected endothelial cells (ECs) with a FRET‐based FAK biosensor capable of specifically detecting the phosphorylation of FAK at Tyr‐397, which is reflected in ECFP/YPet emission ratio. The effects of shear stress on FAK activity in live ECs were tracked with high temporal and spatial resolution by recording the FRET responses with a live cell imaging system under flow. The results showed that FAK activity was induced preferentially on the perinuclear and nuclear regions in ECs. To investigate the roles of microtubules and actin filaments in the dynamics of FAK activity, we examined the FRET response in ECs treated with cytochalasin D (CD) or colchicine, respectively. The analysis of FRET responses showed that CD caused an inhibition of FAK activity. In contrast, chochicine caused an increase in FAK activity, particularly in the perinuclear and nuclear regions. These results indicate that the spatial distribution of FAK activity is dependent on the integrity and re‐organization of actin networks, as well as the dynamics of microtubules. The findings suggest that FAK activity may play a significant role in regulating FA formation and cell adhesion to resist cell detachment in ECs subjected to shear stress. This work was supported by NHLBI Research Grants HL‐080518 and HL‐085159 (S.C.).

Developing reliable, repeatable, and accessible methods to provide high-resolution estimates of fishing-effort distributions from vessel monitoring system (VMS) data

Abstract Lee, J., South, A. B., and Jennings, S. 2010. Developing reliable, repeatable, and accessible methods to provide high-resolution estimates of fishing-effort distributions from vessel monitoring system (VMS) data. – ICES Journal of Marine Science, 67: 1260–1271. Vessel monitoring systems (VMS) are used primarily for fisheries enforcement purposes, but also provide information on the spatial and temporal distribution of fishing activity for use in fisheries and environmental assessment and management. A reliable, repeatable, and accessible method using readily available software for estimating fishing effort from unprocessed VMS data is developed, tested, and applied. Caveats associated with the method are identified, and the biases introduced by our assumptions are quantified. Application of the method provides a high-resolution description of gear-specific fishing activity by UK vessels. An index is developed to describe variation in the spatial pattern of fishing effort generated by different gears. The proposed method for VMS analysis involves removing duplicate VMS records and records close to ports, calculating the time interval between successive records to identify periods of activity, linking each record to a vessel and gear type, differentiating fishing and non-fishing activity, and summing fishing records in time and space to estimate fishing effort. The approach is a step towards the development of standardized methods to facilitate wider exchange and use of European VMS data. A clear audit trail for the methods of VMS analysis already used to inform management needs to be documented.

Adding geography to the new economic geography: bridging the gap between theory and empirics

For reasons of analytical tractability, new economic geography (NEG) models treat geography in a very simple way: attention is either confined to a simple 2-region or to an equidistant multi-region world. As a result, the main predictions regarding the impact of e.g. diminishing trade costs are based on these simple models. When doing empirical or policy work these simplifying assumptions become problematic and it may very well be that the conclusions from the simple models do not carry over to the heterogeneous geographical setting faced by the empirical researcher or policy maker. This paper tries to fill this gap by adding more realistic geography structures to the Puga (1999) model that encompasses several benchmark NEG models. By using extensive simulations we show that many, although not all, conclusions from the simple models do carry over to our multi-region setting with more realistic geography structures. Given these results, we then simulate the impact of increased EU integration on the spatial distribution of regional economic activity for a sample of 194NUTSII regions and find that further integration will most likely be accompanied by higher levels of agglomeration.

Cortical activity during motor execution, motor imagery, and imagery-based online feedback

Imagery of motor movement plays an important role in learning of complex motor skills, from learning to serve in tennis to perfecting a pirouette in ballet. What and where are the neural substrates that underlie motor imagery-based learning? We measured electrocorticographic cortical surface potentials in eight human subjects during overt action and kinesthetic imagery of the same movement, focusing on power in "high frequency" (76-100 Hz) and "low frequency" (8-32 Hz) ranges. We quantitatively establish that the spatial distribution of local neuronal population activity during motor imagery mimics the spatial distribution of activity during actual motor movement. By comparing responses to electrocortical stimulation with imagery-induced cortical surface activity, we demonstrate the role of primary motor areas in movement imagery. The magnitude of imagery-induced cortical activity change was approximately 25% of that associated with actual movement. However, when subjects learned to use this imagery to control a computer cursor in a simple feedback task, the imagery-induced activity change was significantly augmented, even exceeding that of overt movement.

EEG topography-specific BOLD changes: a continuous EEG-fMRI study in a patient with focal epilepsy

Blood oxygenation level dependent (BOLD) response related to interictal activity was evaluated in a patient with post-traumatic focal epilepsy at repeated continuous electroencephalogram (EEG)-functional magnetic resonance imaging examinations. Lateralized interictal EEG activity induced a main cluster of activation co-localized with the anatomical lesion. Spreading of EEG interictal activity to both frontal lobes evoked bilateral clusters of activation indicating that topography of BOLD response might depend on the spatial distribution of epileptiform activity.

Cortical dynamics underlying the visual perception of stationary and moving stimuli

Event Abstract Back to Event Cortical dynamics underlying the visual perception of stationary and moving stimuli Wenqi Sun1*, Alexander Moiseev2, Faisal Beg1, Urs Ribary1 and Naznin Virji-Babul2 1 Simon Fraser University, Canada 2 Down Syndrome Research Foundation, Canada In this study, we investigated the neural responses during the perception of stationary dots, randomly moving point light dots and point light dots representing human motion. We recorded cortical responses from ten right handed subjects with a 151 channel whole head MEG system (VSM MedTech, Coquitlam, BC). For each subject a three-dimensional spatial distribution of source activity was computed using differential SAM beamforming method. The data were spatially normalized to a common brain template and group-averaged for each condition. Locations showing statistically significant differences between conditions were chosen for time frequency analysis. We compared the random motion and human motion with the stationary display and then compared the random and human motion. Perception of random motion was associated with enhanced neural activity in alpha and beta bands in bilateral visual, parietal and MT regions, as compared with stationary dots. Perception of human motion led to enhanced neural activity in alpha and beta bands in the visual, parietal and MT areas in the right hemisphere, in comparison with random motion. Late activation in the gamma band activity was observed in both motion conditions in the visual area. In addition, the perception of human motion led to increased activity in the alpha band in the left motor region. These data suggest that (a) motion processing involves the dorsal pathways via bi-directional pathways, and (b)that action cues depicting human motion are sufficient to selectively activate premotor regions. Supported by NSERC (RGPGP/355878-2008) Conference: Biomag 2010 - 17th International Conference on Biomagnetism , Dubrovnik, Croatia, 28 Mar - 1 Apr, 2010. Presentation Type: Poster Presentation Topic: Neurocognition and Functional Connectivity Citation: Sun W, Moiseev A, Beg F, Ribary U and Virji-Babul N (2010). Cortical dynamics underlying the visual perception of stationary and moving stimuli. Front. Neurosci. Conference Abstract: Biomag 2010 - 17th International Conference on Biomagnetism . doi: 10.3389/conf.fnins.2010.06.00247 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 31 Mar 2010; Published Online: 31 Mar 2010. * Correspondence: Wenqi Sun, Simon Fraser University, Burnaby, Canada, wsa1@sfu.ca Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Wenqi Sun Alexander Moiseev Faisal Beg Urs Ribary Naznin Virji-Babul Google Wenqi Sun Alexander Moiseev Faisal Beg Urs Ribary Naznin Virji-Babul Google Scholar Wenqi Sun Alexander Moiseev Faisal Beg Urs Ribary Naznin Virji-Babul PubMed Wenqi Sun Alexander Moiseev Faisal Beg Urs Ribary Naznin Virji-Babul Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Spatial and temporal patterns of richness and abundance in the anuran assemblage of an artificial water reservoir from the semiarid central region of Argentina

AbstractThis constitutes the first study of anuran fauna composition of an artificial permanent water reservoir, in a semiarid ecosystem of San Luis. Species richness, relative abundance, spatial distribution and pattern of summer activity were estimated in the anuran community of the Embalse La Florida, an artificial water reservoir in the semiarid central region of the sierras of San Luis, Argentina. This reservoir represents one of the few sources of water available for reproduction and early development of amphibian species in the zone. We identified anurans using call surveys during two summers at fifteen sites, belonging to four zones around the shorelines of the reservoir. Eight amphibian species (Rhinella arenarum, Melanophryniscus stelzneri, Leptodactylus bufonius, Leptodactylus mystacinus, Odontophrynus americanus, Odontophrynus occidentalis, Pleurodema tucumanum and Hypsiboas cordobae) were recorded at the shores of the embalse. The highest species richness (seven) was detected in the preserve located on the north shore. Species richness analyzed by month or survey was not correlated with weather variables. The highest relative abundance of anurans was detected at the highly modified campsites area, which may provide stable food and refugia. Relative abundance of all anuran species was positively correlated with precipitation. This permanent water reservoir may act as an important site of amphibian fauna concentration, which is important to monitor and preserve.