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The hydrological regime is the main factor governing the functioning of floodplain rivers. A full comprehension of its dynamic leads to a better understanding of the system’s behaviour and of the proper methods that must be used. We analysed the daily water level of the Paraná River during the last century at three gauge stations using linear and non-linear tools to characterise the hydrological dynamic and to analyse to what extent chaotic behaviour prevails. The three water level time series were characterised as non-linear and non-stationary by power spectrum, autocorrelation function, and surrogate test analyses. A strange attractor was developed when the phase space was reconstructed, having a low dimensional chaos supported by correlation dimension, positive maximum Lyapunov exponents, and recurrence quantification analysis. In line with this, the system resulted unpredictable with a threshold by sample entropy, and with an intermediate hydrological complexity, while Hurst exponent characterised the system as persistent and with sensitive dependence on initial conditions. In a general overview, all the evidence obtained indicates that the Paraná River’s behaviour is at the edge of chaos. A latitudinal gradient of decreasing chaoticity was observed as the floodplain extent increased, whereas complexity was highest at the intermediate river station due to the inflow of tributaries with different hydrology. This paper attempts to offer some additional insights for understanding the hydrological behaviour of floodplain rivers and the proper methods to understand their complexity.

Empirical studies of the EKC hypothesis may be very sensitive to datasets, specifications, and functional forms. The aim of this paper is to investigate the long-run relationship among CO2 emissions, real GDP, and energy consumption using a panel of 9 advanced economies from 1870 to 2008 using both parametric and semi-parametric additive models. While at the panel level the results provide support to the Environmental Kuznets Curve (EKC) only in the post-1950s period, at the individual country level the inverted U-shaped relationship between CO2 and real GDP is validated for a subset of countries only. However, when a semi-parametric regression framework is applied an inverse U-shaped pattern becomes clear for all countries of the sample, except Canada. Empirical findings indicate that relaxing the restrictions associated with parametric regression models may be critical for the question of investigating the existence of the EKC., JEL codes: C14; C23; Q43; Q32

We analyze whether ontogenetic diet change in Aegla uruguayana Schmitt, 1942 is related to the morphological changes in chelae and mandibles. We use a combination of scanning electron microscope (SEM) observation, dietary composition analysis (stomach observation, trophic niche amplitude, trophic overlap, and feeding strategy), and geometric morphometric tools (discriminant analysis and two-block partial least squares analysis). The two structures analyzed by SEM show differences between juvenile and adult specimens, both in their cuticle and morphology specializations. In juveniles, the absence of the lobular tooth is the notable feature. However, in adult sizes, it is marked development. Both groups have simple setae with infracuticular articulation and denticles with different arrangements between groups. In the incisive mandible process, the teeth and spines present sharper points in juveniles and considerable wear in adults. Aegla uruguayana presented two trophic strategies: a profile of more predatory traits when younger and mostly detritivorous when adults. The analysis of geometric morphometry substantiates the patterns observed in SEM and stomach contents analysis. The morphology of smaller specimens is associated with the consumption of animal items (ephemeropteran larvae and cladocerans), while the morphology of larger specimens is related to the consumption of plant remains.

We examine how banking supervisors affect credit at the local level by charging fines to individual banks. Using a macro approach to capture the direct effect on the fined bank and the indirect effect on the other banks operating in the local credit market, we estimate reputational, reallocation and balance sheet effects on Italian provinces over the period 2005–2016 by a fixed effects model and instrumental variables. Provincial gross bank loans expand after a fine independently of its size. The impact of fine frequency depends on the size of the provincial banking sector, but neither on bank governance/ownership nor crises. No statistically significant evidence supports reputational or balance sheet effects. Instead, our results suggest that it would behoove bank supervisors to favor frequency over size of bank fines. Bank fines seem to work more like a good housekeeping seal of approval, enhancing transparency and effective banking practices.

How long is the long run in the relationship between money growth and inflation? How important are high inflation episodes for the unit slope finding in the quantity theory of money? To answer these questions, we study the relationship between excess money growth and inflation over time and across frequencies using annual data from 1870 to 2013 for 16 developed countries. Wavelet-based exploratory analysis shows the existence of a close stable relationship between excess money growth and inflation only over long time horizons, i.e. periods greater than 16–24 years, with money growth mostly leading. When we investigate the sensitivity of the unit slope finding to inflation episodes using a “time-frequency-based” panel data approach, we find that low-frequency regression coefficients estimated over variable-length subsamples are largely affected by high inflation episodes occurring in the 1910s, the 1940s, and the 1970s. Taken together, our results suggest that inflationary upsurges affect regression coefficients, but not the closeness of the long-run relationship. This reconciles the validity of the quantity theory of money with the current disinterest of monetary policymaking in money growth.

We build a mark-to-market model where commercial banks can enlarge their balance sheets, repledging the available collateral several times to exchange liquidity through the interbank market. In bad times, the fall of risky asset price disrupts the length of the repledging chain due to the increase of the haircut and the decrease of external assets' value. In such a scenario, the central bank can intervene implementing unconventional monetary policies by purchasing a fraction of the banking system's external assets, both safe treasury bonds, and risky asset-backed securities, to inject liquidity. Our results show that a quantitative easing policy that purchases only safe assets is highly ineffective in restoring the intermediation activity to the pre-crisis level due to its inability to sustain the risky asset price and the repledging chain of collateral. Instead, focusing on risky assets only, the monetary authority can sustain risky asset prices, avoiding the freezing of the money market.

The presence, density, and distribution pattern of a species in a particular space and time result from evolutionary and ecological processes. We evaluated the density and spatial distribution pattern of the freshwater anomuran crab, Aegla uruguayanaSchmitt, 1942, in relation to temporal and spatial scales. The temporal scale followed a seasonal analysis, and the space scale was evaluated from the study of three streams located in different provinces of Argentina. Specimens were collected in four sampling campaigns during spring, summer, autumn, and winter in three temperate freshwater environments of the La Plata Basin, Argentina, using 1 m2 sampling units. The density varied according to the studied populations and was not by seasonality. The distribution pattern was not influenced by the evaluated scales. The A. uruguayana populations presented a clumped pattern showing a negative binomial distribution. A possible cause of such a pattern is the strong environmental heterogeneity of the three studied sites. The species presented gregarious behavior that could be associated with the spatial arrangement of the shelters available in the particular habitats as well as ecological strategies for optimal and efficient use of resources in these topographies. Our study is the first on the dynamics of the distribution in terms of temporal and spatial scopes of a species of AeglaLeach, 1820, an endemic freshwater anomuran.

Geographical isolation is a key element in allopatric speciation. If gene flow is interrupted for long enough by geographical barriers, populations can evolve independently and eventually form distinct species. Aegla singularis provides an ideal model to study this process due to the characteristics of the geographical area that it occupies and its limited dispersal ability. Aegla singularis inhabits streams of the Uruguay and Paraná River basins in the Neotropical region of South America. The basins are separated by the Sierra Central Mountains. Here we studied the speciation of A. singularis resulting from geographical isolation by using molecular and morphometric data. Individuals of A. singularis were analysed using geometric morphometrics and genetic data (COII and EFα1). We found significant differences in shape and genetics between A. singularis populations from the two basins. These differences suggest ongoing divergence due to restricted gene flow caused by the geographical barrier of the Sierra Central Mountains, indicating that the populations of the Parana and Uruguay River slopes are undergoing divergence.

The paper presents an agent-based model reproducing a stylized credit network that evolves endogenously through the individual choices of firms and banks. We introduce in this framework a financial stability authority in order to test the effects of different prudential policy measures designed to improve the resilience of the economic system. Simulations show that a combination of micro- and macroprudential policies reduces systemic risk but at the cost of increasing banks’ capital volatility. Moreover, the agent-based methodology allows us to implement an alternative meso regulatory framework that takes into consideration the connections between firms and banks. This policy targets only the more connected banks, increasing their capital requirement in order to reduce the diffusion of local shocks. Our results support the idea that the mesoprudential policy is able to reduce systemic risk without affecting the stability of banks’ capital structure.

The rapid degradation of freshwater habitats in southern South America may cause the extinction of the endemic species of Aegla, as well as other freshwater species and components of riverside environments related to them. Information on the distribution of species and their conservation status is essential for developing conservation strategies. The updated distribution of Aegla in its southernmost distribution was analysed in order to prioritize freshwater ecoregions, applying biogeographical, phylogenetic and conservation status and complementarity approaches. The distributions of the species of Aegla were delineated on maps and plotted against freshwater ecoregions. A data matrix of areas versus species was constructed and a taxon–area cladogram was created. Ecoregions were ranked, based on their species richness and using a complementarity criterion, to create a list of those considered important for conservation. The conservation status of Aegla species was assessed on the basis of the categories and criteria of the International Union for Conservation of Nature (IUCN) to produce a decreasing order of the risk of species extinction. These assessments were combined to define a consensus ranking of the priority areas for conservation. The areas of maximum species richness and endemicity, and consequently highest priority of conservation, were the Lower Parana and Patagonia ecoregions. The Cuyan Desaguadero and Mar Chiquita Salinas Grandes ecoregions were the areas of second priority, and the Chaco and Lower Uruguay ecoregions were the areas with the third priority for conservation. Ten out of the 20 species analysed fall within the threat categories of the IUCN. Sixty per cent of the species of Aegla analysed have at least one population contained in protected areas. The results obtained may be used to design strategies for implementing conservation policies on freshwater species, generate biogeographical atlases and contribute to selecting Ramsar sites.

We estimate a DSGE model with financial frictions and banks on subsets of frequency bands corresponding to higher and lower business cycle frequencies. Our results show that goodness of fit and parameter estimates associated with real and financial frictions vary substantially across business cycle frequency bands, with the estimated coefficients related to financial adjustment costs and for the parameter governing the costs associated to capital requirements displaying the largest variations. Moreover, the comparison of the marginal likelihoods with a frictionless framework suggests that the introduction of financial frictions provides a significant improvement at lower business cycle frequencies. This is consistent with the presence of macro-financial linkages where credit market frictions affect spending decisions over longer time horizons.

The heterogeneity of biotic and abiotic factors influencing fitness produce selective pressures that promote local adaptation and divergence among different populations of the same species. In order for adaptations to be maintained through evolutionary time, heritable genetic variation controlling the expression of the morphological features under selection is necessary. Here we compare morphological shape variability and size of the cephalic region of Salvator merianae specimens from undisturbed environments to those of individuals from disturbed environments, and estimated heritability for shape and size using geometric morphometric and quantitative genetics tools. The results of these analyzes indicated that there are statistically significant differences in shape and size between populations from the two environments. Possibly, one of the main determinants of cephalic shape and size is adaptation to the characteristics of the environment and to the trophic niche. Individuals from disturbed environments have a cephalic region with less shape variation and also have a larger centroid size when compared to individuals from undisturbed environments. The high heritability values obtained for shape and size in dorsal view and right side view indicate that these phenotypic characters have a great capacity to respond to the selection pressures to which they are subjected. Data obtained here could be used as an important tool when establishing guidelines for plans for the sustainable use and conservation of S. merianae and other species living in disturbed areas.

The Great Depression of 1929 and the Great Financial Crisis of 2008 have been the two big events of the last 75 years. Not only have they produced serious economic consequences but they also changed our view of economics and policymaking. The aim of this work is to compare these two great crises and highlight similarities as well as differences. Monetary policy, the exchange rate system and the role of banks are our fields of investigation. We find interesting parallels between the two big events but also differences in their specific developments.

El objetivo general de la presente tesis consiste en identificar, desde un abordaje paleoetnobotánico, grados de dependencia en la relación ser humano-planta a lo lago del desarrollo cultural prehispánico en el área del noroeste argentino (NOA) y zonas adyacentes pertenecientes al Área Andina Central y Meridional. En este trabajo de investigación se pretenden establecer, más que las pautas causales de un hecho puntual como el origen de la agricultura, los pasos que se fueron produciendo a lo largo de un proceso continuo de transformaciones en la relación entre comunidades humanas y poblaciones vegetales, fundamentalmente a través de su expresión morfológica en macrorrestos vegetales del género Cucurbita sp. y de la especie Phaseolus vulgaris L.. Se parte del supuesto de que existen distintos grados de dependencia entre seres humanos y plantas, lo cual redunda en una gran diversidad de forma de manejo (recolección, cultivo sin domesticación, cultivo de plantas domesticadas, tolerancia y erradicación) que se reflejan en distintas formas vegetales (plantas silvestres, plantas cultivadas no domesticadas y plantas cultivadas domesticadas y malezas respectivamente). Esta visión se planteó como una vía para sortear las divisiones propuestas entre modos de vida cazador-recolector y agricultor por medio de la superación de la dicotomía silvestre/domesticado. Mediante el análisis cualitativo y cuantitativo de caracteres macroscópicos y microscópicos de macrorrestos vegetales se procuró reconstruir prácticas de manejo del entorno vegetal de los grupos humanos que produjeron el registro arqueológico de los sitios estudiados y las características de las plantas que se relacionaron con los mismos. Se analizaron colecciones arqueológicas de sitios emplazados en el NOA (Pampa Grande en Guachipas, Salta y Puente del Diablo en el sector norte del Valle Calchaquí, Salta) y restos arqueobotánicos de sitios ubicadas en esta misma región (Los Viscos en el Valle del Bolsón, Catamarca; Puente Río La Viña I en el Valle de Lerma, Salta; Campo del Pucara en Andalgalá, Catamarca; Huachichocana en la Quebrada de Purmamarca, Jujuy y El Shincal en el Valle de Hualfín, Catamarca) y en el Área Andina Central y Meridional (sitios peruanos de Bandurria, Curayacu, Jahuay, Cerro Lampay, Chavín y el sitio chileno Tulan 85). Se realizaron también investigaciones etnobotánicas en cuatro comunidades campesinas emplazadas en tres ambientes disímiles del NOA (El Shincal, en la provincia fitogeográfica de Monte, Catamarca; Rachaite y Coranzulí en la provincia fitogeográfica de Puna, Jujuy y Santa Victoria Oeste en la provincia fitogeográfica de Yungas, Salta). Estas investigaciones tuvieron un doble objetivo. Por una parte, relevar prácticas actuales de manejo y criterios de selección aplicados por los cultivadores actuales en las mismas especies identificadas en el registro arqueológico. Por otra parte estos estudios etnobotánicos tuvieron una aplicación etnoarquelógica al generara modelos que exploran el paso de lo comportamental (en este caso: practicas de manejo y selección de formas vegetales) a lo material (en este caso: macrorrestos). El abordaje propuesto permitió la identificación en los restos arqueobotánicos analizados de formas silvestres, domesticadas y cultivos transicionales. La contemporaneidad y asociación contextual de los mismos permitió caracterizarlos como complejos maleza-cultivo-domesticados. Esto indicaría prácticas hortícolas tendientes a la generación y mantenimiento de la diversidad de formas de relación ser humano-plantas en el formativo temprano del NOA y posiblemente también en los sitios del Arcaico Tardío y Formativo temprano del Área Andina Central y Meridional.

Purpose: The study was carried out in a wetland of the Middle Paraná River system, Argentina, in order to evaluate the processes associated with the decomposition of manure, which includes changes in chemical composition, nutrient release of manure, and colonization of invertebrates. We also compared the invertebrate assemblage that colonized manure with that present in the benthos of the wetland. Materials and methods: Nylon bags were filled with fresh cattle manure and anchored to the littoral zone of the wetland. Six bags were collected after 1, 2, 6, 14, 21, 28, 33, 55, and 79 days: three for invertebrate determination and the other three bags for determination of dry mass and chemical analyses. The nutrient content, cellulose, lignin, and total phenolic compounds of manure were determined. In addition, the leachate of manure was collected for nutrient analyses. Samples of the wetland benthic sediment were collected for benthic invertebrate determination and particle size analyses. Spearman rank correlation was used to evaluate the relationship between chemical compounds of manure and breakdown rate. Principal component analysis was used to explore invertebrate assemblage composition of manure and sediment during the experiment. Results and discussion: Limnodrilus, Dero, and Chironomus were dominant in the manure. Gatherer-collector was the dominant group in the manure, comprising almost 95 % of the total density of invertebrates. Breakdown rate was significantly related with nutrients, cellulose and total phenolics of manure. An ordination plot showed changes in invertebrate assemblages of manure and sediment samples over time. Conclusions: This study provides new insight on the importance of manure as a substrate for macroinvertebrate colonization. Cattle manure needs to be considered as a potential source of nutrients for aquatic systems and a substrate for invertebrate assemblages. Fil: Mesa, Leticia Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Maldini, Cecilia. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; Argentina Fil: Mayora, Gisela Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Saigo, Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Marchese Garello, Mercedes Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; Argentina Fil: Giri, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; Argentina

An accommodating monetary policy followed by a sudden increase of the short term interest rate often leads to a bubble burst and to an economic slowdown. Through the implementation of an Agent Based Model with a financial accelerator mechanism we are able to study the relationship between monetary policy and large-scale crisis events. A two-step computational approach is proposed which performs (i) a pattern search of “double dip” episodes and (ii) counter-factual simulations implementing unconventional monetary policy. The main results can be summarized as follow: a) sudden and sharp increases of the policy rate can generate recessions; b) after a crisis, returning too soon and too quickly to a normal monetary policy regime can generate a “double dip” recession, while c) keeping the short term interest rate anchored to the zero lower bound in the short run can successfully avoid a further slowdown.

The presence of freshwater decapods may be considered dependent on the habitat and vegetation characteristics in floodplain rivers. Water level can influence the availability of macrophytes and the associated species composition of freshwater decapods. Changes in the sex ratios, abundances and body sizes of Macrobrachium borellii, Palaemon argentinus and Trichodactylus borellianus were investigated focusing on the type (floating, emergent) and the presence/absence of macrophytes in the Middle Paraná River floodplains. Organisms were sampled and analysed from river sites with floating, emergent vegetation and vegetation-free waters during different hydrological periods. The presence of macrophytes and some environmental variables during different hydrological and seasonal periods affected the variations in the species composition of decapods. M. borellii and T. borellianus tended to increase with the increase in floating vegetation in high waters, while P. argentinus was abundant in emergent vegetation and vegetation-free waters in low waters. Macrophytes provide food and shelter for freshwater decapods, influencing the species abundance according to the ecological response of each species. Variations in macrophytes composition due to water-level fluctuations modify the abundance of freshwater decapods, altering the species composition of decapod assemblages. Floodplain rivers are complex systems that act as macrofactors that regulate other factors that impact species composition. Fil: Torres, María Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Giri, Federico. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias. Departamento de Ciencias Naturales; Argentina Fil: Collins, Pablo Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina

The biogeographical and phylogenetic patterns of Aegla Leach, 1820 were analysed integrating track and cladistic biogeographic methods. We obtained 73 individual tracks, 10 generalised tracks and three nodes. Two taxon-area cladograms were constructed based on previous phylogenetic trees published for Aegla and Brooks Parsimony 26 Analysis (BPA) was applied to the presence-absence matrices of generalised tracks (rows) vs components (columns). Four and three equally most parsimonious trees were obtained and two strict consensus cladograms, respectively. The consensus cladogram shown here has a basal separation among three areas: Argentinean-Chilean Patagonian areas, Cuyan ecoregion in central-western Argentina, and the remaining areas in Argentina, Uruguay, Bolivia and Brazil. Within the latter, north-western Argentina, south-western Bolivian and Uruguay ecoregions were nested within several southern Brazilian areas. Our results support a close relationship between the Parana dominion of the Neotropical region and the Subantarctic subregion of the Andean region, which might be related to a temperate climate prevailing in southern South America before being disrupted by cooling and aridification conditions and to geo-climatic events that occurred since the Mesozoic. The Yungas biogeographic province was also supported by the distribution of Aegla. Nodes were all located in southern Brazil, coinciding with the hydrological processes of headwaters and drainages that occurred due to the Serra do Mar uplift. Some species of Aegla previously classified as a single species might constitute species complexes. Fil: Tumini, Georgina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Giri, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Williner, Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Collins, Pablo Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Morrone, Juan José. Universidad Nacional Autónoma de México; México

A topical issue in macroecology is whether the distribution of organisms is related to biogeographical history or current environmental conditions. Distributions of freshwater decapods in southern South America have been mainly attributed to historical factors, such as geoclimatic events, marine ingressions, tectonic uplifts and glaciations. Here, we test the hypothesis that current distributions are strongly influenced by local environmental conditions. Generalised linear models were used to quantify the importance of altitude, stability of the waterbody, annual temperature range (ATR), pH and conductivity on the distribution of five freshwater decapod families in Argentina (Sergestidae, Palaemonidae, Parastacidae, Aeglidae and Trichodactylidae), while accounting for effects of latitude and longitude. Decapod occurrence was strongly associated with interacting spatial and environmental factors. Latitudinal and/or longitudinal gradients were important predictors for the occurrence of Acetes paraguayensis (Sergestidae), Palaemonidae, Aeglidae and Trichodactylidae. However, the longitudinal pattern for Palaemonidae was reversed, increasing from east to west, when environmental variables were included in the analyses, whereas for Trichodactylidae, the longitudinal pattern was sufficiently explained by inclusion of local environmental variables. Altitude, water stability and ATR were important predictors of all families, while Palaemonidae, Parastacidae and Trichodactylidae were significantly associated with pH and Palaemonidae and Aeglidae with conductivity. Interactions terms were often significant, especially with latitude. Our results show that the macrodistribution of freshwater decapods is not solely a result of historical processes, a finding that disagrees with current understandings. Significant relationships between decapod occurrence and environmental variables indicates limited plasticity and strong adaptation to local habitats, highlighting the importance of including environmental factors in studies of crustacean biogeography and macroecology. Fil: Tumini, Georgina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Giri, Federico. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Williner, Verónica. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Collins, Pablo Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Escuela Superior de Sanidad; Argentina

The study of the cephalic shape of crocodilian is relevant in the fields of ecology, systematics, evolution, and conservation. Therefore, the integration of geometric analysis within quantitative genetics allows the evaluation of the inheritable shape components. In this study, the dorsal cephalic region of 210 Caiman latirostris hatchlings was analyzed from seven populations in Santa Fe, Argentina, to detect intra-, and inter-population phenotypic variability, and to determine the heritability of biological shape and size, using newly available geometric morphometric tools. The principal component analysis showed two configurations of cephalic shape that could be related to sexual dimorphism. In the canonical variate analysis, Procrustes distances between groups indicated that there are differences in shape among populations. Furthermore, the method of partial least squares indicated a covariation between cephalic shape and environmental variables. Regarding to CS of the skull we found significant differences among populations, moreover the partial least squares was also significant. Estimates of the heritability of shape and size were high, indicating that the components of these features are susceptible to the selection. J. Morphol. 277:370–378, 2016. © 2015 Wiley Periodicals, Inc.

The progressive degradation of wetlands has stressed the need of developing sustainable management strategies for maintaining their ecological character within the context of sustainable development. Rotational cattle grazing is a common grazing strategy in aquatic systems but its effect on nutrient dynamics in lakes is scarcely known. The objectives of this study were to evaluate if cattle produces a significant increase of TN and TP in wetlands, and if the value of these nutrients decrease after cattle are removed. Samples of water, sediment and macrophytes were collected for nutrient, organic matter and other chemical analyses. Results showed a significant increase in water nutrients during the presence of cattle, decreasing during their absence. These changes occurred surprisingly rapid, suggesting a high resilience of these systems to this impact. The presence of submerged vegetation in lakes ameliorated the effect of cattle on water nutrients, suggesting an important role of these plants in ecosystem management. Rotational management would minimize the increase of nutrients in water, maintaining the ecological integrity of wetlands.

One of the ongoing debates around metacommunity ecology is to what extent stochastic anddeterministic processes act on community assembly. We explored the influence of both determinism,mediated by environmental filters, and stochasticity, mediated by dispersal and ecological drift, on phytoplankton assembly in a floodplain river. A probabilistic co-occurrence model revealed the presence of 94.1% random and 5.9% non-random species pairwise associations. The latter were higher at both hydrologically isolated (4.42%) and connected environments (2.2%). Variation partitioning analysis showed similar significant explanations by the unique environmental (7.7%, Secchi, conductivity, vegetation, phosphorous) and spatial (7.2%, watercourse distance, longitude) components. Temporal variability was poorly represented (2.4%) because we only considered two lowwater periods. Species co-occurrence patterns showed that most taxa coexist randomly. The environmental explanation is in line with niche-assembly models (species sorting), but the similar proportion explained by spatial organisation related to random dispersal guides the evidence to both deterministic and stochastic processes. The higher percentage of random cooccurrence and the larger assemblage variability observed in isolated environments suggests that random dispersal, ecological drift, and priority effects could promote stochasticity. We concluded that both processes affect the structure of phytoplankton metacommunities in a floodplain system and suggest the preponderance of stochastic organisation. Fil: Devercelli, Melina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Scarabotti, Pablo Augusto. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Mayora, Gisela Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Schneider, Berenice. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Giri, Federico. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina

South America has been influenced by different geoclimatic events ever since its separation from Africa. The inland water fauna has evolved in response to the changing landscape. Currently, there are indications of variations in populations, occurring to different degrees that would indicate a clinal pattern in morphology. Among South America's fauna, the freshwater anomuran, Aegla, is an enigmatic group as a result of its endemicity and is composed of only one genus. Of all the species in this family, Aegla uruguayana has the broadest distribution. Its native habitats have been influenced by several marine transgressions during the Miocene–Quaternary Periods; thus, it is likely that their current distribution has been more recent. Its habitat spreads across a number of isolated basins and sub-basins that display distinct degrees of isolation/connection, making clinal variation patterns in the morphology of this species possible. The present study aimed to evaluate the pattern of carapace shape variation in A. uruguayana and how it relates to the isolation and/or connection of populations from different basins and sub-basins, allowing the determination of any extant clinal patterns. The specimens studied belong to 25 separate populations, representing all areas in which the species currently exists. A total of 523 crabs were analyzed. We identified 13 landmarks and four semi-landmarks in the carapace. The aeglids were divided into seven size intervals to avoid an allometry effect. In each size category, shape relationships analyzed by principal component analysis suggest a geographical pattern corresponding to the distribution of the populations studied. An evaluation of covariation between body shape and geographical coordinates reveals a strong pattern and shows that population distribution had a significant effect on species morphology. Additionally, according to covariance analysis, the variation in shape was not associated with the environmental variables studied. We observed a clinal pattern throughout the species distribution, which could be attributed to genetic drift. It is possible that this process is being amplified by the geographical isolation of the basins, differences in environmental characteristics, and low dispersal ability. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113, 914–930.

Morphometric studies are useful for delineating the shapes of various populations and species over geographical ranges and as evidence of regional differences in crustaceans. Hydrological fluctuations in a floodplain system modulate the dispersal and presence of decapods among habitats and constitute an important macrofactor that regulate other environmental variables and which could explain the richness, distribution and abundance of organisms that live in these systems. Morphological variations among populations of the freshwater prawn Macrobrachium borellii in a floodplain system at a microgeographical scale were studied using geometric morphometrics. Carapace structure was represented using 16 digitised landmarks. Allometry and sexual dimorphism was tested. Variation in shape was explored via Principal Component Analysis. Canonical Variate Analyses was applied to compare the differences in shape between species? populations. The correlations and covariations among shapes and hydrometric level, current velocity, geographical location and hydrologic distances were analysed. The average carapace shape was different between sexes in all sites. Populations that were near each other in terms of hydrological distance had similar shapes, but all of the populations differed in shape from the farthest population. The environmental variables were not good predictors of the carapace shape. Instead, the shape was strongly related to the hydrologic distance and geographical location. The swimming characteristics of these prawns and their passive movements, together with the dynamics of a floodplain system, explain the low morphological variation between populations in this study. The dynamic characteristics of the system influence the dispersal of the prawns and allow populations to remain connected. Fil: Torres, María Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Giri, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias. Departamento de Ciencias Naturales; Argentina Fil: Collins, Pablo Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentina

The aim of this survey is to provide an introductory overview on the problem of heterogeneity in economics with a special attention to macroeconomics. Starting from the classical representative agent Real Business cycle model, we present several possible alternatives in order to introduce heterogeneity into a standard macroeconomics model. Finally, in the last section, we introduce the Agent-Based model as a possible way of dealing with heterogeneity and complexity.

The 'La Niña' phenomenon causes temporary isolation of shallow lakes in rivers with floodplain. Furthermore, as abiotic conditions become more extreme, and intra-interspecific relationships intensify, the risk of local species extinction increases. The Paraná River in South America is a river with an extensive floodplain with many shallow lakes. In these environments, freshwater prawns and many fish species coexist. The aim of the work was to study the interaction between two species of prawns (Palaemonetes argentinus and Macrobrachium borellii) and fishes during 'La Niña' phenomenon. Density variations of prawns and fishes were examined in three shallow lakes at Paraná River. The samples were collected monthly at several points of each aquatic environment with a trawl net. Abiotic and biotic factors were measured. Density and population structure varied in both prawns, and fishes, and the changes have not been simultaneous. These variations might be associated with predation, aggressive behaviour of the prawns and internal micro-migrations. The effect of La Niña creates additional stress on prawn populations when water inflow is delayed. This fact could promote the decrease or the complete disappearance of one or both prawn species in the environments, and modify the trophic web in the next phase of the shallow lakes. Fil: Torres, María Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Giri, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Collins, Pablo Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina

Limnoperna fortunei, or the golden mussel, invaded South America through the Rio de la Plata estuary in 1991. The size-selective predation on this bivalve by freshwater decapods crustaceans could be an important part of selective trophic behavior because shell sizes are correlated with the flesh contents and their resistance to being broken. The aim of the paper was analyze the size selective predation by the freshwater crab Zilchiopsis collastinensis Pretzmann, 1968 on different sizes of the invasive bivalve L. fortunei. We considered three combinations (AC, AD and BD) of equal numbers of three different shell lengths of mussels: A (small) = 7 to 10.99 mm, B (medium) = 11 to 14.99 mm and C = 15 to 18.99 mm and D = 19 to 22.99 mm (large). These combinations were offered to each adult female intermolt crab individually, and the number of mussels remaining was registered after one, two and 24 hours to evaluate prey-size selection. After this trial, ten female crabs were recorded preying on two different sizes of mussels (A and C) in combination (AC), and we registered the selective feeding behavior (feeding methods and time of predation) with each size of mussel. The results indicated that female crabs ate different sizes of golden mussels, showing an increased consumption of large mollusks after 24 hours, although these sizes demanded higher predation times. Large mussels were encountered at the first time (one and two hours) by the crabs, and these mussels were consumed successfully in the combination AD. These female crabs showed several alternative strategies to access the flesh and were efficient in handling large mussels, presenting an advantageous degree of plasticity for their predatory responses. L. fortunei could be a new food resource for adult Z. collastinensis females, and it could be responsible for a new interaction “native predator-invasive prey” in the system.

Fil: Williner, Veronica. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Santa Fe. Instituto Nacional de Limnologia. Universidad Nacional del Litoral. Instituto Nacional de Limnologia; Argentina

Summary Sexual maturity is marked by morphological changes in freshwater anomuran crabs. Specific modifications to the dorsal and ventral forms of the cephalothorax and the coxa of the fifth pereiopod in males indicate reproductive maturity. Here, we describe changes in cephalothorax and coxa that develop during sexual maturity in the freshwater anomuran, Aegla uruguayana. To evaluate shape, the dorsal and ventral cephalothorax and the coxa of the fifth pereiopod of this species were digitally photographed. With specific landmarks as reference points, the crab shape was analyzed for each of the three body parts. Relative warps analysis were performed revealing shape differences among the size forms and sexes. The dorsal cephalothorax and the coxa of the fifth pereiopod are different between juveniles, males and females. Individuals of 12–16 mm cephalothorax length have a shape closest to the “consensus configuration” in the population, which is correlated with the onset of sexual maturity in males. Additi...

The morphological variation of Aegla neuquensis and A. riolimayana was studied using a geometric morphometric. Specimens included both allopatric and sympatric populations from rivers and lakes of the Argentinean Patagonia. Cephalothorax shape was analyzed throughout 16 landmarks representing the half configurations of all specimens after symmetrization process. Ordination analysis of the weight matrix revealed a clear distinction between the two species. Multivariate test run on the weight matrix for A. neuquensis and A. riolimayana was highly significant (P < 0.0001). Females and males of the two species differ significantly (P < 0.0001). Females of A. neuquensis and A. riolimayana present a wider posterior region, probably to carry eggs and juveniles. The first relative warp clearly indicates a difference in the shape of crabs inhabiting rivers vs. those living in lakes (P < 0.0001). Lake specimens show a more compact rostrum than river individuals. This is probably associated with the differe...

Microsatellites are genomic sequences comprised of tandem repeats of short nucleotide motifs widely used as molecular markers in population genetics. FullSSR is a new bioinformatic tool for microsatellite (SSR) loci detection and primer design using genomic data from NGS assay. The software was tested with 2000 sequences of Oryza sativa shotgun sequencing project from the National Center of Biotechnology Information Trace Archive and with partial genome sequencing with ROCHE 454� from Caiman latirostris, Salvator merianae, Aegla platensis, and Zilchiopsis collastinensis. FullSSR performance was compared against other similar SSR search programs. The results of the use of this kind of approach depend on the parameters set by the user. In addition, results can be affected by the analyzed sequences because of differences among the genomes. FullSSR simplifies the detection of SSRs and primer design on a big data set. The command line interface of FullSSR was intended to be used as part of genomic analysis tools pipeline; however, it can be used as a stand-alone program because the results are easily interpreted for a nonexpert user. Fil: Metz, Sebastián Darío. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; Argentina. Universidad Nacional de Entre Ríos. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Cabrera, Juan Manuel. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; Argentina. Universidad Nacional de Entre Ríos. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Rueda, Eva Carolina. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; Argentina. Universidad Nacional de Entre Ríos. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Giri, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Amavet, Patricia Susana. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

The study of the cephalic shape of crocodilian is relevant in the fields of ecology, systematics, evolution, and conservation. Therefore, the integration of geometric analysis within quantitative genetics allows the evaluation of the inheritable shape components. In this study, the dorsal cephalic region of 210 Caiman latirostris hatchlings was analyzed from seven populations in Santa Fe, Argentina, to detect intra-, and inter-population phenotypic variability, and to determine the heritability of biological shape and size, using newly available geometric morphometric tools. The principal component analysis showed two configurations of cephalic shape that could be related to sexual dimorphism. In the canonical variate analysis, Procrustes distances between groups indicated that there are differences in shape among populations. Furthermore, the method of partial least squares indicated a covariation between cephalic shape and environmental variables. Regarding to CS of the skull we found significant differences among populations, moreover the partial least squares was also significant. Estimates of the heritability of shape and size were high, indicating that the components of these features are susceptible to the selection.

Crustacean growth studies typically use modal analysis rather than focusing on the growth of individuals. In the present work, we use geometric morphometrics to determine how organism shape and size varies during the life of the freshwater crab, Aegla uruguayana Schmitt, 1942. A total of 66 individuals from diverse life cycle stages were examined daily and each exuvia was recorded. Digital images of the dorsal region of the cephalothorax were obtained for each exuvia and were subsequently used to record landmark configurations. Moult increment and intermoult period were estimated for each crab. Differences in shape between crabs of different sizes (allometry) and sexes (sexual dimorphism; SD) were observed. Allometry was registered among specimens; however, SD was not statistically significant between crabs of a given size. The intermoult period increased as size increased, but the moult frequency was similar between the sexes. Regarding ontogeny, juveniles had short and blunt rostrum, robust forehead region, and narrow cephalothorax. Unlike juveniles crabs, adults presented a well-defined anterior and posterior cephalothorax region. The rostrum was long and stylised and the forehead narrow. Geometric morphometric methods were highly effective for the analysis of aeglid-individual- growth and avoided excessive handling of individuals through exuvia analysis. Los estudios de crecimiento en crustáceos típicamente utilizan análisis modal en lugar de focalizarse en el crecimiento individual de los organismos. En el presente trabajo, utilizamos morfometría geométrica para determinar cómo varia la forma y el tamaño a lo largo de la vida del cangrejo de agua dulce, Aegla uruguayana Schmitt, 1942. Un total de 66 individuos, en diferentes etapas del ciclo de vida, se examinaron diariamente, registrándose la presencia de exuvias. Imágenes digitales de cada muda fueron obtenidas de la región dorsal del cefalotórax y se utilizaron para registrar las configuraciones de landmarks. El incremento por muda y el período de intermuda se estimaron para cada cangrejo. Diferencias de forma entre tamaños (alometría) y sexos (dimorfismo sexual; SD) se observaron. Se registró la presencia de alometría entre los especímenes; sin embargo, el SD no fue estadísticamente significativo respecto del tamaño. El período intermuda aumentó de manera directamente proporcional al tamaño, pero la frecuencia de muda fue similar entre los sexos. Durante la ontogenia, los juveniles presentaron rostro corto y romo, frente robusta, y ancho del cefalotórax estrecho. Los adultos presentaron la región anterior y posterior del cefalotórax bien definido en relación con los juveniles. El rostro fue largo y estilizado y la frente estrecha. Los métodos de morfometría geométrica fueron muy efectivos para el análisis del crecimiento individual en aéglidos y permitieron evitar la manipulación excesiva de los individuos a través del análisis de las mudas.

Taxonomy of the genus Brachionus (Brachionidae) poses problems common to many members of Rotifera. Like other genera, Brachionus includes species showing a remarkable phenotypic plasticity. Biometric and geometric morphometric analyses were applied to re-evaluate the taxonomic status of two of its morphological forms, Brachionus caudatus “f”. ahlstromi and Brachionus caudatus “f”. austrogenitus using specimens collected in different aquatic environments of the floodplain of the Parana River. The biometric analysis was based on the measurement of the anterior width, maximum width and body length. Fourteen landmarks were considered for the geometric morphometric analysis. The biometric analysis (using the t-test) revealed significant differences ( p 0.0001 ) in the dimensions of all three variables. Multivariate analysis of variance (MANOVA) of geometric morphometric data also showed that these morphs were significantly different ( p 0.0001 ). These results provide substantial evidence to consider both morphs as separate taxonomic entities.

Animal populations have a certain synchronization between their fluctuations and the environmental factors which have a direct influence on density, sex ratio and recruitment. Trichodactylus borellianus is a common freshwater crab of the Trichodactylidae family, originary from South America. This crab is omnivorous and grazes upon the littoral communities. The present study is the first analysis of the natural distribution and population dynamics of freshwater crabs in La Plata Basin (Argentina) and their relationship with certain abiotic and biotic parameters. It was carried out in three environments (riverine zone of streams and river) of the Parana River floodplain. Crab populations were sampled monthly from August 2001 to October 2002. The mean crab abundance among the study sites was significantly different, being lower in samples from the environment surrounding the principal channel of the Parana River. Crab density showed two peaks: the highest occurred during late winter and early spring, and the lowest during late summer. Males were only more abundant in late winter and spring. In spring, summer and autumn, the population showed a contagious distribution. The population displayed a regular arrangement in winter. From mid-spring to mid-autumn juveniles were very frequent whereas adults predominated the rest of the year. Total crab number in the stream nearest to the main channel varied according to the level and temperature of the river. In the other sites, located further from the main channel of the Parana River, crab numbers and vegetation biomass showed a more similar arrangement with a higher correlation.

The predator-prey relationship of Palaemonetes argentinus Nobili, 1901 and Culex pipiens s.l. larvae was studied under laboratory conditions. The prawns were separated in two groups, isolated and grouped ones. Mosquitoe larvae were offered to prawns in two forms, limited and unlimited offer to both groups. In the first analysis, values of predation did not differ significantly between males and females of P. argentinus. Predation in 24 h was 14,9 ± 4,2 larvae/prawn. A reduction of predation was observed with unlimited offer for the same hour, during all the experiment. Predation with unlimited offer was higher on the first day than on the second, but returned to high values on the third day, for both groups. In the grouped experiment, predation with limited offer was total on the first days, decreasing to the last day. As a result, P. argentinus was considered an efficient predator of C. pipiens s.l. larvae under laboratory conditions.