Centro Universitario Regional Este

Maldonado, Uruguay

Centro Universitario Regional Este

Maldonado, Uruguay
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Gianelli I.,UNDECIMAR | Defeo O.,UNDECIMAR | Defeo O.,Centro Universitario Regional Este
Fisheries Research | Year: 2017

The systematic dwindling over time of many commercially important fish stocks in developed countries and the increasing demand of international markets provided a window of opportunity for fishery sector development in many developing countries. Science-based assessments of how market forces impact on fisheries trends are particularly limited in developing countries. This study assessed long-term trends (1960–2013) of the Uruguayan industrial fishery sector, including: (i) landings discriminated by species and resource type; (ii) variations in nominal effort and fleet capacity; (iii) bioeconomic patterns for most important species; and (iv) export and import volumes at the Uruguayan seafood market. Results indicate the sector underwent four phases that depict long-term patterns: development, expansion, stabilization-diversification and declining yields and market contraction. The development of the sector was mainly due to the Argentine hake fishery, which was characterized by a sustained increase in landings, nominal effort and fleet capacity during the initial decades, but showed a decreasing trend afterwards. In response, a fishery diversification policy based on more valuable target species but with lower trophic levels was developed. Uruguay adopted a seafood net exporter role since the very beginning, with exports increasing linearly through time. More recently, seafood imports, with more competitive prices than locally caught seafood, have been gaining ground in the domestic market, reaching a third of all seafood currently consumed. Nowadays, the Uruguayan fishery sector is facing a crisis that is clearly reflected in the decreasing yields of the main species targeted, exports dwindling and increasing seafood imports. These results highlight the pressing need of the industrial sector to shift its model of fisheries exploitation. This study also provides evidence of the need to consider additional bioeconomic analysis to fully understand the behavior of the fishery sector as a dynamic social-ecological system operating in a globalized seafood trade scenario. © 2017 Elsevier B.V.

Mourelle D.,Centro Universitario Regional Este | Prieto A.R.,CONICET | Garcia-Rodriguez F.,Centro Universitario Regional Este
Quaternary Science Reviews | Year: 2017

A detailed palynological record from Laguna Formosa (northeastern campos region, 31°S; 54°W) documents the dynamic balance between grasslands and riparian forests during the late Pleistocene (14,570 to 13,500 cal yr BP) and late Holocene (3280 cal yr BP to the present). Modern pollen-vegetation relationships and the woody pollen dispersal capacity analyses were used to improve the vegetation reconstruction. Grasslands were regionally dominant throughout the record. However, at 14,570 cal yr BP hydrophilous taxa reflect the development of riparian hydrophilous shrublands along freshwater bodies, promoting the fixation of the riverbanks, maintaining shallow, calm and clear water conditions under a relatively wet and not so cool climate. This is the first evidence of woody riparian vegetation development along freshwater bodies for the lowlands of the northern campos during the late glacial period. At 3280 cal yr BP riparian forests consisted of both hydrophilous and mesophilous woody taxa. Since 2270 cal yr BP woody vegetation gradually increased, accompanied by the incorporation of other taxa by 940 cal yr BP, and achieving a composition similar to that of the contemporary time at ca. 540 cal yr BP. The increased woody vegetation since ca. 2270 cal yr BP, and the more frequent and intense flooding events between 1800 and 1200 cal yr BP, could be related to higher precipitation over La Plata Drainage Basin, related with the high ENSO amplitude. In addition, pollen from taxa that currently no longer develops in the study area suggests connections between southern Brazil and Uruguay, and between the campos and the Chaco phytogeographic province. © 2017 Elsevier Ltd

Carranza A.,Centro Universitario Regional Este | Martinez G.,Centro Universitario Regional Este | Arim M.,Centro Universitario Regional Este
Pan-American Journal of Aquatic Sciences | Year: 2017

Adelomelon beckii (Broderip,1836) is the largest Volutidae from the Western Atlantic, and one of the largest marine gastropods worldwide. We analysed data from 516 trawls performed in the Uruguayan continental shelf between 5 and 300 m depth and developed a predictive species distribution model, identifying shelf areas in which fleet activity should be monitored in relation to landings of A. becki. According to our model, the fleets potentially affecting the Uruguayan population of A. beckii include the coastal industrial fleet and, to a lesser extent, the fleet targeting Argentinean Hake in the outer shelf. In order to minimize the likelihood of further reduction of the population of A. beckii within Uruguayan waters, management measures should include the implementation of specific fishery regulations for the commercial fleet and ships' crews, including a) closed areas, that ensure the reproductive success of the population and/ or b) prohibition of shell trade in stores along the coast, aiming to definitively stop landings of A. beckii. An appropriate understanding of the ecological and spatial structure, resilience and dynamics of the species is critical to this end.

Garcia-Alonso J.,Natural History Museum in London | Garcia-Alonso J.,Centro Universitario Regional Este | Rodriguez-Sanchez N.,Natural History Museum in London | Rodriguez-Sanchez N.,Liverpool John Moores University | And 8 more authors.
Science of the Total Environment | Year: 2014

Pollutants affecting species at the population level generate ecological instability in natural systems. The success of early life stages, such as those of aquatic invertebrates, is highly affected by adverse environmental conditions. Silver released into the environment from emerging nanotechnology represents such a threat. Sediments are sinks for numerous pollutants, which aggregate and/or associate with depositing suspended particles. Deposit feeder such as the annelid Platynereis dumerilii, which has a large associated literature on its development, is an excellent model organism for exposure studies in coastal environments. We exposed eggs, larvae, juveniles and adults of P. dumerilii to various concentrations of citrate (cit-Ag NPs) or humic acid (HA-Ag NPs) capped silver nanoparticles (Ag NPs) as well to dissolved Ag (added as AgNO3). We showed that mortality and abnormal development rate increased with younger life stages. While adults and juvenile were the most tolerant life stages, fertilized eggs were highly sensitive to AgNO3, cit-Ag NPs and HA-Ag NPs. Exposures to HA-Ag NPs triggered the highest cute toxicity responses in P. dumerilii and in most cases both Ag NPs were more toxic than AgNO3. Uptake rate of HA-Ag NPs in adult worms was also higher than from other Ag forms, consistent with toxicity to other life stages. The early stages of the life cycle of marine coastal organisms are more affected by Ag NPs than the juvenile or adult life stages, indicating that exposure experiments at the larval level contribute to realistic eco-toxicological studies in aquatic environments. © 2014 Elsevier B.V.

Perez L.,University of the Republic of Uruguay | Perez L.,Centro Universitario Regional Este | Garcia-Rodriguez F.,University of the Republic of Uruguay | Garcia-Rodriguez F.,Centro Universitario Regional Este | And 2 more authors.
Climate of the Past | Year: 2016

The continental shelf adjacent to the Río de la Plata (RdlP) exhibits extremely complex hydrographic and ecological characteristics which are of great socioeconomic importance. Since the long-term environmental variations related to the atmospheric (wind fields), hydrologic (freshwater plume), and oceanographic (currents and fronts) regimes are little known, the aim of this study is to reconstruct the changes in the terrigenous input into the inner continental shelf during the late Holocene period (associated with the RdlP sediment discharge) and to unravel the climatic forcing mechanisms behind them. To achieve this, we retrieved a 10 m long sediment core from the RdlP mud depocenter at 57 m water depth (GeoB 13813-4). The radiocarbon age control indicated an extremely high sedimentation rate of 0.8 cm per year, encompassing the past 1200 years (AD 750-2000). We used element ratios (Ti/Ca, Fe/Ca, Ti/Al, Fe/K) as regional proxies for the fluvial input signal and the variations in relative abundance of salinity-indicative diatom groups (freshwater versus marine-brackish) to assess the variability in terrigenous freshwater and sediment discharges. Ti/Ca, Fe/Ca, Ti/Al, Fe/K and the freshwater diatom group showed the lowest values between AD 850 and 1300, while the highest values occurred between AD 1300 and 1850. The variations in the sedimentary record can be attributed to the Medieval Climatic Anomaly (MCA) and the Little Ice Age (LIA), both of which had a significant impact on rainfall and wind patterns over the region. During the MCA, a weakening of the South American summer monsoon system (SAMS) and the South Atlantic Convergence Zone (SACZ), could explain the lowest element ratios (indicative of a lower terrigenous input) and a marine-dominated diatom record, both indicative of a reduced RdlP freshwater plume. In contrast, during the LIA, a strengthening of SAMS and SACZ may have led to an expansion of the RdlP river plume to the far north, as indicated by higher element ratios and a marked freshwater diatom signal. Furthermore, a possible multidecadal oscillation probably associated with Atlantic Multidecadal Oscillation (AMO) since AD 1300 reflects the variability in both the SAMS and SACZ systems. © 2016 Author(s).

Mourelle D.,Centro Universitario Regional Este | Prieto A.R.,CONICET | Garcia-Rodriguez F.,Centro Universitario Regional Este
Revista Brasileira de Paleontologia | Year: 2015

The palynological analysis from a sedimentary sequence from the wetland Paso Barranca-India Muerta at Laguna Merín Basin (RB1 core, 33°40’36”S-53°49’15”W) of southeastern Uruguay, allowed to reconstruct the vegetation history during the last ca. 2000 cal. yr BP. The modern pollen-vegetation relationship from Laguna Merín Basin at regional scale was used for the interpretation of RB1 fossil record. Results revealed that during the late Holocene grassland vegetation dominated at Paso Barranca-India Muerta, together with the development of riparian forests, palm grooves and freshwater marshes. This suggests a diverse vegetation on the area under either humid climatic conditions or a positive water balance. However, the freshwater marsh showed fluctuations in depth and extent, probably as a response to local soil water content changes. Since ca. 2000 cal. yr BP the marsh water level changes displayed variability, with increased levels at ca. 700 cal. yr BP. Thereafter, conditions remained relatively steady until ca. 300 cal. yr BP, when the marsh water level progressively increased until reaching the current conditions. The local soil water content changes would have responded to the late Holocene climate variability suggested for southeastern Uruguay, even under humid conditions proposed for the campos region of the Río de la Plata grasslands. The vegetation changes inferred from the palynological analysis could not be related to the anthropogenic changes introduced by the prehispanic populations in the region. This work substantially improves our knowledge of the late Holocene vegetation and climate conditions in the Laguna Merín Basin. © 2015 by the Sociedade Brasileira de Paleontologia.

Franco-Trecu V.,University of the Republic of Uruguay | Aurioles-Gamboa D.,National Polytechnic Institute of Mexico | Arim M.,University of the Republic of Uruguay | Arim M.,Centro Universitario Regional Este | And 2 more authors.
Journal of Mammalogy | Year: 2012

In Uruguay, the South American fur seal population (Arctocephalus australis) is increasing, whereas the South American sea lion (Otaria flavescens) population is declining. Previous research using fecal analysis suggested a high degree of trophic overlap between these species. In this study we used stable isotope analysis to assess whether trophic overlap occurs between female fur seals and sea lions during the breeding season. We measured 15N and 13C values in serum and skin from pups of both species (n 47) to reflect pre- and postpartum maternal feeding habits, respectively. Our results suggested a lack of trophic overlap between lactating females; both serum and skin samples from sea lion pups had significantly greater 13C and 15N values than samples from fur seal pups, suggesting that lactating sea lions forage near shore, whereas lactating fur seals forage offshore. The pre- to postpartum diet shift in fur seals would be mainly caused by a reduction in the diversity of the exploited trophic levels, whereas in sea lions the shift could be related to a decrease in the diversity of foraging areas used. The observed trophic segregation between these sympatric otariids is probably driven by their synchronous breeding and similar maternal strategies. © 2012 American Society of Mammalogists.

Mourelle D.,Centro Universitario Regional Este | Prieto A.R.,National University of San Juan
Acta Botanica Brasilica | Year: 2016

In this study we describe and illustrate pollen and spores that have been identified as significant in modern and fossil samples from the campos region of Uruguay. We provide new information about modern pollen assemblages and their relationship to the vegetation types of this region. We discuss the taxonomic limitations of pollen and spores and their representation in both modern and fossil samples. We highlight the importance of identifying both silent and key indicator taxa for making accurate paleoecological interpretations. We also emphasize the importance of knowing the pollination strategies of parental plants because many of them are zoophilous, and so small changes in the proportions of their pollen grains in fossil assemblages could reflect important changes in vegetation. This study presents a practical approach to paleoecological research, which not only produces robust results in studies of the campos region, but can be applied to other grassland ecosystems, including those in temperate regions. © 2016, Sociedade Botanica do Brasil. All rights reserved.

Bozzeda F.,University of Bologna | Zangrilli M.P.,University of Bologna | Defeo O.,UNDECIMAR | Defeo O.,Centro Universitario Regional Este
Estuarine, Coastal and Shelf Science | Year: 2016

A Fuzzy Naïve Bayes (FNB) classifier was developed to assess large-scale variations in abundance, species richness and diversity of the macrofauna inhabiting fifteen Uruguayan sandy beaches affected by the effects of beach morphodynamics and the estuarine gradient generated by Rio de la Plata. Information from six beaches was used to estimate FNB parameters, while abiotic data of the remaining nine beaches were used to forecast abundance, species richness and diversity. FNB simulations reproduced the general increasing trend of target variables from inner estuarine reflective beaches to marine dissipative ones. The FNB model also identified a threshold value of salinity range beyond which diversity markedly increased towards marine beaches. Salinity range is suggested as an ecological master factor governing distributional patterns in sandy beach macrofauna. However, the model: 1) underestimated abundance and species richness at the innermost estuarine beach, with the lowest salinity, and 2) overestimated species richness in marine beaches with a reflective morphodynamic state, which is strongly linked to low abundance, species richness and diversity. Therefore, future modeling efforts should be refined by giving a dissimilar weigh to the gradients defined by estuarine (estuarine beaches) and morphodynamic (marine beaches) variables, which could improve predictions of target variables. Our modeling approach could be applied to a wide spectrum of issues, ranging from basic ecology to social-ecological systems. This approach seems relevant, given the current challenge to develop predictive methodologies to assess the simultaneous and nonlinear effects of anthropogenic and natural impacts in coastal ecosystems. © 2016 Elsevier Ltd.

Celentano E.,UNDECIMAR | Defeo O.,UNDECIMAR | Defeo O.,Centro Universitario Regional Este
Marine Ecology Progress Series | Year: 2016

Climate change is expected to have considerable impacts on sandy beach ecosystems through the loss of intertidal area and changes in physical properties. These changes may affect demography and life history traits of macrofaunal species. We evaluated the role of climate in explaining variations in population traits of the mole crab Emerita brasiliensis over 20 yr on a sandy beach in Uruguay, based on a set of predictive hypotheses recently developed from studies of beach and climate-change ecology. Population abundance increased with sea surface temperature (SST), reproductive and recruitment periods were more extended, and recruitment was higher during warm years, when population structure showed a multi-modal structure. Decreasing asymptotic sizes and increasing growth rates were also observed concurrently with increasing SST. La Niña events, which in coastal Uruguayan waters are characterized by a higher influence of tropical oceanic waters (warm and salty), had marked positive impacts on abundance and individual growth. In a climate change scenario, an increasing frequency of extreme La Niña events is expected and therefore our results have strong implications. In a space-for-time substitution context, our long-term trends are reinforced by macroscale results that reported an increase in growth rates and in reproduction and recruitment periods, together with a decrease in female individual sizes, from temperate to tropical beaches of the Atlantic coast of South America. Spacefor-time substitution is highlighted as an alternative approach to analyze potential population changes resulting from climate change in these data-poor ecosystems. © 2016 Inter-Research.

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