Etude hydrogéologique des séries triasiques dans la région de Jeffara-Dahar (Sud Tunisien): Apport des diagraphies et de la sismique réflexion

The present study concentrates on the interpretation of well logs and seismic reflection data in the Jeffara- Dahar region (Southeast part of Tunisia) for a better characterization of the Triassic aquifer, a potential target of water supply. Lithological columns and their corresponding well logs reveal that Sidi Stout, Kirchaou and Touareg sandstones as well as Mekraneb and Rehach dolomites are the main reservoirs of the Triassic aquifer. Well log analysis highlights many permeable and fractured layers that could play an important role in the groundwater circulation. The interpreted seismic sections and the resulting isochrone maps show a tectonic influence on the Triassic aquifer geometry in the Jeffara-Dahar region. The normal faulting of E-W and NW-SE accidents created an aquifer compartmentalized by raised and tilted blocks. Seismic cross-sections reveal that this structure controls the depth of permeable formations and the circulation of groundwater. These results will be useful for rationalising the future hydrogeological research that will be undertaken in the Jeffara-Dahar area.[fr] La présente étude concerne l’interprétation des données de la sismique réflexion et celles des puits y compris les enregistrements diagraphiques en vue d’une meilleure caractérisation de l’aquifère triasique de la région de Jeffara-Dahar (Sud-Est de la Tunisie) qui constitue une cible potentielle pour l’alimentation en eau. Les logs lithologiques associés aux enregistrements diagraphiques correspondants montrent que les principaux réservoirs sont les grés de Sidi Stout, Kirchaou et Touareg ainsi que les dolomies de Mekraneb et Rehach. L’interprétation diagraphique met en évidence des niveaux de faible perméabilité et d’autres perméables et bien fracturées qui pourraient jouer un rôle dans l’acheminement des eaux souterraines. Les profils sismiques interprétés et la cartographie élaborée en conséquence mettent en évidence que l’aquifère triasique est compartimenté en blocs soulevés et affaissés. Cette structuration, contrôlée par la réactivation des accidents E-W et NW-SE en failles normales au cours du Trias, influence l’épaisseur des formations perméables ainsi que le sens d’écoulement de la nappe d’eau. Les résultats obtenus seront utiles pour la rationalisation des futures recherches hydrogéologiques dans la région de Jeffara – Dahar

Geographical variation in ant foraging activity and resource use is driven by climate and net primary productivity

AIM : Foraging activity is critical for animal survival. Comprehending how ecological drivers influence foraging behaviour would benefit our understanding of the link between animals and ecological processes. Here, we evaluated the influence of ecological drivers on ant foraging activity and relative resource use. LOCATION : Six Brazilian biomes: Amazon, Atlantic rainforest, Caatinga, Cerrado, Pampa and Pantanal. TAXON : Formicidae. METHODS : We assessed ant foraging activity and resource use by sampling across 60 sites. We placed baited tubes that contained one of five liquid resources (sugar, lipids, amino acid, sodium and distilled water). We used model selection to assess the influence of ecological drivers (temperature, precipitation, temperature seasonality and net primary productivity) on ant foraging activity and relative resource use. RESULTS : Foraging activity was higher in wetter, more productive and less thermally seasonal environments. The relative use of amino acids increased at higher temperatures while the relative use of lipids decreased. The relative use of sugar increased in drier and less productive environments with high-temperature seasonality while the relative use of amino acid and sodium decreased in those environments. The relative use of lipids was complex: increasing with increasing temperature seasonality and decreasing with increasing precipitation. Furthermore, the relative use of sodium was greater where the foraging activity was high. MAIN CONCLUSIONS : We demonstrate how ecological drivers are correlated with ant foraging activity and resource use in the field across large spatial scales. The search for resources encompasses different interactions involving ants with abiotic and biotic components in the ecosystem. Thus, we suggest that changes in climate and NPP, which influence the intensity and the way that ants search for resources, will result in changes in ant-mediated ecological processes.Chaim J. Lasmar is a Post-doctoral researcher at the Programa de Pós-Graduação em Ecologia Aplicada (Universidade Federal de Lavras, Brazil). This study was part of his Ph. D. work at the Universidade Federal de Lavras with an internship period at the University of Liverpool.DATA AVAILABILITY STATEMENT: All data have been uploaded to Dryad (https://doi.org/10.5061/dryad.6wwpzgmxc).Fundação de Amparo à Pesquisa do Estado de Minas Gerais and Rufford Foundation.http://wileyonlinelibrary.com/journal/jbiam2022Zoology and Entomolog

Equipamentos, instalações e protocolos de mensuração de consumo de matéria seca em bovinos

Data of dry matter intake (DMI) individually measured in animals are critical to the feed efficiency (FE) indexes. This information guide the decisions made in breeding programs. Here, the objective was describes the technologies and protocols available to measure the DMI in cattle and the use of these information on genetic evaluations. The electronic identification by radio frequency when coupled with weighing bunks (plus storage of data) can be used for monitoring the DMI throughout the day. When performed at individual pens, the cattle feedlot may change the behavior, performance and, consequently, the FE. Thus, the relevance of data at these housing types can be questioned. Calan-gate is an alternative system for collective pens, however, dominant animals can get access to food of subordinates. In the GrowSafe System it is possible obtained data of DMI plus the time (duration) and frequency (bunk attendance). Studies indicate that changes in DMI are due to interactions and behavior of animals in collective pens. In the context of genetic evaluation, although individual pens (IP) are useful for measuring DMI, this condition is not representative. Data from IP can negatively impact on estimates of heritability for DMI and FE. Several studies have shown that there is moderate to strong genetic correlation between the DMI data and FE indexes, showing considerable variation exists among animals. Thus, genetic selection using these features greatly increase profitability in the beef cattle production system. Additionally, the accuracy and precision in the measurement of DMI are critical in this process.Dados de consumo de matéria seca (CMS) são fundamentais para o cálculo dos índices de eficiência alimentar, os quais norteiam as tomadas de decisões nos programas de seleção genética. Objetivou-se abordar as tecnologias disponíveis para medir o CMS em bovinos, os protocolos de mensuração de consumo, bem como a utilização destes nas avaliações genéticas. Entre as tecnologias, a identificação eletrônica por rádio frequência, acoplada a cochos com pesagem e armazenamento dos dados pode ser usada para o monitoramento do CMS ao longo do dia. Quando feito em baias individuais, o confinamento pode alterar o comportamento, desempenho e eficiência alimentar, e, consequentemente, a relevância dos dados nessas instalações pode ser questionada. O Calan-gate é um equipamento alternativo para baias coletivas, contudo animais dominantes podem conseguir acesso ao alimento dos subordinados. Já o GrowSafe, além de registrar o CMS de cada animal, efetua a medição do tempo (duração) e frequência (quantas vezes o animal frequenta o cocho). Visando qualidade dos dados de CMS e eficiência alimentar, os testes de desempenho devem ter duração mínima de 70 dias, contudo esse tempo pode variar de acordo com as diferenças biológicas entre os animais e variabilidade associada ao erro de medição. Vários trabalhos demonstram que existe de moderada a forte correlação genética entre os dados de CMS e os índices de eficiência alimentar, mostrando que considerável variação para esta característica existe entre os animais. Com isso, a seleção genética utilizando essas características aumentaria consideravelmente a rentabilidade no sistema de produção de bovinos de corte, sendo que a acurácia e precisão na mensuração do CMS são fundamentais nesse processo