The interplay among acorn abundance and rodent behavior drives the spatial pattern of seedling recruitment in mature Mediterranean oak forests

The patterns of seedling recruitment in animal-dispersed plants result from the interactions among environmental and behavioral variables. However, we know little on the contribution and combined effect of both kinds of variables. We designed a field study to assess the interplay between environment (vegetation structure, seed abundance, rodent abundance) and behavior (seed dispersal and predation by rodents, and rooting by wild boars), and their contribution to the spatial patterns of seedling recruitment in a Mediterranean mixed-oak forest. In a spatially explicit design, we monitored intensively all environmental and behavioral variables in fixed points at a small spatial scale from autumn to spring, as well as seedling emergence and survival. Our results revealed that the spatial patterns of seedling emergence were strongly related to acorn availability on the ground, but not by a facilitationeffect of vegetation cover. Rodents changed seed shadows generated by mother trees by dispersing most seeds from shrubby to open areas, but the spatial patterns of acorn dispersal/predation had no direct effect on recruitment. By contrast, rodents had a strong impact on recruitment as pilferers of cached seeds. Rooting by wild boars also reduced recruitment by reducing seed abundance, but also by changing rodent's behavior towards higher consumption of acorns in situ. Hence, seed abundance and the foraging behavior of scatter-hoarding rodents and wild boars are driving the spatial patterns of seedling recruitment in this mature oak forest, rather than vegetation features. The contribution of vegetation to seedling recruitment (e.g. facilitation by shrubs) may be context dependent, having a little role in closed forests, or being overridden by directed seed dispersal from shrubby to open areas. We warn about the need of using broad approaches that consider the combined action of environment and behavior to improve our knowledge on the dynamics of natural regeneration in forests

Epidermal growth factor secreted from submandibular salivary glands interferes with the lipolytic effect of adrenaline in mice

We had described that epidermal growth factor (EGF) interfered with the lipolytic effect of catecholamines in isolated adipocytes. Since catecholamines stimulate the release of EGF from submandibular salivary glands to blood plasma in male mice, we studied whether EGF affected also the lipolytic response to adrenaline in whole animals. We studied the effect of adrenaline in sialoadenectomized and sham-operated mice receiving or not a high dose of EGF following adrenaline injection. There was no difference in plasma EGF concentration between sham-operated and sialoadenectomized animals receiving saline. After adrenaline administration plasma EGF increased by 20-fold in sham-operated but did not increase in sialoadenectomized mice. Indeed, the increase was much higher (more than 100-fold) in mice receiving exogenous EGF. The effect of adrenaline on plasma concentration of both glycerol and nonesterified fatty acids was higher as lower was plasma EGF concentration. Isolated adipocytes obtained from sham-operated or sialoadenectomized mice had identical lipolytic response to adrenaline. The lipolytic response of adipocytes to isoproterenol was decreased by addition of EGF. To study whether the interference with the in vivo lipolytic effect of adrenaline had further metabolic consequences, we measured plasma b-hydroxybutyrate concentration in plasma. There was no difference in the response to adrenaline between sham-operated and sialoadenectomized mice in spite of the difference in plasma nonsterified fatty acid concentration. Studies in isolated hepatocytes indicated that ketogenesis run at near maximal rate in this range of substrate concentration. These results suggest that EGF in the physiological range decreases the lipolytic effect of adrenaline but does not compromise further metabolic events like the enhancement of ketogenesis

First application of carbon-based screen-printed electrodes for the voltammetric determination of the organic UV filters oxybenzone and octocrylene

A new voltammetric methodology is proposed for the simultaneous determination of the organic UV filters oxybenzone (benzophenone 3, BP3) and octocrylene (OC) in personal care products and in wastewater extracts.It is based on previous adsorptive stripping voltammetric (AdSV) methods developed for hanging mercury drop electrodes, adapted to the special characteristics of carbon-based screen-printed electrodes. Among the carbon substrates tested, regular carbon screen-printed devices exhibited the best performance, with detection limits of 4.8 and 6.6 μmol L−1 and linearity ranges of 16-400 and 22-400 μmol L−1 for BP3 and OC, respectively, and, as compared to mercury electrodes, with the advantages of environmental safety, easy of use, low cost and compatibility with automation and flow measurements. The methodology has been successfully tested in real samples and compared to the standard methodology by liquid chromatography - tandem mass spectrometry (LCMS/MS)

Context dependency in acorn predation and dispersal by Apodemus sylvaticus in Mediterranean oak forests: the role of seasonality, spatial heterogeneity and animal-animal interactions

La biodiversitat que observem resulta d'una complexa història evolutiva d'interaccions entre els organismes. Les interaccions planta-animal en son un cas paradigmàtic, des de relacions antagòniques a mutualistes, però determinar-ne el resultat pot ser complicat, com en el cas de la dispersió de llavors per rosegadors. Moltes especies de rosegadors son àvids consumidors de llavors, però també actius dispersors, inclús emmagatzemant-ne per al posterior consum, potencialment afavorint la dispersió i regeneració de l’espècie amb la que interactuen. Per això molts estudis s'han centrat en aquesta interacció, tot i que poques vegades s'ha considerat la influència que pot tenir la gran variabilitat temporal i espacial del context on es dóna. L'objectiu principal d'aquesta tesi és estudiar com els patrons de dispersió/depredació d'aglans per rosegadors poden estar influïts per la variabilitat del context en el que té lloc i determinar com pot afectar el reclutament de les espècies sobre les que actuen. Amb aquest fi hem utilitzat un model d'estudi paradigmàtic dels ambients Mediterranis: el ratolí de bosc, Apodemus sylvaticus, com a dispersor i depredador d'aglans en un bosc mixte de roure (Quercus pubescens) i alzina (Quercus ilex) al Parc Natural de Collserola. Hem mostrejat intensivament la població de rosegadors a la zona d'estudi i altres variables ambientals (producció i abundància d'aglans, coberta de vegetació, furgades de senglar), així com el reclutament de plàntules de Quercus. També hem analitzat els patrons de dispersió/depredació d'aglans per rosegadors mitjançant l'enregistrament del seu comportament i el seguiment d'aglans marcats. Els nostres resultats indiquen que les dinàmiques demogràfiques d' A. sylvaticus estan condicionades per la disponibilitat d'aglans, amb importants davallades estivals en l'abundància degut a la sequera i l'escassetat d'aliment. A més, les diferències fenològiques en la producció d'aglans entre roure i alzina també afecten les decisions dels rosegadors, que canvien les seves preferències per l'espècie més abundant. Per altra banda, hem documentat l'efecte de nivells tròfics superiors (carnívors) en el destí de les llavors mitjançant canvis en el comportament dels rosegadors, així com efectes de competidors per aquest recurs (senglars i conspecifics) en els patrons de dispersió/depredació d'aglans. L'activitat dels rosegadors també juga un paper important en l'establiment de plàntules de Quercus, com a dispersors, movent principalment aglans de sota els arbusts cap a zones mes obertes en aquests boscos d’elevada densitat, però també com a "lladres" d'aglans, reduint les oportunitats de reclutament per a la planta. De fet, la distribució espacial de plàntules en la zona d'estudi està determinada principalment per la disponibilitat d'aglans, mentre que el possible efecte protector dels arbusts no té tanta importància com esperàvem prèviament, degut a les característiques del bosc (coberta arbòrea densa). Aquesta tesi documenta que la interacció entre planta i rosegadors pot ser molt variable depenent del context on es dóna, de manera que el paper dels rosegadors com a dispersors i depredadors d'aglans en boscos Mediterranis de Quercus pot diferir en funció de l'estructura del bosc (per exemple deveses vs. boscos tancats). Aquesta variabilitat temporal i espaial es deu principalment a la flexibilitat comportamental dels rosegadors, que adapten les seves decisions al context de cada lloc i moment. En canvi, hem documentat altres comportaments amb una tendència més fixa, com la preferència per llavors grans. En aquest sentit, aquests comportaments més fixes poden exercir pressions selectives importants sobre els trets vitals de la planta, mentre que comportaments més variables no tindran un efecte tant clar. Estudis futurs centrats en aquesta interacció entre planta i rosegadors haurien de tenir en compte aquesta variabilitat temporal i espacial, així com les interaccions assenyalades en el nostre estudi amb altres animals de la xarxa tròfica (carnívors i competidors).Earth's biodiversity results from a complex evolutionary history of interactions among organisms. Plant-animal interactions are a paradigmatic example of such ecological relationships, from antagonistic to mutualistic relationships, although determining its result might be difficult, like in the case of seed dispersal by rodents. Many rodent species are avid seed consumers, but also active dispersers, caching seeds in burrows for further consumption, potentially contributing to the dispersion and regeneration of the species with which they interact. Thus, many studies have focused on this interaction, although the influence of the great spatial and temporal variability of the context where it occurs has not been generally considered. The main objective of this thesis is to assess how the acorn predation/dispersal patterns by rodents may be influenced by the contextual variability, and to determine how this variability might affect the recruitment of the species with whom they interact. To that end we have used a well-known study model paradigmatic of Mediterranean environments: the wood mouse, Apodemus sylvaticus, as seed predator and disperser of acorns in a mixed oak forest of Holm oak (Quercus ilex) and Downy oak (Quercus pubescens) in the Collserola Natural Park. We have intensively monitored the rodent population in the study area, some environmental factors (acorn production and abundance, vegetation cover, wild boar rooting), and oak’s seedling emergence. We have also analyzed the acorn predation/dispersal patterns of rodents by recording their foraging behaviour and monitoring tagged acorns. Our results show that the demographic dynamics of A. Sylvaticus are conditioned by the availability of acorns, with important population declines in the summers, due to the effects of drought and food scarcity. Moreover, the differences in seeding phenology between Q. ilex and Q. pubescens also affect rodent’s foraging decisions, as they change their seed preferences for the most abundant species. We have also documented an effect of upper trophic levels (carnivores) on seed’s fate by influencing rodent’s behaviour, as well as effects from competitors for that resource (wild boars and conspecifics) on the acorn predation/dispersal patterns. Rodent’s activity also plays an important role in oak’s seedling establishment, as seed dispersers, removing many acorns from under shrubs towards open sites in these close canopy forests, but also as seed pilferers, reducing the recruitment opportunities of oaks. In fact, the spatial distribution of oak seedlings in the study area is mainly determined by the availability of acorns, while the potential nursing effect of shrubs does not have such an important effect as we had previously anticipated, due to the forest characteristics (dense tree canopy). This thesis documents the great context dependent variability in the interaction among plants and rodents, so that rodent’s role as acorn predators and dispersers in Mediterranean oak forests may be very different according to the forest structure (e.g. savanah-like forests vs. close canopy forests). This spatial and temporal variability occurs mainly due to the behavioural plasticity of rodents, which adapt their foraging choices to the context of every place and moment. On the other hand, we have also documented other behaviours that show a rather fixed trend, such as the preference for bigger and sound acorns. In this sense, these more fixed behaviours might represent important selective pressures on the life history traits of the plants they interact with, while more variable behaviours will not have such clear effect. Further studies focussed on this interaction among plants and rodents should consider this great temporal and spatial variability, as well as the interactions with other animals of the trophic web shown in our study (carnivores and competitors)

Context dependency in acorn predation and dispersal by Apodemus sylvaticus in Mediterranean oak forests: the role of seasonality, spatial heterogeneity and animal-animal interactions

La biodiversitat que observem resulta d'una complexa història evolutiva d'interaccions entre els organismes. Les interaccions planta-animal en son un cas paradigmàtic, des de relacions antagòniques a mutualistes, però determinar-ne el resultat pot ser complicat, com en el cas de la dispersió de llavors per rosegadors. Moltes especies de rosegadors son àvids consumidors de llavors, però també actius dispersors, inclús emmagatzemant-ne per al posterior consum, potencialment afavorint la dispersió i regeneració de l’espècie amb la que interactuen. Per això molts estudis s'han centrat en aquesta interacció, tot i que poques vegades s'ha considerat la influència que pot tenir la gran variabilitat temporal i espacial del context on es dóna. L'objectiu principal d'aquesta tesi és estudiar com els patrons de dispersió/depredació d'aglans per rosegadors poden estar influïts per la variabilitat del context en el que té lloc i determinar com pot afectar el reclutament de les espècies sobre les que actuen. Amb aquest fi hem utilitzat un model d'estudi paradigmàtic dels ambients Mediterranis: el ratolí de bosc, Apodemus sylvaticus, com a dispersor i depredador d'aglans en un bosc mixte de roure (Quercus pubescens) i alzina (Quercus ilex) al Parc Natural de Collserola. Hem mostrejat intensivament la població de rosegadors a la zona d'estudi i altres variables ambientals (producció i abundància d'aglans, coberta de vegetació, furgades de senglar), així com el reclutament de plàntules de Quercus. També hem analitzat els patrons de dispersió/depredació d'aglans per rosegadors mitjançant l'enregistrament del seu comportament i el seguiment d'aglans marcats. Els nostres resultats indiquen que les dinàmiques demogràfiques d' A. sylvaticus estan condicionades per la disponibilitat d'aglans, amb importants davallades estivals en l'abundància degut a la sequera i l'escassetat d'aliment. A més, les diferències fenològiques en la producció d'aglans entre roure i alzina també afecten les decisions dels rosegadors, que canvien les seves preferències per l'espècie més abundant. Per altra banda, hem documentat l'efecte de nivells tròfics superiors (carnívors) en el destí de les llavors mitjançant canvis en el comportament dels rosegadors, així com efectes de competidors per aquest recurs (senglars i conspecifics) en els patrons de dispersió/depredació d'aglans. L'activitat dels rosegadors també juga un paper important en l'establiment de plàntules de Quercus, com a dispersors, movent principalment aglans de sota els arbusts cap a zones mes obertes en aquests boscos d’elevada densitat, però també com a "lladres" d'aglans, reduint les oportunitats de reclutament per a la planta. De fet, la distribució espacial de plàntules en la zona d'estudi està determinada principalment per la disponibilitat d'aglans, mentre que el possible efecte protector dels arbusts no té tanta importància com esperàvem prèviament, degut a les característiques del bosc (coberta arbòrea densa). Aquesta tesi documenta que la interacció entre planta i rosegadors pot ser molt variable depenent del context on es dóna, de manera que el paper dels rosegadors com a dispersors i depredadors d'aglans en boscos Mediterranis de Quercus pot diferir en funció de l'estructura del bosc (per exemple deveses vs. boscos tancats). Aquesta variabilitat temporal i espaial es deu principalment a la flexibilitat comportamental dels rosegadors, que adapten les seves decisions al context de cada lloc i moment. En canvi, hem documentat altres comportaments amb una tendència més fixa, com la preferència per llavors grans. En aquest sentit, aquests comportaments més fixes poden exercir pressions selectives importants sobre els trets vitals de la planta, mentre que comportaments més variables no tindran un efecte tant clar. Estudis futurs centrats en aquesta interacció entre planta i rosegadors haurien de tenir en compte aquesta variabilitat temporal i espacial, així com les interaccions assenyalades en el nostre estudi amb altres animals de la xarxa tròfica (carnívors i competidors).Earth's biodiversity results from a complex evolutionary history of interactions among organisms. Plant-animal interactions are a paradigmatic example of such ecological relationships, from antagonistic to mutualistic relationships, although determining its result might be difficult, like in the case of seed dispersal by rodents. Many rodent species are avid seed consumers, but also active dispersers, caching seeds in burrows for further consumption, potentially contributing to the dispersion and regeneration of the species with which they interact. Thus, many studies have focused on this interaction, although the influence of the great spatial and temporal variability of the context where it occurs has not been generally considered. The main objective of this thesis is to assess how the acorn predation/dispersal patterns by rodents may be influenced by the contextual variability, and to determine how this variability might affect the recruitment of the species with whom they interact. To that end we have used a well-known study model paradigmatic of Mediterranean environments: the wood mouse, Apodemus sylvaticus, as seed predator and disperser of acorns in a mixed oak forest of Holm oak (Quercus ilex) and Downy oak (Quercus pubescens) in the Collserola Natural Park. We have intensively monitored the rodent population in the study area, some environmental factors (acorn production and abundance, vegetation cover, wild boar rooting), and oak’s seedling emergence. We have also analyzed the acorn predation/dispersal patterns of rodents by recording their foraging behaviour and monitoring tagged acorns. Our results show that the demographic dynamics of A. Sylvaticus are conditioned by the availability of acorns, with important population declines in the summers, due to the effects of drought and food scarcity. Moreover, the differences in seeding phenology between Q. ilex and Q. pubescens also affect rodent’s foraging decisions, as they change their seed preferences for the most abundant species. We have also documented an effect of upper trophic levels (carnivores) on seed’s fate by influencing rodent’s behaviour, as well as effects from competitors for that resource (wild boars and conspecifics) on the acorn predation/dispersal patterns. Rodent’s activity also plays an important role in oak’s seedling establishment, as seed dispersers, removing many acorns from under shrubs towards open sites in these close canopy forests, but also as seed pilferers, reducing the recruitment opportunities of oaks. In fact, the spatial distribution of oak seedlings in the study area is mainly determined by the availability of acorns, while the potential nursing effect of shrubs does not have such an important effect as we had previously anticipated, due to the forest characteristics (dense tree canopy). This thesis documents the great context dependent variability in the interaction among plants and rodents, so that rodent’s role as acorn predators and dispersers in Mediterranean oak forests may be very different according to the forest structure (e.g. savanah-like forests vs. close canopy forests). This spatial and temporal variability occurs mainly due to the behavioural plasticity of rodents, which adapt their foraging choices to the context of every place and moment. On the other hand, we have also documented other behaviours that show a rather fixed trend, such as the preference for bigger and sound acorns. In this sense, these more fixed behaviours might represent important selective pressures on the life history traits of the plants they interact with, while more variable behaviours will not have such clear effect. Further studies focussed on this interaction among plants and rodents should consider this great temporal and spatial variability, as well as the interactions with other animals of the trophic web shown in our study (carnivores and competitors)

FCR Method vs. IR Method: Comparative and intercultural analysis of two human behavior measurements applying extended Fuzzy Logic

Outgoin

FCR Method vs. IR Method: Comparative and intercultural analysis of two human behavior measurements applying extended Fuzzy Logic

Outgoin

FCR Method vs. IR Method: Comparative and intercultural analysis of two human behavior measurements applying extended Fuzzy Logic

Outgoin

Tagged acorns used by rodents and foraging behaviour

Field data obtained from tagged acorns and video-camera

Habitat overlap and body condition in aquatic turtles: are there additive effects between invasive and native species?

Trachemys scripta (Reptilia, Emydidae) is among the most widespread invasive reptiles in the world. In general, it is assumed that this species has negative effects on native aquatic turtles based on experiments conducted under controlled conditions. Here, we analysed a 7‒year time series (2013‒2019) of data from captures of three species of turtles (two natives and one alien) from natural populations in the northeastern Iberian Peninsula. We evaluated (i) the interspecific spatial overlap and (ii) the correlation between the scaled mass index (SMI) of the native turtles and the abundance of T. scripta, including an interaction effect between the species. The analyses revealed that T. scripta has relatively low spatial overlap with Emys orbicularis but high overlap with Mauremys leprosa. Overall, the abundance of T. scripta was not associated with significant variations in the SMI of the native species, although for the female E. orbicularis, we detected a negative trend. The analyses also indicated that the abundance of T. scripta does not have an additive effect on the SMI of other turtles, even if there is a negative effect between native species. These findings suggested that the impact of T. scripta on other turtles could be density-dependent