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    Bernat López

    Los ataques de grandes felinos al ganado son una de las principales causas de conflicto entre humanos y felinos, siendo por ello un tema prioritario para la conservación de estas especies. Se ha argumentado que la reducción en abundancia... more
    Los ataques de grandes felinos al ganado son una de las principales causas de conflicto entre humanos y felinos, siendo por ello un tema prioritario para la conservación de estas especies. Se ha argumentado que la reducción en abundancia de presas naturales incrementa la ocurrencia de ataques a las especies domésticas. Sin embargo son pocos los estudios que han evaluado esta afirmación, algunos con resultados contradictorios. Nosotros investigamos cómo la ocurrencia de ataques al ganado, por parte de puma o jaguar, se relaciona con la abundancia y la riqueza de sus presas naturales. Muestreamos las presas potenciales contando los rastros de presencia a lo largo de transectos lineales en 14 fincas sin ataques (control) y en 14 fincas con ataques en el Noroeste de Costa Rica durante la temporada lluviosa de 2009. Encontramos una relación negativa entre la ocurrencia de ataques al ganado y la riqueza (p=0.0014) y abundancia (p=0.0012) de presas naturales. Nuestros resultados respaldan ...
    Se presenta el primer estudio sobre dendroclimatología de Pinus pseudostrobus y Pinus devoniana en el estado de Michoacán (México). El estudio se realizó en los municipios de Áporo y Zitácuaro de la Reserva de la Biosfera de la Mariposa... more
    Se presenta el primer estudio sobre dendroclimatología de Pinus pseudostrobus y Pinus devoniana en el estado de Michoacán (México). El estudio se realizó en los municipios de Áporo y Zitácuaro de la Reserva de la Biosfera de la Mariposa Monarca (RBMM). Se colectaron cien testimonios de madera tomados a 1.3 m de altura del árbol, repartidas en los ejidos del Rincón del Soto y Arroyo Seco (Áporo), y en el ejido de San Juan de Zitácuaro. Las series dendrocronológicas en Áporo para la especie Pinus pseudostrobus se extendió a 62 años (1949-2010) y para Pinus devoniana 86 años (1925-2010); y las series en Zitácuaro para Pinus pseudostrobus y Pinus devoniana se extendieron a 47 años (1964-2010) y 44 años (1967-2010), respectivamente.Con el objetivo de establecer los parámetros climáticos que controlan el crecimiento radial de las especies estudiadas, se encontró que la serie potencial para hacer estudios dendrocronológicos es la de Pinus pseudostrobus en Zitácuaro. El valor de la serie de...
    ABSTRACT Global change is increasing the occurrence of perturbation events on natural communities, with biological invasions posing a major threat to ecosystem integrity and functioning worldwide. Most studies addressing biological... more
    ABSTRACT Global change is increasing the occurrence of perturbation events on natural communities, with biological invasions posing a major threat to ecosystem integrity and functioning worldwide. Most studies addressing biological invasions have focused on individual species or taxonomic groups to understand both, the factors determining invasion success and their effects on native species. A more holistic approach that considers multispecies communities and species’ interactions can contribute to a better understanding of invasion effects on complex communities. Here we address biological invasions on species-rich food webs. We performed in silico experiments on empirical vertebrate food webs by introducing virtual species characterised by different ecological roles and belonging to different trophic groups. We varied a number of invasive species traits, including their diet breadth, the number of predators attacking them, and the bioenergetic thresholds below which invader and native species become extinct. We found that simpler food webs were more vulnerable to invasions, and that relatively less connected mammals were the most successful invaders. Invasions altered food web structure by decreasing species richness and the number of links per species, with most extinctions affecting poorly connected birds. Our food web approach allows identifying the combinations of trophic factors that facilitate or prevent biological invasions, and it provides testable predictions on the effects of invasions on the structure and dynamics of multitrophic communities.
    The current distribution of climatic conditions will be rearranged on the globe. To survive, species will have to keep pace with climates as they move. Mountains are among the most affected regions owing to both climate and land-use... more
    The current distribution of climatic conditions will be rearranged on the globe. To survive, species will have to keep pace with climates as they move. Mountains are among the most affected regions owing to both climate and land-use change. Here, we explore the effects of climate change in the vertebrate food web of the Pyrenees. We investigate elevation range expansions between two time-periods illustrative of warming conditions, to assess: (i) the taxonomic composition of range expanders; (ii) changes in food web properties such as the distribution of links per species and community size-structure; and (iii) what are the specific traits of range expanders that set them apart from the other species in the community—in particular, body mass, diet generalism, vulnerability and trophic position within the food web. We found an upward expansion of species at all elevations, which was not even for all taxonomic groups and trophic positions. At low and intermediate elevations, predator :...
    Climate change is generating novel communities composed of new combinations of species. These result from different degrees of species adaptations to changing biotic and abiotic conditions, and from differential range shifts of species.... more
    Climate change is generating novel communities composed of new combinations of species. These result from different degrees of species adaptations to changing biotic and abiotic conditions, and from differential range shifts of species. To determine whether the responses of organisms are determined by particular species traits and how species interactions and community dynamics are likely to be disrupted is a challenge. Here, we focus on two key traits: body size and ecological specialization. We present theoretical expectations and empirical evidence on how climate change affects these traits within communities. We then explore how these traits predispose species to shift or expand their distribution ranges, and associated changes on community size structure, food web organization and dynamics. We identify three major broad changes: (i) Shift in the distribution of body sizes towards smaller sizes, (ii) dominance of generalized interactions and the loss of specialized interactions,...
    Characterizing the responses of key tree species to extreme climatic events may provide important information for predicting future forest responses to increased climatic variability. Here we aimed at determining which tree- and... more
    Characterizing the responses of key tree species to extreme climatic events may provide important information for predicting future forest responses to increased climatic variability. Here we aimed at determining which tree- and stand-level attributes were more closely associated with the effect of a severe drought on the radial growth of Scots pine, both in terms of immediate impact and recovery after the drought event. Our dataset included tree-ring series from 393 plots located close to the dry limit of the species range. Time series analysis and mixed-effects models were used to study the growth of each tree and its detailed response to a severe drought event that occurred in 1986. Our results showed that the radial growth responses of Scots pine were determined primarily by tree-level characteristics, such as age and previous growth rate, and secondarily by stand basal area and species richness, whereas local climate had a relatively minor effect. Fast-growing trees were more severely affected by the drought and retained proportionally lower growth rates up to three years after the episode. In absolute terms, however, fast-growing trees performed better both during and after the event. Older trees were found to be less resilient to drought. The effect of stand basal area and species richness indicated that competition for resources worsened the effects of drought, and suggested that the effect of interspecific competition may be particularly detrimental during the drought year.
    ... Cambiar idioma Idioma Català. Cambiar. Análisis de la respuesta de Quercus ilex L. a tratamientos de resalveo selectivo. ... 547-601. Fundación Dialnet. Acceso de usuarios registrados. ...
    Widespread drought-induced tree mortality has been documented around the world, and could increase in frequency and intensity under warmer and drier conditions. Ecophysiological differences between dying and surviving trees might underlie... more
    Widespread drought-induced tree mortality has been documented around the world, and could increase in frequency and intensity under warmer and drier conditions. Ecophysiological differences between dying and surviving trees might underlie predispositions to mortality, but are poorly documented. Here we report a study of Scots pines (Pinus sylvestris L.) from two sites located in north-eastern Iberian Peninsula where drought-associated mortality episodes were registered during the last few decades. Time trends of discrimination against 13C (Δ13C) and intrinsic water-use efficiency (WUEi) in tree rings at an annual resolution and for a 34 year period were used to compare co-occurring now-dead and surviving pines. Results indicate that both surviving and now-dead pines significantly increased their WUEi over time, although this increase was significantly lower for now-dead individuals. These differential WUEi trends corresponded to different scenarios describing how plant gas exchange ...
    Page 1. ORIGINAL PAPER Explaining the successful introduction of the alpine marmot in the Pyrenees Bernat C. López • Joan Pino • Anna López Received: 22 September 2009 / Accepted: 27 January 2010 / Published online ...
    Acceso de usuarios registrados. Acceso de usuarios registrados Usuario Contraseña. ...
    ... I. Figueroa et alii ... Despite other species of marmots (ARNOLD 1990, BLUMSTEIN & ARNOLD 1998, BRYANT 1998, LENTI-BOERO 2003) are sensitive to snow pack duration, we found no significant effect of snow cover duration on... more
    ... I. Figueroa et alii ... Despite other species of marmots (ARNOLD 1990, BLUMSTEIN & ARNOLD 1998, BRYANT 1998, LENTI-BOERO 2003) are sensitive to snow pack duration, we found no significant effect of snow cover duration on the alpine marmot population of the southern ...
    The belowground component of terrestrial ecosystems is much less understood than any of the aboveground components, yet important ecosystem processes such as nutrient recycling, water storage, and long-term carbon accumulation occur... more
    The belowground component of terrestrial ecosystems is much less understood than any of the aboveground components, yet important ecosystem processes such as nutrient recycling, water storage, and long-term carbon accumulation occur largely in this compartment. For instance, belowground structures accounted for up to 83% of the total biomass in 13 Mediterranean woody communities (Hilbert and Canadell 1995), and belowground primary production was 60–80% of the total net primary production in a variety of woody systems (Coleman 1976; Agren et al. 1980; Fogel 1985). Yet both root biomass and production are infrequently studied and technical difficulties make the measurements often inaccurate. Furthermore, plant root distribution and maximum rooting depths play important roles in overall ecosystem function, but it was not until recently that ecosystem-level and global comprehensive studies have been undertaken (Canadell et al. 1996; Jackson et al. 1996).
    There is no sign of saturation in accumulation of alien species (AS) introductions worldwide, additionally the rate of spread for some species has also been shown to be increasing. However, the challenges of gathering information on AS... more
    There is no sign of saturation in accumulation of alien species (AS) introductions worldwide, additionally the rate of spread for some species has also been shown to be increasing. However, the challenges of gathering information on AS are recognized. Recent developments in citizen science (CS) provide an opportunity to improve data flow and knowledge on AS while ensuring effective and high quality societal engagement with the issue of IAS (Invasive Alien Species). Advances in technology, particularly on-line recording and smartphone apps, along with the development of social media, have revolutionized CS and increased connectivity while new and innovative analysis techniques are emerging to ensure appropriate management, visualization, interpretation and use and sharing of the data. In early July 2018 we launched a European CO-operation in Science and Technology (COST) Action to address multidisciplinary research questions in relation to developing and implementing CS, advancing sc...
    ... Wadsworth International Group. Belmont, CA, USA. Carreras, J., J. Carrillo, R. Masalles, J. Ninot, I. Soriano, and J. Vigo. 1996. ... 2006. Ecologically justified charisma: preservation of top predators delivers biodiversity... more
    ... Wadsworth International Group. Belmont, CA, USA. Carreras, J., J. Carrillo, R. Masalles, J. Ninot, I. Soriano, and J. Vigo. 1996. ... 2006. Ecologically justified charisma: preservation of top predators delivers biodiversity conservation. J. Anim. Ecol 43:1049–1055. ...
    Page 1. ORIGINAL PAPER Explaining the successful introduction of the alpine marmot in the Pyrenees Bernat C. López • Joan Pino • Anna López Received: 22 September 2009 / Accepted: 27 January 2010 / Published online ...
    PANORÀMICA • L’educació en temps d’internet. Ressenya del llibre d’A. Finkielkraut i P. Soriano Internet, el éxtasis inquietante, a càrrec de Francesc Torralba • Cap a la conciliació audiovisual. Ressenya del llibre d’Alfonso Puyal.... more
    PANORÀMICA • L’educació en temps d’internet. Ressenya del llibre d’A. Finkielkraut i P. Soriano Internet, el éxtasis inquietante, a càrrec de Francesc Torralba • Cap a la conciliació audiovisual. Ressenya del llibre d’Alfonso Puyal. Teoría de la comunicación audiovisual, a càrrec de Francesc Canosa • Molts focs artístics estan cremant sota l’aigua de l’estètica. Ressenya del llibre de Juan Eduardo
    ABSTRACT Stem radial growth responds to environmental conditions, and has been widely used as a proxy to study long-term patterns of tree growth and to assess the impact of environmental changes on growth patterns. In this study, we use a... more
    ABSTRACT Stem radial growth responds to environmental conditions, and has been widely used as a proxy to study long-term patterns of tree growth and to assess the impact of environmental changes on growth patterns. In this study, we use a tree ring dataset from the Catalan Ecological and Forest Inventory to study the temporal variability of Scots pine (Pinus sylvestris L.) stem growth during the 20th century across a relatively large region (Catalonia, NE Spain) close to the southern limit of the distribution of the species. Basal area increment (BAI) was modelled as a function of tree size and environmental variables by means of mixed effects models. Our results showed an overall increase of 84% in Scots pine BAI during the 20th century, consistent with most previous studies for temperate forests. This trend was associated with increased atmospheric CO2 concentrations and, possibly, with a general increase in nutrient availability, and we interpreted it as a fertilization effect. Over the same time period, there was also a marked increase in temperature across the study region (0.19 °C per decade on average). This warming had a negative impact on radial growth, particularly at the drier sites, but its magnitude was not enough to counteract the fertilization effect. In fact, the substantial warming observed during the 20th century in the study area did not result in a clear pattern of increased summer drought stress because of the large variability in precipitation, which did not show any clear time trend. But the situation may change in the future if temperatures continue to rise and/or precipitation becomes scarcer. Such a change could potentially reverse the temporal trend in growth, particularly at the driest sites, and is suggested in our data by the relative constancy of radial growth after ca. 1975, coinciding with the warmer period. If this situation is representative of other relatively dry, temperate forests, the implications for the regional carbon balance would be substantial.
    ... BERNAT C. LÓPEZ 1 ,; RODOLFO RODRÍGUEZ 2 ,; CARLOS A. GRACIA 3,4 ,; SANTIAGO SABATÉ 3,4. ... Among other fields, WA has been applied to investigate vegetation (Bradshaw & Spies, 1992; Dale & Mah, 1998; Harper... more
    ... BERNAT C. LÓPEZ 1 ,; RODOLFO RODRÍGUEZ 2 ,; CARLOS A. GRACIA 3,4 ,; SANTIAGO SABATÉ 3,4. ... Among other fields, WA has been applied to investigate vegetation (Bradshaw & Spies, 1992; Dale & Mah, 1998; Harper & MacDonald, 2001), and landscape patterns ...
    Alpine marmots were introduced in the French Pyrenees between 1948 and 1988. The exact number of re-introduced individuals is unknown, but it oscillated around 400. The likely preference of marmots for the southern sunny slopes rapidly... more
    Alpine marmots were introduced in the French Pyrenees between 1948 and 1988. The exact number of re-introduced individuals is unknown, but it oscillated around 400. The likely preference of marmots for the southern sunny slopes rapidly facilitated their expansion to the southern Pyrenees, where the lack of both natural predators and of important interspecific competitors also likely facilitated an important
    Trees can reach ages that in some cases amount to thousands of years. In the Mediterranean region, olive trees (Olea europaea) have traditionally been considered a particularly long-lived species. The main objective of this study was to... more
    Trees can reach ages that in some cases amount to thousands of years. In the Mediterranean region, olive trees (Olea europaea) have traditionally been considered a particularly long-lived species. The main objective of this study was to assess the age of large olive trees considered to be millenarian and classified as monumental trees in northeastern Spain. We extracted cores of 14 individuals and obtained 8 sections of trees which had already been cut in the area where the largest olive trees in the northeastern Iberian Peninsula are found. The age of the sampled olive trees was assessed by counting the number of annual growth rings. Tree rings did not cross-date well, neither within nor between individuals, but boundaries between likely annual rings were clearly distinct. We found a linear relationship between DBH and tree age (in years) (Age=2.11×diameter(cm)+88.93, R2=0.80), which was used to estimate the age of unsampled olive trees. The maximum estimated age (627±110 years) is among the greatest ages reported for olive trees around the world (700 years) and among the oldest trees in Mediterranean ecosystems.
    Characterizing the responses of key tree species to extreme climatic events may provide important information for predicting future forest responses to increased climatic variability. Here we aimed at determining which tree- and... more
    Characterizing the responses of key tree species to extreme climatic events may provide important information for predicting future forest responses to increased climatic variability. Here we aimed at determining which tree- and stand-level attributes were more closely associated with the effect of a severe drought on the radial growth of Scots pine, both in terms of immediate impact and recovery after the drought event. Our dataset included tree-ring series from 393 plots located close to the dry limit of the species range. Time series analysis and mixed-effects models were used to study the growth of each tree and its detailed response to a severe drought event that occurred in 1986. Our results showed that the radial growth responses of Scots pine were determined primarily by tree-level characteristics, such as age and previous growth rate, and secondarily by stand basal area and species richness, whereas local climate had a relatively minor effect. Fast-growing trees were more severely affected by the drought and retained proportionally lower growth rates up to three years after the episode. In absolute terms, however, fast-growing trees performed better both during and after the event. Older trees were found to be less resilient to drought. The effect of stand basal area and species richness indicated that competition for resources worsened the effects of drought, and suggested that the effect of interspecific competition may be particularly detrimental during the drought year.