Articles publicats en revistes (Biologia Evolutiva, Ecologia i Ciències Ambientals)

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Postharvesting population dynamics of the South American sea lion (Otaria byronia) in the southwestern Atlantic
(Wiley, 2015-07-01) Franco-Trecu, Valentina; Drago, Massimiliano; Baladán, Claudia; Garcia-Olazabal, Mateo D.; Crespo, Enrique A.; Cardona Pascual, Luis; Inchausti, Pablo
Many pinniped populations precipitously declined during the 19th and 20th centuries due to overharvesting. In Uruguay, the South American sea lion (SASL) was harvested until 1986. Birth rates in two nearby breeding colonies have had opposite trends for at least 20 yr. We assessed different mechanisms that could explain opposite trends in birth rates in the two SASL colonies. We compared feeding habits (δ15N and δ13C) of breeding females, birth mass, individual growth rate and early survival of pups and the social structure between colonies. Breeding females from the two colonies did not differ in their feeding habits. However, male and female pups grew faster but had a lower survival in the second month in the smallest colony. We found differences in the social structures, with a higher proportion of males in the smallest colony. The latter is important because peripheral SASL males may abduct and kill pups, which may explain the lower survival of pups in smaller colonies. We believe that the cumulative effects of population extractions have lowered the local SASL population size and disrupted its social structure to the point where Allee-like effects could become important and hamper the recovery of the Uruguayan SASL population.
Diet-to-female and female-to-pup isotopic discrimination in South American sea lions
(Wiley, 2015-08-30) Drago, Massimiliano; Franco-Trecu, Valentina; Cardona Pascual, Luis; Inchausti, Pablo
Rationale: The use of accurate, species-specific diet-tissue discrimination factors is a critical requirement when applying stable isotope mixing models to predict consumer diet composition. Thus, diet-to-female and female-to-pup isotopic discrimination factors in several tissues for both captive and wild South American sea lions were estimated to provide appropriate values for quantifying feeding preferences at different timescales in the wild populations of this species. Methods: Stable carbon and nitrogen isotope ratios in the blood components of two female-pup pairs and females' prey muscle from captive individuals were determined by elemental analyzer/isotope ratio mass spectrometry (EA/IRMS) to calculate the respective isotopic discrimination factors. The same analysis was carried out in both blood components, and skin and hair tissues for eight female-pup pairs from wild individuals. Results: Mean diet-to-female Δ13C and Δ15N values were higher than the female-to-pup ones. Pup tissues were more 15N-enriched than their mothers but 13C-depleted in serum and plasma tissues. In most of the tissue comparisons, we found differences in both Δ15N and Δ13C values, supporting tissue-specific discrimination. We found no differences between captive and wild female-to-pup discrimination factors either in Δ13C or Δ15N values of blood components. Conclusions: Only the stable isotope ratios in pup blood are good proxies of the individual lactating females. Thus, we suggest that blood components are more appropriate to quantify the feeding habits of wild individuals of this species. Furthermore, because female-to-pup discrimination factors for blood components did not differ between captive and wild individuals, we suggest that results for captive experiments can be extrapolated to wild South American sea lion populations.
Use of epidermis for the monitoring of tissular trace elements in Mediterranean striped dolphins (Stenella coeruleoalba)
(Elsevier Ltd., 2015-03-01) Borrell Thió, Assumpció; Clusa Ferrand, Marcel; Aguilar, Àlex; Drago, Massimiliano
Trace elements accumulate in epidermis, liver, kidney and muscle tissues in cetaceans. However, contrarily to internal tissues, epidermis can be sampled using minimally-invasive techniques. We investigate the patterns of trace element tissue concentrations in relation to individual sex and length and the degree of inter-tissue equilibrium between epidermis and the main internal organs of the Mediterranean striped dolphin. With it, we aim to test whether epidermis is a suitable tissue to predict trace element concentrations of internal tissues in cetaceans. We focused on trace elements with high potential toxicity (mercury and cadmium) or biological significance (zinc, copper and selenium). In contrast to what was found for Cu and Zn, the concentrations of Hg, Cd and Se in epidermis were positively correlated with the levels found in the internal tissues sampled probably due to their capacity to bioaccumulate. Thus, we conclude that sampling and analysing epidermis is appropriate to monitor and predict the concentrations of Hg, Cd and Se in internal tissues but not for Cu and Zn.
Concentrations of mercury in tissues of striped dolphins suggest decline of pollution in Mediterranean open waters
(Elsevier Ltd., 2014-07-01) Borrell Thió, Assumpció; Aguilar, Àlex; Tornero Álvarez, Ma. Victoria; Drago, Massimiliano
The Mediterranean is a semi-enclosed sea subject to high mercury (Hg) pollution from both natural and anthropogenic sources. With the objective of discerning temporal changes in marine Hg pollution in the oceanic waters of the northwestern Mediterranean Sea, we analysed liver and kidney from striped dolphins (Stenella coeruleoalba) collected during 2007–2009 and compared them with previous results from a similar sample from 1990–1993. The effect of body length and sex on tissue Hg concentrations was investigated to ensure an unbiased comparison between the periods. The Hg concentrations did not show significant sex-related differences in any tissue or period but were correlated positively with body length. Using body length as a covariate, Hg concentrations in liver and kidney were higher in 1990–1993 than in 2007–2009. This result suggests that measures to reduce emissions in Western European countries have been effective in reducing mercury pollution in Mediterranean open waters.
Dietary consistency of male South American sea lions (Otaria flavescens) in southern Brazil during three decades inferred from stable isotope analysis
(Springer Verlag, 2015-02-01) Zenteno Devaud, Lisette; Crespo, Enrique A.; Vales, Damián G.; Silva, Laura Alejandra; Saporiti, Fabiana; De Oliveira, Larissa Rosa; Secchi, Eduardo R.; Drago, Massimiliano; Aguilar, Àlex; Cardona Pascual, Luis
Marine predators may undergo remarkable dietary changes through time as a result of both anthropogenic and natural changes in the environment, but this variability is often difficult to tackle and seldom incorporated into ecosystem models. This paper uses the stable isotope ratios of carbon and nitrogen in skeletal material of South American sea lions from Brazilian scientific collections to investigate whether these animals modified their diet from 1986 to 2009, as reported for other marine predators in the region. Stable isotope ratios indicated that demersal potential prey were always enriched in 13C as compared with pelagic prey. Accordingly, the absence of any statistically significant correlation between stranding year and the δ13C values of adult males indicated no major increase in the consumption of pelagic prey from 1986 to 2009. Likewise, the results of the mixing model SIAR revealed a mixed diet including pelagic and demersal prey, with a central role for demersal fishes throughout the whole period. Furthermore, SIAR suggested no major changes in the proportion of pelagic and demersal prey in the diet of adult male South American sea lions during the past three decades. Demersal fishes were also relevant prey for juvenile South American sea lions during the whole period, but they always consumed a larger proportion of pelagic prey than the adults did. These results suggest no major changes in the diet of male South American sea lions during the past three decades in southern Brazil, contrary to what has been reported for other to predators in the regions and for the species in northern Patagonia.
Lithium response in bipolar disorder: Epigenome-wide DNA methylation signatures and epigenetic aging
(Elsevier B.V., 2024-04-25) González-Blanco, Leticia; Bobes García, Julio; Schulze, Thomas G.; Vieta i Pascual, Eduard, 1963-; Benabarre, Antonio; Arias Sampériz, Bárbara; Zafrilla-López, Marina ; Acosta-Díez, Miriam; Mitjans Niubó, Marina; Giménez Palomo, Anna; Saiz, Pilar A.; Barrot i Feixat, Carme; Jiménez Martínez, Ester; Papiol, Sergi; Ruiz, Victoria; Gavín, Patrícia; García-Portilla González, María Paz, 1962-
Lithium (Li) is the first-line treatment for bipolar disorder (BD) even though only 30 % of BD patients are considered excellent responders. The mechanisms by which Li exerts its action are not clearly understood, but it has been suggested that specific epigenetic mechanisms, such as methylation processes, may play a role. In this regard, DNA methylation patterns can be used to estimate epigenetic age (EpiAge), which is accelerated in BD patients and reversed by Li treatment. Our first aim was to compare the DNA methylation profile in peripheral blood between BD patients categorized as excellent responders to Li (Ex-Rp) and non-responders (N-Rp). Secondly, EpiAge was estimated to detect differential age acceleration between the two groups. A total of 130 differentially methylated positions (DMPs) and 16 differentially methylated regions (DMRs) between Ex-Rp (n = 26) and N-Rp (n = 37) were identified (FDR adjusted p-value < 0.05). We found 122 genes mapping the DMPs and DMRs, nine of which (HOXB6, HOXB3, HOXB-AS3, TENM2, CACNA1B, ANK3, EEF2K, CYP1A1, and SORCS2) had previously been linked to Li response. We found genes related to the GSK3β pathway to be highly represented. Using FUMA, we found enrichment in Gene Ontology Cell Component for the synapse. Gene network analysis highlighted functions related to the cell cycle, nervous system development and function, and gene expression. No significant differences in age acceleration were found between Ex-Rp and N-Rp for any of the epigenetic clocks analysed. Our findings indicate that a specific methylation pattern could determine the response to Li in BD patients. We also found that a significant portion of the differentially methylated genes are closely associated with the GSK3β pathway, reinforcing the role of this system in Li response. Future longitudinal studies with larger samples will help to elucidate the epigenetic mechanisms underlying Li response.
Prey dynamics and breeding performance in a generalist predator: the differential role of prey densitiy, biomass, and effective consumption rates
(Elsevier Masson SAS, 2024-05-01) Torre, Ignasi; Grajera, Joan; Amat Orriols, Fèlix; Oro, Daniel; Mañosa, Santi
The breeding performance of predators is influenced by the differential consequences of prey density, prey biomass and effective consumption rates. Using camera traps at nests, we investigated whether changes in prey abundances caused functional and/or numerical responses of the common buzzard (Buteo) in a Mediterranean woodland region. After determining 1150 prey delivered to the nests by adults, we found that the biomass of prey caught was not a good indicator of its influence on individual life history traits such as productivity. Indeed, the consumption of small mammal prey, despite representing only 11% of the biomass delivered, had a much greater influence on buzzards' productivity than the consumption of snakes, which made up 47% of the biomass delivered. Live trapping evidenced that small mammals were roughly preyed according to its availability in the field, and their abundance in spring was directly related to buzzards' productivity and inversely related to hatching dates. Small mammals – mostly mice – can be considered as very suitable prey, owing quick handling times, profitability, and high energy intake. Our results pointed out the relevance of mice on buzzards' breeding performance, and altogether with the outstanding role of open-land small mammals on buzzards' demography during autumn-winter, suggested a key role of small mammals on buzzards’ ecology throughout the year cycle in the Mediterranean area studied. These findings have important implications for our understanding of the foraging strategies of generalist species and the role that habitat and environmental factors play in shaping them.
Invasive crayfish reduce food limitation of alien American mink and increase their resilience to control
(Springer Verlag, 2014-02-01) Melero Cavero, Yolanda; Palazón, Santiago; Lambin, Xavier
Trophic relationships between invasive species in multiply invaded ecosystems may reduce food limitation relative to more pristine ecosystems and increase resilience to control. Here, we consider whether invasive predatory American mink Neovison vison are trophically subsidized by invasive crayfish. We collated data from the literature on density and home range size of mink populations in relation to the prevalence of crayfish in the diet of mink. We then tested the hypothesis that populations of an invasive predator reach higher densities and are more resilient to lethal control when they have access to super-abundant non-native prey, even in the absence of changes in density dependence, hence compensatory capacity. We found a strong positive relationship between the proportion of crayfish in mink diet and mink population density, and a negative relationship between the proportion of crayfish in mink diet and mink home range size, with crayfish contribution to mink diet reflecting their abundance in the ecosystem. We then explored the consequence of elevated mink density by simulating a hypothetical eradication program with a constant harvest in a Ricker model. We found that mink populations were more resilient to harvest in the presence of crayfish. As a result, the simulated number of mink harvested to achieve eradication increased by 500 % in the presence of abundant crayfish if carrying capacity increased by 630 %. This led to a threefold increase in time to eradication under a constant harvest and an approximately 20-fold increase in the cumulative management cost. Our results add to evidence of inter-specific positive interactions involving invasive species, and our simple model illustrates how this increases management cost.
Increased rhizosphere populations of Trichoderma asperellum strain T34 caused by secretion pattern of root exudates in tomato plants inoculated with Botrytis cinerea
(Wiley, 2017-09-01) Fernández Gómez, Elena; Trillas Gay, M. Isabel; Segarra Braunstein, Guillem
Root exudates secreted from plants can modify rhizosphere microbiota by enhancing or inhibiting the growth of biological control agents (BCAs) and/or pathogens. Similarly, microorganisms can modify the secretion of plant root exudates. The aim of this study was to analyse the effect of a Botrytis cinerea leaf infection on the secretion of tomato root exudates and on the populations of the BCA Trichoderma asperellum strain T34 (T34). This study found that the secretion pattern of root exudates in tomato plants was influenced by B. cinerea infection in plant leaves. An increase in the levels of gluconic acid was observed, while levels of sucrose and inositol decreased. A decrease in the severity of B. cinerea by the induction of systemic resistance triggered by T34 was also observed. Tomato plants infected with B. cinerea maintained the populations of T34 in the roots, while populations of T34 decreased in plants not inoculated with the pathogen. Samples exposed to media containing gluconic acid (as the only carbon source or at the same concentration found in roots exudates) saw an increase in the in vitro growth of T34 compared to media without gluconic acid. In conclusion, a change in the secretion pattern of root exudates caused by B. cinerea, together with the enhanced growth of T34 in the presence of gluconic acid, indicates the existence of leaf to root communication. The result of this is enhanced populations of T34, and in turn induced disease resistance and a consequential reduction in disease severity
Religion and Fertility patterns: comparison of life history traits in Catholics and Protestants, Hallstatt (Austria) 1733-1908
(Cambridge University Press (CUP), 2021-03) Gavrus Ion, Alina; Sjøvold, Torstein; Hernández, Miquel; González-José, Rolando; Martínez Abadías, Neus, 1978-; Esteban i Torné, Maria Esther; Esparza Pagès, Mireia
Catholicism and Protestantism have different ways of promoting the family unit that could influence survival and fertility at a population level. Parish records in the Austrian village of Hallstatt allowed the reconstruction of Catholic and Protestant genealogies over a period of 175 years (1733–1908) to evaluate how religion and social changes affected reproduction and survival. Life history traits such as lifespan beyond 15 years, number of offspring, reproductive span, children born out of wedlock and child mortality were estimated in 5678 Catholic and 3282 Protestant individuals. The interaction of sex, time and religion was checked through non-parametric factorial ANOVAs. Religion and time showed statistically significant interactions with lifespan >15 years, number of offspring and age at birth of first child. Protestants lived longer, had a larger reproductive span and an earlier age at birth of first child. Before the famine crisis of 1845–1850, Protestants showed lower values of childhood mortality than Catholics. Comparison of the number of children born out of wedlock revealed small differences between the two religions. Religion influenced reproduction and survival, as significant differences were found between Catholics and Protestants. This influence could be explained in part by differential socioeconomic characteristics, since Protestants may have enjoyed better living and sanitary conditions in Hallstatt.
Regional tree line dynamics in response to global change in the Pyrenees
(Wiley, 2008-11-01) Batllori Presas, Enric; Gutiérrez Merino, Emilia
1 Many studies in northern Europe, North and South America, describe regional trends of population densification at altitudinal and polar tree lines during the 20th century. The purpose of this study was (1) to ascertain if this regeneration enhancement is present across the alpine ecotones of the Pyrenees, (2) if synchronous recruitment trends are common among the studied populations and (3) to determine the tree limit stability during recent decades. 2 Twelve Pinus uncinata tree line populations were studied on the Iberian eastern range of the Pyrenees. Rectangular plots ranging from 940 to 7600 m2 were set along the forest‐alpine grassland transition; more than 3600 P. uncinata individuals were mapped. Tree size and age were used to establish the demographic structure at each stand, and to characterize abrupt or smooth transition patterns along the tree line ecotone. A new procedure for estimating missing rings in off‐centre cores was developed to ensure a correct interval for the age‐classes distribution analysis. 3 Past and recent synchronous recruitment trends (mid 19th century, second half of the 20th century) were apparent at the tree line over the studied area of the Pyrenean range. The ecotone densification since the 1950s occurred in the context of climatic warming and substantial land use abandonment. Both gradual and step‐like transition patterns in tree age and size along the ecotone were observed. 4 Regeneration enhancement in the last approximately 30 years appears as an abrupt change in population age structures, which could indicate the importance of feedback mechanisms for tree line recruitment dynamics. In 50% of the surveyed tree lines ecotone densification has been coupled to tree limit shifts in the recent past. This indicates both great tree limit sensitivity to short‐term climatic changes and the presence of differential tree line dynamics at a regional scale. 5 Synthesis. The observed past and recent synchronous recruitment trends suggest the presence of regional climatic factors modulating tree line structure and dynamics. However, tree line dynamics in the Pyrenees have been widely affected by local anthropogenic activities. We suggest that the presence of step‐like tree line transitions in tree age can be considered an evidence of recent human‐induced disturbances when no other major natural disturbances affect the tree line dynamics.
Evolution of infant mortality and family-based risk factors in a preindustrial Austrian population: 1630–1908
(Cambridge University Press (CUP), 2025-03-31) Gavrus Ion, Alina; Esparza Pagès, Mireia; Sjøvold, Torstein; Hernández, Miquel; Martínez Abadías, Neus, 1978-; Esteban i Torné, Maria Esther
Infant mortality, a reflection of socioeconomic and health conditions of a population, is shaped by diversefactors. This study delves into a pre-industrial population, scrutinizing neonatal and post-neonatal deathsseparately. Family factors such as mortality crises, religion, and legitimacy are also explored. Data of 9,086people obtained through multigenerational information from ecclesiastic records from 1603 to 1908 wereanalysed by means of a joinpoint regression analysis. Death risk was assessed with univariate andmultivariate Cox Proportional Hazard models. Early neonatal mortality was 5.6% of births and showed agradual and steady increase from 1630 to 1908, with no substantial improvement over the three centuriesanalysed. Late neonatal (4.3% of births) and post-neonatal mortality (18.7% of births) shared a differentpattern, showing a decline between the mid-18th and mid-19th centuries, and an increase by the 20thcentury that could be caused by socioeconomic factors and the impact of several epidemics. In thehistorical population of Hallstatt, infant survival was influenced by the sex of the newborn, the death of themother and the precedent sibling, and by the birth interval. Environmental and cultural factors, such asmortality crises and religion, influenced late neonatal and post-neonatal mortality, but not early neonatalmortality. The results highlight the need to independently assess early neonatal mortality in studies ofinfant mortality in historical populations, and to use as complete time periods as possible to capturedifferences in mortality patterns.
Effects of niche marginality on hotter-drought tree mortality in angiosperms and gymnosperms
(John Wiley & Sons, 2025-09-21) Batllori Presas, Enric; Hammond, William M.; Jump, Alistair; Pérez-Navarro, María Ángeles; Allen, Craig D.; Lloret Maya, Francisco
Aim: Current observations of global tree mortality events associated with drought raise concerns about climate change risks to forests' dynamics and function. It is unclear which forests are more susceptible to pulses of mortality under further changing climates. We examined whether tree mortality related to hotter droughts is predominantly occurring in edge or core populations in niche space and assessed whether mortality patterns are consistent with species' drought tolerances. Location: Global. Time Period: 1970–2020. Major Taxa Studied: Angiosperm and gymnosperm trees. Methods: We estimated species' climatic niches on the basis of global occurrences and annual time series of climate. We computed the distance to the niche core of drought mortality sites (982 observations, 44 tree species) and compared it with null models of randomly distributed tree mortality. We assessed how loss of xylem conductance and hydraulic safety margin related to populations' position in niche space and to the degree of climate anomaly during mortality. Results: In the year of mortality, 64.3% of the sites were closer to the species' niche edge than the niche core. However, when considering long-term climate averages, both marginal and central populations experienced drought-associated pulses of mortality. Overall, tree mortality was related to populations' shifts towards the edge of species' climatic niches and, in angiosperm mortality sites, species' drought tolerances were correlated with the intensity of climatic anomalies. In gymnosperm sites, marginal populations were more affected and other processes, such as heat-induced stress or cumulative drought effects, may have affected mortality. Main Conclusions: Both marginal and central populations, even for highly drought-tolerant species, are vulnerable to climate change. Climate anomaly magnitude, cumulative drought effects, plant physiological limits and species niche geometry help explain range-wide patterns of hotter-drought-associated tree mortality.
Vegetation patterns at the alpine treeline ecotone: the influence of tree cover on abrupt change in species composition of alpine communities
(Wiley-Blackwell, 2009-10-01) Batllori Presas, Enric; Blanco Moreno, José Manuel; Ninot i Sugrañes, Josep Maria; Gutiérrez Merino, Emilia; Carrillo, Empar
Aims: The upper elevation limit of forest vegetation in mountain ranges (the alpine treeline ecotone) is expected to be highly sensitive to global change. Treeline shifts and/or ecotone afforestation could cause fragmentation and loss of alpine habitat, and are expected to trigger considerable alterations in alpine vegetation. We performed an analysis of vegetation structure at the treeline ecotone to evaluate whether distribution of the tree population determines the spatial pattern of vegetation (species composition and diversity) across the transition from subalpine forest to alpine vegetation. Location: Iberian eastern range of the Pyrenees. Methods: We studied 12 alpine Pinus uncinata treeline ecotones. Rectangular plots ranging from 940 to 1900 m2 were placed along the forest-alpine vegetation transition, from closed forest to the treeless alpine area. To determine community structure and species distribution in the treeline ecotone, species variation along the forest-alpine vegetation transition was sampled using relevés of 0.5 m2 set every 2 m along the length of each plot. Fuzzy C-means clustering was performed to assess the transitional status of the relevés in terms of species composition. The relation of P. uncinata canopy cover to spatial pattern of vegetation was evaluated using continuous wavelet transform analysis. Results: Vegetation analyses revealed a large degree of uniformity of the subalpine forest between all treeline ecotone areas studied. In contrast, the vegetation mosaic found upslope displayed great variation between sites and was characterized by abrupt changes in plant community across the treeline ecotone. Plant richness and diversity significantly increased across the ecotone, but tree cover and diversity boundaries were not spatially coincident. Conclusions: Our results revealed that no intermediate communities, in terms of species composition, are present in the treeline ecotone. Ecotone vegetation reflected both bedrock type and fine-scale heterogeneity at ground level, thereby reinforcing the importance of microenvironmental conditions for alpine community composition. Tree cover did not appear to be the principal driver of alpine community changes across the treeline ecotone. Microenvironmental heterogeneity, together with effects of past climatic and land-use changes on ecotone vegetation, may weaken the expected correlation between species distribution and vegetation structure.
MEDFATE 2.9.3: a trait-enabled model to simulate Mediterranean forest function and dynamics at regional scales
(European Geosciences Union (EGU), 2023-06-06) Batllori Presas, Enric; Améztegui, Aitor; Cáceres Ainsa, Miquel de; Molowny-Horas, Roberto; Cabon, Antoine; Martínez Vilalta, Jordi, 1975-; Mencuccini, Maurizio; García-Valdés, Raúl; Nadal Sala, Daniel; Sabaté i Jorba, Santi; Martin-StPaul, Nicolas; Morin, Xavier; D'Adamo, Francesco
Regional-level applications of dynamic vegetation models are challenging because they need to accommodate the variation in plant functional diversity, which requires moving away from broadly defined functional types. Different approaches have been adopted in the last years to incorporate a trait-based perspective into modeling exercises. A common parametrization strategy involves using trait data to represent functional variation between individuals while discarding taxonomic identity. However, this strategy ignores the phylogenetic signal of trait variation and cannot be employed when predictions for specific taxa are needed, such as in applications to inform forest management planning. An alternative strategy involves adapting the taxonomic resolution of model entities to that of the data source employed for large-scale initialization and estimating functional parameters from available plant trait databases, adopting diverse solutions for missing data and non-observable parameters. Here we report the advantages and limitations of this second strategy according to our experience in the development of MEDFATE (version 2.9.3), a novel cohort-based and trait-enabled model of forest dynamics, for its application over a region in the western Mediterranean Basin. First, 217 taxonomic entities were defined according to woody species codes of the Spanish National Forest Inventory. While forest inventory records were used to obtain some empirical parameter estimates, a large proportion of physiological, morphological, and anatomical parameters were matched to measured plant traits, with estimates extracted from multiple databases and averaged at the required taxonomic level. Estimates for non-observable key parameters were obtained using meta-modeling and calibration exercises. Missing values were addressed using imputation procedures based on trait covariation, taxonomic averages or both. The model properly simulated observed historical changes in basal area, with a performance similar to an empirical model trained for the same region. While strong efforts are still required to parameterize trait-enabled models for multiple taxa, and to incorporate intra-specific trait variability, estimation procedures such as those presented here can be progressively refined, transferred to other regions or models and iterated following data source changes by employing automated workflows. We advocate for the adoption of trait-enabled and population-structured models for regional-level projections of forest function and dynamics.
Current regeneration patterns at treeline in the Pyrenees indicate similar recruitment processes irrespective of past disturbance regime
(John Wiley & Sons, 2010-10-01) Batllori Presas, Enric; Camarero Martínez, Jesús Julio; Gutiérrez Merino, Emilia
Aim: Impacts of global change, such as land-use and climate changes, could produce significant alterations in the elevational patterns of alpine tree line ecotones and their adjacent vegetation zones. Because the responses of the tree line to environmental variations are directly related to successful tree regeneration, understanding recruitment dynamics is an indispensable step in tree line research. We aimed to compare potential ecological limitations on recent tree line regeneration in undisturbed and disturbed sites by analysing the demographic structure and spatiotemporal patterns of recruits and large trees. Location: Alpine tree line ecotones comprising Pinus uncinata in the Catalan Pyrenees (north-east Spain) and Andorra. Methods: We assessed the demographic structure and spatial pattern of recent recruitment using techniques of point-pattern and autocorrelation analyses. A total of 3639 P. uncinata individuals were mapped, measured and aged at 12 sites. To evaluate the effects of past disturbances on recent tree line response we compared tree lines that had either been recently affected by human-induced disturbances or had remained undisturbed for many years. Results: The age structure of the tree lines, together with the lack of an age gap between seedlings and saplings, did not indicate recent episodes of high seedling mortality and suggest that recruitment has been frequent under current climate conditions. Seedlings appeared highly aggregated at short distances (up to 3 m), irrespective of disturbance history, and were spatially segregated with respect to large trees. However, we found no evidence of patches of even-aged seedlings, and our results suggest that dispersal events at intermediate distances (10–17 m) may be frequent. Autocorrelation analyses revealed different patterns of density and age of recruits between disturbed and undisturbed tree lines, but the strength and small-scale clustering of seedlings and saplings were very similar between sites. Main conclusions: We found no recruitment limitation on recent tree line dynamics in the Pyrenees. Furthermore, processes affecting tree recruitment seem to be similar among populations regardless of their past disturbance regime. Our results suggest that constraints on tree line dynamics causing differential responses between sites may operate on older life stages and not upon recruits, and that such constraints may be more contingent on local site conditions than on disturbance history.
Seedling recruitment, survival and facilitation in alpine Pinus uncinata treeline ecotones. Implications and potential responses to climate warming
(John Wiley & Sons, 2009-07-01) Batllori Presas, Enric; Camarero Martínez, Jesús Julio; Ninot i Sugrañes, Josep Maria; Gutiérrez Merino, Emilia
Aims: Alpine tree line ecotones are harsh environments where low temperatures constrain tree regeneration and growth. However, the expected upward shift of tree line ecotones in response to climate warming has not been ubiquitous. The lack of coupling between tree line dynamics and climate warming might be explained by factors other than climate variation that determine seedling recruitment in these ecotones. We want to assess how the availability of suitable habitat for establishment and the effects of facilitation on seedling survival and growth affect tree recruitment within tree line ecotones and modulate their responses to climate. Location: We evaluate the relevance of these factors for Pinus uncinata tree line ecotones in the Catalan Pyrenees (north-east Spain) and Andorra. Methods: We analysed the microhabitat of naturally established seedlings in rectangular plots at the tree line ecotone, assessing the habitat type and the proximity to potentially protective elements that may improve microsite conditions. We tested whether krummholz individuals influence regeneration at the tree line by performing a transplantation field experiment to evaluate the extent of facilitation on seedling survival and growth in height. A total of 820 seedlings were transplanted at different distances and orientations (resulting in 12 positions) from krummholz mats and monitored over 2 years. Results: Safe sites for P. uncinata recruits consisted of sparse vegetation covering bare soil, gravel or litter, and close to protective elements that may ameliorate microsite conditions. The field experiment showed that directional positive interactions enhance seedling survival and growth, altering the spatial patterns of recruit survivorship, especially during harsh winter conditions (shallow and irregular snowpack). Main conclusions: Our results suggest that scarce availability of safe sites and uneven facilitation by krummholz control seedling recruitment patterns within alpine tree line ecotones. Such constraints may distort or counter the response of tree line ecotones to climate warming at local and regional scales.
Activity and space patterns of Pyrenean desman (Galemys pyrenaicus) suggest non-agressive and non-territorial behaviour
(Springer Verlag, 2014-10-01) Melero Cavero, Yolanda; Aymerich i Boixader, Pere; Santulli Sanzo, Giulia; Gosàlbez i Noguera, Joaquim
The Pyrenean desman is considered a flagship species for biodiversity and evolution. However, its scientific knowledge is still under development and currently on debate, particularly in relation to its behavioural ecology and social organization. Based on the previous hypothesis of individual desmans being solitary and territorial, activity and space patterns were considered to be arranged to avoid conspecifics. However, recent insights into the species’ social behaviour revealed non-interspecific avoidance. With this study, we provide novel insights into the activity and space patterns of the desman, and their relation to its social behaviour. A total of 30 individuals were trapped, 18 of which provided informative radiotracking data to study (1) activity behaviour, (2) the proportion of the home range utilized and the distances travelled, and (3) the dominant movement directionality. Activity and space use patterns were affected by daylight and seasonality, but not by sex, age or number of other conspecifics sharing the home range. In contrast to the previous observations, individuals did not show a pattern of directionality in their movements. Noticeably, we observed encounters between individuals without evidence of aggressive behaviour. Our results suggest that desmans do not alter their activity or their spatial behaviour to avoid encounters with conspecifics, as previously suggested. These novel findings provide more evidence of a social structure and organization with social interactions and non-aggressive behaviour. This is of relevance for management actions and for the conservation of this endemic mammal.
Is the standard Eurasian otter Lutra lutra survey strategy suitable for surveying the American mink Neovison vison?
(Polskiej Akademii Nau, 2013-04-01) Melero Cavero, Yolanda; Palazón, Santiago; Gosàlbez i Noguera, Joaquim; Martelo, Joana; Bonesi, Laura
The American mink Neovison vison is an elusive mustelid that is monitored mostly through the detection of its field signs, namely, footprints and scats. In Europe, the American mink has been often monitored using the standard otter survey strategy developed specifically for the Eurasian otter Lutra lutra, requiring to walk transects of 600 m spaced at least 5 km apart. We tested whether the standard otter survey strategy was appropriate for surveying mink. We studied a high-density population of mink along a 9-km stretch of river between December 2004 and April 2005. Monthly surveys were conducted and scats and footprints were recorded within 100-m sections along the river. The results showed a monthly variation in signs recovery, with the months of December, January and February being the best ones for surveying. Transects of 600 m detected mink between 74 and 90 % of the times in all months, excluding March when detection was as low as 56 %. Taken all together, the results suggest that the standard otter survey strategy was adequate to detect mink, at least in this case where species density was high. The study also highlighted monthly differences in signs detection, suggesting that temporal variations should be taken into account when designing the sampling strategy and the length of the sampling units (transects). In the months immediately following the mating season (and possibly in lower-density mink populations), it may be advisable to increase the length of transects to increase detection of mink.
New insights into social and space use behaviour of the endangered Pyrenean desman (Galemys pyrenaicus)
(Springer Verlag, 2012-02-01) Melero Cavero, Yolanda; Aymerich i Boixader, Pere; Luque-Larena, Juan Jose; Gosàlbez i Noguera, Joaquim
We describe novel aspects of the social organisation of the Pyrenean desman, Galemys pyrenaicus, by studying home range and shelter use behaviour in a local population. A total of 45 individuals were trapped of which 20 provided informative radiotracking data. In contrast to the currently accepted hypothesis [Stone RD. The social organization of the Pyrenean desman (Galemys pyrenaicus) as revealed by radiotelemetry. J Zool 212:117–129; 1987b; Stone RD, Gorman ML. Social organization of the European mole (Talpa europaea) and the Pyrenean desman (Galemys pyrenaicus). Mammal Rev 15 (1):35–42; 1985] individuals were not strictly territorial. Notably, there was no aggression between conspecifics, with simultaneous use of resting sites (shelters used for more than one hour). Resting sites were not permanent or exclusive for any individual. Individuals shared resting sites simultaneously, regardless of sex or age. Our observations recall for a new evaluation of the social structure and organisation of this species based on the new evidence that reveals higher frequency of social interactions than previously described. Resting sites may play an important role in the social organisation of the species, for instance by allowing direct and indirect communicative interactions among neighbouring individuals. This finding is of significance for the management (e.g. census and population monitoring) and conservation (e.g. habitat suitability to allow social interactions) of this endemic and seriously threatened unique mammal.

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