Articles publicats (CTFC)

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    Open Access
    Positive feedbacks and alternative stable states in forest leaf types
    (Nature Research, 2024) Zou, Yibiao; Zohner, Constantin M.; Averill, Colin; Ma, Haozhi; Merder, Julian; Berdugo, Miguel; Bialic-Murphy, Lalasia; Mo, Lidong; Brun, Philipp; Zimmermann, Niklaus E.; Liang, Jingjing; Miguel Magaña, Sergio de; Nabuurs, Gert-Jan; Reich, Peter B.; Niinements, Ulo
    The emergence of alternative stable states in forest systems has significant implications for the functioning and structure of the terrestrial biosphere, yet empirical evidence remains scarce. Here, we combine global forest biodiversity observations and simulations to test for alternative stable states in the presence of evergreen and deciduous forest types. We reveal a bimodal distribution of forest leaf types across temperate regions of the Northern Hemisphere that cannot be explained by the environment alone, suggesting signatures of alternative forest states. Moreover, we empirically demonstrate the existence of positive feedbacks in tree growth, recruitment and mortality, with trees having 4–43% higher growth rates, 14–17% higher survival rates and 4–7 times higher recruitment rates when they are surrounded by trees of their own leaf type. Simulations show that the observed positive feedbacks are necessary and sufficient to generate alternative forest states, which also lead to dependency on history (hysteresis) during ecosystem transition from evergreen to deciduous forests and vice versa. We identify hotspots of bistable forest types in evergreen-deciduous ecotones, which are likely driven by soil-related positive feedbacks. These findings are integral to predicting the distribution of forest biomes, and aid to our understanding of biodiversity, carbon turnover, and terrestrial climate feedbacks.
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    Open Access
    Navigating divergent perspectives on critical habitat designation: Insights from the little bustard (Tetrax tetrax) conservation in Spain
    (Elsevier, 2024) Miret-Minard, Gabriel; Hermoso, Virgilio; Villero Pi, Daniel; Bota, Gerard; Brotons, Lluís; Morán-Ordoñez, Alejandra
    The designation of critical habitats is a conservation tool extensively used worldwide. Although the effectiveness of this tool has been proved globally, its implementation in Spain is scarce, probably due to the ambiguous character of its definition in policy and other related problems. This study provides insight into some of these aspects and how different groups of experts interpret the concept of critical habitat. We used the little bustard (Tetrax tetrax) as a case study of an endangered species for which critical habitats must be designated. We interviewed 47 experts of the species, from researchers to environmental agency technicians, about the objectives that critical habitats should address, and which facilitating and constraining aspects should be considered in such designation. By grouping the answers in different categories and running ordination analyses (Non-Metric Multidimensional Scaling) we found that researchers mainly focused on ecological objectives for critical habitats, compared to the rest of the respondents who also considered socioeconomic aspects as basic objectives for critical habitats. Only 36% of the experts mentioned ecological factors as constraints to such designation, while socioeconomic constraints were mentioned by all but two of the experts (96%). These results suggest differences in the conceptualization of critical habitat between scientists and managers, from pure ecological requirements of the species to the actual implications and socioeconomic constraints of its implementation, respectively. Integrating multiple stakeholders and views will reflect these differences into the operational understanding of critical habitats and will ensure that future critical habitat designations are effective management tools.
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    Open Access
    Climate acts as an environmental filter to plant pathogens
    (Springer Nature Limited, 2024) Caballol, Maria; Redondo, Miguel Ángel; Catalán, Nuria; Corcobado, Tamara; Jung, Thomas; Marcais, Benoit; Milenkovic, Ivan; Nemesio-Gorriz, Miguel; Stenlid, Jan; Oliva Palau, Jonàs
    Climate shapes the distribution of plant-associated microbes such as mycorrhizal and endophytic fungi. However, the role of climate in plant pathogen community assembly is less understood. Here, we explored the role of climate in the assembly of Phytophthora communities at >250 sites along a latitudinal gradient from Spain to northern Sweden and an altitudinal gradient from the Spanish Pyrenees to lowland areas. Communities were detected by ITS sequencing of river filtrates. Mediation analysis supported the role of climate in the biogeography of Phytophthora and ruled out other environmental factors such as geography or tree diversity. Comparisons of functional and species diversity showed that environmental filtering dominated over competitive exclusion in Europe. Temperature and precipitation acted as environmental filters at different extremes of the gradients. In northern regions, winter temperatures acted as an environmental filter on Phytophthora community assembly, selecting species adapted to survive low minimum temperatures. In southern latitudes, a hot dry climate was the main environmental filter, resulting in communities dominated by drought-tolerant Phytophthora species with thick oospore walls, a high optimum temperature for growth, and a high maximum temperature limit for growth. By taking a community ecology approach, we show that the establishment of Phytophthora plant pathogens in Europe is mainly restricted by cold temperatures.
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    Open Access
    Differences in soil water holding capacity and available soil water along growing cycle can explain differences in vigour, yield, and quality of must and wine in the DOCa Rioja
    (MDPI, 2024) Martínez-Vidaurre, José María; Pérez-Álvarez, Eva Pilar; García-Escudero, Enrique; Ramos Martín, Ma. C. (Ma. Concepción); Peregrina, Fernando
    Soil water availability during the vine growth cycle can affect yield and grape quality. The objective was to evaluate the effect of soil water holding capacity (AWC) and available soil water (ASW) throughout the growing cycle on the nutritional status, vigor, production, and composition of grapes and wine. The study was conducted in the municipality of Uruñuela in the DOCa Rioja (Spain). The soils of four rainfed vineyard plots were characterized to determine AWC and its impacts on vine, grape, and wine composition. The N, P, and K foliar content, vigor, grape yield, berry weight, and composition of must and wine were analyzed in those vineyard plots during the period 2010–2014. The ASW was simulated in each plot and each year analyzed, considering the soil properties and the weather conditions, after model calibration in one plot in which soil water content was registered. The results showed that AWC influenced ASW along the growing cycle, so vines suffered from water stress in some periods of the vegetative cycle. Plots with higher AWC had higher ASW from fruit set to ripening and lower water stress during this period, which explains the higher N, P, and K foliar content, vigor and grape yield, and lower polyphenol and anthocyanin content in grapes and wines. The period where water availability had the most influence on the quality of the grapes was from veraison to ripening, during which ASW increased berry weight and acidity and decreased anthocyanins and polyphenolic compounds.
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    Open Access
    Dietary DNA metabarcoding reveals a trophic niche partitioning among sympatric Iberian sandgrouses and bustards
    (Elsevier, 2024) Cabodevilla, Xabier; Ortiz-Santaliestra, Manuel E.; Fernández-Tizón, Mario; Zurdo, Julia; Madeira, María J.; Giralt, David; Sardà-Palomera, Francesc; Fernández-Benéitez, María J.; Mougeot, François
    The study of trophic niche partitioning is of great importance for understanding community structure and species coexistence, particularly if these are threatened. Here DNA metabarcoding was used to assess the diet of four threatened steppe bird species (two bustards and two sandgrouses), with the aim of better understanding their dietary requirements, trophic interactions, and potential threats. The results showed seasonal and interspecific differences in their plant diet, with greater importance of cultivated plants during autumn and winter (around 50 % of their diet) than spring. Plants of the genus Convolvulus and of the family Brassicaceae were frequently consumed by all species. In spring, poppies (Papaver spp.) were a considerable part of their diet, and could be used as a source of carotenoids or for their anti-parasitic properties. Furthermore, results evidenced a trophic niche partitioning among species, with a marked segregation between bustard species and, to a lesser extent, between sandgrouse species. Diet similarity was generally higher between species from different orders that occur in mixed-species flocks (bustard - sandgrouse) than between species of the same order. This partitioning was probably related to a stratification in habitat use rather than to specialisation and might prevent competition to some extent. However, the homogenization of trophic resources resulting from agricultural intensification could pose an important threat, particularly during autumn, when weeds are scarcer and the most abundant trophic resource are sown seeds, which are often treated with pesticides.