Declining population trends of European mountain birds

Lehikoinen A., Brotons L., Calladine J., Campedelli T., Escandell V., Flousek J., Grueneberg C., Haas F., Harris S., Herrando S., Husby M., Jiguet F., Kålås J.A., Lindström Å., Lorrillière R., Molina B., Pladevall C., Calvi G., Sattler T., Schmid H., Sirkiä P.M., Teufelbauer N., Trautmann S. (2019) Declining population trends of European mountain birds. Global Change Biology. 25: 577-588.
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Doi: 10.1111/gcb.14522

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Mountain areas often hold special species communities, and they are high on the list of conservation concern. Global warming and changes in human land use, such as grazing pressure and afforestation, have been suggested to be major threats for biodiversity in the mountain areas, affecting species abundance and causing distribution shifts towards mountaintops. Population shifts towards poles and mountaintops have been documented in several areas, indicating that climate change is one of the key drivers of species’ distribution changes. Despite the high conservation concern, relatively little is known about the population trends of species in mountain areas due to low accessibility and difficult working conditions. Thanks to the recent improvement of bird monitoring schemes around Europe, we can here report a first account of population trends of 44 bird species from four major European mountain regions: Fennoscandia, UK upland, south-western (Iberia) and south-central mountains (Alps), covering 12 countries. Overall, the mountain bird species declined significantly (−7%) during 2002–2014, which is similar to the declining rate in common birds in Europe during the same period. Mountain specialists showed a significant −10% decline in population numbers. The slope for mountain generalists was also negative, but not significantly so. The slopes of specialists and generalists did not differ from each other. Fennoscandian and Iberian populations were on average declining, while in United Kingdom and Alps, trends were nonsignificant. Temperature change or migratory behaviour was not significantly associated with regional population trends of species. Alpine habitats are highly vulnerable to climate change, and this is certainly one of the main drivers of mountain bird population trends. However, observed declines can also be partly linked with local land use practices. More efforts should be undertaken to identify the causes of decline and to increase conservation efforts for these populations. © 2018 John Wiley & Sons Ltd

Llegeix més

Climatic Warming Increases Spatial Synchrony in Spring Vegetation Phenology Across the Northern Hemisphere

Liu Q., Piao S., Fu Y.H., Gao M., Peñuelas J., Janssens I.A. (2019) Climatic Warming Increases Spatial Synchrony in Spring Vegetation Phenology Across the Northern Hemisphere. Geophysical Research Letters. 46: 1641-1650.
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Doi: 10.1029/2018GL081370

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Climatic warming has advanced spring phenology across the Northern Hemisphere, but the spatial variability in temperature sensitivity of spring phenology is substantial. Whether spring phenology will continue to advance uniformly at latitudes has not yet been investigated. We used Bayesian model averaging and four spring phenology models, and demonstrated that the start of vegetation growing season across the Northern Hemisphere will become substantially more synchronous (up to 11.3%) under future climatic warming conditions. Larger start of growing season advances are expected at higher than lower latitudes (3.7–10.9 days earlier) due to both larger rate in spring warming at higher latitudes and larger decreases in the temperature sensitivity of start of growing season at low latitudes. The consequent impacts on the northern ecosystems due to this increased synchrony may be considerable and thus worth investigating. ©2019. American Geophysical Union. All Rights Reserved.

Llegeix més

Short-term effects of prescribed burning in Mediterranean pine plantations on surface runoff, soil erosion and water quality of runoff

Lucas-Borja M.E., Plaza-Álvarez P.A., Gonzalez-Romero J., Sagra J., Alfaro-Sánchez R., Zema D.A., Moya D., de las Heras J. (2019) Short-term effects of prescribed burning in Mediterranean pine plantations on surface runoff, soil erosion and water quality of runoff. Science of the Total Environment. 674: 615-622.
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Doi: 10.1016/j.scitotenv.2019.04.114

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Fires are a complex phenomenon that may generate a chain of responses and processes that affect each part of the ecosystem. Thus, it is important to understand the magnitude of the impacts of fire on soil properties and the response of plants to this disturbance. For the moment, few studies have examined the effects of prescribed fire on large plots in afforested pine plantations in Mediterranean ecosystems. To fill this gap, the effects of a prescribed fire on runoff, soil erosion, and water quality for approximately one year after burning have been evaluated in pine plantations in south-eastern Spain. We constructed six erosion plots in the control area and six erosion plots in the burned area that were 4 m long and 2 m wide, immediately after the prescribed fire. Runoff, soil erosion and runoff water quality were studied after each rainy event in all plots. Our results reveal that prescribed fire did not significantly affect runoff and soil erosion when low intensity precipitations occur at pine plantations. In relation to water quality, water turbidity, salinity, pH, organic matter content and ionic substances concentrations increased immediately after prescribed burn, nevertheless these changes disappeared over time. We can conclude that prescribed fire can be a useful tool for fuel reduction in Mediterranean pine plantations without wide and long-term impacts to soil losses, or water quality. © 2019 Elsevier B.V.

Llegeix més

Author Correction: Trade-offs in using European forests to meet climate objectives (Nature, (2018), 562, 7726, (259-262), 10.1038/s41586-018-0577-1)

Luyssaert S., Marie G., Valade A., Chen Y.-Y., Djomo S.N., Ryder J., Otto J., Naudts K., Lansø A.S., Ghattas J., McGrath M.J. (2019) Author Correction: Trade-offs in using European forests to meet climate objectives (Nature, (2018), 562, 7726, (259-262), 10.1038/s41586-018-0577-1). Nature. 567: 0-0.
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Doi: 10.1038/s41586-019-1023-8

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In this Letter, in “About 75% of this reduction is expected to come from emission reductions and the remaining 25% from land use, land-use change and forestry”, ‘25%’ should read ‘1%’ and '75%' should read '99%'. In the sentence “The carbon-sink-maximizing portfolio has a small negative effect on annual precipitation (−2 mm) and no effect on air temperature (Table 1)” the word ‘precipitation’ was omitted. Denmark was accidentally deleted during the conversion of Fig. 1. The original Letter has been corrected online. © 2019, The Author(s), under exclusive licence to Springer Nature Limited.

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Coupled carbon and nitrogen losses in response to seven years of chronic warming in subarctic soils

Marañón-Jiménez S., Peñuelas J., Richter A., Sigurdsson B.D., Fuchslueger L., Leblans N.I.W., Janssens I.A. (2019) Coupled carbon and nitrogen losses in response to seven years of chronic warming in subarctic soils. Soil Biology and Biochemistry. 134: 152-161.
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Doi: 10.1016/j.soilbio.2019.03.028

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Increasing temperatures may alter the stoichiometric demands of soil microbes and impair their capacity to stabilize carbon (C) and retain nitrogen (N), with critical consequences for the soil C and N storage at high latitude soils. Geothermally active areas in Iceland provided wide, continuous and stable gradients of soil temperatures to test this hypothesis. In order to characterize the stoichiometric demands of microbes from these subarctic soils, we incubated soils from ambient temperatures after the factorial addition of C, N and P substrates separately and in combination. In a second experiment, soils that had been exposed to different in situ warming intensities (+0, +0.5, +1.8, +3.4, +8.7, +15.9 °C above ambient) for seven years were incubated after the combined addition of C, N and P to evaluate the capacity of soil microbes to store and immobilize C and N at the different warming scenarios. The seven years of chronic soil warming triggered large and proportional soil C and N losses (4.1 ± 0.5% °C −1 of the stocks in unwarmed soils) from the upper 10 cm of soil, with a predominant depletion of the physically accessible organic substrates that were weakly sorbed in soil minerals up to 8.7 °C warming. Soil microbes met the increasing respiratory demands under conditions of low C accessibility at the expenses of a reduction of the standing biomass in warmer soils. This together with the strict microbial C:N stoichiometric demands also constrained their capacity of N retention, and increased the vulnerability of soil to N losses. Our findings suggest a strong control of microbial physiology and C:N stoichiometric needs on the retention of soil N and on the resilience of soil C stocks from high-latitudes to warming, particularly during periods of vegetation dormancy and low C inputs. © 2019 Elsevier Ltd

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Greater focus on water pools may improve our ability to understand and anticipate drought-induced mortality in plants

Martinez-Vilalta J., Anderegg W.R.L., Sapes G., Sala A. (2019) Greater focus on water pools may improve our ability to understand and anticipate drought-induced mortality in plants. New Phytologist. : 0-0.
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Doi: 10.1111/nph.15644

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Drought-induced tree mortality has major impacts on ecosystem carbon and water cycles, and is expected to increase in forests across the globe with climate change. A large body of research in the past decade has advanced our understanding of plant water and carbon relations under drought. However, despite intense research, we still lack generalizable, cross-scale indicators of mortality risk. In this Viewpoint, we propose that a more explicit consideration of water pools could improve our ability to monitor and anticipate mortality risk. Specifically, we focus on the relative water content (RWC), a classic metric in plant water relations, as a potential indicator of mortality risk that is physiologically relevant and integrates different aspects related to hydraulics, stomatal responses and carbon economy under drought. Measures of plant water content are likely to have a strong mechanistic link with mortality and to be integrative, threshold-prone and relatively easy to measure and monitor at large spatial scales, and may complement current mortality metrics based on water potential, loss of hydraulic conductivity and nonstructural carbohydrates. We discuss some of the potential advantages and limitations of these metrics to improve our capacity to monitor and predict drought-induced tree mortality. © 2018 The Authors New Phytologist © 2018 New Phytologist Trust

Llegeix més

Building on Margalef: Testing the links between landscape structure, energy and information flows driven by farming and biodiversity

Marull J., Herrando S., Brotons L., Melero Y., Pino J., Cattaneo C., Pons M., Llobet J., Tello E. (2019) Building on Margalef: Testing the links between landscape structure, energy and information flows driven by farming and biodiversity. Science of the Total Environment. 674: 603-614.
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Doi: 10.1016/j.scitotenv.2019.04.129

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The aim of this paper is to test two methodologies, applicable to different spatial scales (from regional to local), to predict the capacity of agroecosystems to provide habitats for the species richness of butterflies and birds, based on the ways their socio-metabolic flows change the ecological functionality of bio-cultural landscapes. First, we use the more general Intermediate Disturbance-Complexity (IDC) model to assess how different levels of human appropriation of photosynthetic production affect the landscape functional structure that hosts biodiversity. Second, we apply a more detailed Energy-Landscape Integrated Analysis (ELIA) model that focusses on the energy storage carried out by the internal biomass loops, and the energy information held in the network of energy flows driven by farmers, in order to correlate both (the energy reinvested and redistributed) with the energy imprinted in the landscape patterns and processes that sustain biodiversity. The results obtained after applying both models in the province and the metropolitan region of Barcelona support the Margalef's energy-information-structure hypothesis by showing positive relations between butterflies' species richness, IDC and ELIA, and between birds' species richness and energy information. Our findings support the view that strong relationships between farming energy flows, agroecosystem functioning and biodiversity can be detected, and highlight the importance of farmers' knowledge and labour to maintain bio-cultural landscapes. © 2019 Elsevier B.V.

Llegeix més

Modelling water fluxes in plants: from tissues to biosphere

Mencuccini M., Manzoni S., Christoffersen B. (2019) Modelling water fluxes in plants: from tissues to biosphere. New Phytologist. : 0-0.
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Doi: 10.1111/nph.15681

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Models of plant water fluxes have evolved from studies focussed on understanding the detailed structure and functioning of specific components of the soil–plant–atmosphere (SPA) continuum to architectures often incorporated inside eco-hydrological and terrestrial biosphere (TB) model schemes. We review here the historical evolution of this field, examine the basic structure of a simplified individual-based model of plant water transport, highlight selected applications for specific ecological problems and conclude by examining outstanding issues requiring further improvements in modelling vegetation water fluxes. We particularly emphasise issues related to the scaling from tissue-level traits to individual-based predictions of water transport, the representation of nonlinear and hysteretic behaviour in soil–xylem hydraulics and the need to incorporate knowledge of hydraulics within broader frameworks of plant ecological strategies and their consequences for predicting community demography and dynamics. © 2019 The Authors. New Phytologist © 2019 New Phytologist Trust

Llegeix més

The use of scenarios and models to evaluate the future of nature values and ecosystem services in Mediterranean forests

Morán-Ordóñez A., Roces-Díaz J.V., Otsu K., Ameztegui A., Coll L., Lefevre F., Retana J., Brotons L. (2019) The use of scenarios and models to evaluate the future of nature values and ecosystem services in Mediterranean forests. Regional Environmental Change. 19: 415-428.
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Doi: 10.1007/s10113-018-1408-5

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Science and society are increasingly interested in predicting the effects of global change and socio-economic development on natural systems, to ensure maintenance of both ecosystems and human well-being. The Intergovernmental Platform on Biodiversity and Ecosystem Services has identified the combination of ecological modelling and scenario forecasting as key to improving our understanding of those effects, by evaluating the relationships and feedbacks between direct and indirect drivers of change, biodiversity, and ecosystem services. Using as case study the forests of the Mediterranean basin (complex socio-ecological systems of high social and conservation value), we reviewed the literature to assess (1) what are the modelling approaches most commonly used to predict the condition and trends of biodiversity and ecosystem services under future scenarios of global change, (2) what are the drivers of change considered in future scenarios and at what scales, and (3) what are the nature and ecosystem service indicators most commonly evaluated. Our review shows that forecasting studies make relatively little use of modelling approaches accounting for actual ecological processes and feedbacks between different socio-ecological sectors; predictions are generally made on the basis of a single (mainly climate) or a few drivers of change. In general, there is a bias in the set of nature and ecosystem service indicators assessed. In particular, cultural services and human well-being are greatly underrepresented in the literature. We argue that these shortfalls hamper our capacity to make the best use of predictive tools to inform decision-making in the context of global change. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.

Llegeix més

The species richness-elevation relationship: global patterns of variation in chironomid richness in mountain lakes

Motta L., Ruggiero A., de Mendoza G., Massaferro J. (2019) The species richness-elevation relationship: global patterns of variation in chironomid richness in mountain lakes. Insect Conservation and Diversity. : 0-0.
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Doi: 10.1111/icad.12341

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The species richness-elevation relationship (SRE) is predominantly hump-shaped along terrestrial gradients, but has been less explored in aquatic environments. Chironomids were used to evaluate the generality of the SRE in mountain lakes, and the role of methodological and biological factors in determining its shape. The shape of 39 chironomid SREs distributed worldwide was identified by consensus between statistical and visual methods. A ‘coefficient of methodological integrity’ (Cin) was developed to combine information on sampling effort and homogeneity, and elevational extent in order to quantify the adherence of each dataset to methodological standards known to influence the SRE. Differences in the shape of the SRE between biogeographical regions, biomes and climatic regions were tested using Fisher's exact tests. A formal meta-analysis was conducted to quantify the overall strength of the SRE, and its association with geographical extent, sampling technique, biogeography, biomes and climate. The SRE presented multiple forms, with considerable variation between identification methods. The most satisfactory datasets (i.e. lowest Cin values), showed predominance of non-linear (low-plateau and hump-shaped) patterns. The Cin explained ~21% of pattern variation. Neither biogeography, nor biomes or climatic regions accounted for differences in the shape of the SRE. The global predominance of non-linear SRE suggests that chironomid richness generally remains high in lakes at mid-elevations, decreasing sharply towards high elevations. As previously known for terrestrial environments, identification of SRE shape is influenced by analytical method. Whenever possible, tailoring the sampling design to increase methodological integrity will reduce uncertainty in the identification of SRE shape in mountain lakes. © 2019 The Royal Entomological Society

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