Fernández-Martínez M., Sardans J., Chevallier F., Ciais P., Obersteiner M., Vicca S., Canadell J.G., Bastos A., Friedlingstein P., Sitch S., Piao S.L., Janssens I.A., Peñuelas J. (2019) Global trends in carbon sinks and their relationships with CO2 and temperature. Nature Climate Change. 9: 73-79.LinkDoi: 10.1038/s41558-018-0367-7
Elevated CO2 concentrations increase photosynthesis and, potentially, net ecosystem production (NEP), meaning a greater CO2 uptake. Climate, nutrients and ecosystem structure, however, influence the effect of increasing CO2. Here we analysed global NEP from MACC-II and Jena CarboScope atmospheric inversions and ten dynamic global vegetation models (TRENDY), using statistical models to attribute the trends in NEP to its potential drivers: CO2, climatic variables and land-use change. We found that an increased CO2 was consistently associated with an increased NEP (1995–2014). Conversely, increased temperatures were negatively associated with NEP. Using the two atmospheric inversions and TRENDY, the estimated global sensitivities for CO2 were 6.0 ± 0.1, 8.1 ± 0.3 and 3.1 ± 0.1 PgC per 100 ppm (~1 °C increase), and −0.5 ± 0.2, −0.9 ± 0.4 and −1.1 ± 0.1 PgC °C−1 for temperature. These results indicate a positive CO2 effect on terrestrial C sinks that is constrained by climate warming. © 2018, The Author(s), under exclusive licence to Springer Nature Limited.
Happe A.-K., Alins G., Blüthgen N., Boreux V., Bosch J., García D., Hambäck P.A., Klein A.-M., Martínez-Sastre R., Miñarro M., Müller A.-K., Porcel M., Rodrigo A., Roquer-Beni L., Samnegård U., Tasin M., Mody K. (2019) Predatory arthropods in apple orchards across Europe: Responses to agricultural management, adjacent habitat, landscape composition and country. Agriculture, Ecosystems and Environment. 273: 141-150.LinkDoi: 10.1016/j.agee.2018.12.012
Local agri-environmental schemes, including hedgerows, flowering strips, organic management, and a landscape rich in semi-natural habitat patches, are assumed to enhance the presence of beneficial arthropods and their contribution to biological control in fruit crops. We studied the influence of local factors (orchard management and adjacent habitats) and of landscape composition on the abundance and community composition of predatory arthropods in apple orchards in three European countries. To elucidate how local and landscape factors influence natural enemy effectiveness in apple production systems, we calculated community energy use as a proxy for the communities’ predation potential based on biomass and metabolic rates of predatory arthropods. Predator communities were assessed by standardised beating samples taken from apple trees in 86 orchards in Germany, Spain and Sweden. Orchard management included integrated production (IP; i.e. the reduced and targeted application of synthetic agrochemicals), and organic management practices in all three countries. Predator communities differed between management types and countries. Several groups, including beetles (Coleoptera), predatory bugs (Heteroptera), flies (Diptera) and spiders (Araneae) benefited from organic management depending on country. Woody habitat and IP supported harvestmen (Opiliones). In both IP and organic orchards we detected aversive influences of a high-quality surrounding landscape on some predator groups: for example, high covers of woody habitat reduced earwig abundances in German orchards but enhanced their abundance in Sweden, and high natural plant species richness tended to reduce predatory bug abundance in Sweden and IP orchards in Spain. We conclude that predatory arthropod communities and influences of local and landscape factors are strongly shaped by orchard management, and that the influence of management differs between countries. Our results indicate that organic management improves the living conditions for effective predator communities. © 2018 Elsevier B.V.
Harjung A., Ejarque E., Battin T., Butturini A., Sabater F., Stadler M., Schelker J. (2019) Experimental evidence reveals impact of drought periods on dissolved organic matter quality and ecosystem metabolism in subalpine streams. Limnology and Oceanography. 64: 46-60.LinkDoi: 10.1002/lno.11018
Subalpine streams are predicted to experience lower summer discharge following climate change and water extractions. In this study, we aimed to understand how drought periods impact dissolved organic matter (DOM) processing and ecosystem metabolism of subalpine streams. We mimicked a gradient of drought conditions in stream-side flumes and evaluated implications of drought on DOM composition, gross primary production, and ecosystem respiration. Our experiment demonstrated a production and release of DOM from biofilms and leaf litter decomposition at low discharges, increasing dissolved organic carbon concentrations in stream water by up to 50%. Absorbance and fluorescence properties suggested that the released DOM was labile for microbial degradation. Dissolved organic carbon mass balances revealed a high contribution of internal processes to the carbon budget during low flow conditions. The flumes with low discharge were transient sinks of atmospheric CO2 during the first 2 weeks of drought. After this autotrophic phase, the metabolic balance of these flumes turned heterotrophic, suggesting a nutrient limitation for primary production, while respiration remained high. Overall our experimental findings suggest that droughts in subalpine streams will enhance internal carbon cycling by transiently increasing primary production and more permanently respiration as the drought persists. We propose that the duration of a drought period combined with inorganic nutrient availability are key variables that determine if more carbon is respired in situ or exported downstream. © 2018 The Authors. Limnology and Oceanography published by Wiley Periodicals, Inc. on behalf of Association for the Sciences of Limnology and Oceanography.
Lanzas M., Hermoso V., de-Miguel S., Bota G., Brotons L. (2019) Designing a network of green infrastructure to enhance the conservation value of protected areas and maintain ecosystem services. Science of the Total Environment. 651: 541-550.LinkDoi: 10.1016/j.scitotenv.2018.09.164
There is a growing demand for holistic landscape planning to enhance sustainable use of ecosystem services (ESS) and maintenance of the biodiversity that supports them. In this context, the EU is developing policy to regulate the maintenance of ESS and enhance connectivity among protected areas (PAs). This is known as the network of Green Infrastructure (GI). However, there is not a working framework defined to plan the spatial design of such network of GI. Here, we use the software Marxan with Zones, to prioritize the spatial distribution of different management zones that accommodate the needs of a network of GI. These zones included a conservation zone, mainly devoted to protecting biodiversity, a GI zone, that aimed at connecting PAs and maintaining regulating and cultural ESS; and a management zone devoted to exploiting provisioning ESS. We performed four planning scenarios that distribute the targets for ESS and biodiversity in different ways across management zones. We also conducted a sensitivity analysis by increasing ESS targets to explore trade-offs that may occur when managing together biodiversity and ESS. We use Catalonia (northeastern Spain) as a case study. We found that the representation of ESS could be achieved for intermediate targets in all scenarios. There was, however, a threshold on these targets over which trade-offs appeared between maintaining regulating and cultural ESS and biodiversity versus getting access to provisioning ESS. These “thresholds values” were displaced towards higher ESS targets when we moved from more strict to more flexible planning scenarios (i.e., scenarios that allowed mixing representation of objectives for biodiversity and ESS within the same zone). This methodological approach could help design a framework to integrate biodiversity and ESS management in holistic plans and decision making and, at the same time, meeting European mandates concerning the design of GI networks, or similar needs elsewhere. © 2018 Elsevier B.V.
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.LinkDoi: 10.1111/gcb.14522
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
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.LinkDoi: 10.1111/nph.15644
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
Mencuccini M., Manzoni S., Christoffersen B. (2019) Modelling water fluxes in plants: from tissues to biosphere. New Phytologist. : 0-0.LinkDoi: 10.1111/nph.15681
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
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.LinkDoi: 10.1111/icad.12341
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
Padró J.-C., Carabassa V., Balagué J., Brotons L., Alcañiz J.M., Pons X. (2019) Monitoring opencast mine restorations using Unmanned Aerial System (UAS) imagery. Science of the Total Environment. 657: 1602-1614.LinkDoi: 10.1016/j.scitotenv.2018.12.156
Open-pit mine is still an unavoidable activity but can become unsustainable without the restoration of degraded sites. Monitoring the restoration after extractive activities is a legal requirement for mine companies and public administrations in many countries, involving financial provisions for environmental liabilities. The objective of this contribution is to present a rigorous, low-cost and easy-to-use application of Unmanned Aerial Systems (UAS) for supporting opencast mining and restoration monitoring, complementing the inspections with very high (
Peterson A.T., Anderson R.P., Beger M., Bolliger J., Brotons L., Burridge C.P., Cobos M.E., Cuervo-Robayo A.P., Di Minin E., Diez J., Elith J., Embling C.B., Escobar L.E., Essl F., Feeley K.J., Hawkes L., Jiménez-García D., Jimenez L., Green D.M., Knop E., Kühn I., Lahoz-Monfort J.J., Lira-Noriega A., Lobo J.M., Loyola R., Mac Nally R., Machado-Stredel F., Martínez-Meyer E., McCarthy M., Merow C., Nori J., Nuñez-Penichet C., Osorio-Olvera L., Pyšek P., Rejmánek M., Ricciardi A., Robertson M., Rojas Soto O., Romero-Alvarez D., Roura-Pascual N., Santini L., Schoeman D.S., Schröder B., Soberon J., Strubbe D., Thuiller W., Traveset A., Treml E.A., Václavík T., Varela S., Watson J.E.M., Wiersma Y., Wintle B., Yanez-Arenas C., Zurell D. (2019) Open access solutions for biodiversity journals: Do not replace one problem with another. Diversity and Distributions. 25: 5-8.LinkDoi: 10.1111/ddi.12885
[No abstract available]
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