Anna Avila

Ecological impacts of atmospheric pollution and interactions with climate change in terrestrial ecosystems of the mediterranean basin: Current research and future directions

Mediterranean Basin ecosystems, their unique biodiversity, and the key services they provide are currently at risk due to air pollution and climate change, yet only a limited number of isolated and geographically-restricted studies have addressed this topic, often with contrasting results. Particularities of air pollution in this region include high O3 levels due to high air temperatures and solar radiation, the stability of air masses, and dominance of dry over wet nitrogen deposition. Moreover, the unique abiotic and biotic factors (e.g., climate, vegetation type, relevance of Saharan dust inputs) modulating the response of Mediterranean ecosystems at various spatiotemporal scales make it difficult to understand, and thus predict, the consequences of human activities that cause air pollution in the Mediterranean Basin. Therefore, there is an urgent need to implement coordinated research and experimental platforms along with wider environmental monitoring networks in the region. In particular, a robust deposition monitoring network in conjunction with modelling estimates is crucial, possibly including a set of common biomonitors (ideally cryptogams, an important component of the Mediterranean vegetation), to help refine pollutant deposition maps. Additionally, increased attention must be paid to functional diversity measures in future air pollution and climate change studies to establish the necessary link between biodiversity and the provision of ecosystem services in Mediterranean ecosystems. Through a coordinated effort, the Mediterranean scientific community can fill the above-mentioned gaps and reach a greater understanding of the mechanisms underlying the combined effects of air pollution and climate change in the Mediterranean Basin.

Atmospheric pollutants in peri-urban forests of Quercus ilex: evidence of pollution abatement and threats for vegetation.

Peri-urban vegetation is generally accepted as a significant remover of atmospheric pollutants, but it could also be threatened by these compounds, with origin in both urban and non-urban areas. To characterize the seasonal and geographical variation of pollutant concentrations and to improve the empirical understanding of the influence of Mediterranean broadleaf evergreen forests on air quality, four forests of Quercus ilex (three peri-urban and one remote) were monitored in different areas in Spain. Concentrations of nitrogen dioxide (NO2), ammonia (NH3), nitric acid (HNO3) and ozone (O3) were measured during 2xa0years in open areas and inside the forests and aerosols (PM10) were monitored in open areas during 1xa0year. Ozone was the only air pollutant expected to have direct phytotoxic effects on vegetation according to current thresholds for the protection of vegetation. The concentrations of N compounds were not high enough to directly affect vegetation but could be contributing through atmospheric N deposition to the eutrophization of these ecosystems. Peri-urban forests of Q. ilex showed a significant below-canopy reduction of gaseous concentrations (particularly NH3, with a mean reduction of 29–38xa0%), which indicated the feasibility of these forests to provide an ecosystem service of air quality improvement. Well-designed monitoring programs are needed to further investigate air quality improvement by peri-urban ecosystems while assessing the threat that air pollution can pose to vegetation.

Throughfall and bulk deposition of dissolved organic nitrogen to holm oak forests in the Iberian Peninsula: flux estimation and identification of potential sources

Deposition of dissolved organic nitrogen (DON) in both bulk precipitation (BD) and canopy throughfall (TF) has been measured for the first time in the western Mediterranean. The study was carried out over a year from 2012 to 2013xa0at four evergreen holm oak forests located in the Iberian Peninsula: two sites in the Province of Barcelona (Northeastern Spain), one in the Province of Madrid (central Spain) and the fourth in the Province of Navarra (Northern Spain). In BD the annual volume weighted mean (VWM) concentration of DON ranged from 0.25xa0mgxa0l(-1) in Madrid to 1.14xa0mgxa0l(-1) in Navarra, whereas in TF it ranged from 0.93xa0mgxa0l(-1) in Barcelona to 1.98xa0mgxa0l(-1) in Madrid. The contribution of DON to total nitrogen deposition varied from 34% to 56% in BD in Barcelona and Navarra respectively, and from 38% in Barcelona to 72% in Madrid in TF. Agricultural activities and pollutants generated in metropolitan areas were identified as potential anthropogenic sources of DON at the study sites. Moreover, canopy uptake of DON in Navarra was found in spring and autumn, showing that organic nitrogen may be a supplementary nutrient for Mediterranean forests, assuming that a portion of the nitrogen taken up is assimilated during biologically active periods.

Quantitative study on nitrogen deposition and canopy retention in Mediterranean evergreen forests

To assess the impact of nitrogen (N) pollutants on forest ecosystems, the role of the interactions in the canopy needs to be understood. A great number of studies have addressed this issue in heavily N-polluted regions in north and central Europe. Much less information is available for the Iberian Peninsula, and yet this region is home to mountain forests and alpine grasslands that may be at risk due to excessive N deposition. To establish the basis for ecology-based policies, there is a need to better understand the forest response to this atmospheric impact. To fill this gap, in this study, we measured N deposition (as bulk, wet, and throughfall fluxes of dissolved inorganic nitrogen) and air N gas concentrations from 2011 to 2013 at four Spanish holm oak (Quercus ilex) forests located in different pollution environments. One site was in an area of intensive agriculture, two sites were influenced by big cities (Madrid and Barcelona, respectively), and one site was in a rural mountain environment 40xa0km north of Barcelona. Wet deposition ranged between 0.54 and 3.8xa0kgxa0Nxa0ha−1xa0year−1 for ammonium (NH4+)-N and between 0.65 and 2.1xa0kgxa0Nxa0ha−1xa0year−1 for nitrate (NO3−)-N, with the lowest deposition at the Madrid site for both components. Dry deposition was evaluated with three different approaches: (1) a canopy budget model based in throughfall measurements, (2) a branch washing method, and (3) inferential calculations. Taking the average dry deposition from these methods, dry deposition represented 51–67% (reduced N) and 72–75% (oxidized N) of total N deposition. Canopies retained both NH4+-N and NO3-N, with a higher retention at the agricultural and rural sites (50–60%) than at sites located close to big cities (20–35%, though more uncertainty was found for the site near Madrid), thereby highlighting the role of the forest canopy in processing N pollutant emissions.

The Critical Levels of Atmospheric Ammonia in a Mediterranean Holm-Oak Forest in North-Eastern Spain

Despite recent regulations, atmospheric ammonia (NH3) emissions have not changed much over the last decades and excessive nitrogen remains as one of the major drivers for biodiversity changes. To prevent deleterious effects on species and ecosystems, it is very important to establish safety thresholds, such as those defined by the Critical Level (CLE) concept, “the concentration above which direct adverse effects on receptors may occur, based on present knowledge.” Empirical critical levels of atmospheric NH3 have mainly been reported for temperate forests and there is a lack of information for Mediterranean forests. Here, we provide a case study on NH3 CLEs for a typical Mediterranean ecosystem, the holm-oak (Quercus ilex) forest. To derive the CLE value, we measured NH3 concentrations for 1xa0year at a distance gradient in the forest surrounding a point source (cattle farm) and used diversity changes of lichen functional groups to indicate the onset of adverse effects. We estimate a NH3 CLE threshold of 2.6xa0μgxa0m−3, a value that is higher than that reported in other Mediterranean ecosystems and suggests that the site has been already impacted by NH3 pollution in the past. In a more general context, this study confirms the validity of lichen functional groups to derive CLEs in Mediterranean forests and woodlands and contribute to the body of knowledge regarding the impacts of NH3 on ecosystems.

Monitorización y tendencias de la deposición de N en España, incluyendo polvo sahariano

Rocío Alonso Miguel Álvarez Cobelas Jose Manuel Álvarez-Martínez Mariano Amoroso Enrique Andivia Gabriel Arellano Cristina Armas María Arróniz Crespo Anna Avila Isabel Banos-González Eulogio Bedmar Raquel Benavides Marta Benito Garzón Juan A. Blanco Francisco Javier Bonet García Raphael Boulay Santiago Fernando Burneo Francisco Cabezas Rafael Calama Silvia Calvo Aranda Julio A. Camargo Daisy Cárate-Tandalla José A. Carreira de la Fuente Myriam Catalá Miquel De Cáceres Pilar de la Rua Thibaut Dominique Delsinne Dennis Denis Lucía DeSoto Suárez María T. Domínguez David A. Donoso David A Donoso Jorge Durán María José Endara Blanca Figueroa-Rangel Rubén G. Mateo José M. García del Barrio Enrique García de la Riva Ana I. García-Cervigón Morales Héctor García-Gómez Óscar Godoy Uriel Hernandez Gomez Lorena Gémez Aparicio Penélope González José González Novoa Manuela González Suárez Daniel Griffith Roberto José Guerrero David Gutiérrez Xavier Haro Carrión Laura Hernández Mateo Javier Herrero Asier Herrero Méndez Sheila Izquieta Rojano Luis Lassaletta John Lattke Alex Leverkus Francisco Lloret Jorge Lozano Yudi Lozano Manuel Macía Jaime Madrigal González Esteban Manrique Santiago Martín Alcón Pilar Martín Isabel Javier Martínez Abaigar Jesús Martínez Fernández José Luis Martínez Menéndez Isabel Martínez Moreno Francisco Javier Martínez Vega Marcos Méndez Iglesias Rubén Milla Marcos Miñarro Daniel Moya Navarro Sven Mutke Rafael Ma Navarro Cerrillo Francisco Bruno Navarro Reyes Susana Ochoa Gaona Raúl Ochoa Hueso Daniel Paredes Mauricio Parra Quijano Sergio Pérez Guerrero Carolina Puerta Piñero Neptalí Ramírez-Marcial José V. Roces Díaz Alexandra Rodríguez Carlos Rodríguez Osorio Itziar Rodríguez Urbieta Susana Rodríguez-Echeverría Pere Rovira Paloma Ruiz-Benito Asunción Saldaña Ángela Sánchez-Miranda Fábio Suzart de Albuquerque María Fernanda Tapia-Armijos Jerónimo Torres-Porras María Triviño Raúl Vaca Alejandro Valdecantos Jordi Vayreda Alejandro Velázquez Martínez Albert Vila-Cabrera Rafael Villar Francisco Javier Zamora Camacho Carlos Zamorano-Elgueta Galo Zapata Ríos Lista de revisores que han completado revisiones en el año 2016Visconti, F., de Paz, J.M. 2017. Estimation of the potential CO 2 sequestration and emission capacity of the agricultural soils of the Valencian Community. Ecosistemas 26(1): 91-100. Doi.: 10.7818/ECOS.2017.26-1.15 Agricultural soils have capacity to sequester CO 2 in the form of organic matter. However, this capacity has hardly been quantified and mapped for large territories and with a wide variety of crops, such as the Valencian Community. This task is required to properly size the role of agriculture in any strategy to mitigate climate change. In this paper a first estimate of the potential CO 2 sequestration and emission capacity of the agricultural soils of the Valencian Community down to 20 cm depth has been made. This estimate has been carried out based on the average and spatial variability of the agricultural soil organic matter content in homogeneous agro-ecological zones in climate, soil class and land use, and using GIS, geostatistics and map algebra techniques. The sequestration and emission capacities were found to be 24.0 and 22.0 Mt of carbon, respectively. These values are equivalent to roughly ± 8 years of carbon emissions by use of fossil fuels in the Community itself. This sequestering capacity, which could be reached in 15 to 100 years with the global adoption of management practices that foster soil organic matter accumulation, has an important but insufficient effect compared to the current emission rate. In any case, increasing carbon sequestration in soils, either through management improvement or through organic matter incorporation programs, is very important both to improve sequestration capacity and even more to adapt agroecosystems to climate change.