Open Access
Metatranscriptomics sheds light on the links between the functional traits of fungal guilds and ecological processes in forest soil ecosystems
(Blackwell Scientific Publications Ltd, 2023) Auer, Lucas; Buée, Marc; Fauchery, Laure; Lombard, Vincent; Barry, Kerrie; Clum, Alicia; Copeland, Alex; Daum, Chris; LaButti, Kurt; Singan, Vasanth; Yoshinaga, Yuko; Martineau, Christine; Castillo Martínez, Federico; Alfaro Sánchez, Manuel; Imbert Rodríguez, Bosco; Ramírez Nasto, Lucía; Castanera Andrés, Raúl; Pisabarro de Lucas, Gerardo; Finlay, Roger; Lindahl, Björn D.; Olson, Ake; Séguin, Armand; Kohler, Annegret; Henrissat, Bernard; Grigoriev, Igor V.; Martin, Francis; Agronomía, Biotecnología y Alimentación; Agronomia, Bioteknologia eta Elikadura; Institute for Multidisciplinary Research in Applied Biology - IMAB
Soil fungi belonging to different functional guilds, such as saprotrophs, pathogens, and mycorrhizal symbionts, play key roles in forest ecosystems. To date, no study has compared the actual gene expression of these guilds in different forest soils. We used metatranscriptomics to study the competition for organic resources by these fungal groups in boreal, temperate, and Mediterranean forest soils. Using a dedicated mRNA annotation pipeline combined with the JGI MycoCosm database, we compared the transcripts of these three fungal guilds, targeting enzymes involved in C- and N mobilization from plant and microbial cell walls. Genes encoding enzymes involved in the degradation of plant cell walls were expressed at a higher level in saprotrophic fungi than in ectomycorrhizal and pathogenic fungi. However, ectomycorrhizal and saprotrophic fungi showed similarly high expression levels of genes encoding enzymes involved in fungal cell wall degradation. Transcripts for N-related transporters were more highly expressed in ectomycorrhizal fungi than in other groups. We showed that ectomycorrhizal and saprotrophic fungi compete for N in soil organic matter, suggesting that their interactions could decelerate C cycling. Metatranscriptomics provides a unique tool to test controversial ecological hypotheses and to better understand the underlying ecological processes involved in soil functioning and carbon stabilization.
Open Access
Changes in long-term light properties of a mixed conifer–broadleaf forest in Southwestern Europe
(MDPI, 2021) Ruiz de la Cuesta Vela, Ignacio; Blanco Vaca, Juan Antonio; Imbert Rodríguez, Bosco; Peralta de Andrés, Francisco Javier; Rodríguez Pérez, Javier; Ciencias; Zientziak; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Natural and anthropogenic factors affect forest structure worldwide, primarily affecting forest canopy and its light properties. However, not only stand-replacing events modify canopy structure, but disturbances of lower intensity can also have important ecological implications. To study such effects, we analyzed long-term changes in light properties of a conifer–broadleaf mixed forest in the Southwestern Pyrenees, placed in the fringe between the Mediterranean and Eurosi- berian biogeographical regions. At this site, a thinning trial with different intensities (0%, 20%, and 30–40% basal area removed) took place in 1999 and 2009, windstorms affected some plots in 2009 and droughts were recurrent during the sampling period (2003, 2005, 2011). We monitored light properties during 14 years (2005–2019) with hemispherical photographs. We applied partial autocorrelation functions to determine if changes between years could be attributed to internal canopy changes or to external disturbances. In addition, we mapped the broadleaf canopy in 2003, 2008, and 2016 to calculate broadleaf canopy cover and richness at the sampling points with different buffer areas of in- creasing surface. We applied generalized linear mixed models to evaluate the effects of light variables on canopy richness and cover. We found that light variables had the most important changes during the period 2008 to 2010, reacting to the changes caused that year by the combined effects of wind and forest management. In addition, we found that an area of 4.0 m radius around the sampling points was the best to explain the relationship between light properties and species richness, whereas a radius of 1.0 m was enough to estimate the relationship between light and canopy cover. In addition, light-related variables such as diffuse light and leaf area index were related to species richness, whereas structural variables such as canopy openness were related to canopy cover. In summary, our study demonstrates that non stand-replacing disturbances such as windstorms, thinning, or droughts can have an important role in modifying structural and light-related canopy properties, which in turn may inﬂuence natural processes of stand development and ecological succession.
Open Access
8ª Edición de la Escuela de verano de Ecología de Navarra: ecólogas/os por un día
(Asociación Española de Ecología Terrestre, AEET, 2022) Imbert Rodríguez, Bosco; Blanco Vaca, Juan Antonio; Ciencias; Zientziak; Institute for Multidisciplinary Research in Applied Biology - IMAB
Durante los pasados 23 y 24 de junio tuvo lugar la 8ª edición de la Escuela de Verano de Ecología de Navarra de la Universidad Pública de Navarra (UPNA) con el título ‘Ecólogas/os por un día’. En la jornada se impartieron cuatro ponencias por parte de los miembros del grupo de investigación de Ecología y Medio Ambiente de la Universidad Pública de Navarra, pero la mayor parte del tiempo se dedicó al trabajo de campo en el parque. En dicho trabajo de campo los asistentes pudieron trabajar tres temas diferentes: el estudio de las comunidades vegetales en pastos, el estudio de la estructura de una comunidad arbórea y la observación y estimación de censos de aves. Los trabajos incluyeron la demostración y familiarización de los estudiantes con las distintas técnicas y aparatos para medir variables ambientales como luz ambiental, temperatura del suelo, humedad del suelo, diámetro y altura de árboles, así como las técnicas para realizar inventarios florísticos o de fauna.
Open Access
Cubierta vegetal bajo las cepas: una alternativa al control de las malas hierbas en los viñedos
(INTIA (Tecnologías e Infraestructuras Agroalimentarias), 2023) Abad Zamora, Francisco Javier; Cibriain Sabalza, Félix; Sagüés Sarasa, Ana; Santesteban García, Gonzaga; Lezáun San Martín, Juan Antonio; Fabo Boneta, Jesús María; Virto Quecedo, Íñigo; Imbert Rodríguez, Bosco; Marín Arroyo, Remedios; Garbisu Crespo, Carlos; Ciencias; Zientziak; Agronomía, Biotecnología y Alimentación; Agronomia, Bioteknologia eta Elikadura; Institute for Multidisciplinary Research in Applied Biology - IMAB; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD
En este artículo se presentan los resultados obtenidos con una cubierta vegetal de trébol sembrada bajo las cepas para competir con las malas hierbas, de manera que no sea necesario recurrir al empleo de herbicidas o laboreos intercepas.
Open Access
Coarse woody debris' invertebrate community is affected directly by canopy type and indirectly by thinning in mixed scots pine-European beech forests
(MDPI, 2020) Herrera Álvarez, Ximena; Blanco Vaca, Juan Antonio; Imbert Rodríguez, Bosco; Álvarez, Willin; Rivadeneira Barba, Gabriela; Zientziak; Institute for Multidisciplinary Research in Applied Biology - IMAB; Ciencias
Research Highlights: Thinning and tree species alter the forest floor microclimate by modifying canopy cover, radiation, wind, and humidity. Thus, forest management can directly influence the edaphic mesofauna responsible for decomposing coarse woody debris (CWD). Background and Objectives: This research was carried out in the Southwestern Pyrenees Mountains (Northern Spain) and aimed to determine the influence of forest thinning and canopy type (pure Pinus sylvestris L. or a mix of P. sylvestris and Fagus sylvatica L.) on CWD colonization by edaphic fauna. Materials and Methods: CWD samples were collected belonging to intermediate and advanced decomposition stages, approximately 10 cm long and 5 cm in diameter. Using a design of three thinning intensities (0%, 20%, and 40% of basal area removed), with three replications per treatment (nine plots in total), four samples were taken per plot (two per canopy type) to reach 36 samples in total. Meso- and macrofauna were extracted from CWD samples with Berlese-Tullgren funnels, and individuals were counted and identified. Results: 19 taxonomic groups were recorded, the most abundant being the mesofauna (mites and Collembola). Mixed canopy type had a significant positive influence on richness, whereas advanced decay class had a positive significant influence on total abundance and richness. In addition, there were non-significant decreasing trends in richness and abundance with increasing thinning intensity. However, interactions among thinning intensity, canopy type, and decay class significantly affected mesofauna. Furthermore, some taxonomic groups showed differential responses to canopy type. CWD water content was positively correlated with total invertebrate abundance and some taxonomic groups. Our results suggest that stand composition has the potential to directly affect invertebrate communities in CWD, whereas stand density influence is indirect and mostly realized through changes in CWD moisture. As mesofauna is related to CWD decomposition rates, these effects should be accounted for when planning forest management transition from pure to mixed forests.
Open Access
Drought limits tree growth more than greenness and reproduction: insights from five case studies in Spain
(KeAi Communications, 2025-08-01) Camarero, Jesús Julio; Rubio-Cuadrado, Álvaro; González de Andrés, Ester; Valeriano, Cristina; Pizarro, Manuel; Imbert Rodríguez, Bosco; Lo, Yueh-Hsin; Blanco Vaca, Juan Antonio; Ciencias; Zientziak; Institute for Multidisciplinary Research in Applied Biology - IMAB
Droughts impact forests by influencing various processes such as canopy greenness, tree growth, and reproduction, but most studies have only examined a few of these processes. More comprehensive assessments of forest responses to climate variability and water shortages are needed to improve forecasts of post-drought dynamics. Iberian forests are well-suited for evaluating these effects because they experience diverse climatic conditions and are dominated by various conifer and broadleaf species, many of which exhibit masting. We assessed how greenness, evaluated using the normalized difference vegetation index (NDVI), tree radial growth, and seed or cone production responded to drought in five tree species (three conifers: silver fir (Abies alba), Scots pine (Pinus sylvestris), and stone pine (Pinus pinea); two broadleaves: European beech (Fagus sylvatica) and holm oak (Quercus ilex) inhabiting sites with different aridity. We correlated these data with the standardized precipitation evapotranspiration index (SPEI) using the climate window analysis (climwin) package, which identifies the most relevant climate window. Drought constrained growth more than greenness and seed or cone production. Dry conditions led to high seed or cone production in species found in cool, moist sites (silver fir, beech, and Scots pine). We also found negative associations of cone production with summer SPEI in the drought-tolerant stone pine, which showed lagged growth−cone negative correlations. However, in the seasonally dry holm oak forests, severe droughts constrained both growth and acorn production, leading to a positive correlation between these variables. Drought impacts on greenness, growth, seed, and cone production depended on species phenology and site aridity. A negative correlation between growth and reproduction does not necessarily indicate trade-offs, as both may be influenced by similar climatic factors.
Open Access
Pinus sylvestris L. and Fagus sylvatica L. effects on soil and root properties and their interactions in a mixed forest on the Southwestern Pyrenees
(Elsevier, 2021) Yeste Yeste, Antonio; Blanco Vaca, Juan Antonio; Imbert Rodríguez, Bosco; Zozaya Vela, Helena; Elizalde Arbilla, Martín; Zientziak; Institute for Multidisciplinary Research in Applied Biology - IMAB; Ciencias
Tree species alter soil properties, potentially modifying forest nutrients cycling. In the current management context in which mixed species forests are favoured over monocultures due to their biodiversity and productivity-related advantages, the assessment of species effects on soils, as well as their interactions with other species, gains increasing relevance. In this study, the effects of Scots pine (Pinus sylvestris L.) and European beech (Fagus sylvatica L.) on soil properties were evaluated. Fine roots were paid special attention, measuring their biomass, functional traits (specific root length, root tissue density) and vertical distribution in order to discern the direction of these species interaction, either complementary or competitive. The research was carried out in the Southwestern Pyrenees (northern Spain), in an originally Scots pine stand transformed nowadays into a mixed forest by European beech natural regeneration. Soil and root samples were taken close to pine trees surrounded by other pines in areas that remain similar to pine monospecific stands, and close to pine and beech trees surrounded by both species in mixed areas. A lower C/N ratio was found in the soil close to beech stems. This suggests better quality in mixed litter in comparison to pine litter, leading to higher decomposition rates. Higher fine root biomass was found in the mixed areas mainly due to beech fine roots great abundance, which correlated positively with microbial biomass. Fine roots functional traits such as specific root length and diameter did not vary depending on their proximity to different tree species, though Scots pine fine root biomass decreased sharply when close to beech trees. This reduction, together with the already more abundant fine root biomass of beech, with higher specific root length and root tissue density than pine, lead to a competitive interaction in which European beech tends to dominate the soil at all depths. In this case, no complementarity effect at belowground level, strong enough to allow Scots pines to cope with beech soil colonization, was found under natural conditions.
Open Access
Constrained trait variation by water availability modulates radial growth in evergreen and deciduous mediterranean oaks
(Elsevier, 2024) González de Andrés, Ester; Serra-Maluquer, Xavier; Gazol, Antonio; Olano, José Miguel; García Plazaola, José Ignacio; Fernández Marín, Beatriz; Imbert Rodríguez, Bosco; Coll, Lluís; Ameztegui, Aitor; Espelta, Josep Maria; Alla, Arben Q.; Camarero, Jesús Julio; Ciencias; Zientziak; Institute for Multidisciplinary Research in Applied Biology - IMAB
Spatial and temporal variation in functional traits allows trees to adjust to shifting environmental conditions such as water stress. However, the change of traits, both mean and variances, along water availability gradients and across growing seasons, as well as their covariation with tree performance, have been rarely assessed. We examined intraspecific trait variation in coexisting evergreen (Quercus ilex ssp. ilex and Q. ilex ssp. ballota) and deciduous (Quercus faginea and Quercus humilis) Mediterranean oaks along a wide water availability gradient in northeastern Spain during six years. We measured leaf area (LA), shoot twig mass (Sm), leaf mass per area (LMA) and the ratio of shoot twig to leaf biomass (Sm:Lm). We characterized tree performance through basal area increment (BAI) and drought resilience indices. Higher variation was found within individuals than between individuals across populations and years. Within species, we found trait adjustments toward more conservative water-use (low LA and Sm and high LMA) with increasing drier conditions. Intraspecific trait variation was constrained by water availability, particularly on the deciduous species. In Q. ilex, trait variance of LMA positively covaried with annual BAI, whereas variance of LA, Sm and Sm:Lm was positively related to resistance and resilience against the severe 2012 drought in deciduous oaks. Our results support a tradeoff between the ability to tolerate drought and the capacity to cope with unpredictable changes in the environment through increased intraspecific trait variation, which may have implications on tree performance in the face of increased extreme events.
Open Access
Invertebrate community of Scots pine coarse woody debris in the Southwestern Pyrenees under different thinning intensities and tree species
(MDPI, 2021) Herrera Álvarez, Ximena; Blanco Vaca, Juan Antonio; Imbert Rodríguez, Bosco; Álvarez, Willin; Rivadeneira Barba, Gabriela; Zientziak; Institute for Multidisciplinary Research in Applied Biology - IMAB; Ciencias
Background and Objectives: The forest in the Southwestern Pyrenees Mountains (Northern Spain) is mainly composed of pure Pinus sylvestris L. or a mix of P. sylvestris and Fagus sylvatica L. The most common forest management technique to harvest pine is the application of forest thinning with different intensities. It promotes a change in the forest composition and structure. Taking into consideration this region as a site specific research about this topic, we aimed to understand the CWD invertebrate composition response to different thinning intensities and canopy type of these tree species. Materials and Methods: CWD samples were collected belonging to intermediate and advanced decay classes, approximately 10 cm long and 5 cm in diameter. Using a design of three thinning intensities (0%, 20%, and 40% of basal area removed), with three replications per treatment (nine plots in total), four samples were taken per plot (two per canopy type) to reach 36 samples in total. Meso- and macrofauna were extracted from CWD samples with Berlese– Tullgren funnels, and individuals were counted and identified. Results: Most of the taxonomic groups belonged to mesofauna, mainly to Acari and Collembola orders. On the other hand, the macrofauna represented a minimum percentage of the community composition. Our results indicated that although thinning intensities did not significantly affect the invertebrate community, canopy type and CWD water content influenced significantly. It is imperative to consider in forest management the responses of canopy type and thinning intensities in CWD water content, this disturbance could also slow down the organic matter decomposition process in the soil, thus affecting in the long term the natural cycle of nutrients.
Open Access
Long-term carbon sequestration in pine forests under different silvicultural and climatic regimes in Spain
(MDPI, 2022) Navarro Cerrillo, Rafael M.; Ruiz Gómez, Francisco Javier; Camarero, Jesús Julio; Castillo, Víctor M.; Barberá, Gonzalo G.; Palacios Rodríguez, Guillermo; Navarro, Francisco B.; Blanco Vaca, Juan Antonio; Imbert Rodríguez, Bosco; Cachinero Vivar, Antonio M.; Molina, Antonio J.; Campo, Antonio D. del; Zientziak; Institute for Multidisciplinary Research in Applied Biology - IMAB; Ciencias
Proactive silviculture treatments (e.g., thinning) may increase C sequestration contributing to climate change mitigation, although, there are still questions about this effect in Mediterranean pine forests. The aim of this research was to quantify the storage of biomass and soil organic carbon in Pinus forests along a climatic gradient from North to South of the Iberian Peninsula. Nine experimental Pinus spp trials were selected along a latitudinal gradient from the pre-Pyrenees to southern Spain. At each location, a homogeneous area was used as the operational scale, and three thinning intensity treatments: unthinned or control (C), intermediate thinning (LT, removal of 30–40% of the initial basal area) and heavy thinning (HT, removal of 50–60%) were conducted. Growth per unit area (e.g., expressed as basal area increment-BAI), biomass, and Soil Organic Carbon (SOC) were measured as well as three sets of environmental variables (climate, soil water availability and soil chemical and physical characteristics). One-way ANOVA and Structural Equation Modelling (SEM) were used to study the effect of thinning and environmental variables on C sequestration. Biomass and growth per unit area were higher in the control than in the thinning treatments, although differences were only significant for P. halepensis. Radial growth recovered after thinning in all species, but it was faster in the HT treatments. Soil organic carbon (SOC10, 0–10 cm depth) was higher in the HT treatments for P. halepensis and P. sylvestris, but not for P. nigra. SEM showed that Pinus stands of the studied species were beneficed by HT thinning, recovering their growth quickly. The resulting model explained 72% of the variation in SOC10 content, and 89% of the variation in silvicultural condition (basal area and density) after thinning. SOC10 was better related to climate than to silvicultural treatments. On the other hand, soil chemical and physical characteristics did not show significant influence over SOC10- Soil water availability was the latent variable with the highest influence over SOC10. This work is a new contribution that shows the need for forest managers to integrate silviculture and C sequestration in Mediterranean pine plantations