Relaciones de poder y servicios del ecosistema

7 páginas.- Presentación elaborada para las III Jornadas IPErinas, celebradas el 11 de diciembre de 2014.Peer reviewe

Drought impacts on tree growth of two pine species along an altitudinal gradient and their use as early-warning signals of potential shifts in tree species distributions.

Mediterranean pine forests are at risk of experiencing a decline in tree growth in response to climatewarming if rising temperatures amplify drought stress. In mountain areas, tree growth could be enhancedin temperature-limited high elevations, whilst it might decline at water-constrained low elevations.Species differential responses could, however, modulate the impact of drought on forests along altitudinalgradients. To test for evidence of species differential drought impacts along an altitudinal gradient, westudied the growth responses of two Iberian pine species (Pinus sylvestris and Pinus nigra) subjected toMediterranean conditions in Eastern Spain. We analysed the stability of growth (basal area increment)responses to climate and drought during the 1950&-2014 period by using resistance and resilience indices.Pinus sylvestris growth was enhanced by warm spring temperatures, while Pinus nigra growth wasimproved by a positive spring water balance. Pinus sylvestris growth decreased temporally at the lowerend of its altitudinal range, whereas Pinus nigra growth decreased at the upper end. Pinus sylvestris exhibitedlow growth stability at its low-elevation limit. Pinus nigra resistance also decreased along its altitudinalrange, but this effect was compensated by a high resilience. In mixed stands the results werecontrasting, with Pinus sylvestris (at the lower altitudinal range) being more vulnerable to droughtinducedgrowth decline than Pinus nigra (at the upper altitudinal range).Ministerio de Economía y Competitivida

Papel de los factores bióticos y las sequías en el decaimiento del bosque: aportaciones desde la dendroecología

[ES] El aumento de la mortalidad y la pérdida de vitalidad de los bosques son procesos que afectan a diversas especies de árboles y biomas. Estos fenómenos de decaimiento forestal se han asociado a la interacción de múltiples factores relacionados con el cambio global, como el aumento de las sequías o la mayor incidencia de factores bióticos que generan estrés. Sin embargo, el papel que juegan estos organismos en el decaimiento del bosque en relación a la sequía no está del todo comprendido. En este trabajo caracterizamos retrospectivamente los efectos que ejercen dichos organismos sobre el crecimiento radial de árboles estresados por sequía utilizando dendrocronología. El efecto combinado del muérdago y las sequías reducen el crecimiento del pino silvestre y aumentan la defoliación, siendo estos efectos más evidentes en el ápice del árbol. La procesionaria induce pérdidas de crecimiento en pino laricio, pero en general se observa una recuperación dos años después. No encontramos un papel determinante de los hongos patógenos de raíz en el decaimiento del abeto. Finalmente, pinos carrasco muertos que presentaban ataques de insectos perforadores mostraron patrones de crecimiento similares a pinos vivos. Este estudio nos permite caracterizar algunos de los complejos y múltiples efectos de diferentes factores bióticos de estrés sobre el crecimiento y la vulnerabilidad de los bosques susceptibles a los efectos negativos de las sequías.[EN] Increasing mortality and decline of forests are affecting several tree species and biomes. These events of forest decline have been related to the interaction of several global change elements, like the increase in drought stress or a higher incidence of biotic stress factors. However, the roles played by biotic stressors have been scarcely explored as related to drought stress. In this paper we retrospectively characterize the effects of these organisms on radial growth of trees already stressed by drought using dendrochronology. The combined effect of mistletoe and droughts reduce tree growth in Scots pine and increase defoliation, being these effects more noticeable in the apex. The pine processionary moth induces growth losses in the affected stands of black pine, but they usually recover two years after the outbreak. We did not find a determinate role of root pathogens on silver fir dieback. Finally, dead Aleppo pine trees infested by bark beetles showed similar growth patterns than living pine trees. This study allows characterizing some of the complex and multiple effects of different biotic stressors on growth and vulnerability of forests subjected to the negative effects exerted by droughts.Este estudio ha sido financiado por los proyectos CGL2007- 66066-C04-02/BOS, CGL2008-04847-C02-01, CGL2011-26654 (MINECO), 387/2011 (Organismo Autónomo de Parques Nacionales) y PROCLIM (La Caixa-Gobierno de Aragón). Agradecemos la revisión realizada por dos revisores anónimos de una versión previa del texto. También queremos agradecer la ayuda prestada por todos los miembros del Laboratorio de Sanidad Forestal de Mora de Rubielos (Gobierno de Aragón), a todo el personal del Parque Nacional de Ordesa y Monte Perdido, al servicio de parques y jardines del Ayuntamiento de Zaragoza (Montserrat Hernández y José Bellosta), y a todos los APNs que nos han ayudado en las numerosas jornadas de campo. Finalmente, agradecemos a nuestros compañeros del IPE (CSIC) J.D. Galván y A.Q. Alla por su ayuda en los muestreos y la discusión de las ideas presentadas.Peer Reviewe

Recent increase in tree damage and mortality and their spatial dependence on drought intensity in Mediterranean forests

Resumen de la comunicación oral presentada en XVI Congreso Nacional de la AEET, 16 al 20 de octubre de 2023, Universidad de AlmeríaLand-use and climate change are leading to more frequent and intense tree damage and mortality events. Drought-induced tree mortality is occurring worldwide leading to broad-scale events, but the spatial patterns of tree damage and mortality, their underlying drivers and their variation over time is largely unknown. We investigated the spatial patterns of tree damage and mortality across Mediterranean forests of the Iberian Peninsula, the underlying effects of competition and climate, and how the spatial patterns and relationships with underlying drivers changed over time. We used the Spanish Forest Inventory to analyse the autocorrelation in tree damage and mortality across forest types, hurdle-gamma models to quantify the effect of competition and climate on tree damage and mortality, and cross-correlograms to assess their spatial dependence and its change over time. We observed a greater magnitude and a stronger autocorrelation in tree damage than mortality, with positive aggregation up to 20 kilometres. There was a spatial dependence between tree damage and mortality with their drivers, with spatial aggregation increasing with water availability, drought intensity and competition. The spatial dependence of tree damage and mortality with the underlying drivers increased over time, particularly for drought intensity. Our results suggest that the combined effect of intense competition and drought could favour more extensive die-off and tree mortality events, providing key information for identifying vulnerable areas and the planning of adaptation measures

Widespread spring phenology effects on drought recovery of Northern Hemisphere ecosystems

The time required for an ecosystem to recover from severe drought is a key component of ecological resilience. The phenology effects on drought recovery are, however, poorly understood. These effects centre on how phenology variations impact biophysical feedbacks, vegetation growth and, ultimately, recovery itself. Using multiple remotely sensed datasets, we found that more than half of ecosystems in mid- and high-latitudinal Northern Hemisphere failed to recover from extreme droughts within a single growing season. Earlier spring phenology in the drought year slowed drought recovery when extreme droughts occurred in mid-growing season. Delayed spring phenology in the subsequent year slowed drought recovery for all vegetation types (with importance of spring phenology ranging from 46% to 58%). The phenology effects on drought recovery were comparable to or larger than other well-known postdrought climatic factors. These results strongly suggest that the interactions between vegetation phenology and drought must be incorporated into Earth system models to accurately quantify ecosystem resilience.X.W. was financially supported by the National Natural Science Foundation of China (grant nos. 41922001 and 42171050), the Second Tibetan Plateau Scientific Expedition and Research Program (grant no. 2019QZKK0306) and the National Key Research and Development Program of China (grant no. 2022YFF0801800). S.A.K. was supported by the US Department of Energy Environmental System Science program grant no. DE-SC0022052. A.G. is supported by the Ramon y Cajal Program of the Spanish MICINN under grant RyC2020- 030647-I, and by CSIC under grant PIE-20223AT003. W.K.S. and W.Z. were supported by the NASA Carbon Cycle and Ecosystems Program under grant 80NSSC21K1709.Peer reviewe

Tree growth response to drought partially explains regional-scale growth and mortality patterns in Iberian forests

Tree-ring data has been widely used to inform about tree growth responses to drought at the individual scale, but less is known about how tree growth sensitivity to drought scales up driving changes in forest dynamics. Here, we related tree-ring growth chronologies and stand-level forest changes in basal area from two independent data sets to test if tree-ring responses to drought match stand forest dynamics (stand basal area growth, ingrowth, and mortality). We assessed if tree growth and changes in forest basal area covary as a function of spatial scale and tree taxa (gymnosperm or angiosperm). To this end, we compared a tree-ring network with stand data from the Spanish National Forest Inventory. We focused on the cumulative impact of drought on tree growth and demography in the period 1981–2005. Drought years were identified by the Standardized Precipitation Evapotranspiration Index, and their impacts on tree growth by quantifying tree-ring width reductions. We hypothesized that forests with greater drought impacts on tree growth will also show reduced stand basal area growth and ingrowth and enhanced mortality. This is expected to occur in forests dominated by gymnosperms on drought-prone regions. Cumulative growth reductions during dry years were higher in forests dominated by gymnosperms and presented a greater magnitude and spatial autocorrelation than for angiosperms. Cumulative drought-induced tree growth reductions and changes in forest basal area were related, but initial stand density and basal area were the main factors driving changes in basal area. In drought-prone gymnosperm forests, we observed that sites with greater growth reductions had lower stand basal area growth and greater mortality. Consequently, stand basal area, forest growth, and ingrowth in regions with large drought impacts was significantly lower than in regions less impacted by drought. Tree growth sensitivity to drought can be used as a predictor of gymnosperm demographic rates in terms of stand basal area growth and ingrowth at regional scales, but further studies may try to disentangle how initial stand density modulates such relationships. Drought-induced growth reductions and their cumulative impacts have strong potential to be used as early-warning indicators of regional forest vulnerability.This study was financially supported by Xunta de Galicia, Grant/Award Number PGIDIT06PXIB502262PR, GRC GI-1809; INIA, Grant/Award Number RTA2006-00117; CANOPEE, 2014-2020-FEDER funds, Spanish Science Ministry RTI2018-096884-B-C31, RTI2018-096884-B-C33, AGL2017-83828-C2-2R, RTI2018-096884-B-C3,1 and RTI2018-096884-B-C32 projects. Gabriel Sangüesa-Barreda was supported by a “Juan de la Cierva-Formación” grant from MINECO (FJCI 2016-30121). Antonio Gazol and Paloma Ruiz-Benito were supported by a project “2018 Leonardo Grant for Researchers and Cultural Creators, BBVA Foundation.” Ana-Maria Hereş was supported by the project PN-III-P1-1.1-TE-2019-1099 financed by the Romanian Ministry of Education and Research through UEFISCDI. Raúl Sánchez-Salguero was supported by VULBOS project (UPO-1263216, FEDER Funds, Andalusia Regional Government, Consejería de Economía, Conocimiento, Empresas y Universidad 2014-2020). Paloma Ruiz-Benito was supported by the Community of Madrid Region under the framework of the multi-year Agreement with the University of Alcalá (Stimulus to Excellence for Permanent University Professors, EPU-INV/2020/010) and the University of Alcalá “Ayudas para la realización de Proyectos para potenciar la Creación y Consolidación de Grupos de Investigación.” Andrea Hevia was supported by PinCaR project (UHU-1266324, FEDER Funds, Andalusia Regional Government, Consejería de Economía, Conocimiento, Empresas y Universidad 2014-2020).Peer reviewe

The performance of Mediterranean subshrubs depends more on microsite than on regional climate conditions

[EN] Question: To what extent do small-scale biotic interactions and local variations determine the spatial pattern and plant performance of three Mediterranean subshrubs growing under contrasting climatic conditions? Location: Three sites subjected to climatically contrasting conditions in Aragón (Javalambre, cold site; Bernués, mesic site; Monegros, xeric site), NE Spain. Methods: The three species studied wereHormathophylla spinosa,Ononis fruticosa and Linum suffruticosum in the cold, mesic and xeric sites, respectively. Two transects (100 9 5 m) were located in each site, one in the upper part and another in the north-oriented slope of a hill. All adult individuals located within each transect of each species were tagged, spatially located and their size measured (height and crown diameter).We also estimated visually the cover of other woody species around each subshrub individual to study inter-specific interactions. We estimated the age of all subshrub individuals by counting annual rings in basal wood sections. To investigate the spatial patterns and plant performance of the three species we used spatial point pattern analyses and structural equation modelling. Results: The density of individuals and the spatial pattern of the species varied greatly among and within sites.H. spinosaandL. suffruticosumshowed higher variability in density among transects and a more aggregated spatial pattern than O. fruticosa. Similarly, the three subshrubs presented different architecture and performed differently in the two transects studied for each species. All three species presented higher growth rates in the upper part of the hill than in the north-oriented slope. Inter-specific interactions were more important than intraspecific ones in determining the performance of the three subshrubs, and were more intense in the case of H. spinosa and L. suffruticosum than in the case of O. fruticosa. Conclusions: Our results demonstrate that the spatial patterns of the three species studied varied within sites as a function of local environmental conditions. Moreover, plant–plant interactions can play an important role in explaining subshrub spatial patterns and performance in Mediterranean ecosystems. Inter- and intra-specific interactions acting at local scales should be considered for understanding the responses of Mediterranean subshrubs to regional climate.Antonio Gazol is supported by the ERMOS programme (co-funded by Marie Curie Actions) Grant nr. 14. This work was supported by the research project CGL2008- 04847-C02-01/BOS financed by the Spanish Commission of Science and Technology and FEDER. J.J.C. acknowledges the support of ARAID. We thank G. Sangu¨esa-Barreda and H. A. Chaparro for their brave help in the field and C. Sancho for advice on histological analyses. We also thank J. Price for revising the English in previous versions of this manuscript.Peer Reviewe

Mediterranean dwarf shrubs and coexisting trees present different radial-growth synchronies and responses to climate

[EN] Due to their diversity and dominance in environmentally harsh sites, Mediterranean dwarf shrubs are a valuable tool to understand the consequences of climatic variability on radial growth in woody plants. We evaluate the dendrochronological potential of three Mediterranean dwarf shrubs versus three coexisting tree species inhabiting cold- (Hormathophylla spinosa vs. Pinus sylvestris), mesic- (Ononis fruticosa vs. Abies alba), and xeric sites (Linum suffruticosum vs. Pinus halepensis). Cross-sectional wood sections of the three shrub species and cores in the case of trees were visually cross-dated and ring-widths were measured and converted into residual growth indices. We used linear mixed-effects models to assess how growth indices respond to local factors and climatic variables. The radial growth of the three dwarf shrub species was more asynchronous, i. e., ring-width series differed among conspecific individuals, than that of coexisting tree species. Growth asynchrony was higher for H. spinosa than for O. fruticosa and L. suffruticosum. Similarly, the ring-width series of O. fruticosa and L. suffruticosum was strongly correlated with that of coexisting tree species, while growth series of H. spinosa and P. sylvestris was not related at all. The growth of the three dwarf shrub species was influenced by the regional climatic conditions, but to a lesser degree than coexisting tree species. The highest responsiveness of growth to climate was observed in Mediterranean dwarf shrubs from xeric sites. However, local conditions are also major drivers of growth in Mediterranean dwarf shrubs as indicated by the stronger asynchrony in ring formation of these species as compared with coexisting trees, particularly in cold sites. © 2012 Springer Science+Business Media B.V.Antonio Gazol is supported by the ERMOS programme (co-founded by Marie Curie Actions), Grant number 14. This work has been supported by research projects CGL2008-04847-C02-01/BOS and CGL2011-26654 financed by the Spanish Commission of Science and Technology and FEDER. J. Julio Camarero acknowledges the support of ARAID. We thank G. Sanguesa and H. A. Chaparro for their brave help in the field, and M.C. Sancho for her advice in the laboratoryPeer Reviewe

La biodiversidad es inversamente proporcional al tamaño del país

12 páginas.- Presentación elaborada para las III Jornadas IPErinas, celebradas el 11 de diciembre de 2014.Peer reviewe

Attributing forest responses to global-change drivers: Limited evidence of a CO2-fertilization effect in Iberian pine growth

© 2015 John Wiley & Sons Ltd. Aim: Forest responses to global-change drivers such as rising atmospheric CO2 concentrations (Ca), warming temperatures and increased aridification will depend on tree species and site characteristics. We aim to determine if rising Ca enhances growth of coexisting pine species along broad ecological gradients in a drought-prone area. Location: Iberian Range, Spain. Methods: We sampled 557 trees of five pine species encompassing a wide climatic gradient and measured their radial growth. We used nonlinear flexible statistics (generalized additive mixed models) to characterize growth trends and relate them to Ca, temperature and water balance. Results: The sites most responsive to the growing-season water balance were dominated by Pinus pinaster and Pinus nigra at low elevations, whereas those most responsive to temperatures were high-elevation Pinus sylvestris and Pinus uncinata stands. From 1950 onwards, most sites and species showed decreasing radial growth trends. Growth trends were coherent with a CO2-related fertilization effect only in one P. sylvestris site. Main conclusions: We found little evidence of growth stimulation of Iberian pine forests due to rising Ca. The results indicated that any positive effect of a Ca-induced growth increase was unlikely to reverse or cancel out the drought-driven trends of reduced growth in most Mediterranean pine forests. Further assessments of CO2-fertilization effects on forest growth should be carried out in sites where climatic stressors such as drought do not override the effects of rising Ca on forest growth.We thank the referees for improving a previous version of the manuscript. We are particularly indebted to all the support provided by the people from the “Laboratorio de Sanidad Forestal” (Mora de Rubielos, Aragón Government), particularly Rodolfo Hernández, Juan Manuel Gil, Miguel Ros, Víctor Pérez Fortea and Araceli Órtiz. We also thank Melissa Hoffer and Justin Waito for their help with laboratory work. Antonio Gazol is supported by a Postdoctoral grant from MINECO (Contrato Formacion Postdoctoral MINECO – FPDI 2013–16600). This study was supported by projects CGL2011–26654 (Spanish Ministry of Economy and Competitiveness), 387/2011 and 1032S/2013 (Spanish Ministry of Agriculture and Environment, OAPN, Spain). The research was also partly funded by the Canada Research Chair Program and a NSERC discovery grant to J.C. Tardif. We are also indebted to all people who helped us sampling in the field. We thank AEMET, CRU and ESRL-NOAA for providing climatic and CO2 data.Peer Reviewe