Efectos especie-específicos en la distribución espacial de variables edáficas en bosques mixtos mediterráneos

6 páginas, 3 figuras, 2 tablas, 11 referencias.-- Actas de la III Reunión del Grupo de Trabajo sobre Ecología, Ecofisiología y Suelos Forestales. Investigación sobre Ecología y Suelos Forestales: Aportaciones a y desde la Gestión Forestal, celebrada del 9-11, noviembre, 2011, en Huelva, España.Las especies arbóreas y el matorral regulan la disponibilidad de diferentes recursos (e.g. luz, humedad, nutrientes) en los sistemas forestales. La capacidad de modificación del medio es generalmente característica de cada especie, por lo que el funcionamiento del ecosistema va a depender en gran medida de la composición de la comunidad vegetal. El conocimiento de estos procesos de retroalimentación son fundamentales para entender la dinámica del bosque. El presente estudio se desarrolla en el Parque Natural de Los Alcornocales (Cádiz-Málaga). El objetivo de este trabajo es estudiar la variabilidad espacial de las características físico-químicas del suelo y su relación con el dosel arbóreo en seis parcelas de bosque mixto, analizando muestras superficiales (0-10 cm) de suelo recolectadas en las seis parcelas. Se relacionan las variables edáficas con la presencia en el dosel de una determinada especie arbórea y se caracteriza la intensidad de su "huella" edáfica. Existe un efecto de las especies de Quercus en el contenido de nutrientes en el suelo, detectándose a su vez un incremento en el contenido de fósforo en las vecindades de alcornoque. Concluimos que las distintas especies arbóreas coexistentes en los bosques mixtos de Los Alcornocales modifican de forma diferencial las características edáficas.Este estudio ha sido financiado por una beca FPI a B.I. del Ministerio de Ciencia e Innovación, el proyecto INTERBOS (CGL2008-450-C03-01) y los fondos europeos FEDER.Peer reviewe

Tree species-specific effects on soil properties in declining mixed oak

Póster presentado al 4th International Congress EUROSOIL 2012.-- Celebrado del 2 - 6 julio 2012, en Bari, Italia.Proyecto coordinado del Plan Nacional de I+D+i Ministerio de Ciencia e Innovación. CGL2008-04503-C03-01Peer reviewe

Dinámicas de vecindad y regeneración del bosque

24 páginas, 3 figuras, 3 tablas, 33 referencias.Los árboles modifican el suelo en su entorno inmediato tanto a través del aporte directo de biomasa como de sus efectos indirectos al producir cambios en las condiciones abióticas del medio (luz, humedad). El árbol adulto deja por tanto una huella característica en el ambiente de su vecindad que puede afectar a la dinámica de la población y a la distribución de las especies. En el presente trabajo se estudia la demografía de plántulas de dos de las principales especies arbóreas de los bosques del Campo de Gibraltar: Quercus suber y Quercus canariensis, en tres parcelas de estudio localizadas en la zona. Las parcelas se caracterizan por presentar signos de decaimiento del alcornoque, uno de los principales problemas de conservación que afectan al Parque Natural de los Alcornocales. Se analiza la relación de las características de la vecindad con el crecimiento, emergencia y supervivencia de plántulas, con especial atención al efecto que los árboles enfermos y muertos de alcornoque tienen sobre la regeneración. Resultados preliminares muestran cómo existe un efecto tanto especie-específico como del estado de decaimiento del alcornoque en la regeneración de estos bosques. Ante los cambios en las condiciones actuales como consecuencia del Cambio Global, el entendimiento de las dinámicas de vecindad en el bosque será de gran utilidad para la gestión y conservación de nuestros bosques.Peer Reviewe

Across-scale patterning of plant–soil–pathogen interactions in Quercus suber decline

12 páginas.-- 4 figuras.-- 3 tablas.-- 80 referencias.-- The online version of this article (doi:10.1007/s10342-017-1064-1) contains supplementary material, which is available to authorized usersForests worldwide have been recently affected by severe decline and mortality, while our understanding about forest decline across spatial scale is still limited. In this work, we study how Quercus suber trees adjust their physiology, in terms of water use efficiency and secondary growth, to pathogen-induced oak decline at the whole-tree, local and landscape scales. This work was carried out in Mediterranean mixed forests where their dominant key species Q. suber is affected by a severe decline and mortality induced by the exotic soil-borne pathogen Phytophthora cinnamomi. Significant differences were not observed between defoliated and healthy trees, either in terms of water use efficiency or growth at the whole-tree scale. We found that limiting conditions, such as low soil depth and high pathogen abundance, induced trees to higher water use efficiency at local and landscape scales. Overall our findings point out that Q. suber trees subjected to soil drought and root pathogens increase water use efficiency to some extent, while this response might not be enough for the trees to overcome the physiological stress associated with the pathogen-induced dieback. We discuss the complex way by which adult Q. suber trees physiologically respond to P. cinnamomi-induced mortality, improving our understanding of the likely consequences of chronic oak decline in the future.This research was supported by the Ministerio de Ciencia e Innovación (MICINN) projects CGL2011-26877 (RETROBOS) and CGL2014-56739-R (INTERCAPA). J.M.A. was supported by a Formación de Profesorado Universitario FPU-Ministerio de Educación y Ciencia grant (AP2010-0229).Peer reviewe

Plant-soil feedbacks in declining Quercus suber forests

Póster presentado en el citado Congreso, celebrado del 30 de septiembre-2 de octubre 2013, en Baeza (Jaén), España.In a plant-soil feedback process, plant species change the chemical, physical or biological soil properties, which in turn modifies the performance of the own plant community. Many recent studies have demonstrated that these feedbacks play an important role in determining the abundance and coexistence of species in plant communities.Peer reviewe

The role of plant-soil feedbacks in succesional dynamics of declining Quercus forests

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Growth and water use efficiency of Quercus suber trees affected by Phytophthora cinnamomi. Does scale matter?

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Les modifications du sol associés á le dépérissement du chene-liege génerent des effets négatifs sur les semis co-spécifiques

Trabajo presentado al citado Congreso, celebrado del 8-11 octubre 2013, en Domaine de Bousquety Belambra, L'Isle-sur-la-Sorgue (Vaucluse), Francia. Los autores pertenecen al Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS-CSIC)y al Departamento de Agronomía, Patología Agroforestal de la Universidad de Córdoba, España.[EN]: Plant species can change biotic or abiotic soil properties with implications in growth and survival for the plant community. These plant-soil feedback processes could play an important role in determining the abundance and coexistence of species in plant communities. We evaluated the existence of plant-soil feedback processes in two declining Quercus suber forests at SW Spain: open woodland with high abundance of the pathogen Phytophthora cinnamomi, and a closed forest with low P. cinnamomi abundance. A greenhouse experiment was conducted by sowing Q. suber acorns in pots with soils collected under adults Q. suber of three health categories: healthy, defoliated, and dead. Half of the soils were sterilized to separate abiotic from biotic effects on seedling performance. After 4 months, we measured shoot and root dry biomass in all the seedlings. In the open woodland, seedling growth did not vary among soil types. However, it was positively affected by sterilization, suggesting the existence of a net negative effect of soil pathogen community on seedling growth. In the closed forest, seedling growth in soils under dead trees was much lower than in soils under healthy trees. Sterilization did not affect seedling growth at this site, suggesting that soils effects were mainly abiotic. Overall, our results revealed that the decline and mortality of Q. suber trees induce biotic and abiotic soil changes that decrease the growth of conspecific seedlings. These changes could imply a competitive disadvantage for this species, with negative consequences for the maintenance of its abundance.[FR]: Les plantes peuvent modifier les propriétés biotiques ou abiotiques du sol, avec des implications pour la croissance et la survie de la communauté végétale. Ces mécanismes de rétroaction plantes-sol pourraient jouer un rôle important dans la détermination de l'abondance et de la coexistence des espèces dans les communautés végétales. Nous avons évalué l'existence de mécanismes de rétroaction plantes-sol dans deux forêts dépérissantes de Quercus suber au sud de l'Espagne: un bois ouvert avec une grande abondance de Phytophthora cinnamomi et une forêt dense avec une faible abondance de P. cinnamomi. Une expérience en serre a été réalisée avec des glands de Q. suber semés dans des pots avec des sols prélevés sous des Q. suber adultes des trois catégories: sains, défoliés et morts. La moitié des sols a été stérilisée pour distinguer les effets abiotiques des biotiques sur la performance des semis. Après 4 mois, nous avons mesuré la biomasse sèche des pousses et des racines de tous les plants. Dans le bois ouvert la croissance des semis n'a pas varié selon le type de sol. Cependant, elle a élé favorisée par la stérilisation, ce qui suggère l'existence d'un effet net négatif de la communauté pathogène du sol sur la croissance des semis. Dans la forêt dense, la croissance des plants dans les sols sous les arbres morts était plus faible que dans les sols sous les arbres sains. La stérilisation n'a pas affecté la croissance des semis sur ce sol, ce qui suggère que les effets ont été principalement abiotiques. Nos résultats ont révélé que le dépérisement et la mortalité de Q. suber induisent des changements biotiques et abiotiques du sol qui diminuent la croissance des plants co-spécifiques. Ces changements pourraient impliquer un désavantage pour cette espèce, avec des conséquences négatives pour maintenir son abondance.Peer reviewe

Genetics, host range, and molecular and pathogenic characterization of Verticillium dahliae from sunflower reveal two differentiated groups in Europe

This article is part of the Research Topic: Advances in Oil Crops Research—Classical and New Approaches to Achieve Sustainable Productivity.-- Edited by: Dragana Miladinović, Johann Vollmann, Leire Molinero-Ruiz and Mariela Torres.Verticillium wilt and leaf mottle of sunflower, caused by the fungus Verticillium dahliae (Vd) has become a major constraint to sunflower oil production in temperate European countries. Information about Vd from sunflower is very scarce despite genetics, molecular traits and pathogenic abilities of fungal strains affecting many other crops being widely known. Understanding and characterizing the diversity of Vd populations in those countries where sunflowers are frequent and severely affected by the fungus are essential for efficient breeding for resistance. In this study, we have analyzed genetic, molecular and pathogenic traits of Vd isolates affecting sunflower in European countries. When their genetics was investigated, almost all the isolates from France, Italy, Spain, Argentina, and Ukraine were assigned to vegetative compatibility group (VCG) 2B. In Bulgaria, Turkey, Romania, and Ukraine, some isolates were assigned to VCG6, but some others could not be assigned to any VCG. Genotyping markers used for Vd affecting crops other than sunflower showed that all the isolates were molecularly identified as race 2 and that markers of defoliating (D) and non-defoliating (ND) pathotypes distinguished two well-differentiated clusters, one (E) grouping those isolates from Eastern Europe and the other (W) all those from the Western Europe and Argentina. All the isolates in cluster W were VCG2B, while the isolates in cluster E belonged to an unknown VCG or to VCG6. When the host range was investigated in the greenhouse, the fungus was highly pathogenic to artichoke, showing the importance of farming alternatives in the management of Verticillium attacks. Sunflower genotypes were inoculated with a selection of isolates in two experiments. Two groups were identified, one including the isolates from Western Europe, Argentina, and Ukraine, and the other including isolates from Bulgaria, Romania, and Turkey. Three pathogenic races were differentiated: V1, V2-EE (Eastern Europe) and V2-WE (Western Europe). Similarly, three differentials are proposed for race identification: HA 458 (universal susceptible), HA 89 (resistant to V2-EE, susceptible to V2-WE) and INRA2603 (susceptible to V2-EE, resistant to V2-WE). The diversity found in Vd affecting sunflower must be taken into account in the search for resistance to the pathogen for European environments of sunflower production.Financial support for this research was partially provided by the Spanish Ministry of Economy, Industry and Competitiveness (AGL2010-17909 and AGL2016-80483-R grants) and the European Regional Development Fund (ERDF).Peer reviewe