Seed dispersers, seed predators, and browsers act synergistically as biotic filters in a mosaic landscape

In this study, we analize the functional influence of animals on the plants they interact with in a mediterranean mountain. We hypothesise that seed dispersers, seed predators, and browsers can act as biotic filters for plant communities. We analyse the combined effects of mutualistic (seed dispersal) and antagonistic (seed predation, herbivory) animal interactions in a mosaic landscape of Mediterranean mountains, basing our results on observational and experimental field. Most of the dispersed seeds came from tree species, whereas the population of saplings was composed predominantly of zoochorous shrub species. Seed predators preferentially consumed seeds from tree species, whereas seeds from the dominant fleshy-fruited shrubs had a higher probability of escaping these predators. The same pattern was repeated among the different landscape units by browsers, since they browsed selectively and far more intensely on tree-species saplings than on the surrounding shrubs. In synthesis, our work identifies the major biotic processes that appear to be favoring a community dominated by shrubs versus trees because seed dispersers, predators, and herbivores together favored shrub dispersal and establishment versus trees.This work was supported by Ministerio de Ciencia e Innovación (Spanish Government) Project CGL2011-29910 to R.Z. and by EU Marie Curie Fellowship to L.M (FP7-2011-IEF-300825)

Efectos de la variación en el régimen de precipitación sobre la regeneración del bosque montano mediterráneo

Herrero A & Zavala MA, editores (2015) Los Bosques y la Biodiversidad frente al Cambio Climático: Impactos, Vulnerabilidad y Adaptación en España. Ministerio de Agricultura, Alimentación y Medio Ambiente, Madrid.Peer Reviewe

Environmental heterogeneity and the ecology of carnivorous plants: implications for conservation

En la cuenca mediterránea, la mayoría de las plantas carnívoras pertenecientes al género Pinguicula habitan las paredes húmedas de montañas calizas. Estos escenarios rocosos condicionan la ecología de las poblaciones situadas en distintos exposiciones (solana versus umbría). Las diferencias temporales en la floración entre plantas que crecen en distintos microhábitats, unido a las diferencias espaciales en la distribución y abundancia de las especies de polinizadores, provocan barreras al flujo genico vía polen entre microhábitats soleados y umbríos. Estos mecanismos ecológicos pueden actuar sinérgicamente con otros factores que limitan el flujo génico, como distancia geográfica y la compleja orografía de las montañas, favoreciendo la diferenciación local. Las poblaciones de Pinguicula vallisneriifolia muestran también diferentes abundancias y estructuras demográficas dependiendo del microhábitat donde crecen las plantas. El carácter perenne y la reproducción asexual de esta planta le permite ralentizar la extinción poblacional, incluso en ausencia de reclutamiento via plántula en los lugares secos y soleados. Sin embargo, con la actual tendencia hacia una mayor aridez, los escasos micrositios adecuados para la germinación y establecimiento de plántulas se desplazan hacia los sectores de las paredes más umbríos y húmedos, pero donde el desarrollo reproductivo está limitado por la escasez de luz. Para la conservación de esta planta carnívora hay que llevar a cabo medidas de manejo para mantener un número mínimo de nichos de regeneración efectivos. La conservación de P. vallisneriifolia pasa por mantener la riqueza de escenarios ecológicos (i.e., mantener poblaciones de sol versus de sombra), como parte de la variabilidad total a conservar, no solo geográfica, sino también de escenario microclimático.Most carnivorous plants belonging to the Pinguicula genus inhabit mountains in the Mediterranean basin. Pinguicula vallisneriifolia inhabits wet limestone rock walls and cliffs, being able to reproduce by seeds and asexually (by stolons and axillary buds). The complex orography of Mediterranean mountains favors sunny (hot and dry) and shady (cool and wet) contrasting expositions. Along the sun-shade gradient, there were variations in plant flowering phenology, as well as in animal species that interacted with the plants (prey, pollinators and kleptoparasites), even at a very restricted spatial scale. The ecological consequence is that the marked spatial variability in abiotic conditions results in a site-specific mosaic of plant-animal interactions, and hence of selective pressures of animals upon plants. Plant populations have also different demographic structures depending on the microhabitat (sunny, dry versus wet, shady). As a result, different demographic patterns appear on different localities or different habitats within the same locality: populations living in moist, shady patches show high proportions of seedlings as plants reproduce both sexually and asexually, resulting in viable populations. On the contrary, plants living in dry, sunny rocky substrates, despite sexual and asexual reproduction, have no seedling recruitment because of wet microsite limitation. These populations are, therefore, dominated by vegetative individuals. Practical guiadance are provided in order to preserve these microclimatically structured populations

Las interacciones planta-planta y planta-animal en el contexto de la sucesión ecológica

24 páginas, 2 cuadros, 6 figuras, 103 referencias. La publicación está en la Sección C: Interacciones, capítulo 13 de la 2ª edición. Colección Naturaleza y Parques Nacionales. Serie técnica. Existe una 1ª edición de 2004. Estas investigaciones no se hubieran podido llevar a cabo sin los permisos y facilidades para investigar en los espacios protegidos Parque Nacional de Sierra Nevada y Parque Natural de la Sierra de Baza, proporcionados por la Consejería de Medio Ambiente de la Junta de Andalucía.[EN]: Plant-plant and plant-animal interactions in the context of ecological succession. In Mediterranean environments, the regeneration of a great number of woody species, both tree and shrub, present a spatial pattern associated with established plants, suggesting a net positive balance in plant-plant interactions. In this chapter, from the perspective of successional process, we analyse the mechanisms and ecological consequences of the interactions between pioneer shrubs and tree seedlings, and between these and ungulate herbivores that consume these plants. Under stress situations, the environmental alteration caused by a neighbouring plant (in terms of microclimate, soil, protection from herbivores) can offer a benefit that exceeds the costs that any spatial proximity implies, favouring the development of facilitation between the pioneer shrubs and the seedlings of slow-growing woody species. The positive effect of shrubs on the regeneration of woody species need not to be restricted to only one demographic phase, nor to be generated by only one mechanism, but rather it may be manifested in several stages of recruitment. The spatial association with thorny or unpalatable plants enables more palatable woody species to establish themselves even in habitats where there is high and chronic herbivore pressure. Given that the Mediterranean woodlands can hardly regenerate in open areas for lack of water and/or excessive herbivory, either under the canopy of established trees for lack of light and/or excessive herbivory (or seed predation), the main regeneration niche for many tree species under a wide range of ecological conditions are pioneer plants, capable of colonizing precisely the sites with these conditions of stress and herbivory. A good shrub cover, both of pioneer species and of the intermediate stages of succession, is the best insurance to avoid soil erosion, to achieve natural regeneration of woodlands, and to boost the success of reforestation, since these species encourage progression towards more mature communities.[ES]: Las interacciones planta-planta y planta animal en el contexto de la sucesión ecológica. En ambientes mediterráneos, la regeneración de gran número de especies leñosas arbóreas y arbustivas presenta un patrón espacial asociado a plantas ya establecidas, lo que sugiere la existencia de un balance neto positivo de las interacciones planta- planta. En este capítulo analizamos los mecanismos y consecuencias ecológicas de las interacciones entre arbustos pioneros y plántulas de árboles, y entre éstas y los herbívoros ungulados que las consumen desde una perspectiva de proceso sucesional. En ambientes como los mediterráneos, donde las plantas suelen padecer situaciones de estrés, la modificación ambiental producida por una planta vecina (microclima, suelo, protección frente a herbívoros) puede ofrecer un beneficio que supere los costos que toda proximidad espacial conlleva, lo que favorece el desarrollo de interacciones de facilitación entre los arbustos pioneros y las plántulas de especies leñosas de crecimiento lento. El efecto positivo de los arbustos sobre la regeneración de especies leñosas no tiene por qué estar restringido a una sola fase demográfica, ni ser generado por un solo mecanismo, sino que puede manifestarse en varios estadíos del reclutamiento. La asociación espacial con plantas espinosas o poco palatables permite a las especies leñosas más palatables establecerse incluso en hábitats donde existe una presión de herbivoría elevada y crónica. Ya que el bosque mediterráneo apenas puede regenerarse en áreas abiertas por falta de agua y/o por exceso de herbivoría, ni bajo la copa de los árboles ya establecidos por falta de luz y/o exceso de depredadores de semillas o herbivoría, el nicho de regeneración principal para muchas especies arbóreas en una amplia gama de condiciones ecológicas es bajo las plantas pioneras, capaces de colonizar precisamente lugares con esas condiciones de estrés y herbivoría. Una buena cobertura de matorral, tanto de especies pioneras como de etapas intermedias de la sucesión, es el mejor seguro para evitar la erosión del suelo, conseguir la regeneración natural de los bosques, y mejorar el éxito de las reforestaciones, ya que dichas especies favorecen la progresión hacia comunidades más maduras.Las investigaciones expuestas en este capítulo han sido financiadas a través de los proyectos: FEDER 1FD97-0743-CO3-02, REN2001-4552-E y HETEROMED (REN 2002 4041/GLO y DINAMED CGL 2005-05830-CO3-03/BOS) del MCYT a R.Z y LGA, y a través de los proyectos GV94-2311 y FEDER 1FD97-0551 y AGL2001-1061 a PG-F. Las investigaciones expuestas en este capítulo han sido financiadas a través de los proyectos: FEDER 1FD97-0743-CO3-02, REN2001-4552-E y HETEROMED (REN 2002 4041/GLO y DINAMED CGL 2005-05830-CO3-03/BOS) del MCYT a R.Z y LGA, y a través de los proyectos GV94-2311 y FEDER 1FD97-0551 y AGL2001-1061 a PG-F.Peer reviewe

Implications of mistletoe parasitism for the host metabolome: A new plant identity in the forest canopy

Catalan Government, Grant/Award Number: SGR 2017-1005; European Research Council Synergy, Grant/Award Number: IMBALANCE-P ERC-2013-SyG-610028; Ministerio de Ciencia e Innovacion, Grant/Award Numbers: CLAVINOVA CGL2011-29910, ELEMENTALSHIFT PID2019-110521GB-I00; Ministerstvo Skolstvi, Mladeze a Te. lovychovy, Grant/Award Number: SustES CZ.02.1.01/0.0/0.0/16_019/0000797; Secretaria de Estado de Investigaci ~on, Desarrollo e Innovaci~on, Grant/Award Number: BES-2012-057125Mistletoe–host systems exemplify an intimate and chronic relationship where mistletoes represent protracted stress for hosts, causing long-lasting impact. Although host changes in morphological and reproductive traits due to parasitism are well known, shifts in their physiological system, altering metabolite concentrations, are less known due to the difficulty of quantification. Here, we use ecometabolomic techniques in the plant–plant interaction, comparing the complete metabolome of the leaves from mistletoe (Viscum album) and needles from their host (Pinus nigra), both parasitized and unparasitized, to elucidate host responses to plant parasitism. Our results show that mistletoe acquires metabolites basically from the primary metabolism of its host and synthesizes its own defence compounds. In response to mistletoe parasitism, pines modify a quarter of their metabolome over the year, making the pine canopy metabolome more homogeneous by reducing the seasonal shifts in topdown stratification. Overall, host pines increase antioxidant metabolites, suggesting oxidative stress, and also increase part of the metabolites required by mistletoe, which act as a permanent sink of host resources. In conclusion, by exerting biotic stress and thereby causing permanent systemic change, mistletoe parasitism generates a new host-plant metabolic identity available in forest canopy, which could have notable ecological consequences in the forest ecosystem.Catalan Government SGR 2017-1005European Research Council Synergy IMBALANCE-P ERC-2013-SyG-610028Instituto de Salud Carlos III Spanish Government European Commission CLAVINOVA CGL2011-29910ELEMENTALSHIFT PID2019-110521GB-I00Ministerstvo Skolstvi, Mladeze a Telovychovy SustES CZ.02.1.01/0.0/0.0/16_019/0000797Secretaria de Estado de Investigacion, Desarrollo e Innovacion BES-2012-05712

Mistletoe generates non-trophic and trait-mediated indirect interactions through a shared host of herbivore consumers

Indirect interactions emerge among a wide range of herbivores sharing the same plant resource. Consumers usually belong to different trophic guilds, from folivores and sapsuckers to parasitic plants. We propose that mistletoes parasitizing pines could play a key role acting as herbivores on host pines and coming indirectly into competition with other herbivores feeding on the same host. Changes caused by mistletoes on its host have been well studied, but its effects running across trophic webs remain unrevealed. In this study, we investigate the effect of European mistletoe (Viscum album subsp. austriacum) on the host-feeding herbivores via trait-mediated indirect interactions (TMIIs) across their shared pine host (Pinus nigra subsp. salzmannii). We performed field and laboratory experiments, and analyzed the net effect of different mistletoe parasite loads on three host-phytophagous species: the sapsucker Cinara pini (Aphididae), the winter folivore Thaumetopoea pityocampa (Thaumetopoeidae), and the summer folivore Brachyderes sp. (Curculionidae), all being members of different functional feeding groups (FFGs). We summarize the mistletoe–host–herbivore interactions by means of a TMII, where mistletoe parasitism causes non-trophic links and detrimental indirect interactions on pine-feeding herbivores across its shared host, suggesting a worsening of host quality as food. These indirect interactions vary according to three parameters. First, the intensity has a non-proportional relation with parasite load, showing an impact threshold on highly parasitized pines. Second, the movement capacity of insect herbivores determines their response, by decreasing the abundance of herbivores with low movement ability (aphids and pine processionary caterpillars) while altering the behavior (plant selection) of more mobile herbivores (pine weevils). Finally, FFG determines the intensity of mistletoe parasitism effects, folivores being more responsive than sapsuckers. Overall, mistletoe generates non-trophic interaction linkages in the forest able to modify community structure by becoming a nexus of the entire herbivore community of the pine canopy.This study was supported by project CLAVINOVA CGL2011-29910 to Regino Zamora from the Spanish Ministry of Science and Innovation, and FPI predoctoral grant BES-2012-057125 to Alba Lázaro- González from the Spanish Ministry of Economy and Competitiveness

Colonization Pattern of Abandoned Croplands by Quercus pyrenaica in a Mediterranean Mountain Region

Land abandonment is a major global change driver in the Mediterranean region, where anthropic activity has played an important role in shaping landscape configuration. Understanding the woodland expansion towards abandoned croplands is critical to develop effective management strategies. In this study, we analyze the colonization pattern of abandoned croplands by Quercus pyrenaica in the Sierra Nevada mountain range (southern Spain). We aimed to assess differences among populations within the rear edge of the Q. pyrenaica distribution. For this purpose, we characterized (i) the colonization pattern of Q. pyrenaica, (ii) the structure of the seed source (surrounding forests), and (iii) the abundance of the main seed disperser (Eurasian jay, Garrulus glandarius). The study was conducted in five abandoned croplands located in two representative populations of Q. pyrenaica located on contrasting slopes. Vegetation plots within three habitat types (mature forest, edge-forest and abandoned cropland) were established to compute the abundance of oak juveniles. The abundance of European jay was determined using data of bird censuses (covering 7 years). Our results indicate that a natural recolonization of abandoned croplands by Q. pyrenaica is occurring in the rear edge of the distribution of this oak species. Oak juvenile abundance varied between study sites. Neither the surrounding-forest structure nor the abundance of jays varied significantly between study sites. The differences in the recolonization patterns seem to be related to differences in the previous- and post-abandonment management.LIFE-ADAPTAMED (LIFE14CCA/ES/000612) projectMIGRAME Project (Excellence Research Group Programme of the Andalusian Government (RNM 6734)eLTER H2020 projec

Species, site and seasonal variation in leaf-chemistry diversity of woody mediterranean plants

This study analyses the biochemical diversity, under field conditions, of 10 important woody-plant species of south-eastern Spain, belonging to 7 families. We describe differences between species and between sites (two mountain ranges), as well as the seasonal variability of three chemical characteristics related to plant nutritional value (nitrogen content, phenols and tannins). Our results reveal that the plants studied differed in their chemical characteristics between species, between times, and between sites. This high variability in the plant chemical features suggests that the species-specific strategies can be as much or even more important to characterize the chemical plant quality as food than the presumed responses depending on the current general theories. Mediterranean mountain vegetation is highly variable in the temporal and spatial distribution of leaf-quality characteristics, due both to the internal process of tissues maturation as well as to environmental variation and specific differences. All these sources of variability create a diverse and changing chemical landscape in which herbivores have to select their diet, not only between species, but also between different times and sitesLa présente étude analyse, dans les conditions du terrain, la diversité biochimique de 10 plantes ligneuses importantes, appartenant à 7 familles, du sud-est de l'Espagne. Sont décrites les différences entre espèces et entre sites (deux chaînes de montagne), de même que la variabilité saisonnière, de trois caractéristiques chimiques liées à la valeur nutritive des plantes (teneur en azote, phénols et tannins). Les résultats révèlent que les caractéristiques chimiques des plantes étudiées diffèrent selon l'espèce, la saison et le site. Cette grande variabilité chimique suggère que les stratégies propres aux espèces peuvent être autant sinon plus importantes que les réponses présumées découlant des théories habituelles pour caractériser la qualité chimique des plantes en tant qu'aliment. La végétation montagnarde méditerranéenne est hautement variable en ce qui concerne la distribution temporelle et spatiale des caractéristiques de la qualité nutritionnelle foliaire, en raison à la fois du processus interne de maturation des tissus, de la variation environnementale et des différences spécifiques. Toutes ces sources de variabilité créent un paysage chimique divers et changeant dans lequel les herbivores doivent sélectionner leur régime alimentaire, en fonction du temps et du site