Phylogenetic relatedness as a tool in restoration ecology: a meta-analysis

7 pages, 1 figure, 2 tables, 52 references.Biotic interactions assembling plant communities can be positive (facilitation) or negative (competition) and operate simultaneously. Facilitative interactions and posterior competition are among the mechanisms triggering succession, thus representing a good scenario for ecological restoration. As distantly related species tend to have different phenotypes, and therefore different ecological requirements, they can coexist, maximizing facilitation and minimizing competition. We suggest including phylogenetic relatedness together with phenotypic information as a predictor for the net effects of the balance between facilitation and competition in nurse-based restoration experiments. We quantify, by means of a Bayesian meta-analysis of nurse-based restoration experiments performed worldwide, the importance of phylogenetic relatedness and life-form disparity in the survival, growth and density of facilitated plants. We find that the more similar the life forms of neighbouring plants are the greater the positive effect of phylogenetic distance is on survival and density. This result suggests that other characteristics beyond life form are also contained in the phylogeny, and the larger the phylogenetic distance, the less is the niche overlap, and therefore the less is the competition. As a general rule, we can maximize the success of the nurse-based practices by increasing life-form disparity and phylogenetic distances between the neighbour and the facilitated plant.This work was funded by AECID (Projects A017475/08, A023461/09), DGAPA-UNAM (Project IN-224808-3) and CYTED (Acción 409AC0369).Peer reviewe

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

Maximum likelihood methods and their application in neighbourhood models

Los métodos de máxima verosimilitud (MMV) ofrecen un marco alternativo a la estadística frecuentista convencional, alejándose del uso del p-valor para el rechazo de una única hipótesis nula y optando por el uso de las verosimilitudes para evaluar el grado de apoyo en los datos a un conjunto de hipótesis alternativas (o modelos) de interés para el investigador. Estos métodos han sido ampliamente aplicados en ecología en el marco de los modelos de vecindad. Dichos modelos usan una aproximación espacialmente explícita para describir procesos demográficos de plantas o procesos ecosistémicos en función de los atributos de los individuos vecinos. Se trata por tanto de modelos fenomenológicos cuya principal utilidad radica en funcionar como herramientas de síntesis de los múltiples mecanismos por los que las especies pueden interactuar e influenciar su entorno, proporcionando una medida del efecto per cápita de individuos de distintas características (ej. tamaño, especie, rasgos fisiológicos) sobre los procesos de interés. La gran ventaja de aplicar los MMV en el marco de los modelos de vecindad es que permite ajustar y comparar múltiples modelos que usen distintos atributos de los vecinos y/o formas funcionales para seleccionar aquel con mayor soporte empírico. De esta manera, cada modelo funcionará como un “experimento virtual” para responder preguntas relacionadas con la magnitud y extensión espacial de los efectos de distintas especies coexistentes, y extraer conclusiones sobre posibles implicaciones para el funcionamiento de comunidades y ecosistemas. Este trabajo sintetiza las técnicas de implementación de los MMV y los modelos de vecindad en ecología terrestre, resumiendo su uso hasta la fecha y destacando nuevas líneas de aplicación.Maximum likelihood methods (MLM) offer an alternative framework to the traditional frequentist approach of data analysis, where the use of p-values to reject a single null (usually trivial) hypothesis is replaced by the use of likelihoods to evaluate the support in the data for a set of alternative working hypotheses of scientific relevance. These methods have been widely applied in the ecological framework of the neighbourhood models. These models use a spatially-explicit approach to describe demographic or ecosystem processes as a function of the attributes of neighbouring plants. They are therefore phenomenological models that serve as a tool of synthesis of the multiple mechanisms by which species can interact and modify its immediate environment, offering an estimate of the per-capita influence of individuals of different characteristics (e.g. size, species, functional traits) on the processes of study. A fundamental advantage of applying MMV in the framework of the neighbourhood models is that it allows fitting and comparing multiple models that use contrasting neighbour attributes and/or functional forms to select the one with the largest empirical support. In this way, each model works as a “virtual experiment” to answer questions related with the magnitude and spatial extent of the effects of different coexisting species and their potential implications for the function of communities and ecosystems. This paper reviews the use of MMV and neighborhood models in terrestrial ecology, synthesizing the state of the art and emphasizing new avenues of application

Climate change impact on the population dynamics of exotic pathogens: The case of the worldwide pathogen Phytophthora cinnamomi

Worldwide, Mediterranean-climate type forests are seriously threatened by climate change and Phytophthora cinnamomi, an extremely aggressive soilborne pathogen listed among the 100 worst invasive alien species. This study examines for first time the effects of annual and seasonal changes in temperature and rainfall under different climatic scenarios on P. cinnamomi dynamics in a Mediterranean forest naturally infested. We followed seasonally and during four years (2016–2020) P. cinnamomi abundance in the soil taking advantage of a climate change infrastructure that simulates a 30% rainfall reduction using rainout shelters and an increase in soil temperature using open top chambers. Seasonal abundance of P. cinnamomi was strongly linked to spring precipitation: the large inoculum density during this season suffered a strong decrease during the dry summer that was maintained until the next spring, despite of fall rains. Thus, inoculum density in spring may be considered the best indicator of the potential of P. cinnamomi infection in natural ecosystems. The two climatic treatments had significant effects on P. cinnamomi abundance, but only in some combinations of seasons and years. Rainfall exclusion had a negative effect on the spring abundance of P. cinnamomi mostly in wet years, causing a reduction as large as 30% in comparison with the control treatment. Meanwhile, warming effect varied from slightly negative in winter to positive in spring and early summer, causing increases as large as 31% in comparison with the control treatment. Overall, we provide novel experimental evidence suggesting that a drier climate might limit the abundance and activity of P. cinnamomi in water-limited forests, but that this negative effect might be at least partly counteracted by the positive effects of warming. These results also imply that P. cinnamomi represents an increasing threat under climate change for the conservation of forest ecosystems where water is not a limiting factor

Fine Scale Determinants of Soil Litter Fauna on a Mediterranean Mixed Oak Forest Invaded by the Exotic Soil-Borne Pathogen Phytophthora cinnamomi

16 páginas.-- 5 figuras.-- 1 tablas.-- 56 referencias.-- This article belongs to the Special Issue "Ecology and Management of Invasive Species in Forest Ecosystems".There is growing recognition of the importance of soil fauna for modulating nutrient cycling processes such as litter decomposition. However, little is known about the drivers promoting changes in soil fauna abundance on a local scale. We explored this gap of knowledge in a mixed oak forest of Southern Spain, which is under decline due to the invasion of the exotic soil-borne pathogen Phytophthora cinnamomi. Meso-invertebrate abundance found in soil litter was estimated at the suborder level. We then explored their statistical correlations with respect to light availability, tree and litter characteristics, and P. cinnamomi abundance. Oribatida and Entomobryomporpha were the most abundant groups of Acari and Collembola, respectively. According to their trophic level, predator and detritivore abundances were positively correlated while detritivores were, in turn, positively correlated with pathogen abundance and negatively influenced by light availability and tree defoliation. These overall trends differed between groups. Among detritivores, Diplopoda preferred highly decomposed litter while Oribatida and Psocoptera preferred darker environments and Poduromorpha were selected for environments with lower tree defoliation. Our results show the predominant role of light availability in influencing litter fauna abundances at local scales and suggest that the invasive soil-borne pathogen P. cinnamomi is integrated in these complex relationships.O.G. acknowledges postdoctoral financial support provided by the European Union Horizon research and innovation program under the Marie Sklodowska-Curie grant agreement No 661118-BioFUNC. O. G. also thanks research support from the Spanish Ministry of Economy and Competitiveness through the IMPLANTIN project (CGL2015-65346-R). L.G.A. acknowledges support from the MICINN project INTERCAPA (CGL-2014-56739-R)

An excess of niche differences maximizes ecosystem functioning

10 páginas.- 3 figuras.- 1 tabla.- 47 referencias.- Supplementary information is available for this paper at https://doi.org/10.1038/s41467-020-17960-5Ecologists have long argued that higher functioning in diverse communities arises from the niche differences stabilizing species coexistence and from the fitness differences driving competitive dominance. However, rigorous tests are lacking. We couple field-parameterized models of competition between 10 annual plant species with a biodiversity-functioning experiment under two contrasting environmental conditions, to study how coexistence determinants link to biodiversity effects (selection and complementarity). We find that complementarity effects positively correlate with niche differences and selection effects differences correlate with fitness differences. However, niche differences also contribute to selection effects and fitness differences to complementarity effects. Despite this complexity, communities with an excess of niche differences (where niche differences exceeded those needed for coexistence) produce more biomass and have faster decomposition rates under drought, but do not take up nutrients more rapidly. We provide empirical evidence that the mechanisms determining coexistence correlate with those maximizing ecosystem functioning.O.G. acknowledges postdoctoral financial support provided by the European Union Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No 661118-BioFUNC.Peer reviewe

Análisis del decaimiento de Quercus Suber a escala regional en Andalucía: aplicación para una gestión eficaz

1 página. Comunicación oral presentada en la Sesión Ecología y Ecofisiología de la referida Reunión, celebrada en Huelva, 9-11, noviembre, 2011.Los sistemas forestales se están viendo afectados por el cambio global, uno de cuyos principales impulsores es el cambio climático. Actualmente estos cambios ocurren a mayor velocidad de la experimentada hasta ahora a lo largo de la evolución, lo que provoca una gran incertidumbre sobre la capacidad de adaptación de muchas especies. Como consecuencia es necesario conocer la dinámica de los sistemas forestales y los efectos del cambio global para dirigir todos los esfuerzos de gestión hacia objetivos alcanzables para la conservación de estos sistemas y sus valores.Peer reviewe

Structuring evidence for invasional meltdown: broad support but with biases and gaps

Negative interactions have been suggested as a major barrier for species arriving in a new habitat. More recently, positive interactions drew attention from community assembly theory and invasion science. The invasional meltdown hypothesis (IMH) introduced the idea that positive interactions among non-native species could facilitate one another’s invasion, even increasing their impact upon the native community. Many studies have addressed IMH, but with contrasting results, reflecting various types of evidence on a multitude of scales. Here we use the hierarchy-of-hypotheses (HoH) approach to differentiate key aspects of IMH, organizing and linking empirical studies to sub-hypotheses of IMH. We also assess the level of empirical support for each sub-hypothesis based on the evidence reported in the studies. We identified 150 studies addressing IMH. The majority of studies support IMH, but the evidence comes from studies with different aims and questions. Supporting studies at the community or ecosystem level are currently rare. Evidence is scarce for marine habitats and vertebrates. Few sub-hypotheses are questioned by more than 50% of the evaluated studies, indicating that non-native species do not affect each other’s survival, growth, reproduction, abundance, density or biomass in reciprocal A ↔ B interactions. With the HoH for IMH presented here, we can monitor progress in empirical tests and evidences of IMH. For instance, more tests at the community and ecosystem level are needed, as these are necessary to address the core of this hypothesis

Efectos del clima y la estructura del rodal sobre procesos de mortalidad en los bosques ibéricos.

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

Quercus suber dieback alters soil respiration and nutrient availability in Mediterranean forests

12 páginas.-- 5 figuras.-- 1 tablas.-- 106 referencias.-- Additional Supporting Information may be found in the online version of this article: http://dx.doi.org/10.1111/1365-2745.12618.-- Data available from the Dryad Digital Repository, http://dx.doi.org/10.5061/dryad.6nd4k (Avila et al. 2016)An increase in tree mortality rates has been recently detected in forests world-wide. However, few works have focused on the potential consequences of forest dieback for ecosystem functioning. Here we assessed the effect of Quercus suber dieback on carbon, nitrogen and phosphorus cycles in two types of Mediterranean forests (woodlands and closed forests) affected by the aggressive pathogen Phytophthora cinnamomi. We used a spatially explicit neighbourhood approach to analyse the direct effects of Q. suber dieback on soil variables, comparing the impact of Q. suber trees with different health status, as well as its potential long-term indirect effects, comparing the impact of non-declining coexistent species. Quercus suber dieback translated into lower soil respiration rates and phosphorus availability, whereas its effects on nitrogen varied depending on forest type. Coexistent species differed strongly from Q. suber in their effects on nutrient availability, but not on soil respiration rates. Our models showed low interannual but high intra-annual variation in the ecosystem impacts of tree dieback. Synthesis. Our results support that tree dieback might have important short- and long-term impacts on ecosystem processes in Mediterranean forests. With this work, we provide valuable insights to fill the existent gap in knowledge on the ecosystem-level impacts of forest dieback in general and P. cinnamomi-driven mortality in particular. Because the activity and range of this pathogen is predicted to increase due to climate warming, these impacts could also increase in the near future altering ecosystem functioning world-wideThis research was supported by the Ministerio de Ciencia e Innovación (MICINN) projects CGL2008-04503-C03-03, CGL2010-21381 and CGL2011-26877. J.M.A. was supported by a FPU-MEC grant (AP2010-0229) and B.I. by a FPI-MICINN grant (BES-2009-017111).Peer reviewe