Drivers of oak establishment in Mediterranean old fields from 25-year-old woodland islets planted to assist natural regeneration

14 p.Planted woodland islets can provide seeds for restoring forest ecosystems in Mediterranean old fields lacking seed sources, but other factors than seed arrival can also hinder the establishment of woody species. We experimentally examined factors affecting the emergence, survival, growth and recruitment of holm oak (Quercus ilex) seedlings juveniles from 25-year-old 100-m2 oak woodland islets planted in a Mediterranean old field. Wet springs and summers increased seedling emergence and survival. Distance to the islets per se did not affect seedling performance. However, emergence and survival increased in microsites close to the islets in less sun-exposed orientations of the islets and far from the islets in more sun-exposed orientations. Damage by wild boar reduced emergence, and unsheltered seedlings had 26% lower survival than sheltered ones, reflecting herbivory. Herb community biomass and light reduction by herbs increased with distance from nearest islet; the sparse herb cover around islets was due to competition from woodland islets, not to herbivory. There was a mismatch between the pattern of seedling survival and how the abundance of naturally recruited oaks varied with distance from the nearest islet; this suggests that other drivers can counteract the spatial pattern of seedling survival. We conclude that natural regeneration of Q. ilex in old fields from planted woodland islets is slow (5.7 seedlings ha?1 yr?1) due to acorn and seedling predation, and drought during spring and summer. Despite their small size, planted islets affected survival of oak juveniles depending on the orientation and distance relative to the islets.Ministerio de Ciencia y TecnologíaMinisterio de Ciencia e InnovaciónComunidad Autónoma de Madri

Predation and aridity slow down the spread of 21-year-old planted woodland islets in restored Mediterranean farmland

Las figuras y material suplementario que contiene el documento se localizan al final del mismo.Planted woodland islets act as sources of seed that may accelerate woodland development in extensive agricultural landscapes. We assessed a 1-ha plot that was planted with 16 100-m2 islets of holm oak Quercus ilex subsp. ballota seedlings near Toledo (Spain) in 1993. In spring 2014 we measured (1) acorn predation and (2) seedling emergence from seeded acorns at different distances from and orientations around the islets with half of the acorns protected to prevent predation, (3) survival of emerged seedlings, and (4) natural tree establishment outside of the planted islets. Most (96.9 %) unprotected acorns were removed or predated. Seedling emergence from protected acorns ranged from 42.9 % on the northern side of the islets to 13.2 % on the southern side, suggesting a less stressful microclimate on the northern side. Survival of naturally established seedlings was 28.6 % by the end of first summer; seedling mortality was chiefly due to drought (45.0 %) and herbivory (35.0 %). Density of emerged seedlings, surviving seedlings after first dry season, and established oaks >1-year old was similar at different distances from the islets. Over the 21 year time period, 58 new oak individuals >1-year old have established (an average of 3.3 established individuals per ha per year) at an average distance of 6.3 ± 5.4 m away from the closest islet. We conclude that initial oak regeneration triggered by small planted islets in Mediterranean abandoned farmland is slowed down by high acorn predation, seedling herbivory, and stressful microclimatic conditions. Regardless, these islets are a viable tool for regeneration of Mediterranean oak woodland.Projects from the Spanish Ministry of Science and Education (CGL2010-18312 and CGL2014-53308-P) and the Government of Madrid (S2013/MAE-2719, REMEDINAL-3) are currently providing financial support for this body of research. We are indebted to Aurora Mesa and Paula Meli for their help for acorn seeding and to Laura Ferna´ndez and Luis Cayuela for their input with some statistical analyses. The subject editor and two anonymous reviewers provided valuable comments on a former version of this manuscript

Production of extracts with anaesthetic activity from the culture of Heterosigma akashiwo in pilot-scale photobioreactors

The shear-sensitive microalga Heterosigma akashiwo is known to produce brevetoxin-like compounds that are active in voltage-dependent sodium channels. In this work, we present a study on the production of anaesthetic extracts from H. akashiwo biomass obtained in low-shear bioreactors at different growth phases. The photobioreactors (PBRs) used had specific configurations and were operated in such a way as to avoid cellular damage by hydrodynamic stress. Cultures were developed in small static-control flasks and PBRs with volumes ranging from 1.5 L to 200 L. The bioactivity of the produced extracts was assessed in vitro (Neuro-2a cell-based assay) and in vivo (Zebra fish model). Bioactivity depended slightly on the growth phase and culture system, with greater toxicity with the Neuro-2a model when stationary-phase extracts were used. Interestingly, extracts were not cytotoxic against other human cell lines. Steady production of anaesthetic bioactives was observed. In vivo anaesthetic efficacy, assessed with the Zebra fish model, was similar to that of commercial products, and without any observed mortality at 24-h post exposure

Sublethal effect of the toxic dinoflagellate Karlodinium veneficum on early life stages of zebrafish (Danio rerio)

Dinoflagellates of the genus Karlodinium are ichthyotoxic species that produce toxins including karlotoxins and karmitoxins. Karlotoxins show hemolytic and cytotoxic activities and have been associated with fish mortality. This study evaluated the effect of toxins released into the environment of Karlodinium veneficum strain K10 (Ebro Delta, NW Mediterranean) on the early stages of Danio rerio (zebrafish). Extracts of the supernatant of K10 contained the mono-sulfated KmTx-10, KmTx-11, KmTx-12, KmTx-13, and a di-sulfated form of KmTx-10. Total egg mortality was observed for karlotoxin concentration higher than 2.69 μg L−1. For 1.35 μg L−1, 87% of development anomalies were evidenced (all concentrations were expressed as KmTx-2 equivalent). Larvae of 8 days postfertilization exposed to 1.35 µg L−1 presented epithelial damage with 80% of cells in the early apoptotic stage. Our results indicate that supernatants with low concentration of KmTxs produce both lethal and sublethal effects in early fish stages. Moreover, apoptosis was induced at concentrations as low as 0.01 μg L−1. This is of great relevance since detrimental long-term effects due to exposure to low concentrations of these substances could affect wild and cultured fish

Effective nut dispersal by magpies (Pica pica L.) in a Mediterranean agroecosystem

Scatter-hoarding animals such as corvids play a crucial role in the dispersal of nut-producing tree species. This interaction is well known for some corvids, but remains elusive for other species such as the magpie (Pica pica), an abundant corvid in agroecosystems and open landscapes of the Palearctic region. In addition, the establishment of the individual dispersed seeds—a prerequisite for determining seed-dispersal effectiveness—has never before been documented for the interaction between corvids and nut-producing trees. We analyzed walnut dispersal by magpies in an agroecosystem in southern Spain. We used several complementary approaches, including video recording nut removal from feeders, measuring dispersal distance using radio tracking (with radio transmitters placed inside nuts), and monitoring the fate of dispersed nuts to the time of seedling emergence. Magpies were shown to be highly active nut dispersers. The dispersal distance averaged 39.6 ± 4.5 m and ranged from 4.1 to 158.5 m. Some 90% of the removed walnuts were cached later, and most of these (98%) were buried in the soil or hidden under plant material. By the time of seedling emergence, ca. 33% of nuts remained at the caching location. Finally, 12% of the cached nuts germinated and 4% yielded an emerged seedling, facilitating the transition to the next regeneration stage. The results demonstrate for the first time that magpies can be an effective scatter-hoarding disperser of a nut-producing tree species, suggesting that this bird species may play a key role in the regeneration and expansion of broadleaf forests in Eurasia.Gobierno de EspañaComunidad de MadridMinisterio de Economía y Competitivida

Caching territoriality and site preferences by a scatter-hoarder drive the spatial pattern of seed dispersal and affect seedling emergence

1. For plants with seeds dispersed by scatter-hoarders, decision-making by animals when caching determines the spatial pattern of seed dispersal and lays the initial template for recruitment, driving the regeneration of many species. However, the mechanism by which animal behaviour shapes seed distributions in spatially complex landscapes is not well understood. We investigated caching territoriality and site preferences to determine the spatial pattern of seed caching at different scales and whether scatter-hoarding behaviour drives the spatial distribution of seedling emergence. 2. We used radio-tracking and automatic wildlife cameras to monitor holm oak (Quercus ilex) acorn caching by Eurasian magpies (Pica pica), who are effective scatter-hoarders in agroforestry systems. We assessed the effect of caching territories, distance to seed source, habitat, subhabitat, microsites, and caching material in the spatial pattern of acorn dispersal by magpies. In addition, we analysed the relationship between the density of cached acorns and of emerged seedlings in different habitats. 3. Breeding magpies cached the acorns inside their caching territories, where they preferred tilled areas over oak plantations and mostly avoided old fields. These differences in habitat preference were maximized at relatively short to medium dispersal distances, where most acorns were cached, and decreased or disappeared at long-distances. Within tree plantations, magpies preferred high plant-productivity sites over low productivity ones. At the finest spatial scale, magpies preferred structures built by animals, such as rabbit grit mounds and latrines and ant litter mounds, to cache the acorns. In many sites, magpies selected uncommon materials such as stones and litter to cover caches. In the subsequent spring, seedling emergence was positively correlated with acorn cache density. 4. Synthesis. Scatter-hoarding is a hierarchical process in which caching sites are selected using different criteria at different spatial scales driven by territoriality and site preferences. Territoriality constrained dispersal distance and the habitats available for acorn caching. Magpie territoriality therefore indirectly drives oak seedling emergence and can determine oak recruitment and forest regeneration.CGL2014-459 53308-P (Ministerio Ciencia y Tecnología) PID2019-106806GB-I00 (Ministerio Ciencia e Innovación) S2013/MAE-2719 and S2018/EMT-4338 (Remedinal, CAM) CCG2014/BIO-02 & GP2019-6 (UAH) BES-2015-075276(FPI, MCT

Services provided by birds (high-mobile link species) in farmland and forest mosaics: forest regeneration and plague regulation

Este trabajo ha sido financiado con fondos de los proyectos CICYT Ministerio de Educación y Ciencia (CGL2007−60533/BOS, CGL2010−18312/BOS) y del Ministerio de Economía y Competitividad (CGL2014−53308−P), de la red REMEDINAL (S−0505/AMB/ 0335, S2009 AMB−1783, S2013/MAE−2719 y TE-CM S2018/EMT- 4338), de la Universidad de Alcalá (CCG2014/BIO−002) y del MAGRAMA y la Fundación Biodiversidad a través de la Fundación Internacional para la Restauración de Ecosistemas. GGS fue financiado con una beca FPU (AP2006−00891) y SMH por una beca FPI (BES−2008−006630), ambas del Ministerio de Educación y Ciencia. LMB fue financiada por una beca FPI (BES-2015-075276) del Ministerio de Ciencia y Tecnología. NM fue financiada por una beca de la Universidad de Alcalá. ABL agradece ayudas postdoctorales Juan de la Cierva (FJCI-2015-23687) y de la Fundación Alexander von Humboldt. Agradecemos la colaboración de la Dirección Xeral de Conservación da Natureza de la Xunta de Galicia por las facilidades para desarrollar las investigaciones realizadas en esta Comunidad y de las bodegas de Abadía Retuerta y Martín Berdugo y de Haciendas Bio. Finalmente, agradecemos la contribución de un revisor anónimo que mejoró la versión original de este artículo.Los elementos que soportan las funciones y servicios de los ecosistemas son insuficientemente conocidos, mermando nuestra capacidad para planificar la conservación, restauración y manejo de los ecosistemas. Entre dichos elementos, el papel de la avifauna es especialmente relevante al ser especies de gran movilidad (high mobile link species) que conectan distintas unidades del paisaje. Este trabajo analiza servicios ecosistémicos importantes dependientes de interacciones biológicas mediadas por la avifauna en mosaicos agroforestales. Abordamos tres objetivos específicos: el papel de (1) los córvidos en la dispersión y reclutamiento de quercíneas, (2) la avifauna insectívora en la regulación de plagas en cultivos leñosos y (3) las aves rapaces en la regulación de avifauna-plaga en viñedos. Nuestros resultados evidencian que la avifauna realiza funciones y servicios claves para la regeneración forestal y la regulación de plagas en mosaicos agroforestales. Identificamos especies que se desconocía que realizaban una función relevante, en particular la urraca (Pica pica), cuya actividad resulta en una dispersión efectiva de nueces y bellotas, y el abejero europeo (Pernis apivorus), con un elevado consumo de avispa asiática (Vespa velutina). La instalación de cajas-nido en cultivos leñosos aumenta las poblaciones de aves insectívoras que regulan plagas; sin embargo, la capacidad de regulación de las plagas es moderada y depende del contexto ambiental o estudio de caso. Las rapaces diurnas existentes en los paisajes estudiados contribuyen al control de plagas agrícolas como la del estornino negro (Sturnus unicolor). Proponemos integrar los servicios que proporcionan las aves en la ordenación del territorio para alcanzar modelos de desarrollo más sostenibles.The elements that support functions and ecosystem services are not well known yet, and this gap reduces our capacity to plan the conservation, restoration, and management of ecosystems. Among these elements, the role of avifauna is especially relevant as birds are high-mobile link species that connect different landscape units. This article analyzes important ecosystem services driven by biological interactions that are mediated by birds in farmland and forest mosaics. We propose three specific goals: to assess the role of (1) corvids in the dispersal and recruitment of oak species, (2) insectivorous birds in pest regulation of woody crops, and (3) raptors in regulation of plague birds in vineyards. Our results show that the avifauna performs key functions and services for forest regeneration and pest regulation in agroforestry mosaics. We identified species that were not known to perform relevant functions, particularly the magpie (Pica pica) and its effective dispersion of nuts and acorns, and the honey buzzard (Pernis apivorus) and its high consumption of Asian black hornet (Vespa velutina). The installation of nest-boxes in woody crops increases the populations of insectivorous birds that regulate pests; however, the capacity of pest control is moderate and depends on the environmental context or case study. The diurnal raptors thriving in the studied landscapes contribute to the control of agricultural pests such as the spotless starling (Sturnus unicolor). We propose to integrate the services provided by birds in landscape planning to achieve more sustainable development systems.Financiado con fondos de los proyectos CICYT Ministerio de Educación y Ciencia (CGL2007−60533/BOS, CGL2010−18312/BOS) y del Ministerio de Economía y Competitividad (CGL2014−53308−P), de la red REMEDINAL (S−0505/AMB/ 0335, S2009 AMB−1783, S2013/MAE−2719 y TE-CM S2018/EMT- 4338), de la Universidad de Alcalá (CCG2014/BIO−002) y del MAGRAMA y la Fundación Biodiversidad a través de la Fundación Internacional para la Restauración de Ecosistemas. GGS fue financiado con una beca FPU (AP2006−00891) y SMH por una beca FPI (BES−2008−006630), ambas del Ministerio de Educación y Ciencia. LMB fue financiada por una beca FPI (BES-2015-075276) del Ministerio de Ciencia y Tecnología. NM fue financiada por una beca de la Universidad de Alcalá. ABL agradece ayudas postdoctorales Juan de la Cierva (FJCI-2015-23687) y de la Fundación Alexander von Humbold

Metaheuristics “In the Large”

Many people have generously given their time to the various activities of the MitL initiative. Particular gratitude is due to Adam Barwell, John A. Clark, Patrick De Causmaecker, Emma Hart, Zoltan A. Kocsis, Ben Kovitz, Krzysztof Krawiec, John McCall, Nelishia Pillay, Kevin Sim, Jim Smith, Thomas Stutzle, Eric Taillard and Stefan Wagner. J. Swan acknowledges the support of UK EPSRC grant EP/J017515/1 and the EU H2020 SAFIRE Factories project. P. GarciaSanchez and J. J. Merelo acknowledges the support of TIN201785727-C4-2-P by the Spanish Ministry of Economy and Competitiveness. M. Wagner acknowledges the support of the Australian Research Council grants DE160100850 and DP200102364.Following decades of sustained improvement, metaheuristics are one of the great success stories of opti- mization research. However, in order for research in metaheuristics to avoid fragmentation and a lack of reproducibility, there is a pressing need for stronger scientific and computational infrastructure to sup- port the development, analysis and comparison of new approaches. To this end, we present the vision and progress of the Metaheuristics “In the Large”project. The conceptual underpinnings of the project are: truly extensible algorithm templates that support reuse without modification, white box problem descriptions that provide generic support for the injection of domain specific knowledge, and remotely accessible frameworks, components and problems that will enhance reproducibility and accelerate the field’s progress. We argue that, via such principled choice of infrastructure support, the field can pur- sue a higher level of scientific enquiry. We describe our vision and report on progress, showing how the adoption of common protocols for all metaheuristics can help liberate the potential of the field, easing the exploration of the design space of metaheuristics.UK Research & Innovation (UKRI)Engineering & Physical Sciences Research Council (EPSRC) EP/J017515/1EU H2020 SAFIRE Factories projectSpanish Ministry of Economy and Competitiveness TIN201785727-C4-2-PAustralian Research Council DE160100850 DP20010236

Bio-inspired computation: where we stand and what's next

In recent years, the research community has witnessed an explosion of literature dealing with the adaptation of behavioral patterns and social phenomena observed in nature towards efficiently solving complex computational tasks. This trend has been especially dramatic in what relates to optimization problems, mainly due to the unprecedented complexity of problem instances, arising from a diverse spectrum of domains such as transportation, logistics, energy, climate, social networks, health and industry 4.0, among many others. Notwithstanding this upsurge of activity, research in this vibrant topic should be steered towards certain areas that, despite their eventual value and impact on the field of bio-inspired computation, still remain insufficiently explored to date. The main purpose of this paper is to outline the state of the art and to identify open challenges concerning the most relevant areas within bio-inspired optimization. An analysis and discussion are also carried out over the general trajectory followed in recent years by the community working in this field, thereby highlighting the need for reaching a consensus and joining forces towards achieving valuable insights into the understanding of this family of optimization techniques

Metaphor-based metaheuristics, a call for action: the elephant in the room

International audienceTaking inspiration from natural behaviors to devise new optimization algorithms has played an important role in the history of the field of metaheuristics (Sörensen et al. 2017). Unfortunately, in the last two decades we have been witnessing a new trend by which dozens of metaphor-based metaheuristics based on the most diverse possible set of natural, artificial, social, and sometimes even supernatural phenomena and behaviors are proposed, without a clear motivation beyond the desire of their authors to publish their papers