Shifting demographic conflicts across recruitment cohorts in a dynamic post-disturbance landscape

Seed dispersal effectiveness, which measures the number of adult plant individuals produced by seed dispersal, is the product of the number of seeds dispersed and the probability a seed produces an adult. Directed dispersal to certain habitat types may enhance some stages of recruitment but disfavor others, generating demographic conflicts in plant ontogeny. We asked whether temporal changes in habitat features may affect the distribution of seedlings recruited from dispersed acorns, and whether this could induce shifts in the life-stage conflicts experienced by successive cohorts of naturally recruited plants. As early successional habitats are characterized by rapid change, we used a burnt pine stand in southern Spain to monitor the recruitment and performance of a major tree species (Quercus ilex) across 7 yr in four types of post-fire habitats. These differed in structure and included patches of unburnt forest and three management alternatives of burnt trees: logging, partial cutting, and nonintervention. Young oaks that resprouted after the fire were mainly located near acorn sources, while new seedlings initially emerged mostly in habitats with standing snags due to habitat selection by European jays, Garrulus glandarius, for dispersal. The dead pines gradually collapsed and attracted less dispersal, so subsequent seedling cohorts mainly recruited within patches of unburnt pines. These live pines enhanced the survival of the oaks located beneath their canopy but greatly reduced their growth as compared to the other post-fire habitats, thus representing a demographic conflict that was absent elsewhere. As a consequence of the directional shift in the habitat where seedlings recruited, successive seedling cohorts experienced a gradual improvement in their likelihood of survival but a reduction in growth. The progressive intensification of this life-stage conflict hinged on the reduction of vertical structures in the habitat with standing burnt pines. Recruitment success thus involved temporal variation in the habitat where recruitment occurred, likely resulting from changes in the direction of seed dispersal, and spatial variation in habitat suitability for seedling establishment and growth. Temporal changes in habitat structure can indirectly change the environment in which recruitment occurs, and consequently seed dispersal effectiveness, by shifting the direction of seed dispersal.Ministerio de Ciencia e InnovaciónComunidad de MadridMinisterio de Ciencia y Educació

Does post-disturbance salvage logging affect the provision of ecosystem services? A systematic review protocol

Background. Forest fires, insect outbreaks, and windstorms are common forest disturbances that are expected to increase in importance in coming decades. Post-disturbance management often involves salvage logging, i.e. the felling and removal of the affected trees. However, harvesting these biological legacies may represent a second disturbance whose effects on ecosystem processes add on those of the initial disturbance. Many of the potentially affected processes, such as soil erosion and stream water quality, represent regulating and supporting ecosystem services important for human society. In the last 15 years, much empirical evidence has been gathered on the ecological consequences of this management practice, and it has now become necessary to synthesise this evidence in meaningful ways for managers and decision-makers.Methods. With this systematic review we aim to synthesise the literature on the effects of salvage logging on ecosystem services and determine the effects of major effect modifiers such as disturbance type and intensity, the timing and method of logging, and the type of forest. We will conduct searches of the primary scientific literature, which will be selected and categorised according to its relevance to the topic and its quality. Each relevant article will be read in full to obtain the necessary data for meta-analysis and to identify its main conclusions. Mixed-effects models will be performed to assess the effects of the identified effect modifiers on the effect sizes of the salvage intervention on ecosystem services and to account for random effects arising from studies being performed in the same area. Sensitivity analyses will test the potential effects of study quality, and publication bias will be assessed with the trim and fill method. We will present the results as a narrative review and a meta-analysis

Suitability of the management of habitat complexity, acorn burial depth, and a chemical repellent for post-fire reforestation of oaks

Acorn sowing is a reforestation technique that can potentially render high-quality oak seedlings and high seedling survival, although it is often discarded due to high rates of seed predation. Predator activity can be modified by habitat complexity due to its effects on accessibility and protection for different predators. In this study we analysed how habitat complexity generated by different post-fire management treatments, sowing depth, and capsaicin (a chemical repellent) affect acorn predation by two guilds of post-dispersal predators that differ in size and foraging behaviour. We carried out two acorn predation experiments. In Experiment #1 we buried acorns at two depths (2 and 8 cm) in two post-fire burnt-wood management treatments of different habitat complexity, namely: (1) Salvage Logging (SL), where the burnt trunks were cut and piled and the branches were masticated (lower habitat complexity), and (2) Non-Intervention (NI), with no action after the fire and 100% of the trees naturally fallen by 2009, thus leaving a habitat with lying burnt logs and branches (higher habitat complexity). In Experiment #2 we repeated Experiment #1, with the addition of capsaicin as a mammal repellent treatment. Most acorns were consumed in both years (ca. 90%), mainly by rodents. In Experiment #1 predation by boars accounted for 4.1% of overall predation, and it was about twice as high in SL than in NI, likely due to the physical difficulty for large mammals to forage in an area with a complex structure created by lying logs and branches. In contrast, rodents consumed ca. 1.4 times more acorns in NI than in SL, which led to overall greater predation in NI in both experiments. This was likely due to the protection provided by the branches for the rodent community. Deeper burial reduced predation by small percentages, although in Experiment #1 it had a negligible effect in NI. Capsaicin did not reduce predation, and it reduced seedling emergence to half. This study suggests that habitat complexity created by trunks and branches reduced predation by wild boars, but favoured rodent acorn predation. We conclude that other methods for the protection of individual acorns need to be identified to increase the success of oak reforestation via seeding.Ministerio de Ciencia e InnovaciónComunidad de MadridMinisterio de Ciencia y EducaciónUnión Europe

Post-fire regeneration of the Holm oak in Mediterranean pine reforestations

Después de un incendio forestal es común la retirada de la madera quemada, pero se sabe poco sobre cómo esta práctica afecta a la recolonización de la zona quemada por parte de especies del género Quercus como la encina. En un pinar de repoblación quemado de Sierra Nevada (sur de España) se estableció una parcela de 18 ha con tres tratamientos experimentales de la madera quemada: Extracción (corte y desramado de los árboles, con apilamiento de los troncos y astillado de las ramas), Ramas (corte del 90 % de los troncos, sin extracción) y Control (sin acciones). Dentro de esta parcela sobrevivieron algunos rodales de pinos (1.5 ha en total), y al lado de ella quedaron unos rodales de encinas (Quercus ilex subsp. ballota) productoras de bellotas desde donde se produjo dispersión biótica. En la parcela se monitoreó la emergencia, supervivencia y tamaño de plántulas de encina a lo largo de siete años. Se establecieron 801 plántulas de encina antes de la implementación de los tratamientos, ya por rebrote o dispersadas poco después del incendio. Después del manejo post-incendio emergieron 447 plántulas en toda la parcela, previsiblemente como consecuencia de la dispersión por arrendajos (Garrulus glandarius): el 62.9 % bajo los pinos vivos y el 37.1 % en el resto de la parcela. La emergencia fue mayor en el tratamiento Control en los primeros años. El factor tratamiento perdió importancia tras la paulatina caída de los árboles quemados, ya que en los últimos años la mayor parte de las bellotas fue dispersada hacia los rodales de pinos vivos. Estos rodales incrementaron la probabilidad de supervivencia pero redujeron el crecimiento, efecto posiblemente asociado a la competencia por nutrientes, luz y agua. Concluimos que pequeños núcleos de pinos que sobreviven un incendio, al igual que los árboles quemados durante los primeros años, pueden atraer dispersores de bellotas y que en el caso de los pinos vivos será necesaria una segunda perturbación para liberar a las encinas reclutadas de la competencia del dosel. Las prácticas de manejo post-incendio que favorezcan estas estructuras pueden favorecer la regeneración natural del ecosistema.The extraction of the burnt wood is a common practice after wildfire, yet its effects on the recolonisation by Quercus species are poorly known. We established an 18-ha plot in a burnt pine reforestation in Sierra Nevada (S Spain), with three experimental wood-management treatments: Salvage Logging (felling the trees, chopping off the main branches, piling the logs, and masticating the remaining branches), Partial Cut (felling 90 % of the trees without further actions), and Control (no actions taken). Some clusters of pines survived within the limits of the plot and were left standing (totalling 1.5 ha), and adjacent to the plot were some unburnt, acorn-producing Holm oaks (Quercus ilex subsp. ballota) from which biotic dispersal occurred. We monitored emergence, survival, and size of oak seedlings in the plot for seven years. We found 801 oak seedlings the first year, corresponding either to post-fire resprouts or to acorns dispersed right after the fire and before treatment implementation. After post-fire treatment implementation, 447 seedlings emerged throughout the plot, likely due to dispersal by European jays (Garrulus glandarius): 62.9 % under live pines and 37.1 % in the rest of the plot. Emergence was greatest in the control treatment during the first years. The treatment factor lost importance in later years, as acorn dispersal became more directed towards the live pines. Seedlings under pines had greater survival but lower growth, likely due to competition for nutrients, light, and water. We conclude that small patches of pines that survive a fire, as well as dead standing trees during the first years, can attract acorn dispersers and that, in case of the surviving pines, a second disturbance will be needed to release the recruited oaks from competition. Management practices that favour these structures can aid the natural recovery of the ecosystem.Ministerio de Ciencia e InnovaciónOrganismo Autónomo de Parques NacionalesComunidad de MadridMinisterio de Ciencia, Cultura y Deport

Salvage logging effects on regulating and supporting ecosystem services. A systematic map

Wildfires, insect outbreaks, and windstorms are increasingly common forest disturbances.Post-disturbance management often involves salvage logging, i.e. the felling and removal of the affected trees. However, this practice may represent an additional disturbance witheffects on ecosystem processes and services. We developed a systematic map to provide an overview of the primary studies on this topic, and created a database with information on the characteristics of the retrieved publications, including information on stands, disturbance, intervention, measured outcomes, and study design. Of 4341 retrieved publications, 90 were retained in the systematic map. These publications represented 49 studies, predominantly from North America and Europe. Salvage logging after wildfire was addressed more frequently than after insect outbreaks or windstorms. Most studies addressed logging after a single disturbance event, and replication of salvaged stands rarely exceeded 10. The most frequent response variables were tree regeneration, ground cover, and deadwood characteristics.Junta de AndalucíaREMEDINA

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

Massive and effective acorn dispersal into agroforestry systems byan overlooked vector, the Eurasian magpie (Pica pica)

Oak regeneration and the expansion of forested sites in Eurasia rely on acorn dispersal by animals,especially the Eurasian jay (Garrulus glandarius). However, in open agroforestry systems where jaysare absent, such as old fields far from acorn sources, oak recruitment still occurs. We hypothesize that theEurasian magpie (Pica pica), an abundant corvid in this system, substitutes the jay in its seed dispersal function.By ringing 169 magpies, video recording >7500 acorn removal events with trail cameras, and radiotagging337 acorns, we quantified that (1) magpies cached 41&#-56% of the annual acorn production of Quercusilex trees in single caches on the ground; (2) breeding pairs, and especially males, were the main acorndispersers; (3) each breeding magpie cached 169&#-1372 acorns in 6 weeks; and (4) the effectiveness of dispersal(percentage of cached acorns resulting in seedlings) was 0.6&-2.4%, which (5) yielded a high densityof emerged seedlings (56&-439 seedlings/ha). We evidence that magpie could be a key species in the regenerationof oak agroforestry mosaics because they massively and effectively dispersed acorns. However, inour particular study site, effectiveness was low probably due to herbivory and summer drought stress (i.e.,a context limitation rather than an intrinsic limitation of the disperser). As the distributions of magpies andoaks overlap widely in Eurasia, effective acorn dispersal by magpies could have a significant role in largescaleoak forest recovery in strongly fragmented landscapes.Ministerio de Ciencia y TecnologíaREMEDINALUniversidad de AlcaláMinisterio de Ciencia, Innovación y Universidade

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