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

Enabling conditions for the implementation and conservation outcomes of a private nature reserve

Expanding conservation efforts to private land is paramount to halt biodiversity loss and achieve global conservation targets. Individual landowners can play disproportionately important roles by establishing private parks and managing them with biodiversity‐focused objectives. However, several constraints hinder the expansion of such initiatives, and little is known about their extent, characteristics and keys for success.Here, we provide insights on the conditions that favoured the establishment and conservation outcomes of a private reserve in central Spain whose management has been fully conservation‐oriented for the past two decades. We report on the actions implemented to accomplish four key targets that aimed at protecting and enhancing wildlife populations, and on the landholder's motivations to devote his personal resources to pursue this goal.The landholder suggests that public policy should reduce the bureaucratic burden to intrinsically motivated landowners and provide them technical advice, trust and financial incentives to expand conservation on private land.Ministerio de Asuntos Económicos y Transformación DigitalMinisterio de Ciencia e InnovaciónMinisterio de Educación, Cultura y DeporteComunidad de Madri

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

Revegetation through seeding or planting: A worldwide systematic map

Roughly 2 billion ha of land are degraded and in need of ecological restoration worldwide. Active restoration frequently involves revegetation, which leads to the dilemma of whether to conduct direct seeding or to plant nursery-grown seedlings. The choice of revegetation method can regulate plant survival and performance, with economic implications that ultimately feed back to our capacity to conduct restoration. We followed a peer -reviewed protocol to develop a systematic map that collates, describes and catalogues the available studies on how seeding compares to planting in achieving restoration targets. We compiled a database with the charac-teristics of all retrieved studies, which can be searched to identify studies of particular locations and habitats, objectives of restoration, plant material, technical aspects, and outcomes measured. The search was made in eight languages and retrieved 3355 publications, of which 178 were retained. The systematic map identifies research gaps, such as a lack of studies in the global South, in tropical rainforests, and covering a long time period, which represent opportunities to expand field-based research. Additionally, many studies overlooked reporting on important technical aspects such as seed provenance and nursery cultivation methods, and others such as watering or seedling protection were more frequently applied for planting than for seeding, which limits our capacity to learn from past research. Most studies measured outcomes related to the target plants but avoided measuring general restoration outcomes or economic aspects. This represents a relevant gap in research, as the choice of revegetation method is greatly based on economic aspects and the achievement of restoration goals goes beyond the establishment of plants. Finally, we identified a substantial volume of studies conducted in temperate regions and over short periods (0-5 y). This research cluster calls for a future in-depth synthesis, potentially through meta-analysis, to reveal the overall balance between seeding and planting and assess whether the response to this question is mediated by species traits, environmental characteristics, or technical aspects. Besides identifying research clusters and gaps, the systematic map database allows managers to find the most relevant scientific literature on the appropriateness of seeding vs. planting for particular conditions, such as certain species or habitats

Estimating retention benchmarks for salvage logging to protect biodiversity

S.T. was supported by the Humboldt-Foundation and by the MOST (Ministry of Science and Technology) Taiwan Research Fellowship to work with A.C. at National Tsing Hua University, Taiwan. S.T. received funds from the Gregor Louisoder Environmental Foundation. A.B.L. received funds from the Humboldt-Foundation.Forests are increasingly affected by natural disturbances. Subsequent salvage logging, a widespread management practice conducted predominantly to recover economic capital, produces further disturbance and impacts biodiversity worldwide. Hence, naturally disturbed forests are among the most threatened habitats in the world, with consequences for their associated biodiversity. However, there are no evidence-based benchmarks for the proportion of area of naturally disturbed forests to be excluded from salvage logging to conserve biodiversity. We apply a mixed rarefaction/extrapolation approach to a global multi-taxa dataset from disturbed forests, including birds, plants, insects and fungi, to close this gap. We find that 75 ± 7% (mean ± SD) of a naturally disturbed area of a forest needs to be left unlogged to maintain 90% richness of its unique species, whereas retaining 50% of a naturally disturbed forest unlogged maintains 73 ± 12% of its unique species richness. These values do not change with the time elapsed since disturbance but vary considerably among taxonomic groups.Open Access funding enabled and organized by Projekt DEA

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