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Runoff and sediment yields in semiarid areas have often been reported to be scale-dependent. However, scale relationships in these areas have been poorly quantified using empirical data. Commonly, previous empirical works on scale issues have focused on the effect of the size of the contributing area for a particular scale (e.g. catchments of different sizes), or the scale effect has been confounded with other co-varying controlling factors (mainly vegetation cover). In this study, we established quantitative scale relationships for runoff and sediment yields measured during 4 years at several nested scale levels (plot, microcatchment and catchment), covering a range of contributing-area sizes from 16 m2 to 20 ha, and without major differences in vegetation cover between the scales analyzed. From finer to coarser scales, rainfall thresholds for runoff production increased, runoff frequency decreased, and unit-area runoff decreased. These relationships were well fitted to power law relations with exponents close to −1/2. The decrease in runoff with the coarsening of scale was attributed to the increase in the opportunity for runoff infiltration in vegetation patches along the slope and to other properties appearing at the catchment scale, such as runoff infiltration through limestone fractures and transmission losses through the channel bed. Sediment yield was very low at the plot scale and negligible at the catchment scales. The definition and quantification of the scale-dependent variation in runoff yield obtained in this study clearly show the important effect of scale on semiarid hydrology regardless of the influence of vegetation cover variations and could be used to improve the hydrological modeling and water management of semiarid areas., Depto. de Biodiversidad, Ecología y Evolución, Fac. de Ciencias Biológicas, TRUE, pub

Depto. de Biodiversidad, Ecología y Evolución, Fac. de Ciencias Biológicas, TRUE, pub

Several management actions are applied to restore ecosystem services in degraded Mediterranean rangelands, which range from adjusting the grazing pressure to the removal of grazers and pine plantations. Four such actions were assessed in Quercus coccifera L. shrublands in northern Greece: (i) moderate grazing by goats and sheep; (ii) no grazing; (iii) no grazing plus pine (Pinus pinaster Aiton) plantation in forest gaps (gap reforestation); and (iv) no grazing plus full reforestation of shrubland areas, also with P. pinaster. In addition, heavy grazing was also assessed to serve as a control action. We comparatively assessed the impact of these actions on key provisioning, regulating and supporting ecosystem services by using ground-based indicators. Depending on the ecosystem service considered, the management actions were ranked differently. However, the overall provision of services was particularly favoured under moderate and no grazing management options, with moderate grazing outranking any other action in provisioning services and the no grazing action presenting the most balanced provision of services. Pine reforestations largely contributed to water and soil conservation and C sequestration but had a negative impact on plant diversity when implemented at the expense of removing natural vegetation in the area. Heavy grazing had the lowest provision of ecosystem services. It is concluded that degraded rangelands can be restored by moderating the grazing pressure rather than completely banning livestock grazing or converting them into pine plantations., Depto. de Biodiversidad, Ecología y Evolución, Fac. de Ciencias Biológicas, TRUE, pub

Identified as essential mechanisms promoting alternative stable states, positive feedbacks have been the focus of most former studies on the potential for catastrophic shifts in drylands. Conversely, little is known about how negative feedbacks could counterbalance the effects of positive feedbacks. A decrease in vegetation cover increases the connectivity of bare-soil areas and entails a global loss of runoff-driven resources from the ecosystem but also a local increase in runoff transferred from bare-soil areas to vegetation patches. In turn, these global resource losses and local resource gains decrease and increase vegetation cover, respectively, resulting in a global positive and a local negative feedback loop. We propose that the interplay of these two interconnected ecohydrological feedbacks of opposite sign determines the vulnerability of dryland ecosystems to catastrophic shifts. To test this hypothesis, we developed a spatially explicit model and assessed the effects of varying combinations of feedback strengths on the dynamics, resilience, recovery potential, and spatial structure of the system. Increasing strengths of the local negative feedback relative to the global positive feedback decreased the risk of catastrophic shifts, facilitated recovery from a degraded state, and promoted the formation of banded vegetation patterns. Both feedbacks were most relevant at low vegetation cover due to the nonlinear increase in hydrological connectivity with decreasing vegetation. Our modelling results suggest that catastrophic shifts to degraded states are less likely in drylands with strong source–sink dynamics and/or strong response of vegetation growth to resource redistribution and that feedback manipulation can be useful to enhance dryland restoration., Depto. de Biodiversidad, Ecología y Evolución, Fac. de Ciencias Biológicas, TRUE, pub

Increasing wildfire frequency in the Mediterranean Basin could affect future plant-soil–water-dynamics. The capacity of soils to retain water is a key parameter affecting plant post-fire regeneration. Yet, few research has looked at how different soil properties related to water retention is affected by increasing wildfire frequency. This study aimed at understanding the relationship between wildfire frequency, soil–water-related properties and the dynamics of surface water in soils. To this, after a 2012-summer wildfire in Portugal, three sets of three replicate maritime pine stands with contrasted wildfire frequency were selected (0 vs. 1 vs. 4 fires since 1975). At each of the nine study sites, three re-sprouter shrubs and neighbouring bare soil were chosen (54 microsites). There, soil cover, soil–water retention curves and surface (0–5 cm) soil–water-related properties (texture, bulk density, organic matter content, soil moisture, soil surface water repellency) were monitored for one year. Furthermore, records of post-fire soil moisture dynamics were analysed continuously using 72 probes installed at 2.5 and 7.5 cm depth. The hillslopes affected by 1 fire showed higher plant recovery than the 4 fires hillslopes. During the dry season, the threshold for water stress was reached 17 days sooner in the 4 fires hillslopes, and also 10 days sooner on bare microsites. Periods of plant water stress were longer and bare soil patches size bigger. The increase in wildfire frequency promoted high soil organic matter contents but less available water content, stressing the importance of soil organic matter quality characterization in water-related properties.

Corrigendum to New Phytologist 225 (2020), 1500–1515, doi: 10.1111/nph.16252. Since its publication, the authors of Baudena et al. (2020) have identified an error for the set of parameter values representing flammability in Table 2. In this correction, the authors would also like to report that, when using the flammability values as originally published in Baudena et al. (2020; i.e. a factor 2 larger than those actually used in the simulations), the main results do not change qualitatively (see Supporting Information Figs S1, S2 to this correction). Namely, when increased aridity was simulated as negatively affecting oak post-fire recovery and colonization rate, while positively affecting the community flammability, the authors observed that the forest state was resilient to the separate impact of fires and increased aridity. Yet, water stress could convert forests into open shrublands by hampering post-fire recovery and at the same time either increasing flammability or decreasing the oak forest colonization rate (or both). A tipping point (emerging from bistability of the open shrubland and forest state) was detected at intermediate levels of aridity (Fig. S1). In the ‘short-term’ run, that is a century, the authors observed again that the probability of a mixed successional community becoming an oak forest after 100 yr decreased drastically with increasing aridity (moving from bottom left to top right in Fig. S2, e.g. with flammability equal to 1.5 times the baseline value as published in table 2 in Baudena et al., 2020). The main differences between the two parameter sets were that the effects of aridity were more dramatic in Figs S1 and S2, as their baseline flammability (given in table 2 in Baudena et al., 2020) was twice as high as the baseline flammability that we actually used in figs 3 and 4 in Baudena et al. (2020) (as reported here in Table 2). We apologize to our readers for this mistake. 2 Table List of symbols, names, values, units and their source fo

Understanding the factors that control grass–shrub interactions and coexistence is critical to the design of dryland management and restoration strategies. Using Stipa tenacissima tussocks as adult neighbor and Olea europaea var. sylvestris as target woody species, we performed a 5-year-long, large-scale manipulative experiment to investigate the independent and combined effects of water and nutrient availability, and the modulating effects of O. europaea ontogeny on the net outcome of grass–shrub interaction. At two contrasting dryland sites, we conducted experimental plantings of Olea seedlings on two microsites: contiguous to a Stipa tussock (Stipa microsite) and on the intertussock bare-soil areas (Open microsite), and manipulated resource availability by combining nutrient and water addition. The experiment followed a full factorial design, with all treatment combinations applied at each site. We monitored survival, height, and stem basal diameter of Olea individuals over a study period of 5 years. All across the wide range of conditions considered, negative effects of Stipa on Olea largely prevailed during the first 2 years after the plantation. We found that competition was stronger in the drier steppe, where extra inputs of water favored neutral interactions. Conversely, nutrient addition increased competition strength, particularly when combined with water inputs, pointing to the contrasting role of different resources and the importance of interactions between them in the control of plant–plant interaction outcome. The competition effects of Stipa faded with time and gradually shifted to neutral interaction as Olea individuals aged. Our results are particularly relevant to guide restoration efforts in formerly wooded xeric grasslands and rangelands.

Recurrent fires can impede the spontaneous recruitment capacity of pine forests. Empirical studies have suggested that this can lead to a prolonged replacement of pine forest by shrubland, especially if shrub species are pyrophytic. Model-based studies, however, have suggested that post-fire succession of pine forest under current climatic conditions will eventually tend towards the dominance of oaks under high fire severity and recurrence. These previous modelling studies did not address the role of the various post-fire regeneration traits of the understory shrub species. Considering the dichotomy of obligate seeder vs. resprouter species, either obligate or facultative resprouter, we hypothesized that when the shrubs present are post-fire seeders, the oaks steadily occupy the forest, whereas resprouter shrub species might compete with oaks and delay or arrest post-fire succession. To test this hypothesis, we developed a dynamic, cellular automaton model for simulating post-fire successional transitions in pine forests, including shrubs, pines and oaks, and stochastic fires of regular frequency. Our results showed a strong tendency towards oak dominance as final model state and a very reduced role of fire recurrence in this final state, with low yearly acorn input delaying oak dominance. Most relevantly, and in line with our hypothesis, the trend towards oak dominance depended markedly on the two types of shrub species, being delayed by resprouter species, which extended the shrub-dominated succession stage for several centuries. Our simulation results supported the view that the type of understorey species should be a key consideration in post-fire restoration strategies aiming to enhance fire resilience.

La disciplina de Investigación e Innovación Responsable, conocida por su acrónimo inglés RRI Responsible Research and Innovation, surge en la última década buscando establecer las directrices para una actuación socialmente responsable e innovadora de la actividad científica. Aunque el planteamiento de la dimensión ética de la ciencia respecto a la sociedad no es nuevo, la RRI ofrece una renovada filosofía y una específica perspectiva metodológica, basadas en la democratización profunda, la implementación de beneficios sociales y la sostenibilidad. Desde dicho enfoque se favorece la participación de todos los stakeholders, determinando el ámbito educativo como una de sus prioritarias áreas de actuación. El objetivo de la presente investigación es doble. Por un lado, se pretende ofrecer una visión general sobre la nueva disciplina Investigación e Innovación Responsables, y por otro, analizar una de las experiencias pioneras de su aplicación en la docencia universitaria, profundizando en la visión del alumnado. Para comenzar, se realizará un exhaustivo análisis documental acerca de la RRI, su conceptualización y aplicaciones en el ámbito educativo. A continuación, se describirá la innovación docente llevada a la práctica en la asignatura de Planteamientos y diseño de la investigación, en los grupos A y B, del Máster Comunicación de las Organizaciones, impartida en la Facultad de Ciencias de la Información de la UCM durante el curso pasado. Para conocer las opiniones del alumnado, se ha realizado una encuesta mediante la herramienta de formularios de Google con el fin de medir su grado de satisfacción con la experiencia de aprendizaje, su percepción sobre el aumento de competencias de investigación responsable y su grado de concienciación respecto a las posibilidades de RRI. De los 41 alumnos matriculados contestaron 33, el 80% de la clase. Así mismo, se exponen los resultados referentes al uso de la herramienta del trabajo colaborativo utilizado en el proyecto, obtenid

La conectividad se define como el grado en que la estructura espacial del paisaje facilita el flujo de organismos y substancias. Diversos modelos conceptuales y evidencias empíricas atribuyen a la conectividad hidrológica un papel clave en el funcionamiento de los ecosistemas y paisajes áridos, pero aún falta una perspectiva integrada sobre los distintos aspectos y procesos hidrológicos y ecológicos que vinculan la conectividad con la degradación y la recuperación de zonas áridas. Aquí, describimos la conectividad ecohidrológica como una propiedad emergente de los ecosistemas y paisajes que captura la interacción entre conectividad hidrológica y procesos ecológicos, y discutimos cómo la conectividad ecohidrológica controla el funcionamiento de los ecosistemas áridos, subyace a las dinámicas de desertificación y puede manejarse para facilitar la recuperación de las zonas áridas degradadas. Una conectividad ecohidrológica disfuncional sería aquella en la que la mayor parte del flujo de recursos asociado a la conectividad del suelo desnudo a escala de ladera o paisaje no puede ser retenido y explotado por el efecto sumidero de la vegetación. Las actuaciones para la recuperación del sistema degradado irían encaminadas a interrumpir la conectividad general de la matriz suelo desnudo, fomentar la dinámica fuente-sumidero y potenciar la capacidad de sumidero de las manchas o teselas de vegetación. A escala de paisaje, la interrupción de la conectividad hidrológica puede, a su vez, crear teselas de hábitat y corredores para una gran variedad de especies, facilitando sus desplazamientos y, de este modo, su conservación y adaptación al cambio climático., Connectivity is defined as the degree to which the spatial structure of the landscape facilitates the flow of organisms and materials. Various conceptual models and empirical evidence attribute a key role to hydrological connectivity in the functioning of dryland ecosystems and landscapes, yet an integrated perspective on the different facets and processes that link connectivity with the degradation and recovery of drylands is still lacking. Here, we describe ecohydrological connectivity as an emergent property of ecosystems and landscapes that captures the interaction between hydrological connectivity and ecological proceses, and discuss how ecohydrological connectivity controls dryland ecosystem functioning, underlies the dynamics of desertification, and can be managed to facilitate the recovery of degraded drylands. A dysfunctional ecohydrological connectivity would be one in which most of the resource flow associated with bare soil connectivity at the slope or landscape scale cannot be retained and exploited by the sink effect of vegetation. Actions for the recovery of the degraded system would be aimed at interrupting the general connectivity of the bare soil matrix, promoting source-sink dynamics and enhancing the sink capacity of the vegetation patches or tiles. At the landscape scale, the disruption of hydrological connectivity can, in turn, create habitat patches and corridors for a wide variety of species, facilitating their movements and thus their conservation and adaptation to climate change.

The development of silvicultural practices that seek to promote structural heterogeneity is increasingly demanded. This work investigates the effect of thinning spatial pattern on the response to pre-commercial thinning of dense Aleppo pine post-fire stands. On three replicated experimental sites in SE Spain, we applied the following treatments: 600 trees/ha, regular thinning pattern (600R), with residual trees evenly spaced; 600 trees/ha, aggregated thinning pattern (600A), with residual pines arranged in clumps of ∽25 trees with a local within-clump density of 2500 trees/ha; and control treatment, with no thinning applied (> 20,000 trees/ha). We assessed treatment effects on pine growth, size-growth relationships, soil water content, and understory vegetation over the first three years after thinning application. Both regular and aggregated thinning pattern similarly increased pine radial growth. In general, dbh growth rates in response to thinning were faster for smaller trees than for larger trees. The growth rate of pine height was higher for 600R and control than for 600A, indicating a positive effect on height of both low and very high pine densities. We found a near-term positive effect of aggregated pattern on water availability at the stand level, mostly resulting from enhanced soil water content in the canopy gaps. For both thinning patterns, the recovery of understory vegetation was dominated by resprouter species. This study highlights the potential of aggregated thinning patterns to enhance the complexity and heterogeneity of the pine stands without compromising pine growth, which could be of great use to managing pine forests in Mediterranean areas.

There is strong empirical evidence on the importance of the spatial pattern of vegetation in dryland hydrologic and geomorphologic dynamics. However, changes in vegetation cover and spatial pattern are often linked, making it difficult to disentangle and assess their independent hydro-geomorphologic roles. We used synthetic sponges placed on the soil surface to mimic the aboveground structure of vegetation patches, and manipulated patch cover and pattern as well as the sink capacity of the patches on a set of 24 (2 × 1 m) runoff plots. Combining natural-rainfall and simulated-rainfall experiments, we aimed to test that (1) both vegetation cover and pattern independently control runoff and sediment yield; (2) for any given cover, coarsening the vegetation pattern entails increasing runoff and sediment yield; and (3) pattern effect is mostly exerted by modulating the source-sink dynamics of the system. We found that increasing either patch cover or patch density decreased runoff and sediment yields from natural rainfalls, yet the effect of patch density largely disappeared when the effect of the co-varying patch cover was removed. Simulated-rainfall experiments on plots with equal medium-low patch cover showed however that coarser patterns (lower patch density; higher patch size) increased runoff coefficients and reduced time to runoff as compared with finer patterns. The effect of patch density was particularly clear when the sink function of vegetation patches was also mimicked. Rainfall interception and direct soil protection proved to be critical mechanisms underlying the effects of patch cover, yet they barely contributed to the effects of patch pattern. The control of overland flow by patch pattern was exerted through changes in the level of runoff disruption. However, physical obstructions to runoff hardly reduced runoff unless coupled to mimicked soil sinks. Overall this work demonstrates the independent effects of patch cover and pattern on the hydro-geomorph

It contains the slide show of the classes corresponding to the international course of the UIMP in November 22nd and 23rd 2021 entitled Sustainable land use policies for agroforestry production in Spain in relation to other EU countries and the world. They are distributed under license Attribution- Non-Commercial - No Derivative Work (by-nc-nd).