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[Background] The global human footprint has fundamentally altered wildfire regimes, creating serious consequences for human health, biodiversity, and climate. However, it remains difficult to project how long-term interactions among land use, management, and climate change will affect fire behavior, representing a key knowledge gap for sustainable management. We used expert assessment to combine opinions about past and future fire regimes from 99 wildfire researchers. We asked for quantitative and qualitative assessments of the frequency, type, and implications of fire regime change from the beginning of the Holocene through the year 2300., [Results] Respondents indicated some direct human influence on wildfire since at least ~ 12,000 years BP, though natural climate variability remained the dominant driver of fire regime change until around 5,000 years BP, for most study regions. Responses suggested a ten-fold increase in the frequency of fire regime change during the last 250 years compared with the rest of the Holocene, corresponding first with the intensification and extensification of land use and later with anthropogenic climate change. Looking to the future, fire regimes were predicted to intensify, with increases in frequency, severity, and size in all biomes except grassland ecosystems. Fire regimes showed different climate sensitivities across biomes, but the likelihood of fire regime change increased with higher warming scenarios for all biomes. Biodiversity, carbon storage, and other ecosystem services were predicted to decrease for most biomes under higher emission scenarios. We present recommendations for adaptation and mitigation under emerging fire regimes, while recognizing that management options are constrained under higher emission scenarios., [Conclusion] The influence of humans on wildfire regimes has increased over the last two centuries. The perspective gained from past fires should be considered in land and fire management strategies, but novel fire behavior is likely given the unprecedented human disruption of plant communities, climate, and other factors. Future fire regimes are likely to degrade key ecosystem services, unless climate change is aggressively mitigated. Expert assessment complements empirical data and modeling, providing a broader perspective of fire science to inform decision making and future research priorities.

La gestión del riesgo de inundación a escala local precisa de instrumentos metodológicos que den apoyo a la toma de decisiones de forma rápida y eficiente. A partir de datos recogidos por estaciones hidrométricas, ubicadas en puntos estratégicos de las cuencas de drenaje, es posible el desarrollo de instrumentos de monitorización de la precipitación y del caudal de los ríos y torrentes. La correlación entre los datos registrados y los episodios de inundación facilitan la puesta en marcha de sistemas de alerta temprana. En este marco se trabaja en el desarrollo de instrumentos de ayuda a la gestión del riesgo a nivel municipal. La información del peligro de inundación se combina con información territorial (catastro, ocupación del suelo, infraestructuras, etc.) mediante el uso de sistemas de información geográfica para realizar una evaluación integrada de la vulnerabilidad por exposición. En este artículo se presentan resultados iniciales del análisis de la vulnerabilidad frente a inundaciones de la ciudad de Palma (Illes Balears). Los resultados muestran un elevado grado de exposición de las zonas residenciales del este de la ciudad constatando incrementos considerables en los últimos decenios., Flood risk management at the local scale requires methodological tools to support decision-making in an efficient way. Based on data collected by hydrometric stations, located at strategic points in drainage river catchments, it is possible to develop tools for monitoring their rainfall and runoff dynamics. The correlation between the data recorded and flood episodes facilitates the implementation of early warning systems. In this framework, work is ongoing to develop tools to support risk management at the municipal scale. Flood hazard information is combined with territorial one (cadastre, land use, infrastructures, etc.) through the use of geographic information systems to perform an integrated vulnerability assessment by exposure. This communication presents the initial results of the vulnerability assessment to flooding in the city of Palma (Balearic Islands). The results showed a high degree of exposure of the residential areas in the east of the city, with considerable increases in recent decades.

[CAT] El segle XXI serà recordat, de ben segur, per una multitud d’esdeveniments, però no hi ha dubte que passarà a la història com el segle en què es començaren a notar els efectes del que s’ha vingut a dir el canvi climàtic, això és, la primera gran variació d’origen antròpic (provocada pels efectes de l’activitat humana) de les condicions climàtiques del planeta. Un dels efectes més tangibles d’aquest nou període que comença és una major proliferació dels fenòmens meteorològics adversos i extrems, moltes vegades amb efectes catastròfics. Un dels més greus que s’ha patit a les Illes Balears els darrers 20 anys es va produir els dies 10 i 11 de novembre de 2001, quan un temporal ciclònic de vent va afectar greument tota la conca mediterrània occidental. A Mallorca, quatre persones varen perdre la vida i diverses resultaren ferides; unes 175.000 persones es quedaren sense llum i es van haver de tallar 29 carreteres. L’impacte socioeconòmic fou brutal (es calcularen pèrdues per valor de més de 37 milions d’euros) i les modificacions substancials en el paisatge encara són paleses en alguns indrets de l’illa dues dècades després. L’anàlisi geoambiental exhaustiva d’aquest i d’altres tres temporals de vent significatius que afectaren els boscos de les Illes Balears és l’objecte d’estudi d’aquesta publicació que sorgeix fruit de la col·laboració interadministrativa entre la Universitat de les Illes Balears i la Conselleria de Medi Ambient i Territori. Aquest estudi pretén aprofundir en el coneixement de les dinàmiques dels nostres ecosistemes i hàbitats insulars, especialment després del greu impacte produït per una pertorbació natural com són els temporals de vent, un fenomen intrínsec a les regions de climes mediterranis, però que, en el context actual, en què es produeix un efecte combinat entre l’escalfament global i els canvis dràstics en els usos del sòl, tendeix a intensificar-se.

The influence of the sea and topography are vital factors in the atmospheric processes affecting any island, as they introduce peculiarities in the hydrosedimentary response of fluvial systems. In view of that, the relationship between the surface atmospheric conditions (weather types, WTs), rainfall, runoff and erosion dynamics in three small catchments located in Mallorca were analysed. The catchments are representative in terms of geomorphology and land use but also due to their location within the major rainfall areas previously identified in the island by (Sumner et al., 1993). Data of rainfall, runoff and sediment variables, coupled with calculated WTs were used for the 2013–2017 period. WTs frequency and distribution during this period were compared to the last climatic period reference (1981–2010) to test the climate validity of the study period. The results illustrated how hydrosedimentary response was mostly caused by eco-geographical patterns but also by differences in the response of each catchment to WTs, related to the intrinsic geographical position in the island and different exposures to humid winds. Anticyclonic WT was the most frequent, despite it being only involved in one flood event at the eastern catchment. Conversely, eastern and northeastern WTs generated more than 85% of the total runoff and sediment, representing only 39% of flood events. The understanding of the specific role of WTs on the island's hydrology was improved, considering that freshwater resources are scarce and eco-sociologically crucial.

[EN] A flash-flood event hit the northeastern part of Mallorca on 9 October 2018, causing 13 casualties. Mal- lorca is prone to catastrophic flash floods acting on a sce- nario of deep landscape transformation caused by Mediter- ranean tourist resorts. As global change may exacerbate dev- astating flash floods, analyses of catastrophic events are cru- cial to support effective prevention and mitigation measures. Field-based remote-sensing and modelling techniques were used in this study to evaluate rainfall¿runoff processes at the catchment scale linked to hydrological modelling. Continu- ous streamflow monitoring data revealed a peak discharge of 442 m³ s¿¹ with an unprecedented runoff response. This ex- ceptional behaviour triggered the natural disaster as a com- bination of heavy rainfall (249 mm in 10 h), karstic features and land cover disturbances in the Begura de Salma River catchment (23 km²). Topography-based connectivity indices and geomorphic change detection were used as rapid post- catastrophe decision-making tools, playing a key role dur- ing the rescue search. These hydrogeomorphological preci- sion techniques were combined with the Copernicus Emer- gency Management Service and ¿ground-based¿ damage as- sessment, which showed very accurately the damage-driving factors in the village of Sant Llorenç des Cardassar. The main challenges in the future are to readapt hydrological modelling to global change scenarios, implement an early flash-flood warning system and take adaptive and resilient measures on the catchment scale.

Soil moisture conditions play a key role in runoff and sediment load dynamics in river catchments of contrasting ecosystems. However, the highly marked seasonality of Mediterranean climate affects hydrological processes and sediment transport strongly, as evapotranspiration determines a succession of wet, transition and dry periods throughout a hydrological year. This study examines results of soil moisture, water and sediment fluxes during five hydrological years in a representative small mid-mountain Mediterranean catchment. It aims to assess the sediment load contribution and its variability at different temporal scales. Precipitation, runoff and suspended sediment load were calculated at annual, seasonal and event scales to assess inter- and intra-annual variability. A database with 45 events was used to identify the main controlling factors over sediment load thought bivariate relationships and an analysis of soil moisture-discharge and discharge-suspended sediment concentration hysteresis. At the annual scale, lithology, land use and soil conservation structures characteristic of the catchment caused low values of sediment yield, although inter-annual rates varied by up to three orders of magnitude (0.08 to 11.86 t km−2 y−1). Seasonal analysis of accumulated sediment load showed that 80% was generated during the autumn and winter seasons. At the event scale, streamflow and soil moisture were the controlling factors for the largest sediment load contributions. The highest frequency of clockwise discharge-suspended sediment concentration hysteresis revealed that most of the sediment was generated from nearby sources, although the largest sediment loads were contributed under wet antecedent conditions, as depicted by the soil moisture-discharge hysteresis assessment.

A flash-flood event hit the northeastern part of Mallorca on 9 October 2018, causing 13 casualties. Mallorca is prone to catastrophic flash floods acting on a scenario of deep landscape transformation caused by Mediterranean tourist resorts. As global change may exacerbate devastating flash floods, analyses of catastrophic events are crucial to support effective prevention and mitigation measures. Field-based remote-sensing and modelling techniques were used in this study to evaluate rainfall–runoff processes at the catchment scale linked to hydrological modelling. Continuous streamflow monitoring data revealed a peak discharge of 442 m3 s−1 with an unprecedented runoff response. This exceptional behaviour triggered the natural disaster as a combination of heavy rainfall (249 mm in 10 h), karstic features and land cover disturbances in the Begura de Salma River catchment (23 km2). Topography-based connectivity indices and geomorphic change detection were used as rapid post-catastrophe decision-making tools, playing a key role during the rescue search. These hydrogeomorphological precision techniques were combined with the Copernicus Emergency Management Service and “ground-based” damage assessment, which showed very accurately the damage-driving factors in the village of Sant Llorenç des Cardassar. The main challenges in the future are to readapt hydrological modelling to global change scenarios, implement an early flash-flood warning system and take adaptive and resilient measures on the catchment scale.

Rainfall is the key factor to understand soil erosion processes, mechanisms, and rates. Most research was conducted to determine rainfall characteristics and their relationship with soil erosion (erosivity) but there is little information about how atmospheric patterns control soil losses, and this is important to enable sustainable environmental planning and risk prevention. We investigated the temporal and spatial variability of the relationships of rainfall, runoff, and sediment yield with atmospheric patterns (weather types, WTs) in the western Mediterranean basin. For this purpose, we analyzed a large database of rainfall events collected between 1985 and 2015 in 46 experimental plots and catchments with the aim to: (i) evaluate seasonal differences in the contribution of rainfall, runoff, and sediment yield produced by the WTs; and (ii) to analyze the seasonal efficiency of the different WTs (relation frequency and magnitude) related to rainfall, runoff, and sediment yield. The results indicate two different temporal patterns: the first weather type exhibits (during the cold period: autumn and winter) westerly flows that produce the highest rainfall, runoff, and sediment yield values throughout the territory; the second weather type exhibits easterly flows that predominate during the warm period (spring and summer) and it is located on the Mediterranean coast of the Iberian Peninsula. However, the cyclonic situations present high frequency throughout the whole year with a large influence extended around the western Mediterranean basin. Contrary, the anticyclonic situations, despite of its high frequency, do not contribute significantly to the total rainfall, runoff, and sediment (showing the lowest efficiency) because of atmospheric stability that currently characterize this atmospheric pattern. Our approach helps to better understand the relationship of WTs on the seasonal and spatial variability of rainfall, runoff and sediment yield with a regional scale ba

Mediterranean-climate catchments are characterized by significant spatial and temporal hydrological variability caused by the interaction of natural as well human-induced abiotic and biotic factors. This study investigates the non-linearity of rainfall-runoff relationship at multiple temporal scales in representative small Mediterranean-climate catchments (i.e., <10 km2) to achieve a better understanding of their hydrological response. The rainfall-runoff relationship was evaluated in 43 catchments at annual and event—203 events in 12 of these 43 catchments—scales. A linear rainfall-runoff relationship was observed at an annual scale, with a higher scatter in pervious (R2: 0.47) than impervious catchments (R2: 0.82). Larger scattering was observed at the event scale, although pervious lithology and agricultural land use promoted significant rainfall-runoff linear relations in winter and spring. These relationships were particularly analysed during five hydrological years in the Es Fangar catchment (3.35 km2; Mallorca, Spain) as a temporal downscaling to assess the intra-annual variability, elucidating whether antecedent wetness conditions played a significant role in runoff generation. The assessment of rainfall-runoff relationships under contrasted lithology, land use and seasonality is a useful approach to improve the hydrological modelling of global change scenarios in small catchments where the linearity and non-linearity of the hydrological response—at multiple temporal scales—can inherently co-exist in Mediterranean-climate catchments.

The diagnosis of land degradation requires a deep understanding of ecosystem functioning and evolution. In dryland systems, in particular, research efforts must address the redistribution of scarce resources for vegetation, in a context of high spatial heterogeneity and non-linear response. This fact explains the prevalence of eco-hydrological perspectives interested in runoff processes and, the more recent, focused on connectivity as an indicator of system resource optimisation. From a geomorphological perspective and reviewing the concepts of eco-hydro-geomorphological interactions operating in ecosystems, this paper explores the effects of erosion on vegetation configuration through two case studies at different spatio-temporal scales. We focus on the structure-function linkage, specifically on how morphological traits relate with different stages in the erosional sequence, both in the abiotic and the biotic domain. Results suggest that vegetation dynamics are affected by structural boundary conditions at both scales, i.e. by surface armouring related with rock fragments at the patch scale, and by the degree of hillslope-channel coupling at the hillslope scale. Our preliminary results can serve as new working hypotheses about the structure-function interplay on hillslopes. All this, taking advantage of the recent technological achievements for acquiring very high-resolution geospatial data that offer new analytical possibilities in a range of scales.