21 p. | [ESP] La lluvia es el primer proveedor de agua de los ecosistemas forestales. En las áreas de estación seca tiene gran importancia además al contabilizarse las entradas de bioelementos que se depositan como polvos atmosféricos durante la sequía y se disuelven parcialmente al inicio de la estación húmeda. Más tarde, las aguas de lluvia se enriquecen de bioelementos al atravesar el dosel arbóreo (aunque no siempre es así, puesto que algunos nutrientes pueden ser absorbidos en medios oligotrofos). Posteriormente, el agua atraviesa la hojarasca forestal en descomposición donde se producen intercambios de bioelementos, aveces con ganancias, a veces con pérdidas. En algunos ecosistemas cobra importancia (por la alta concentración en bioelementos) el escurrimiento cortical, fracción hídrica que se concentra en el área de las raíces de los árboles. Gran parte de los bioelementos que han enriquecido el agua de lluvia al alcanzar el epipedon edáfico son absorbidos en los primeros centímetros del suelo, por lo que la concentración de los mismos en el agua que circula por los macroporos edáticos disminuye al atravesar el horizonte superior. Por otro lado, la concentración de la solución edáfica que ocupa los microporos varía dependiendo tanto de la presión utilizada para extraer el agua, como también de la intensidad de la actividad vegetal. Por último, parte del agua de drenaje profundo puede aflorar a la superficie para formar arroyos con una composición químicageneralmente similar al agua libre del suelo. Para ilustrar toda esta dinámica se exponen la metodología y resultados obtenidos en un bosque (Monte Medio dc unos 00 iños, de rebollo (Querrurpyrma~\v illd. ,situado en la Sierra de Gata Qistemd Cenrral es.na ñol., .n róxinii>.t In fronrera rwirrurursa (B;irrrr~do s Foios. A'ava<i'rii<.P riivinciadcSalamanca,: 1.1 A - . . ~Juviometríae s cercana a los 1500 L m~ 'a ño^' con acusada sequía estival y la temoeratura media anual próxima a los 11 "C. Son dominantes los esquistos, originándose Cambisoler húmicos (suelo forestal ácido poco evolucionado), sin que existan síntomas erosivos de importancia (pendientes entre el S y el 15%). | [ENG]Rainfall is the first input of water in forest ecosystems. In areas with dry season, it is important to quantify the inputs of bioelements by bulk precipitation but also those inputs provoked by the atmospheric dusts, part of which could be dissolved during the rainy season (autumn and spring in Mediterranean areas).In general, the rain water is enriched by bioelements when it crosses the forest canopy (thrnughfall); nevertheless, sometimes it is possible to observe leaf absorption of some bioelements). There is also an element concentration because of the partial evaporation of the rain water at the canopy level (water interception). Both processes can exist together. Later on, throughfall water leaches the forest litter, modifying the chemical composition. In some cases can also exist a superficial runoff, which is very low in the Mediterranean forest ecosystem studied. In addition, stemflow concentrates bioelements close to the trunk area. When the leaching water moists the soil, there is an exchange of bioelements that frequently drives to an impoverishment of the water solution owed to soil and plant hioelement-sorptions. In this way, the water solution is generally diluted when reaches the inorganic, deeper soil-horizon depth. Also, soil pores hold water solutions that change their composition according to pore sizes. A part of the water that crosses the soil can spring up, creatingllausing (more or less intermittent) streams; the composition of this water is quite similar to the soil solution at the deepest soil horizon. To illustrate these dynamics and processes, the results obtained in an oak (Quercurpyrenaica) coppice hated at Navasfrias ('Sierra de Gutu', Western Spain) are shown and discussed. The forest plot has a mean annual pluviometry near 1500 L m-2 yr.', a mean annual temperature close to 11 "C, and dominant soils are humic Cambirolr on Palamzoic schist; the slopes range from 5 till 15 % and the catchment area of the intermittent stream that drains the forest plot is about 20 ha. | Peer reviewed

This paper presents a comparison of several simulation models of interception process commonly used in numerous studies, such as the classic versions of Rutter and Gash, also the version of Valente adapted by sparse forests. The aim is to analyze the applicability of different models in isolated especimens of two species of Mediterranean climate, Pinus pinea and Cistus ladanifer. The data collection was carried out in the watershed of “El Cabril” (Córdoba), from October 2010 to June 2015. The differences obtained between measurements and the results of the different models are less than 6%. Original version of Rutter model and original version of Gash model present a greater adjustment for pine and for cistus respectively. | En este trabajo se realiza una comparación de varios modelos de simulación del proceso de interceptación, comúnmente utilizados en numerosos estudios, como son las versiones clásicas de Rutter y de Gash, además de la versión adaptada por Valente a bosques dispersos. El objetivo es analizar la aplicabilidad de los diferentes modelos en ejemplares aislados de dos especies de clima mediterráneo, Pinus pinea y Cistus ladanifer. La toma de datos se ha realizado en la cuenca de “El Cabril” (Córdoba), desde octubre de 2010 a junio de 2015. Las diferencias obtenidas entre las medidas de campo y los resultados de los diferentes modelos son inferiores al 6%, siendo el modelo de Rutter en su versión original el que mejor se ajusta en pino y el modelo original de Gash el que mejor se ajusta en el caso de la jara.

High and variable levels of salinity were investigated in an intermittent stream in a high-rainfall area (∼800 mm/year) of the Mt. Lofty Ranges of South Australia. The groundwater system was found to have a local, upslope saline lens, referred to here as a groundwater salinity ‘hotspot’. Environmental tracer analyses (δ¹⁸O, δ²H, ⁸⁷/⁸⁶Sr, and major elements) of water from the intermittent stream, a nearby permanent stream, shallow and deep groundwater, and soil-water/runoff demonstrate seasonal groundwater input of very saline composition into the intermittent stream. This input results in large salinity increases of the stream water because the winter wet-season stream flow decreases during spring in this Mediterranean climate. Furthermore, strontium and water isotope analyses demonstrate: (1) the upslope-saline-groundwater zone (hotspot) mixes with the dominant groundwater system, (2) the intermittent-stream water is a mixture of soil-water/runoff and the upslope saline groundwater, and (3) the upslope-saline-groundwater zone results from the flushing of unsaturated-zone salts from the thick clayey regolith and soil which overlie the metamorphosed shale bedrock. The preferred theory on the origin of the upslope-saline-groundwater hotspot is land clearing of native deep-rooted woodland, followed by flushing of accumulated salts from the unsaturated zone due to increased recharge. This cause of elevated groundwater and surface-water salinity, if correct, could be widespread in Mt. Lofty Ranges areas, as well as other climatically and geologically similar areas with comparable hydrogeologic conditions.