Departamento de geografía física y agr

River basin modeling under complexity requires analytical frameworks capable of dealing with the multiple scales and dimensions of environmental problems as well as uncertainty in the evolution of social systems. Conceptual and methodological developments can now be framed using the wide socio-eco-hydrological approach. We add hierarchy theory into the mix to discuss the conceptualization of river basins as complex, holarchic social-ecological systems. We operationalize the social-ecological systems water metabolism framework in a semiarid watershed in Spain, and add the governance dimension that shapes human-environment reciprocity. To this purpose, we integrate an eco-hydrological model with the societal metabolism accounting scheme for land use, human activity, and water use. We explore four types of interactions: between societal organization and water uses/demands, between ecosystem organization and their water requirements/supplies, between societal metabolism and aquatic ecosystem health, and between water demand and availability. Our results reveal a metabolic pattern of a high mountain rural system striving to face exodus and agricultural land abandonment with a multifunctional economy. Centuries of social-ecological evolution shaping waterscapes through traditional water management practices have influenced the eco-hydrological functioning of the basin, enabling adaptation to aridity. We found a marked spatial gradient on water supply, use pattern, and impact on water bodies from the head to the mouth of the basin. Management challenges posed by the European water regulatory framework as a new driver of social-ecological change are highlighted.

Doñana temporary ponds (southwest Spain) form a system of water bodies of remarkable ecological singularity with a high protection status. However, its species composition, diversity, and distribution of algal communities are largely unknown. During a biological survey carried out in shallow temporary ponds in 2010, several unknown diatom taxa were found in various population densities in the epiphyton of these systems. Detailed light and scanning electron microscopy observations allowed the description of five of them (Eunotia vozmedianoi, Planothidium lacustre, Halamphora tharsis, G. undulans and Pinnularia acidophila var. baetica) as taxa new to science. Differential diagnostic criteria with respect to similar taxa, together with ecological and biogeographical implications of these findings, are briefly discussed. Our results support recent studies indicating that endemism in diatoms might be a widespread pattern.

Se analiza el modelo de funcionamiento hidro-geomorfológico de la laguna de Charco del Toro perteneciente al Complejo Palustre del Manto Eólico Litoral de El Abalario-Doñana (Huelva). Se definen los principales elementos estructurales y funcionales que componen el sistema y se establece un modelo teórico en el que se identifican dos escenarios opuestos para el ciclo anual: un máximo seco y un máximo húmedo. Se determina finalmente que la principal entrada de agua al humedal procede del acuífero.

Two specific problems concerning to tholos of  montelirio (Castilleja de Guzmán, Seville, Spain), which features a large passage roofed by stone slabs, are investigated. Firstly, we analyse the main geologic features (lithology, petrography, structures...) of the 42 capstones that cover its long corridor (over 36 m in length and an average width of 1.8 m); among these rocks, 29 of them are sandstones (67.4%), 10 are grey or green shale (23.2%) and three are granite (6.9%). Secondly, we locate potential source areas of these materials, concluding that both granites and shales, either grays or green, come from palaeozoic outcrops located on the southern edge of the Iberian Massif (Sierra Morena, around Gerena-Aznalcóllar, Sevilla), while sandstones, most likely, came from of the outcrops of Mio-Pliocene facies of the El Aljarafe marine sequence.

The study of the edafo-sedimentary sequence of the low Guadalquivir floodplain allows extrapolating Palaeoenvironmental conclusions to the neighboring funerary complex of the Copper Age of Valencina-Guzmán (Seville). For that purpose, the alluvial archives adjacent to the Montelirio tholos site (Santiponce-Seville sector) have been studied, with special emphasis on the analysis of climatic, hydro-geomorphological, anthropic and eustatic factors recorded during the second half of the Holocene close the mouth of the Guadalquivir. Results allow to establish the existence of four large phases characterized by a predominance of alluvial sedimentation (4833-3206 cal BP; 3130-1989 cal BP, 1620 cal BP-XI century AD, and last 500 years), separated by as many episodes of stability favorable to the development of alluvial soils. From the Palaeoenvironmental point of view, it is concluded that only the first of these alluvial phases, (between the Chalcolithic and the Bronze Age), can be unequivocally associated with arid and cold conditions, assuming that these climatic features could be the most adequate for a higher incidence of floods and the accumulation of sediments. However, the strong anthropic impact recorded in this period in the Guadalquivir valley suggests that part of this aridity conditions and this tendency towards sedimentary accumulation also has to do with the human impact on vegetation cover and soils.