las comunidades de peces del río guadiamar y el accidente minero ...

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Relaciones peces/hábitat en el Guadiamar coleopteran communities, Cárdenas and Hidalgo, 2006; ant communities, Luque et al., 2007; crayfish, Alcorlo et al., 2006; reptile community, Marquez-Ferrando et al., 2009; mice, Bonilla-Valverde et al., 2004; otters, Delibes et al., 2009; etc.), providing different results about the remaining spill influence. Unfortunately, few studies have focused on monitoring the recovery of the fish community (but see Fernández-Delgado and Drake, 2008). To the best of our knowledge, this is one of the first studies that address the recovery of the fish community in the Guadiamar River and its relationships with habitat conditions several years after the toxic spill. Fish community structure is determined by a wide range of biotic and abiotic processes, and community composition changes over time and space (Magalhaes et al., 2002a, 2002b; Blanchet et al., 2009). Community relationships with these processes should be considered at different scales, since fish have both local and catchment mobility (Tolonen et al., 2003; Pinto et al., 2006). The recovery of aquatic systems from anthropogenic impacts depends not only on revealing the causes of impairment, but also on anticipating their responses to stressors operating at multiple scales (Ferreira et al., 2007). Recent attempts to meet these needs include studies identifying ecological indicator metrics (e.g., Karr, 1991; Wright, 1995; Barbour et al., 1999; Norris and Hawkins, 2000; Hermoso et al., 2010) and efforts comparing the effects of anthropogenic land use at various scales, from the stream reach to the entire basin (e.g., Roth et al., 1996; Lammert and Allan, 1999; Sponseller et al., 2001; Wang et al., 2001; Wasson et al., 2010). Consequently, it is important to consider the scale at which habitat variables are recorded (Allan et al., 1997a, b; Allan, 2004; Pinto et al., 2006; Hughes et al., 2009; Hermoso et al., 2010), and thus identify the spatial scale at which the most important variables for the community are acting. In this study, the main aims were 1) to identify the main environmental variables that currently determine both native and exotic fish species richness and diversity in the Guadiamar River basin at different scales, and 2) to assess whether the toxic spill can still be considered influential for fish richness and diversity eight years after the accident. 55
Las comunidades de peces del río Guadiamar y el accidente minero de Aznalcóllar Materials and Methods Study area The Guadiamar River basin is located in the South-western Iberian Peninsula at latitude 37º 10’ to 37º 45’ N and longitude 6º 10’ to 6º 25’ W, near the Guadalquivir River mouth in the Atlantic Ocean (Fig. 1). The basin area is 1.325 km 2 , and altitude ranges from 4 to 544 m.a.s.l. Climate is sub-humid Mediterranean with oceanic influences, with average temperatures between 9ºC in winter and 29ºC in summer. Mean annual rainfall is 624 mm, oscillating between 754 mm in the source and 543 mm in the mouth. Rain falls abundantly in autumn, winter and spring and is completely absent in summer. This severe drought causes the drying of most small streams or the creation of isolated pools of different sizes (Gasith and Resh, 1999). The basin shows a geological transition linked to river section type. The upper section (near the source) runs between narrow and steep valleys formed by Palaeozoic slates and quartzite crests. The middle section crosses quaternary alluvial deposits, loams, sands and edge limestone rolling hills. Finally, the lower section flows through clay and lime deposits forming a marshland. Pine forests (Pinus spp.) and dehesas (cleared, savannah-like Quercus spp. Mediterranean forest) are the predominant vegetation in the upper section; olive groves, cereal fields and vineyards form a mosaic in the middle section; and the marsh starts in the lower section, close to Doñana Natural Park, dominated by Salicornia spp. shrubs, and pastures with Sylibus marianum, Hordeum murinum and Plantago coronopus. The hydrological network is disrupted by three dams (Fig. 1). Two small ones that collect less than 4 hm 3 in the source area and one large reservoir (20 hm 3 ) in the Agrio River, slightly upstream from the spill point (Borja et al., 2001). 56
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DEPARTAMENTO DE ZOOLOGÍA UNIVERSID
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DEPARTAMENTO DE ZOOLOGÍA UNIVERSID
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TITULO DE LA TESIS: LAS COMUNIDADES
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A mi Madre,
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A mis antiguos compañeros del Grup
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Material and Methods 39 Results 45
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ABSTRACT This PhD Thesis analyzes t
Page 17 and 18: Las comunidades de peces del río G
Page 25 and 26: ÁREA DE ESTUDIO Cuenca del río Gu
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Page 31 and 32: Área de estudio Principales impact
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Page 50 and 51: Condición somática de L. sclateri
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Las comunidades de peces del río G
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Appendix 1. Environmental variables
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