Augusto Pérez-Alberti

Phosphorus in seagull colonies and the effect on the habitats. The case of yellow-legged gulls (Larus michahellis) in the Atlantic Islands National Park (Galicia-NW Spain)

During the period 1980-2000, the yellow-legged gull population underwent exponential growth due to an increase in the availability of anthropogenic food resources. The aim of this study was to highlight the effect of the gull colonies on the P soil cycle and the associated effects on coastal ecosystems. Samples of soil, water and faecal material were collected in a colony of yellow-legged gulls (Cíes Islands) and in a control area. Four sampling plots were installed in the study areas, and samples were collected in summer and winter in 1997 and 2011. Sample analysis included soil characterization and determination of the total P content (TP), bioavailable-P and fractionated-P forms in the soils and faecal material. The (31)P NMR technique was also used to determine organic P forms. Clear differences between the gull colony soils and the control soil were observed. The TP was 3 times higher in the gull colony soil, and the bioavailable P was 30 times higher than in the control soil. The P forms present at highest concentrations in the faecal material (P-apatite, P-residual and P-humic acid) were also present at high concentrations in the colony soil. The absence of any seasonal or annual differences in P concentration indicates that the P has remained stable in the soil over time, regardless of the changes in the gull population density. The degree of P saturation indicated that soils are saturated with P due to the low concentration of Fe/Al-hydroxides, which is consistent with a high P concentration in the run-off from the colonies. The P output from the colony soils to coastal waters may cause eutrophication of a nearby lagoon and the disappearance of a Zostera marina seagrass meadow. Similarly, the enrichment of P concentration in dune system of Muxieiro may induce irreversible changes in the plant communities.

A comprehensive analysis of groundwater resources using GIS and multicriteria tools (Caldas da Cavaca, Central Portugal): environmental issues

Hard-rock watersheds are essentially confined to fractured and weathered horizons, but they are a source of valuable water resources at a regional level, namely for domestic, industrial and agricultural purposes, and public supply. They commonly exhibit complex geological bedrock and morphological features as well as distinctive gradients in rainfall and temperature. Hydromineral and geothermal resources have relevant economic value both for the bottled water/thermal spas industry and for energy supply. A comprehensive evaluation and integrated groundwater resources study has been carried out for the Caldas da Cavaca hydromineral system in Central Portugal, using hydrogeomorphology and GIS mapping techniques. Thematic maps were organised from a geodatabase comprising several layers, namely lithology, tectonic lineaments density, slope, drainage density, rainfall, net groundwater recharge and water quality. Normalised weights were assigned to all these categories according to their relative importance to groundwater potential, based on their effectiveness factors. Hydrogeochemistry, natural radioactivity and intrinsic vulnerability assessment (GOD-S, DRASTIC-Fm, SINTACS, SI indexes) issues were also cross-checked. Based on all the compiled information, a hydrogeomorphological map was produced. This multidisciplinary approach highlights the importance of hydrogeomorphological mapping as a tool to support hydrological conceptualisation, contributing to groundwater decision-making process in different stages, like water resources management and territory planning, and thus, to environmental sustainability.

Chapter 6 The rock coast of continental Europe in the Atlantic

Abstract Rocky coasts occur along more than one-third (37%) of the Atlantic continental European coastline, approximately 3666 km, often forming vertical cliffs and characteristically gently sloping shore platforms. The continental European Atlantic rocky coasts show a great variability of rock types and structural contexts, as well as different wave climates and tidal ranges. Through a review of previously published data on cliff retreat rates and shore platform erosion measured on monthly, seasonal, annual and decadal timescales, this paper highlights the different processes and agents, their magnitude and frequency in shaping rocky coasts. In particular, the links between cliff retreat, shore platform evolution, present dynamics and inheritance (understood as whether platform and other rock coast features were shaped by a higher sea level than the present) comprise one of the major contributions from continental European Atlantic rocky coasts to a global understanding of rock coast coastal geomorphology.

Trace elements in biomaterials and soils from a Yellow-legged gull ( Larus michahellis ) colony in the Atlantic Islands of Galicia National Park (NW Spain)

Seabird colonies drastically transform the sites that they inhabit. Although the influence of seabirds on nutrient cycling has been investigated in numerous studies, the effects on trace elements has scarcely been considered. In this study, we determined the total contents of 9 trace elements in biomaterials (excrement, pellets, feathers and eggs) and soils in relation to the presence the Yellow-legged gull Larus michahellis. The concentrations of Zn, Cu and As were particularly high in the pellets and excrement. The total contents of the trace elements were significantly higher in the soils in the sub-colonies in which Yellow-legged gulls predominate than in soil from the control zone (with no gulls). The difference was even higher for the most reactive geochemical fractions. We observed that the oxidizable fraction was the most relevant fraction for almost all trace elements, indicating the importance of organic matter in trace element retention in sandy soils.

Enrichment of trace elements in colonies of the yellow-legged gull (Larus michahellis) in the Atlantic Islands National Park (Galicia-NW Spain)

Marine-derived nutrients are known accumulate in seabird breeding colonies due to the deposition of nutrient-rich biological materials, thus greatly altering the functioning and dynamics of these terrestrial ecosystems. Here we present the results of a sampling survey carried out during three years in yellow-legged gull colonies in the Atlantic Islands of Galicia National Park (NW Spain) with the aim of evaluating the influence of the colonies on the accumulation of trace elements, including micronutrients (Cu, Zn, Se, Co, Mo, Ni) and toxic elements (Cr, Cd, Hg, Pb, As, Ag), in the surrounding environments. For this purpose, we analysed samples of biological materials produced by the seabirds (pellets, excrement, feathers, eggs) and of soil, plants and inland water from several different subcolonies and control zones without seabirds. The concentrations of most of the elements were higher in excrement and pellets (mean values: Zn: 152, As: 50 mg kg-1, Cd: 6, Co: 5 mg kg-1) than in feathers and eggs. The flow of trace elements into the breeding colonies, considering only the excrement, revealed a very high level of trace element deposition for a supposedly pristine environment (Zn: 2667, Cd: 70, Cu: 315, As: 64 g ha-1). The total concentrations of trace elements in soil were consistent with the long-term impact of the seabirds. Thus, the values in areas which this impact was greatest were significantly higher than in the control zones, particularly considering the most labile geochemical fractions of the soil. The concentrations of some elements (i.e. Co, As, Cd) were also higher in the inland waters in the colonies than in control zones. Finally, the concentration of trace elements in plants varied depending on the species and element considered.

The Rocky Coasts of Northwest Spain

The coastline of Galicia is more than 2100 km long (POL Galicia 2010) (Fig. 2.1). Two broad types of coast can be differentiated in the region: zones with rias and zones without rias. Marine inlets dominate in the former, whereas rectilinear stretches dominate in the latter and only small coves or estuaries occur. The megaforms of coastal relief in northwest Spain are clearly determined by the tectonic structure, whereas lithological differentiation has played a predominant role in the genesis of meso and microforms (Perez-Alberti and Blanco-Chao 2005). In general, different factors are involved in shaping the coastline: the overall structure is determined by tectonic processes; the lithology causes differential erosional processes that define the broad features of the coastal front; and, finally, the succession of geomorphological processes that have taken place over time have determined the specific forms and distribution of the different environments. In addition, human activity has affected many areas, particularly the low-lying coastline.

Geomorphic classification of rivers: a new methodology applied in an Atlantic Region (Galicia, NW Iberian Peninsula)

The classification of rivers based on geomorphological criteria played, in the past, a secondary role for management decision making, although in the last years they have experienced a shift from the scientific field to that of the technical. Currently, managers require the most simplified form of classifications in order to use them in plans and planning projects, management and restoration. On the one hand, this means that classifications should be directed toward simplifying the diversity of fluvial environments in a number of manageable types, and on the other hand, to apply to each geomorphic type a management model. In this study, we have developed a method of “Geomorphic Classification of Rivers” according to specific stream power variables and median grain size. The new method is dynamic (ability to readjust and gain robustness with the incorporation of new data) and predictive. We obtained six types directly from the method, although we added a seventh type (bedrock rivers) for its special singularity. Each geomorphic type presents concrete values of specific stream power and median grain size, which additionally involves a hydraulic geometry adjusted to terms of balance. The change from a geomorphic type to another would reflect a geomorphologic imbalance in the form of greater power and sediment size. Our results have been compared with six commonly used classifications (e.g., Rosgen Classification System or River Styles Framework). “Geomorphic Classification of Rivers” stands as a flexible tool that allows the development of a “personalized” geomorphic classification for rivers of the same geomorphological province. Through the temporary revision of various sites that act as control points, we can learn, should the case arise, the intensity and geomorphic change of the site. “Geomorphic Classification of Rivers” acts as an alert system for any geomorphologic disturbance. Its simple application and interpretation facilitate the implementation in the administrative environment, or its attachment to other commonly used classifications.

Combining coastal geoscience mapping and photogrammetric surveying in maritime environments (Northwestern Iberian Peninsula): focus on methodology

Digital photogrammetry and GIS-based mapping are increasingly recognised as powerful tools in littoral issues. This paper considers the interoperability framework for high-resolution imagery acquisition and the development of coastal geoscience maps. The layered system architecture of the cartographic methodology is also explained. Moreover, it highlights a new approach to assessing heterogeneous geologic, geomorphological and maritime environments. The main goal of the present study was to test a new concept for photogrammetric images in order to assist modelling techniques, spatial analysis and coastal conceptual models. This approach proposes a methodological approach to coastal zone monitoring and to maritime forcing conditions evaluating. This approach will allow: (1) the acquisition of a large archive of high-resolution imagery; (2) the development of a coastal database including the entire data field and in situ assessments; (3) the study of coastal dynamics and shoreline evolution; (4) the assessment of the rock platforms and hydraulic structures; (5) the production of coastal geosciences maps. An integrated coastal geoscience and engineering methodology was outlined in NW of Iberian Peninsula (South Galicia and North/Central Portugal regions). This paper reports on the increased knowledge of the studied regions, providing essential data concerning coastal geo-morphodynamics. The overall assessment revealed additional evidence of erosion issues, which contributes to a better understanding of the hydraulic conditions. The main results are presented in regional coastal geoscience maps and local approach-outputs that could help government, local authorities and stakeholders to develop coastal management plans and to recommend strategies.