Hermelindo Castro

Application of the Kohonen neural network in coastal water management: methodological development for the assessment and prediction of water quality.

Kohonen neural network (KNN) was applied to nutrient data (ammonia, nitrite, nitrate and phosphate) taken from coastal waters in a Spanish tourist area. The activation maps obtained were not sufficient to evaluate and predict the trophic status of coastal waters. To achieve this aim, a new methodology is proposed which uses as its starting point the activation maps obtained from KNN. Firstly, to evaluate the trophic status of the coastal waters, it consists of the development of a quadrat system which enables a better classification than the traditional classification based simply on standardized data. The new classification allows clear differentiation of water quality within the mesotrophic band. Secondly, and in order to use the activation maps as predictive tools, the trophic classification, obtained from activation maps, was transposed onto new activation maps. To do this, the activation maps of the sampling points which defined each trophic group were superimposed. To avoid unnecessary complexity and to facilitate the process, this superimposition was undertaken only where the frequency exceeded 0.05. In this way, four frequency maps related to the trophic status of coastal waters (potentially eutrophic, high mesotrophic, low mesotrophic and oligotrophic) were obtained. There was no loss of relevant information in the new maps thus obtained. These frequency maps served as the basis for the successful prediction of the trophic status of random samples of coastal waters. This methodology, based on KNN, is proposed as a tool to aid the decision-making in coastal water quality management.

Agricultural development vs biodiversity conservation: the Mediterranean semiarid vegetation in El Ejido (Almera, southeastern Spain)

The development of a greenhouse agriculture in the traditionally impoverished region of Poniente de Almería, on the Mediterranean coast of Spain, has caused an enormous rise in living standards. However, the environmental impact of this badly-planned growth threatens the every dynamics of the exploitation system. A special examination must be made of the use of the three major resources responsible for the functioning of greenhouse production and its impact on the ecosystems and particularly on the vegetation. These resources are: clayey soils, sand from fossil dunes and ground water. While the use of the clayey soils and sand have negative effects on the conservation of ecologically valuable communities found nowhere else in Europe, ground water overexploitation has produced an increase in salinity in most of the aquifers. Of these, sand has been by far the best monitored resource and restoration programmes have been implemented in the extraction zones. This survey deals with the recent evolution of areas where the arto (Maytenus senegalensis subsp. europaeus) and the sabina (Juniperus phoenicea subsp. turbinata) have long been the dominant species, although the presence of the former is nowadays notoriously diminished. The study is based on aerial photographs taken in 1957, 1977 and 1985, together with our own field work. Curiously enough, all this man-made process of degradation has stimulated ornithological diversity. Finally, we propose here some measures which aim to preserve the most important enclaves of these Mediterranean shrub formations, specially those of the arto, since sabina-dominated communities already belong to existing conservation areas.

Differentiation of Clams from Fishing Areas as an Approximation to Coastal Quality Assessment

The quality assessment of fishing areas on the basis of the levels of heavy metals in clams ( Chamelea gallina) was attempted by using discriminant analysis. Five metals, Hg, Pb, Cd, Cu and Zn, were analyzed in the soft edible parts of clams from three fishing areas. The descriptive methods applied to data obtained do not show enough differences between sampling stations for management purposes. Only discriminant analysis is successful in the differentiation between all fishing areas. Through the first discriminant function, the group centroids are proposed as index of different source of clams. These values standardized are proposed as coastal quality index.

From supply to social demand: a landscape-scale analysis of the water regulation service

Worldwide water managers and policy makers are faced by the increasing demands for limited and scarce water resources, particularly in semi-arid ecosystems. This study assesses water regulation service in semi-arid ecosystems of the southeastern Iberian Peninsula. Comparisons between the supply–demand sides were analyzed across different landscape units. We mapped the biophysical supply as the potential groundwater recharged by aquifers and water supplies from reservoirs. The social demand was focused on an analysis of water consumed or used for irrigation and the stakeholder’s perceptions regarding water regulation importance and vulnerability. Results show that some landscape units are able to maintain and conserve water regulation service when the volume of recharge water by aquifers and the water supply from reservoirs is greater than its consumption (e.g. rural landscape units). However, we also found potential social conflicts in landscape units where water consumption and use is much greater than the water recharge and supply. This particularly occurs in the non-protected littoral areas with the highest water consumption and where water is perceived as a non-important and vulnerable natural resource. Overall, our results emphasized the importance of assessing ecosystem services from both supply to demand sides, for identifying social conflicts and potential trade-offs, and to provide practical information about how to integrate the ecosystem service research into landscape management and planning.

Selection of ecological indicators for the conservation, management and monitoring of Mediterranean coastal salinas

Salinas systems are artificial wetlands which are interesting from the viewpoint of nature conservation. They play an important role both as habitats for migratory waterbird species and as nodes of biotic connectivity networks. In the Mediterranean basin, where the coastal salinas are highly significant as alternative and complementary habitats for waterbirds, a process of abandonment occurs, and many seminatural systems of this kind are disappearing. This abandonment is having serious consequences for migratory bird populations and for the ecological role these play. In the present paper, this group of waterbird species has been used to evaluate these wetlands for conservation purposes. We have developed a methodological approach for the selection of ecological indicators for the conservation and management of these Mediterranean habitats and waterbird assemblages, the main consumers therein. The stepwise procedure developed constitutes a practical tool for this task. Application thereof enabled us to differentiate the habitats available for the waterbirds and to identify the biotic and abiotic indicators for the maintenance and management of the salina ecosystems. These variables can then be incorporated into monitoring programs.

Selección de áreas prioritarias para la conservación de flora gipsícola en el sureste de la Península Ibérica

Recent studies have highlighted the gypsum outcrops of Almeria (southeast Spain) as the most outstanding for the conservation of Iberian gypsophilous flora. The need of preserving this natural heritage and the impossibility to protect all the outcrops present within the territory, led us to identify which areas should be considered as of priority for conservation. To this end, we establish as a priority that the proposed conservation network of sites should include all gypsophyte species at least once. Other possible conservation goals on which to base the area selection and the associated scenarios were also taken into account. We first elaborated a cartography for the gypsophytes based on 10 km sided-cells. Next, in order to rank the importance of each locality, several commonly employed conservation criteria (diversity, rarity of the flora, complementarity) were applied to the cartographic information, and the findings obtained by each procedure contrasted. The results showed that protecting the deposits found in three cells (Sorbas, already protected because of its geomorphological singularity, Venta de los Yesos and Topares) would allow the representation of each species at least once and to achieve several complementary conservation targets. The findings are discussed within the context of the social and administrative peculiarities of the area.

Modeling spatial distribution of European badger in arid landscapes: an ecosystem functioning approach

Understanding the factors determining the spatial distribution of species is a major challenge in ecology and conservation. This study tests the use of ecosystem functioning variables, derived from satellite imagery data, to explore their potential use in modeling the distribution of the European badger in Mediterranean arid environments. We found that the performance of distribution models was enhanced by the inclusion of variables derived from the Enhanced Vegetation Index (EVI), such as mean EVI (a proxy for primary production), the coefficient of variation of mean EVI (an indicator of seasonality), and the standard deviation of mean EVI (representing spatial heterogeneity of primary production). We also found that distributions predicted by remote sensing data were consistent with the ecological preferences of badger in those environments, which may be explained by the link between EVI-derived variables and the spatial and temporal variability of food resource availability. In conclusion, we suggest the incorporation of variables associated with ecosystem function into species modeling exercises as a useful tool for improving decision-making related to wildlife conservation and management.

PLS and PCR Methods in the Assessment of Coastal Water Quality

Partial least squares regression analysis (PLS) and principal component regression analysis (PCR) were examined asmethodological procedures for assessing the quality of coastalwaters in a tourist area. Four variables related to the trophicstate of waters, namely nitrate, nitrite, ammonia and phosphate were analyzed. The models resulting from PLS and PCR were verysimilar. Both defined three groups of water masses characterizedby different nutrient loadings. These groups were in accordancewith those obtained by numerical classification. The PLS methodwas selected as the optimal model, on the basis of its lowerprediction errors (lower Press and Rmsd values). For managementpurposes, this statistical model allows mesotrophic conditions,reflecting some nutrient enrichment over background conditions,to be characterized and the successful diagnosis of additionalsamples within this context.

Remote-sensing based approach to forecast habitat quality under climate change scenarios

As climate change is expected to have a significant impact on species distributions, there is an urgent challenge to provide reliable information to guide conservation biodiversity policies. In addressing this challenge, we propose a remote sensing-based approach to forecast the future habitat quality for European badger, a species not abundant and at risk of local extinction in the arid environments of southeastern Spain, by incorporating environmental variables related with the ecosystem functioning and correlated with climate and land use. Using ensemble prediction methods, we designed global spatial distribution models for the distribution range of badger using presence-only data and climate variables. Then, we constructed regional models for an arid region in the southeast Spain using EVI (Enhanced Vegetation Index) derived variables and weighting the pseudo-absences with the global model projections applied to this region. Finally, we forecast the badger potential spatial distribution in the time period 2071–2099 based on IPCC scenarios incorporating the uncertainty derived from the predicted values of EVI-derived variables. By including remotely sensed descriptors of the temporal dynamics and spatial patterns of ecosystem functioning into spatial distribution models, results suggest that future forecast is less favorable for European badgers than not including them. In addition, change in spatial pattern of habitat suitability may become higher than when forecasts are based just on climate variables. Since the validity of future forecast only based on climate variables is currently questioned, conservation policies supported by such information could have a biased vision and overestimate or underestimate the potential changes in species distribution derived from climate change. The incorporation of ecosystem functional attributes derived from remote sensing in the modeling of future forecast may contribute to the improvement of the detection of ecological responses under climate change scenarios.

Landscape influence on the feeding habits of European badger (Meles meles) in arid Spain

This study evaluates the influence of landscape on the feeding habits of the European badger (Meles meles) in the southern Iberian Peninsula and discusses some potential implications that the scenarios of climate change and land use and land cover changes proposed for this region could have on the diet of badgers. We particularly explore whether different vegetation types and land uses affect its feeding habits across three arid landscapes: maquia, xeric shrubland, and forestry. Although badger diet in Mediterranean environments has been described as frugivorous, in which the key food resources are wild or cultivated fruit (e.g., olives or figs), this species’ diet may vary in response to landscape composition, with individuals locally consuming different key items in an arid Mediterranean context. Based on the analysis of 252 scats collected monthly from June 2011 to May 2012, we found that diet significantly varied among the landscapes studied: Insects, carob, and small mammals were the key items in the maquia, figs, and oranges in the xeric shrubland, and earthworms and insects in the forestry. This shows that in an arid context, badgers adapt their diet to particular landscape conditions. Thus, our results support the important role of human activities, specifically the fruit orchards, in shaping badger diet and highlight the contrasting dietary differences of badgers, i.e., from an animal-based diet to one dominated by cultivated fruits when this type of crops are relevant in the landscape. In these circumstances and based on the proven effect of precipitation and land management practices on the food items identified here, we suggest that crop abandonment and less precipitation could reduce the availability of the badger’s key food resources, locally affecting its fitness and including local extinction where the habitats are extremely arid or crop abandonment is dominant.