Predictive models of turbidity and water depth in the Doñana marshes using Landsat TM and ETM+ images

We have used Landsat-5 TM and Landsat-7 ETM+ images together with simultaneous ground-truth data at sample points in the Doñana marshes to predict water turbidity and depth from band reflectance using Generalized Additive Models. We have point samples for 12 different dates simultaneous with 7 Landsat-5 and 5 Landsat-7 overpasses. The best model for water turbidity in the marsh explained 38% of variance in ground-truth data and included as predictors band 3 (630–690 nm), band 5 (1550–1750 nm) and the ratio between bands 1 (450–520 nm) and 4 (760–900 nm). Water turbidity is easier to predict for water bodies like the Guadalquivir River and artificial ponds that are deep and not affected by bottom soil reflectance and aquatic vegetation. For the latter, a simple model using band 3 reflectance explains 78.6% of the variance. Water depth is easier to predict than turbidity. The best model for water depth in the marsh explains 78% of the variance and includes as predictors band 1, band 5, the ratio between band 2 (520–600 nm) and band 4, and bottom soil reflectance in band 4 in September, when the marsh is dry. The water turbidity and water depth models have been developed in order to reconstruct historical changes in Doñana wetlands during the last 30 years using the Landsat satellite images time series.     

Integrating Landscape Analysis and Planning: A Multi-Scale Approach for Oriented Management of Tourist Recreation

Tourism and landscape are interdependent concepts. Nature- and culture-based tourism are now quite well developed activities and can constitute an excellent way of exploiting the natural resources of certain areas, and should therefore be considered as key objectives in landscape planning and management in a growing number of countries. All of this calls for careful evaluation of the effects of tourism on the territory. This article focuses on an integrated spatial method for landscape analysis aimed at quantifying the relationship between preferences of visitors and landscape features. The spatial expression of the model relating types of leisure and recreational preferences to the potential capacity of the landscape to meet them involves a set of maps showing degrees of potential visitor satisfaction. The method constitutes a useful tool for the design of tourism planning and management strategies, with landscape conservation as a reference.     

Sediment integrative assessment of the Bay of Cádiz (Spain): An ecotoxicological and chemical approach

This study consisted of the sediment toxicity assessment of the Bay of Cádiz based on two endpoints: growth inhibition for Cylindrotheca closterium (benthic microalgae) and fecundity inhibition for Tisbe battagliai (harpacticoid copepod). A new methodology to eliminate (but not as storage technique) the autochthonous biota present in the sediment samples by immersing them in liquid nitrogen (? 196 °C) was also assessed. Sediment toxicity data showed different toxicity levels for both organisms. In general, T. battagliai was more sensitive; however a good correlation (r = 0.75; p  < 0.05) between sediment toxicity results for both species was found. Data in pore water (pH, redox potential, and toxicity for microalgae and copepod) and sediment (pH, redox potential, organic carbon, and metal concentrations) demonstrated that ultra-freezing did not alter sample characteristics; thus, this technique can be adopted as a pre-treatment in whole-sediment toxicity tests in order to avoid misleading results due to presence of autochthonous biota. Multivariate statistical analysis such as cluster and principal component analysis using chemical and ecotoxicological data were employed. Silt and organic matter percentage and lead concentration were found to be the factors that explain about 77% of sediment toxicity in the Bay of Cádiz. Assay methodology determined in this study for both assayed species is considered adequate to be used in sediment toxicity monitoring programs. Results obtained using both species show that the Bay of Cádiz can be considered a moderately polluted zone.     

Sorption of alkylphenols on Ebro River sediments: comparing isotherms with field observations in river water and sediments

This study reports sorption isotherms of the endocrine disruptors nonylphenol (NP) and octylphenol (OP) in three sediment samples from the Ebro River basin (NE Spain), with organic carbon fractions (f_OC) ranging from 0.0035 to 0.082 g_OC g⁻¹. All isotherms were fitted to the Freundlich model with slightly nonlinear exponents ranging from 0.80 to 0.94. The solubility of the compounds as well as the organic carbon (OC) content had the strongest influences on the sorption behavior of these compounds. Comparison of the laboratory-spiked samples with the native contamination of NP of 45 water and concurrent sediment samples resulted in reasonable matches between both data sets, even though the lowest concentrations in the field were not completely reached in laboratory tests. This good agreement indicates that sorption laboratory data can be extrapolated to environmental levels and therefore the distribution of nonylphenol between sediments and water can be predicted with a precision of one order of magnitude. Furthermore, laboratory experiments with simultaneous loading of NP and OP revealed negligible competition for sorption sites at low concentrations.     

Anoxic-aerobic treatment of the liquid fraction of cattle manure

Cattle manure from a dairy farm was treated in order to reduce its pollution potential. The manure came from a farm with 120 cows kept in stables in a free stall barn. As pretreatment, the manure is usually filtered on the farm using a screw press separator with a 0.5 mm mesh. Approximately 70% of the total filtered volume passes through the screen, thus constituting the liquid fraction. This fraction, with a composition of around 64,500 mg COD/l, 5770 mg total-N/l and 800 mg total-P/l, was subjected to centrifugation followed by a two-step biological treatment (anoxic-aerobic) to reduce organic matter (COD), nitrogen and phosphorus compounds. Centrifugation led to the following removal efficiencies: 35% total solids, 60% COD, 75% total phosphorus and 20% total nitrogen (mainly organic nitrogen). With the subsequent anoxic-aerobic treatment, average removal efficiencies of 85% for COD, 90% for total phosphorus and 75% for total nitrogen were achieved.     

Injury and loss concentration by sinkings in fishing fleets

Sinkings of fishing vessels, when accompanied by human loss, are accidents which lead to a great social upheaval, especially in the local area where they occur. In order to avoid or reduce these accidents, national governments must include in their legislation for this sector the appropriate safety measures. These resources and their distribution must be assigned in accordance with the needs of the accidentality, this requiring a detailed knowledge of the concentration of accidentality of a country’s fishing sector. In this context, the aim of the present work is twofold: first, to formulate a methodology for the fishing sector of a country, allowing the inequalities in the concentration of sinking accidents to be analysed; and second, to apply this methodology to the Spanish fishing fleet. Thus, two indices are constructed per region and type of fishing, for two variables: fishermen and vessels. Results are obtained both for the concentration of accidents and the associated Lorenz curves. An increase in the inequality in the spatial and functional distribution of these accidents is verified.     

Ecological footprint: an indicator of environmental sustainability of a surface coal mine

Ecological footprint of mining can be used as an indicator to monitor and regulate mining operations and ensure long-term environmental sustainability. It can be viewed as a mining footprint, which is surrogate of the environmental impacts of mining. In this paper, a methodological framework is developed to demonstrate how ecological footprint can be used as an indicator of environmental degradation. Nine air quality and 26 soil quality samples are collected from the adjoining area of a mechanized coal mine, located in Raniganj coal mining belt of Burdwan district, West Bengal. Geographical information system is used for data interpolation and preparation of air and soil quality maps. The weights of different air and soil quality parameters are calculated by running principal component analysis. These derived weights are used for preparation of final composite air and soil quality maps. The composite maps show the mining footprints, expressed as land equivalent, around the active mine sites. The impact zones reveal the extent of degradation of the soil and air qualities in the areas near a mine. It is found that the impact zones, with respect to air and soil qualities, extend over areas which are 7.7 and 7.8 times the actual mining areas, that is, the area covered under mining operations, respectively. The results show the extent of degradation of air and soil qualities of the area. At different stages of mining, these footprints can be used as indicators to reveal the areas where soil and air qualities are adversely impacted.     

Sustainable cooking energy options for rural poor people in India: an empirical study

Currently, energy consumption for cooking in rural households of India is mostly based on fuelwood used in traditional stoves. This paper presents results of a study carried out in a forest fringe area of India on cooking energy use. The concept of calculating levelized cost as cost per unit of useful energy is applied on source–device combinations of cooking and validated in Bargaon Community Development Block of Sundergarh District in Odisha, India. About 92 % of the households in the study area use fuelwood as the only energy source for cooking; the total use of fuelwood for only cooking, in the Block is nearly 1.8 times the total sustainable wood supply showing an urgent need for promoting alternative cooking energy options. This paper also presents an assessment of different cooking options in terms of cost per unit of useful cooking energy. LPG, biogas and gasifier stoves are found to be far too expensive for the local people. Briquette-fired improved stoves appear to be a promising cooking energy option in the study area. Government support and intervention are recommended for promoting this option.     

Using linear regression to measure bird abundance

This study investigated methods for identifying daily incidence rates for bird species. It focused on relationships between incidence rates, site and season. We used sightings of 23 common resident species routinely reported every month from January 2004 to December 2007 at seven wetland locations in the Thale Noi non-hunting area of southern Thailand. Our findings revealed that the log-linear model gives a quite satisfactory fit, so it appears a suitable type of model for bird abundance. On taking logarithms of the incidence rates though, the zero counts must be replaced by an appropriate constant. Our model suggests that Cattle Egret (Bubulcus ibis) was found at the Thale Noi non-hunting area with the highest incidence rate. In contrast, we found a low mean of model outputs for Lesser Whistling-Duck (Dendrocygna javanica) relative to the mean in the data, and this species was not observed on at least 25 % or 3 days per year. These data had a low number of zeros and a large number of various species. Therefore, we recognize a remark on “what is being counted” that it is important to reasonably explain the species abundance in terms of statistical and ecological approaches.