Remote Sensing and GIS Technologies as Tools to Support Sustainable Management of Areas Devastated by Landslides

IKONOS panchromatic images from a single year were used to characterise the effects of an extreme rainstorm event on six mountain catchment areas in Venezuela. Image registrations were accomplished using topographic base maps at 1 : 5000 scale giving a mapping accuracy between 37 and 40 m. It was used an 8-bit channel for correction, rectification, filteration and tone enhancements.Landsliding was discerned in the affected watersheds using morphometric criteria, including the shape of the slope failure and its position, exposure bedrock in the scar and deposition of debris down-slope. This study is restricted to the impact analysis of the distribution of landslide erosion scars and the depositional processes on the valley floor. Remote sensing data were combined into a geographic information system (GIS) with planimetric data, contour lines, hydrology and vegetation types to evaluate the distribution of the scars and their effects on the highly populated areas located on the alluvial fans. Hillslope mass wasting induced mass movements, logging and increased the mud and silt in floodwaters affecting settlement down-slope.     

The Tourism Carrying Capacity of Underwater Trails in Isabel Island National Park, Mexico

The popularity of ecotourism in the marine protected areas of Mexico has increased over the last 10 years; in particular there is a large development of a SCUBA diving industry in the Mexican Pacific including Isabel Island. Given the risks associated with human activity in the marine environments around this island, we propose two ecotourism management strategies: (1) the creation and use of underwater trails, and (2) the estimation of the specific tourism carrying capacity (TCC) for each trail. Six underwater trails were selected in sites that presented elements of biological, geological, and scenic interest, using information obtained during field observations. The methodology used to estimate the TCC was based upon the physical and biological conditions of each site, the infrastructure and equipment available, and the characteristics of the service providers and the administrators of the park. Correction factors of the TCC included elements of the quality of the visit and the threat and vulnerability of the marine environment of each trail (e.g., divers’ expertise, size and distance between groups of divers, accessibility, wind, coral coverage). The TCC values ranged between 1,252 and 1,642 dives/year/trail, with a total of 8,597 dives/year for all six trails. Although these numbers are higher than the actual number of recreational visitors to the island (~1,000 dives per year), there is a need for adequate preventive management if the diving sites are to maintain their esthetic appeal and biological characteristics. Such management might be initially directed toward using only the sites and the TCC proposed here.     

Persistent Detection of Cosavirus and Saffold Cardiovirus in Riachuelo River,Argentina

Food and Environmental Virology - Cosaviruses (CoSV) and Saffold cardiovirus (SAFV) are novel members of the Picornaviridae family. The Matanza-Riachuelo river basin covers a total area of 2200 km2...     

Chemosensory assessment of rival body size is based on chemosignal concentration in male Spanish terrapins

Assessment of the fighting ability of potential opponents is an essential skill to minimize the costs of agonistic interactions between males. Previous research showed that chemical cues released in the water by male turtles may convey information about body size, which is important for intrasexual competition. However, the mechanistic basis of such chemical signaling of body size remains poorly understood. Here, we aimed to experimentally examine whether the release of chemosignals is quantitatively or qualitatively dependent on body size in male Spanish terrapins Mauremys leprosa. We compared the time that turtles spent in a pool with clean water versus water containing chemical stimuli of conspecific males of different body sizes at two different concentrations (“diluted” or “undiluted”). Male terrapins avoided water with chemicals secreted by relatively larger males when these chemicals were undiluted, but not after the chemical stimuli were diluted. In contrast, male terrapins did not avoid chemicals of relatively smaller males in any treatment. Thus, male M. leprosa may assess the size of their rivals on the basis of the concentration or the amounts of their chemical cues released into the water and consequently avoid occupying these ponds with higher concentrations of chemicals. This study gives important hints about the mechanism of chemical signaling in freshwater turtles and demonstrates that male turtles may discriminate different concentrations of chemosignals of conspecifics and modify their behavior accordingly. Likewise, our results support the notion that relative body size is a key factor during male interactions in Spanish terrapins.     

Relationship between blood concentrations of heavy metals and cytogenetic and endocrine parameters among subjects involved in cleaning coastal areas affected by the 'Prestige' tanker oil spill

The sinking of the 'Prestige' oil tanker in front of the Galician coast (NW of Spain) in November 2002 offered a unique opportunity to analyze intermediate cytogenetic and endocrine effects among people exposed to the complex mixture of substances that oil constitutes, including several toxic heavy metals. In this work we evaluated the relationship between exposure to heavy metals (blood concentrations of aluminium, cadmium, nickel, lead and zinc) and genotoxic parameters (sister chromatid exchanges, micronucleus test and comet assay) or endocrine parameters (plasmatic concentrations of prolactin and cortisol) in subjects exposed to 'Prestige' oil during cleaning tasks developed after the spillage. Concentrations of lead were significantly related to the comet assay even after adjusting by age, sex and smoking. Cortisol concentrations were significantly influenced by aluminium, nickel (both, inversely) and cadmium (positively). Women had clearly higher concentrations of prolactin and cortisol, even when adjusting by age, smoking, cadmium, aluminium or nickel. Plasmatic cortisol was jointly influenced by gender, smoking and aluminium or nickel (all p<0.05). In women there was a strong relationship between concentrations of cadmium and prolactin (beta=0.37, p=0.031). When the effects of cadmium, aluminium and nickel on cortisol were simultaneously assessed, only the latter two metals remained statistically significant. Among parameters analysed, cortisol appeared to be the most sensitive to the effects of metal exposure. Plasma levels of cortisol deserve further evaluation as a potentially relevant biomarker to assess the effects of exposure to heavy metals.     

Response of Pinus halepensis Mill. seedlings to biosolids enriched with Cu, Ni and Zn in three Mediterranean forest soils

We investigated the response of Pinus halepensis seedlings to the application of biosolids enriched with Cu, Ni and Zn on three Mediterranean forest soils under semiarid conditions. One-year-old seedlings were planted in lysimeters on soils developed from marl, limestone and sandstone which were left unamended, amended with biosolids, or amended with biosolids enriched in Cu, Ni and Zn. Enriched biosolids increased plant heavy metal concentration, but always below phytotoxic levels. Seedlings receiving unenriched biosolids showed a weak reduction in Cu and Zn concentration in needles, negatively affecting physiological status during drought. This effect was alleviated by the application of enriched sludge. Sewage sludge with relatively high levels of Cu, Zn and Ni had minor effects on plant performance on our experimental conditions. Results suggest that micronutrient limitations in these soils may be alleviated by the application of biosolids with a higher Cu, Zn and Ni content than those established by current regulations.     

Enantiospecific sublethal effects of the antidepressant fluoxetine to a model aquatic vertebrate and invertebrate

Many contaminants are chiral compounds with enantiomers that may differ markedly in environmental fate, bioavailability, and toxicity. Enantiospecific environmental fate and ecotoxicological information are lacking for many chiral contaminants. The primary objective of this investigation included an assessment of potential enantiospecific differences in sublethal standardized and behavioral responses of the model organisms Pimephales promelas (teleost) and Daphnia magna (crustacean) to the widely prescribed chiral antidepressant fluoxetine. Endpoints assessed included D. magna immobilization, reproduction, and grazing rate and P. promelas survival, growth, and feeding rate. S-Fluoxetine was found to be more toxic to sublethal standardized and behavioral endpoints in P. promelas, potentially because its primary active metabolite, S-norfluoxetine, is more potent than the same metabolite of R-fluoxetine in mammals. This was not observed for D. magna responses. This differential enantiospecific response between model organisms may have resulted from closer target homology between mammals and fish than between mammals and crustaceans. P. promelas feeding rate, an ecologically relevant and mode-of-action related response, was the most sensitive endpoint tested for R- and S-fluoxetine with 10% effect concentration (EC10) values (+/-SE) of 16.1 (+/-20.2) and 3.7 (+/-4.6) microg l(-1), respectively. Up to a 9.4-fold difference in toxicity between enantiomers was observed; P. promelas growth EC10s (+/-SE) for R- and S-fluoxetine were 132.9 (+/-21.2) and 14.1 (+/-8.1) microg l(-1), respectively. Such differences in sublethal responses to fluoxetine enantiomers suggest that enantiospecific toxicity and mode-of-action related responses that are ecologically relevant (e.g., feeding rate) should be considered in future ecological hazard and risk assessments for chiral contaminants.     

Using Canonical Correlation Analysis to Identify Environmental Attitude Groups: Considerations for National Forest Planning in the Southwestern U.S.

As public land management agencies pursue region-specific resource management plans, with meaningful consideration of public attitudes and values, there is a need to characterize the complex mix of environmental attitudes in a diverse population. The contribution of this investigation is to make use of a unique household, mail/internet survey data set collected in 2007 in the Southwestern United States (Region 3 of the U.S. Forest Service). With over 5,800 survey responses to a set of 25 Public Land Value statements, canonical correlation analysis is able to identify 7 statistically distinct environmental attitudinal groups. We also examine the effect of expected changes in regional demographics on overall environmental attitudes, which may help guide in the development of socially acceptable long-term forest management policies. Results show significant support for conservationist management policies and passive environmental values, as well as a greater role for stakeholder groups in generating consensus for current and future forest management policies.     

Competitive sorption of cis-DCE and TCE in silica gel as a model porous mineral solid

The competitive sorption of 1,2-cis-dichloroethene (cis-DCE) and trichloroethene (TCE) was investigated by means of column experiments using a model porous mineral solid represented by silica gel. The experimental isotherms were obtained by employing a chromatographic method. The competitive sorption isotherms were modelled with the extended Freundlich and extended Langmuir isotherms, using the parameters from single-solute experiments. The breakthrough curves were modelled with the advection-dispersion transport equation coupled with the lumped pore diffusion model. The best results were obtained when the extended Freundlich isotherm was employed. The competitive sorption was revealed with the presence of an overshoot in the breakthrough curve of cis-DCE and a decrease in the degree of sorption of cis-DCE (20%) and TCE (12%). A linear dependency of the overshoot with an increase in the concentration of cis-DCE at a fixed concentration of TCE was observed, between 16% and 20%, and at least at concentrations <6 mg L(-1) in the liquid phase. The displaced molecules of cis-DCE by TCE were accumulated through the column causing its overshoot; thus short columns may hinder its observation. Thermodynamic analysis shows an exothermic adsorption process of -34 to -41 kJ mol(-1), which is enhanced by sorption in micropores. The Gibbs free energy is positive for cis-DCE in the multi-component case, due to its displacement by TCE.