Mechanical separation-oriented characterization of electronic scrap

The ever-increasing amount of electronic scrap and the steadily-decreasing contents of the precious metals used in electronics, as well as the ever-growing environmental awareness, challenges such conventional precious-metal-oriented recycling techniques as pyrometallurgy. Separation and beneficiation of various materials encountered in electronic scrap might provide a correct solution ahead. In this context, mechanical separation-oriented characterization of electronic scrap was conducted in an attempt to evaluate the amenability of mechanical separation processes. Liberation degrees of various metals from the non-metals, which are crucial for mechanical separation, were analyzed by means of a grain counting approach. It is found that the metallic particles below 2 mm achieve almost complete liberation. Particle shapes were also quantified through an image processing system. The results obtained show that the shapes of the particles, as a result of shredding, turn out to be heterogeneous, thereby complicating mechanical separation processes. In addition, separability of various materials was ascertained by a sink–float analysis. It has been shown that density-based separation techniques shall be viable in separating metals from plastics, light plastics (ABS, PS and PVC, etc.) from glass fiber reinforced resins and aluminum from heavy metals. Specifically, a high quality copper concentrate can be expected by density-based separation techniques. Moreover, FT-IR spectra of plastics pieces from the light fractions after the sink–float testing show that PC scrap primarily contains ABS, PS and PVC plastics with the density range of +1.0–1.5 g/cm³, whereas PCB scrap mainly contains glass fiber reinforced epoxy resins plastics with the density range of +1.5–2.0 g/cm³.     

Aluminum recovery from electronic scrap by High-Force® eddy-current separators

The amount of electronic scrap which contains a substantial portion of non-ferrous metals, primarily copper and aluminum, has been growing. The present study is directed toward aluminum recovery by a newly developed eddy current separator. The investigation on shredded personal computer and printed circuit board scrap demonstrates that the High-Force® eddy-current separator will be applicable for this purpose. It has been shown that, by a single pass of the materials on the High-Force® eddy-current separator, an aluminum concentrate out of personal computer scrap can be obtained with a purity of 85%, while maintaining a recovery in excess of 90%, with the feed rate being up to 0.3 kg/min.     

Mechanical performance of woodfibre–waste plastic composite materials

Plastic products used for packaging are often discarded after a single use resulting in an inexhaustible supply of waste polymeric materials. The stiffness and strength of polymeric materials have been known to improve with the addition of lignocellulosic fibres available in abundance in nature. Hence, composite materials containing natural fibres and waste plastics would result in the reduction of solid wastes and the use of cheap, renewable resources. Composite specimens, consisting of waste plastics obtained from a Kerbside collection (high density polyethylene (HDPE) waste, Janitorial waste, Kerbside waste I and Kerbside waste II) and Pinus radiata woodfibres (medium density fibres (MDF)), have been produced through melt blending and injection moulding. The effects of fibre content, matrix type and interfacial bonding on the tensile and flexural properties of these composite materials have been determined through extensive testing at various conditions. The mechanical properties of these composites at room temperature and humidity depend on the amount of woodfibres, the mechanical properties of the waste plastics used and the presence of a suitable coupling agent. The tensile strengths of MDF/waste plastic composites do not generally change with fibre content except for 40% MDF/HDPE waste and 40% MDF/Kerbside waste II (plus 1% Epolene™) composites, where the tensile strengths increase by about 25% compared to those of the corresponding waste plastics. Flexural strengths of MDF/waste plastic composites increase with the addition of medium density fibres with the exception of MDF/Kerbside waste I composites. The tensile and flexural moduli of MDF/waste plastic composites mostly increase with increasing fibre content.     

Soft subgrades’ stabilization by using various fly ashes

This publication presents the results of research involving different types of self-cementing fly ashes (without any other activators) for the stabilization of four different types of soft subgrades from various road sites in Wisconsin, USA. The strength approaches were applied to estimate the optimum mixture design and to determine the thickness of the stabilized layer. The stabilized soil samples were prepared by mixing fly ash at different contents at varying water contents. The performance of fly ash stabilized subbase depends both on the specific source of fly ash and the engineering properties of soils. It is suggested that the performance analysis of fly ash should be based upon the laboratory tests such as index properties, compaction, unconfined compressive strength and CBR tests of a specific site. This is suggested rather than using the study of the physical properties and chemical composition of fly ash and soil. As disclosed in the literature, the strength gain due to stabilization depends mainly upon three factors; ash content, molding water content and compaction delay. The samples were subjected to unconfined compression strength and California bearing ratio (CBR) tests after 7 days curing time to develop water content–strength relationship. To evaluate the impact of compaction delay that commonly occurs in the field during construction, the sets of samples were compacted 2 h later after mixing with water. The unconfined compression strength and CBR tests were performed and used to determine the thickness of the stabilized layer in pavement design. All of these factors were taken into account throughout this research.     

Environmental consequences of recycling aluminum old scrap in a global market

Nowadays, aluminum scrap is traded globally. This has increased the need to analyze the flows of aluminum scrap, as well as to determine the environmental consequences from aluminum recycling. The objective of this work is to determine the greenhouse gases (GHG) emissions of the old scrap collected and sorted for recycling, considering the market interactions. The study focused on Spain as a representative country for Europe. We integrate material flow analysis (MFA) with consequential life cycle assessment (CLCA) in order to determine the most likely destination for the old scrap and the most likely corresponding process affected. Based on this analysis, it is possible to project some scenarios and to quantify the GHG emissions (generated and avoided) associated with old scrap recycling within a global market. From the MFA results, we projected that the Spanish demand for aluminum products will be met mainly with an increase in primary aluminum imports, and the excess of old scrap not used in Spain will be exported in future years, mainly to Asia. Depending on the scenario and on the marginal source of primary aluminum considered, the GHG emission estimates varied between −18,140 kg of CO₂ eq. t⁻¹ and −8427 of CO₂ eq. t⁻¹ of old scrap collected. More GHG emissions are avoided with an increase in export flows, but the export of old scrap should be considered as the loss of a key resource, and in the long term, it will also affect the semifinished products industry. Mapping the flows of raw materials and waste, as well as quantifying the GHG impacts derived from recycling, has become an essential prerequisite to consistent development from a linear toward a circular economy (CE).     

Effects of mechanical fracturing and experimental trampling on Hawaiian corals

In situ trampling occurred under experimental conditions to quantify the differences in the responses to anthropogenic trampling in four dominant species of Hawaiian corals, Porites compressa, Porites lobata, Montipora capitata, and Pocillopora meandrina. Trampling was simulated daily for a period of nine days at which time further breakage was minimal. Forty treatment colonies produced 559 fragments. Trampling was followed by an 11-month recovery period. Coral colony and fragment mortality was low. All four species were highly tolerant of inflicted damage, suggesting that some species of corals can withstand limited pulse events that allow time for recovery. Growth rates following trampling were significantly lower in the treatment groups for three of the four species. This study demonstrated that very few trampling events can produce significant changes in growth even after a long recovery period. Survivorship of fragments is clearly size- and species-dependent in M. capitata and P. compressa. Smaller fragments (<5 cm) had higher mortality than larger fragments (>5 cm). High breakage rates for M. capitata and P. compressa are consistent with the nearshore, low-energy regions they inhabit—the same environment frequented by skin divers and waders. Mechanical tests were conducted to determine tensile and compressive strengths. Pocillopora meandrina exhibited the strongest skeletal strength, followed in decreasing order by Porites lobata, Porites compressa, and Montipora capitata. The skeletal strength obtained from the experiments correlate with the wave energy present in the environments in the regions they inhabit, suggesting that structural strength of corals is an adaptive response to hydraulic stress.     

Optimization of the high-pressure, near-critical liquid-based microsortation of recyclable post-consumer plastics

High-pressure, near-critical liquids were used as float-sink separation media for the microsortation of polyolefin mixtures and PET/PVC mixtures. Near-critical carbon dioxide was used for the refinement of the polyolefins, and sulfur hexafluoride was used to separate post-consumer PVC from PET. Preliminary experiments indicated that there was no overlap in the density ranges of post-consumer HDPE, LDPE and PP containers. There was no overlap in the PET and PVC densities, with the exception of a single PVC packaging material with a density in the PET range. These initial results indicated that a float-sink separation was a viable means of microsortation. Separations of 91% LDPE (1/8′ beads)/9% PP (1/8′ chopped strands) resin mixtures and mixed post-consumer polyolefin flakes were then conducted in a laboratory-scale, 1-I batch apparatus. This apparatus not only permitted the observation of the separation, but also enabled the separated fractions to be removed from the high-pressure environment. The results indicated that LDPE purity of greater than 98.9% was obtained in 3 min or less if (a) the fluid density was 0.018 g/cm³ greater than the PP density and only 0.002 g/cm³ less than the LDPE density, thereby providing the greatest buoyancy force for the removal of the PP, (b) the fluid was recirculated upward through the bed of mixed plastics, facilitating the upward movement of the PP, and (c) the loading was kept at levels below 40% by volume. HDPE purity of 99% was also attained with clean, dry, post-consumer mixed plastic flakes. The loadings for these separations were very low, however, due to the difficulty in agitating the mixed bed of plastics using fluid recirculation. An economic analysis of these microsortation processes indicated that the value of the sorted plastics relative to the mixed feed must increase by approx. $0.08/lb for the CO₂-based separation and approx. $0.27/lb for the SF₆-based separation to justify the implementation of these high-pressure processes.     

Effect of culture time on the growth curve and power performance in a microbial fuel cell at a fixed amount of liquid culture

The microbial fuel cell uses the microorganism biochemistry to carry on the energy conversion. Concerning the experimental precision, the colony culture would be replaced by a fixed amount of liquid culture for Microbial fuel cell of Escherichia coli. The anode and cathode chambers whose each volume is 100 mL were utilized, the effective surface area of proton exchange membrane Nafion-117 is about 9 cm². In addition, the electrode area of carbon cloth is 20 cm². Three kinds of Escherichia coli, named as BCRC No. 10322, 10675 and 51534, respectively, would be selected. Results show that the electricity performance of Escherichia coli of BCRC No.51534 is better than the other microorganism studied because of having a larger open circuit voltage of 1.01 V and limiting current 22 mA, the maximum power density of 1342 mW/m^2, and average working power density of 295 mW/m² would be produced. These results would be useful to improve the performance of microbial fuel cell.     

Evaluation of tidal marsh restoration: Comparison of selected macroinvertebrate populations on a restored impounded valley marsh and an unimpounded valley marsh within the same salt marsh system in Connecticut,USA

Macroinvertebrates were examined on an impounded valley marsh in Stonington, Connecticut, that has changed from aTypha-dominated system to one with typical salt-marsh vegetation during 13 years following the reintroduction of tidal exchange. Animal populations on this restored impounded marsh were evaluated by comparing them with populations on a nearby unimpounded valley marsh of roughly the same size. Populations of the high marsh snail,Melampus bidentatus Say, were quantitatively sampled along transects that extended from the water-marsh edge to the upland; those of the ribbed mussel,Geukensia demissa Dillwyn, were sampled in low marsh areas on transects along the banks of creeks and mosquito ditches. The occurrence of other marsh invertebrates also was documented, but their abundance was not measured. The mean density ofMelampus was 332±39.6 SE/m² on the restored impounded marsh and 712±56.0 SE/m² on the unimpounded marsh. However, since snails were larger on the restored impounded marsh, the difference in snail biomass was less pronounced than the difference in snail density. MeanMelampus biomass was 4.96±0.52 SE g dry wt/m² on the restored impounded marsh and 6.96±0.52 SE g dry wt/m² on the unimpounded marsh. On the two marshes, snail density and biomass varied in relation to plant cover and other factors. The density and biomass ofGeukensia at the edge of the marsh were comparable on the restored impounded and unimpounded marshes. Mean mussel densities ranged from 80 to 240/m² and mean mussel biomass varied from 24.8–64.8 g dry wt/m² in different low marsh areas. In contrast, below the impoundment dike, meanGeukensia density was 1100±96.4 SE/m² and meanGeukensia biomass was 303.6±33.28 SE g dry wt/m². A consideration of all available evidence leads to the conclusion that the impounded marsh is in an advanced phase of restoration.     

In-depth analysis of aluminum flows in Austria as a basis to increase resource efficiency

Based on the method of material flow analysis (MFA), a static model of Austrian aluminum (Al) flows in 2010 was developed. Extensive data research on Al production, consumption, trade and waste management was conducted and resulted in a detailed model of national Al resources. Data uncertainty was considered in the model based on the application of a rigorous concept for data quality assessment. The model results indicated that the growth of the Austrian “in-use” Al stock amounts to 11 ± 3.1 kg yr⁻¹ cap⁻¹. The total “in-use” Al stock was determined using a bottom-up approach, which produced an estimate of 260 kg Al cap⁻¹. Approximately 7 ± 1 kg of Al yr⁻¹ cap⁻¹ of old scrap was generated in 2010, of which 20% was not recovered because of losses in waste management processes. Quantitatively, approximately 40% of the total scrap input to secondary Al production originated from net imports, highlighting the import dependency of Austrian Al refiners and remelters. Uncertainties in the calculation of recycling indicators for the Austrian Al system with high shares of foreign scrap trade were exemplarily illustrated for the old scrap ratio (OSR) in secondary Al production, resulting in a possible range of OSRs between 0 and 66%. Overall, the detailed MFA in this study provides a basis to identify resource potentials as well as resource losses in the national Al system, and it will serve as a starting point for a dynamic Al model to be developed in the future.     

Toxicity and uptake of mercurials in a cyanobacterium

Nostoc calcicola cells exposed to mercuric chloride (0.05–0.25 M), methyl mercuric chloride (0.05–0.15 M) and the fungicide ceresan (phenyl mercuric acetate; 0.05–0.20 M) showed sensitivity in the sequence: methyl mercury3) over phenyl mercuric acetate (0.51×10³); inorganic mercury occupied the intermediate position with a bioconcentration factor of 1.32×10³. The data infer that larger molecules of organomercurials may not be taken up by cells at the rate and extent comparable to the smaller species.     

Model-Based Assessment of Aspen Responses to Elk Herbivory in Rocky Mountain National Park,USA

In Rocky Mountain National Park (RMNP), aspen (Populus tremuloides Michx.) has been observed to be declining on elk (Cervus elaphus nelsoni) winter range for many decades. To support elk management decisions, the SAVANNA ecosystem model was adapted to explore interactions between elk herbivory and aspen dynamics. The simulated probability of successful vegetative regeneration for senescent aspen stands declines sharply when elk densities reach levels of 3–5 elk/km², depending on model assumptions for the seasonal duration of elk foraging activities. For aspen stands with a substantial component of younger trees, the simulated regeneration probability declines more continuously with increasing elk density, dropping below 50% from densities at 8–14 elk/km².At the landscape scale, simulated aspen regeneration probability under a scenario of extensive seasonal use was little affected by elk population level, when this level was above 300–600 elk (25%–50% current population) over the ca. 107 km² winter range. This was because elk distribution was highly aggregated, so that a high density of elk occupied certain areas, even at low population levels overall. At approximately current elk population levels (1000–1200 elk), only 35%–45% of senescent aspen stands are simulated as having at least a 90% probability of regeneration, nearly all of them located on the periphery of the winter range. Successful management for aspen persistence on core winter range will likely require some combination of elk population reduction, management of elk distribution, and fencing to protect aspen suckers from elk browsing.     

Comparison of Three Algaecides for Controlling the Density of Prymnesium parvum1

Rodgers, John H., Jr., Brenda M. Johnson, and West M. Bishop, 2010. Comparison of Three Algaecides for Controlling the Density of Prymnesium parvum. Journal of the American Water Resources Association (JAWRA) 46(1):153-160. DOI: 10.1111/j.1752-1688.2009.00399.x Abstract: Prymnesium parvum has become more prevalent in water resources of the southern United States. As the potential impacts of P. parvum are relatively well known, especially its capability to severely affect fish, managers have sought efficacious, environmentally sound, and socially acceptable strategies for mitigating this noxious species. Laboratory testing was used to identify an effective algaecide for control of P. parvum from Texas, Arizona, Florida, North Carolina, and South Carolina. Cutrine^®-Plus at 0.2 mg Cu/l significantly decreased the density of P. parvum in samples from all of these locations. Both copper sulfate and Phycomycin^® were less effective for controlling the population growth of P. parvum. The predicted response from the laboratory study was confirmed in the field at the Arizona site. Strategic use of Cutrine^®-Plus in larger water resources could provide toxin-free refugia to allow some fish to survive and repopulate the water resource when the golden alga infestation abates.     

Soil water repellency induced by long-term irrigation with treated sewage effluent

This study describes soil water repellency developed under prolonged irrigation with treated sewage effluent in a semiarid environment. Soil surface layer (0-5 cm) and soil profile (0-50 cm) transects were sampled at a high resolution at the close of the irrigation season and rainy winter season. Samples from 0- to 5-cm transects were subdivided into 1-cm slices to obtain fine scale resolution of repellency and organic matter distribution. Extreme to severe soil water repellency in the 0- to 5-cm soil surface layer persisted throughout the 2-yr study period in the effluent-irrigated Shamouti orange [Citrus sinensis (L.) Osbeck cv. Shamouti] orchard plot. Nearby Shamouti orange plots irrigated with tap water were either nonrepellent or only somewhat repellent. Repellency was very variable spatially and with depth, appearing in vertically oriented "repellency tongues." Temporal and spatial variability in repellency in the uppermost 5-cm soil surface layer was not related to seasonality, soil moisture content, or soil organic matter content. Nonuniform distribution of soil moisture and fingered flow were observed in the soil profile after both seasons, demonstrating that the repellent layer had a persistent effect on water flow in the soil profile. A lack of correlation between bulk density and volumetric water content in the soil profile demonstrates that the observed nonuniform spatial distribution of moisture results from preferential flow and not heterogeneity in soil properties. Soil water repellency can adversely affect agricultural production, cause contamination of underlying ground water resources, and result in excessive runoff and soil erosion.     

Usage of polystyrene disposable food dishes in the lightweight concrete making

The increasing use and subsequent accumulation of polystyrene containers has triggered a substantial environmental problem. This study investigated using varied percentages of solid waste polystyrene disposable food dishes in the production of lightweight concrete samples with 350 kilograms per cubic meter (kg/m³) of cement and a density of 1,300 kg/m³. The polystyrene disposable dishes were ground into beads of 0–3 millimeters (mm) and 3–6 mm in size. First, the characteristics of Type II Portland cement, polystyrene, and aggregates were examined. The following characteristics of concrete using ASTM International and British Standards Institution standards were tested: slump, compressive strength, ability to resist chloride ion penetration, and resistance of concrete to rapid freezing and thawing cycles. Scanning electron microscopy (SEM) and energy dispersive X‐ray spectroscopy analytical techniques were also used. The slump of samples varied between 40 and 70 mm and was not dependent on either the polystyrene percentage or the size of the polystyrene beads in the concrete samples (p‐value > .05). The compressive strength of the concrete samples after 90 days of curing, and using different percentages of polystyrene, varied between 96 and 113 kilograms per square centimeter (kg/cm²). The resistance of the samples to the freezing and thawing cycle and chloride ion penetration were affected unfavorably by the presence of the polystyrene. The SEM technique indicated that concrete samples containing 15% and 25% polystyrene had denser crystals and less void than concrete samples with 40% and 55% polystyrene.     

Earthworm density,casting activities and its impact on canopy soil nutrient profile under different aboveground vegetations

Efforts were made to assess the earthworm’s density and their casting activity under different surface plant stands (Citrus reticulata, Rosa indica, Citrus + Rosa, Tabernaemontana divaricata, Dalbergia sissoo, and Cynodon dactylon) at few natural and planted sites of a semiarid part of Rajasthan, India. The role of earthworm community in nutrient dynamics of different layers of canopy soils was also measured during this study. Results suggested a direct impact of aboveground vegetation cover on soil microclimatic conditions and earthworm density. The maximum earthworm population density and casts production was under mixed plantation, i.e., Citrus + Rosa (119.2 ind. m⁻² and 2,127.27 gm m², respectively), while T. divaricata supported the minimum earthworm density and casting activities. The population density and total casts production was in the order: C. reticulata + R. indica > R. indica > D. sissoo > C. dactylon > C. reticulata > T. divaricata. Earthworm casts and canopy soils (0–10 and 10–20 cm depth) under different plant stand were analyzed for organic C, total N, available P, and exchangeable cations (K⁺, Ca²⁺ and Mg²⁺). Earthworm casts collected under Citrus + Rosa showed the maximum level of organic C, total N, available P, and exchangeable cations (K⁺ and Mg²⁺). It is concluded that resource input by standing plant community directly affects the canopy soil quality and, thereby nutrient level in earthworm casts. This study suggested that aboveground vegetation pattern plays an important role to improve the nutrient level of canopy soils and belowground earthworm activities.     

Historical evolution of anthropogenic aluminum stocks and flows in Italy

Dynamic stocks and flows analysis was applied to the anthropogenic aluminum cycle in Italy in order to detect and quantify metal flows and in-use stocks over the years 1947–2009. The model utilized a top-down approach, including data for production, consumption, loss, and trade flows of aluminum. Seven end-use markets were considered, namely buildings and construction, transportation, consumer durables, machinery and equipment, electrical engineering, containers and packaging, and miscellaneous appliance types. The results of this dynamic stocks and flows analysis model quantified the contemporary anthropogenic reservoirs (or in-use stocks) of aluminum at about 320 kg per capita, mainly embedded within the transportation and building and construction sectors. Cumulative in-use stock represents approximately 11 years of supply at current usage rates (about 20 Mt versus 1.7 Mt/year), implying significant potential for recycling in the future as this stock comes out of use. Flow analysis revealed that Italy imports mainly unwrought aluminum and exports final products, while the main material losses occur during alumina refining and collection of old scrap: specifically, containers and packaging have the highest old scrap generation rate, but for the lowest recovery rate (50%). Increasing support to collection of scrap and initiatives oriented to aluminum recovery specifically would allow Italy to increase its reliance on domestic material, and may also allow a decline of the country import-dependence on primary sources. The dynamic stocks and flows model created here provides a quantitative historical record of the aluminum required by Italian society during important periods of development and provides guidance for future decision-making around the use of domestic secondary resources.     

Application of Artificial Neural Networks to Predict Total Dissolved Solids at the Karaj Dam

We applied multilayer perceptron (MLP) and radial basis function (RBF) neural networks using data from two water quality monitoring stations at the Karaj Dam in Iran. Input data were calcium ions (Ca²⁺), magnesium ions (Mg²⁺), sodium ions (Na⁺), chloride ions (Cl^?), sulfate (), and pH, and the output data were total dissolved solids (TDS). An MLP with one hidden layer containing eight neurons was selected for the upstream water quality station using normalized input data. We developed a second MLP neural network for the downstream station with one hidden layer containing 10 neurons in the hidden layer using normalized input data. Considering applying normalized input data and one hidden layer, the coefficient of determination (R ²) and index of agreement (IA) between the observed and the predicted data for the upstream and downstream monitoring stations using the MLP neural networks were 0.985, 0.84, 0.99, and 0.92, respectively. The RBF neural network with 100 neurons in its hidden layer reached the minimum errors between the observed and the predicted results in upstream and downstream stations. The R ² between observed and predicted data for upstream and downstream monitoring stations for the RBF was 0.999 and 0.998, respectively. Data normalization improved the performance of the MLP neural networks. Sensitivity analysis indicated that magnesium is the most effective water quality parameter for predicting TDS, and sulfate is the second most effective water quality parameter affecting TDS prediction at the Karaj Dam.     

Assessing the Impact of Areal Precipitation Input on Streamflow Simulations Using the SWAT Model1

Masih Ilyas, Shreedhar Maskey, Stefan Uhlenbrook, and Vladimir Smakhtin, 2011. Assessing the Impact of Areal Precipitation Input on Streamflow Simulations Using the SWAT Model. Journal of the American Water Resources Association (JAWRA) 47(1):179‐195. DOI: 10.1111/j.1752‐1688.2010.00502.x Abstract: Reduction of input uncertainty is a challenge in hydrological modeling. The widely used model Soil Water Assessment Tool (SWAT) uses the data of a precipitation gauge nearest to the centroid of each subcatchment as an input for that subcatchment. This may not represent overall catchment precipitation conditions well. This paper suggests an alternative – using areal precipitation obtained through interpolation. The effectiveness of this alternative is evaluated by comparing its simulations with those based on the standard SWAT precipitation input procedure. The model is applied to mountainous semiarid catchments in the Karkheh River basin, Iran. The model performance is evaluated at daily, monthly, and annual scales by using a number of performance indicators at 15 streamflow gauging stations each draining an area in the range of 590‐42,620 km². The comparison suggests that the use of areal precipitation improves model performance particularly in small subcatchments in the range of 600‐1,600 km². The modified areal precipitation input results in increased reliability of simulated streamflows in the areas of low rain gauge density. Both precipitation input methods result in reasonably good simulations for larger catchments (over 5,000 km²). The use of areal precipitation input improves the accuracy of simulated streamflows with spatial resolution and density of rain gauges having significant impact on results.     

Mosaics of Exotic Forest Plantations and Native Forests as Habitat of Pumas

There is a general lack of information on the impact of forest plantations and the presence of urban settlements on populations of resource-demanding species such as large felids. To partially address this problem, a project study was conducted to find out whether mosaics of forest plantations and native vegetation can function as an adequate habitat for pumas (Puma concolor) in southern Brazil. The study was conducted within a 1255-km² area, managed for planted stands of Pinus spp. and Eucalyptus spp. Individual identification of pumas was carried out using a combination of track-matching analysis (discriminant analysis) and camera-trapping. Both techniques recorded closely similar numbers of individual pumas, either total (9–10 individuals) or resident (5–6 individuals). A new approach, developed during this study, was used to individualize pumas by their markings around the muzzle. The estimated density varied from 6.2 to 6.9 individuals/100 km², ranking among the highest across the entire puma range and indicating a potential total population of up to 87 individuals in the study site. In spite of the availability of extensive areas without human disturbance, a radio-tracked female used a core home range that included forest plantations, an urbanized village, and a two-lane paved road with regular vehicular traffic. The high density of pumas and the species’ intensive use of modified landscapes are interpreted here as deriving from conditions rarely found near human settlements: mutual tolerance by pumas and humans and an adequate habitat (regardless of plantations) largely due to the inhibition of invasions and hunting and maintenance of sizable extents of native forest patches. More widely, it suggests the potential of careful management in forestry operations to provide habitat conditions for resource-demanding species such as the puma. Furthermore, it highlights the importance of curbing invasions and hunting, in this case provided by the presence of company employees, for the maintenance of wildlife populations.