Kill before being killed: an experimental approach supports the predator-removal hypothesis as a determinant of intraguild predation in top predators

Intraguild predation (IGP) has been explained in terms of competitor-removal, food-stress and predator-removal hypotheses. Only the first two hypotheses have been fairly well studied. To test the predator-removal hypothesis as a force determining IGP in avian predators, we performed a field experiment to simulate the presence of an IG predator (eagle owl Bubo bubo dummy) in the surrounding of the nests of four potential IG prey (black kite Milvus migrans, red kite Milvus milvus, booted eagle Aquila pennata and common buzzard Buteo buteo). To discard the possibility that an aggressive reaction towards the eagle owl was not related to the presence of the IG predator, we also presented a stuffed tawny owl Strix aluco, which is a potential competitor but cannot be considered an IG predator of the studied diurnal raptors considered in the experiment. While almost always ignoring the tawny owl, raptors chiefly showed an interspecific aggressive behaviour towards their IG predator. Our results seem to support the predator-removal hypothesis, as the IG prey may take advantage of the diurnal inactivity of the IG predator to remove it from their territory. However, the recorded behaviour may be also considered as a special variety of mobbing (i.e. a prey’s counter-strategy against its predator), where the mobber is sufficiently powerful to escalate predator harassment into deliberate killing attempts. In their turn, eagle owls can respond with an IG predatory behaviour aimed at removing IG prey species which are highly aggressive mobbers.     

Impacts of changes in land use and fragmentation patterns on Atlantic coastal forests in northern Spain

Changes in forested landscapes may have important consequences for ecosystem services and biodiversity conservation. In northern Spain, major changes in land use occurred during the second half of the 20th century, but their impacts on forests have not been quantified. We evaluated the dynamics of landscape and forest distribution patterns between 1957 and 2003 in Fragas do Eume Natural Park (northwestern Spain). We used orthoimages and a set of standard landscape metrics to determine transitions between land cover classes and to examine forest distribution patterns. Eucalypt plantations showed the greatest increase in area (197%) over time. Furthermore, transitions to eucalypt plantations were found in all major land cover classes. Forest showed a net decline of 20% in total area and represented 30% of the landscape area in 2003. Forest losses were mainly due to eucalypt plantations and the building of a water reservoir, while forest gains were due to increases in shrubland, meadows and cultivated fields which had been recolonised. Forest patch size and core area decreased, and edge length increased over time. In turn, increases were obtained in mean distance between forest patches, and in adjacency to eucalypt plantations and to a water reservoir. These results suggest an increase in forest fragmentation from 1957 to 2003, as well as a change in the nature of the habitat surrounding forest patches. This study shows that land use changes, mostly from eucalypt plantation intensification, negatively affected forested habitats, although some regeneration was ongoing through ecological succession from land abandonment.     

Variation of surface ozone in Campo Grande,Brazil: meteorological effect analysis and prediction

The effect of meteorological variables on surface ozone (O₃) concentrations was analysed based on temporal variation of linear correlation and artificial neural network (ANN) models defined by genetic algorithms (GAs). ANN models were also used to predict the daily average concentration of this air pollutant in Campo Grande, Brazil. Three methodologies were applied using GAs, two of them considering threshold models. In these models, the variables selected to define different regimes were daily average O₃ concentration, relative humidity and solar radiation. The threshold model that considers two O₃ regimes was the one that correctly describes the effect of important meteorological variables in O₃ behaviour, presenting also a good predictive performance. Solar radiation, relative humidity and rainfall were considered significant for both O₃ regimes; however, wind speed (dispersion effect) was only significant for high concentrations. According to this model, high O₃ concentrations corresponded to high solar radiation, low relative humidity and wind speed. This model showed to be a powerful tool to interpret the O₃ behaviour, being useful to define policy strategies for human health protection regarding air pollution.     

Mercury in the Mediterranean. Part 2: processes and mass balance

Mass balance of contaminants can provide useful information on the processes that influence their concentrations in various environmental compartments. The most important sources, sinks and the equilibrium or non-equilibrium state of the contaminant in individual environmental compartments can also be identified. Using the latest mercury speciation data, the results of numerical models and the results of recent studies on mercury transport and transformation processes in the marine environment, we have re-evaluated the total mercury (HgT) mass balance in the Mediterranean Sea. New calculations have been performed employing three distinct marine layers: the surface layer, the thermocline and the deep sea. New transport mechanisms, deep water formation and density-driven sinking and upwelling, were included in the mass balance calculations. The most recent data have even enabled the calculation of an approximate methylmercury (MeHg) mass balance. HgT is well balanced in the entire Mediterranean, and the discrepancies between inputs and outputs in individual layers do not exceed 20 %. The MeHg balance shows larger discrepancies between gains and losses due to measurement uncertainties and gaps in our knowledge of Hg species transformation processes. Nonetheless, the main sources and sinks of HgT (deposition and evasion) and MeHg (fluxes from sediment, outflow through the Gibraltar Strait) are in accordance with previous studies on mercury in the Mediterranean Basin. Mercury in the Mediterranean fish harvest is the second largest MeHg sink; about 300 kg of this toxic substance is consumed annually with sea food.     

Identification of best available techniques in the seafood industry: a case study

A Best Available Techniques (BAT) analysis of a mussel canning processing facility in northwest Spain was undertaken to investigate potential cleaner production and efficiency improvements. Potential techniques were identified from the literature and from our experience in the seafood sector. BATs were then assessed for possible implementation in a mussel canning facility. This work describes, in considerable detail, the advantages and disadvantages of the techniques discussed.     

Estimation of potential quantity and value of used and in-use stocks of urban mines in Korea

Journal of Material Cycles and Waste Management - The urban mine industry plays an essential role in environmental sustainability to minimize the creation of landfills and to maximize the reuse of...     

Enhancement of conservation knowledge through increased access to botanical information

Herbarium specimens are increasingly recognized as an important resource for conservation science and virtual herbaria are making specimens freely available to a wider range of users than ever before. Few virtual herbaria are designed with conservation use as a primary driver. Exceptionally, Brazil's Reflora Virtual Herbarium (RVH) was created to increase knowledge and conservation of the Brazilian flora. The RVH is closely integrated with the Flora of Brazil 2020 platform on which Brazil's new national Flora is under construction. Both resources are accessible via the Reflora home page and thousands of users move seamlessly between these Reflora resources. To understand how the Reflora resources are currently used and their impact on conservation science, we conducted a literature review and an online survey. We searched for publications of studies in which Reflora resources were used and publications resulting from Brazilian researchers who were part of Reflora's research and mobility program. The survey contained multiple choice questions and questions that required a written response. We targeted Reflora webpage visitors with the survey to capture a wider range of Reflora users than the literature review. Reflora resources were used for a variety of conservation-relevant purposes. Half the 806 scientific publications in which Reflora was cited and 81% of the 1069 survey respondents accessing Reflora resources mentioned conservation-relevant research outputs. Most conservation-relevant uses of the Reflora resources in scientific publications were research rather than implementation focused. The survey of Reflora users showed conservation uses and impacts of virtual herbaria were more numerous and diverse than the uses captured in the literature review. Virtual herbaria are vital resources for conservation science, but they must document use and impacts more comprehensively to ensure sustainability.     

Degradation of pharmaceuticals in wastewater matrices through solar light-driven photocatalyst prepared from petrochemical waste

Environmental Science and Pollution Research - Pharmaceuticals, such as dipyrone (DIP), paracetamol (PCT), and propranolol (PPN), are widely used analgesics and beta-blockers with the greatest...     

Production patterns of packaging waste categories generated at typical Mediterranean residential building worksites

The construction sector is responsible for around 28% of the total waste volume generated in Europe, which exceeds the amount of household waste. This has led to an increase of different research studies focusing on construction waste quantification. However, within the research studies made, packaging waste has been analyzed to a limited extent. This article focuses on the packaging waste stream generated in the construction sector. To this purpose current on-site waste packaging management has been assessed by monitoring ten Mediterranean residential building works. The findings of the experimental data collection revealed that the incentive measures implemented by the construction company to improve on-site waste sorting failed to achieve the intended purpose, showing low segregation ratios. Subsequently, through an analytical study the generation patterns for packaging waste are established, leading to the identification of the prevailing kinds of packaging and the products responsible for their generation. Results indicate that plastic waste generation maintains a constant trend throughout the whole construction process, while cardboard becomes predominant towards the end of the construction works with switches and sockets from the electricity stage. Understanding the production patterns of packaging waste will be beneficial for adapting waste management strategies to the identified patterns for the specific nature of packaging waste within the context of construction worksites.     

A new species of Penaeus (Crustacea: Penaeidae) revealed by allozyme and cytochrome oxidase I analyses

 Penaeid shrimps comprise an important portion of the world's industrial fisheries and mariculture. In the Southwest Atlantic, Penaeus (Farfantepenaeus) subtilis, P. (F.) paulensis, P. (F.) brasiliensis and P. (Litopenaeus) schmitti are the most important commercially exploited species. Despite their high commercial value, there is little information available on the different aspects of their biology or genetics and almost no data on stock structure. Also, the taxonomic status of P. subtilis populations in relation to P. paulensis and their geographic ranges have been recently questioned. In this paper we used both nuclear (allozymes) and mitochondrial (cytochrome oxidase subunit 1) data to compare species of south-western Atlantic penaeids and to estimate their phylogenetic relationships. We could readily discriminate among the four main Brazilian penaeid species and detected a fifth, new, species of Penaeus. This new species corresponded to one of the described morphotypes of P. subtilis. Based on these analyses, the geographic ranges of P. subtilis and P. paulensis were clarified. Our data also support the conclusion of Baldwin et al. (1998) that the subgenus Farfantepenaeus is polyphyletic. Received: 6 January 2000 / Accepted: 13 June 2000