A moral panic over cats

Some conservationists believe that free-ranging cats pose an enormous risk to biodiversity and public health and therefore should be eliminated from the landscape by any means necessary. They further claim that those who question the science or ethics behind their arguments are science deniers (merchants of doubt) seeking to mislead the public. As much as we share a commitment to conservation of biodiversity and wild nature, we believe these ideas are wrong and fuel an unwarranted moral panic over cats. Those who question the ecological or epidemiological status of cats are not science deniers, and it is a false analogy to compare them with corporate and right-wing special interests that perpetrate disinformation campaigns over issues, such as smoking and climate change. There are good conservation and public-health reasons and evidence to be skeptical that free-ranging cats constitute a disaster for biodiversity and human health in all circumstances. Further, there are significant and largely unaddressed ethical and policy issues (e.g., the ethics and efficacy of lethal management) relative to how people ought to value and coexist with cats and native wildlife. Society is better served by a collaborative approach to produce better scientific and ethical knowledge about free-ranging cats.     

Bioaccumulation of cadmium,lead and zinc in liver and kidney of red fox (Vulpes vulpes) from NW Spain: influence of gender and age

Cd, Pb, and Zn were quantified in liver and kidney of red foxes (Vulpes vulpes) which were hunted during the 2003–2011 hunting seasons in Galicia (NW Spain). The effects of age and gender were evaluated to determine whether these variables should be included in future biomonitoring studies. The concentrations of hepatic and renal Cd (average 0.6 and 1.3 µg/g) and Pb (0.8 and 0.06 µg/g, respectively) were similar to background levels, with no known toxicological relevance. Similarly, the average levels of Zn in liver and kidney (77 and 17 µg/g) were in the range of physiological levels for canids. Although no significant gender-dependent variations were observed, the effect of aging was evident: the levels of hepatic Pb and both hepatic and renal Cd were higher in adults than in juveniles. Age should be included as a parameter during future biomonitoring programs focusing on trace metal bioaccumulation in red foxes.     

Reduction of CO2 emission by optimally tracking a pre-defined target

The recent global financial crisis has highlighted the need for balanced and efficient investments in the reduction of the greenhouse effect caused by emissions of CO₂ on a global scale. In a previous paper, the authors proposed a mathematical model describing the dynamic relation of CO₂ emission with investment in reforestation and clean technology. An efficient allocation of resources to reduce the greenhouse effect has also been proposed. Here, this model is used to provide estimates of the investments needed in land reforestation and in the adoption of clean technologies for an optimum emission and abatement of CO₂, for the period of 1996–2014. The required investments are computed to minimize deviations with respect to the emission targets proposed in the Kyoto Protocol for European Countries. The emission target can be achieved by 2014 with investments in reforestation peaking in 2004, and a reduction of the expected GDP of 42%, relative to 2006. Investments in clean technology should increase between 2008 and 2010 with maximum transfer figures around 70 million American dollars. Total (cumulative) costs are, however, relatively high depending on the price of carbon abatement and the rate at which the expected CO₂ concentration in the atmosphere should be reduced. Results highlight the advantages for policy makers to be able to manage investments in climate policy more efficiently, controlling optimum transfers based on a portfolio of actions that tracks a pre-defined CO₂ concentration target.     

Spike dives of juvenile southern bluefin tuna (<Emphasis Type="Italic">Thunnus maccoyii</Emphasis>): a navigational role?

Tunas make sharp descents and ascents around dawn and dusk called spike dives. We examine spike dives of 21 southern bluefin tuna (Thunnus maccoyii) implanted with archival tags in the Great Australian Bight. Using a new way to categorize this behavior, we show that spike dives are similar among all the fish in the study. The dive profiles are mirror images at dawn and dusk and are precisely timed with respect to sunrise and sunset. We analyze the possible reasons for spike dives, considering the timing of spike dives, the characteristic dive profile, and the tuna's magnetic habitat. In addition, we present anatomical evidence for elaboration of the pineal organ, which is light mediated and has been implicated in navigation in other vertebrates. The new evidence presented here leads us to suspect that spike dives represent a survey related to navigation.     

Comparative acute toxicity of organic pollutants and reference values for crustaceans. I. Branchiopoda, Copepoda and Ostracoda

The acute toxicity of 468 organic pollutants to planktonic crustaceans (Branchiopoda, Copepoda and Ostracoda) from pre-existing data was compared by means of statistical analysis and relative tolerance indices (Trel). A surrogate species commonly used in toxicity bioassays (Daphnia magna) showed toxicity levels--within one order of magnitude--similar to all other Cladocera species, at least for 82% of the chemicals studied. All neurotoxic insecticides except neonicotinoids, PCBs, organometallic compounds and PAHs are the most toxic substances to these organisms. Sensitivity levels among taxa were compared for individual chemicals as well as groups of chemicals with similar characteristics. Whilst there are marked differences in sensitivity among taxa and particular groups of chemicals, no consistent trends were found for freshwater and saltwater species in relation to the latter groups. No correlation between LC50 and size of these organisms was found other than by chance, making extrapolations based on allometric equations impossible.     

Pesticide removal from cotton farm tailwater by a pilot-scale ponded wetland

A pilot-scale, ponded wetland consisting of an open pond and a vegetated pond in series was constructed on a cotton farm in northern New South Wales, Australia, and assessed for its potential to remove pesticides from irrigation tailwater. Ten incubation periods ranging from 7 to 13 days each were conducted over two cotton growing seasons to monitor removal of residues of four pesticides applied to the crop. Residue reductions ranging 22–53% and 32–90% were observed in the first and second seasons respectively. Average half-lives during this first season were calculated as 21.3 days for diuron, 25.4 days for fluometuron and 26.4 days for aldicarb over the entire wetland. During the second season of monitoring, pesticide half-lives were significantly reduced, with fluometuron exhibiting a half-life of 13.8 days, aldicarb 6.2 days and endosulfan 7.5 days in the open pond. Further significant reductions were observed in the vegetated pond and also following an algal bloom in the open pond, as a result of which aldicarb and endosulfan were no longer quantifiable. Partitioning onto sediment was found to be a considerable sink for the insecticide endosulfan. These results demonstrate that macrophytes and algae can reduce the persistence of pesticides in on-farm water and provide some data for modelling.