Songbird response to increased willow (Salix spp.) growth in Yellowstone's northern range

After nearly a century of height suppression, willows (Salix spp.) in the northern range of Yellowstone National Park, U.S.A., are increasing in height growth as a possible consequence of wolf (Canis lupus) restoration, climate change, or other factors. Regardless of the drivers, the recent release of this rare but important habitat type could have significant implications for associated songbirds that are exhibiting declines in the region. Our objective was to evaluate bird response to releasing willows by comparing willow structure and bird community composition across three willow growth conditions: height suppressed, recently released, and previously tall (i.e., tall prior to the height increase of released willows). Released and previously tall willows exhibited high and similar vertical structure, but released willows were significantly lower in horizontal structure. Suppressed willows were significantly shorter and lower in horizontal cover than released or previously tall willows. Bird richness increased along a gradient from lowest in suppressed to highest in previously tall willows, but abundance and diversity were similar between released and previously tall willows, despite lower horizontal cover in the released condition. Common Yellowthroat (Geothlypis trichas) and Lincoln's Sparrow (Melospiza lincolnii) were found in all three growth conditions; however, Yellow Warbler (Dendroica petechia), Warbling Vireo (Vireo gilvus), Willow Flycatcher (Empidonax traillii), and Song Sparrow (Melospiza melodii) were present in released and previously tall willows only. Wilson's Warbler (Wilsonia pusilla) was found in previously tall willows only, appearing to specialize on tall, dense willows. The results of our a priori habitat models indicated that foliage height diversity was the primary driver of bird richness, abundance, and diversity. These results indicate that vertical structure was a more important driver of bird community variables than horizontal structure and that riparian and willow-dependent bird species have responded positively to increased willow growth in the region.     

Metals and organotins in multiple bivalve species in a one-off global survey

The Galathea 3 expedition circumnavigated the globe in 2006-2007 and collected marine samples from six continents. Bivalves were collected from harbours, other impacted locations and reference sites, and samples from 57 sites were analyzed for metals and 47 for organotins, to assess current contamination levels on a global scale. Metal concentrations in nine bivalve species were normalised to the Mytilidae family using conversion factors based on cosampled species and literature bioconcentration factors. The lowest metal and tributyltin concentrations were below background assessment concentrations (BACs) agreed in the Oslo-Paris convention (OSPAR) for the North Sea, and at most harbours the concentrations were orders of magnitude above BACs. The lowest concentrations of Cd and Pb measured here suggest that the BACs should be lower in a worldwide context. The sources of metals were classified according to human impact using principal component analysis. High relative concentrations of Hg, Pb and P were source indicators for industrial activity and land use; Zn, organotins, Cd and Cu for shipping activities, and V for oil spills. Generally the concentration levels at reference sites were low, but not always lower than expected impacted areas. The most contaminated areas were harbours, where especially Copenhagen, St Croix and Sydney, can be considered hotspots of tributyltin as well as a number of metals.     

Evaluation of the readsorption of plutonium and americium in dynamic fractionations of environmental solid samples

A dynamic extraction system exploiting sequential injection (SI) for sequential extractions incorporating a specially designed extraction column is developed to fractionate radionuclides in environmental solid samples such as soils and sediments. The extraction column can contain up to 5 g of a soil sample, and under optimal operational conditions it does not give rise to creation of back pressure. Attention has been placed on studies of the readsorption problems during sequential extraction using a modified Standards, Measurements and Testing (SM&T) scheme with four-step sequential extractions. The degree of readsorption in dynamic and conventional batch extraction systems is compared and evaluated by using a double-spiking technique. A high degree of readsorption of plutonium and americium (>75%) was observed in both systems, and they also exhibited similar distribution patterns of the two radionuclides. However, the dynamic system is fully automated, eliminates manual separations, significantly reduces the operational time required, and offers detailed kinetic information.     

Degradation of zearalenone and ochratoxin A in three Danish agricultural soils

Degradation of two mycotoxins: zearalenone (ZON) produced by species of Fusarium and ochratoxin A (OTA) produced by species of Penicillium were followed in pot experiments using agricultural topsoils from Danish experimental farms: a sandy soil, a sandy clay soil and a gyttja soil with a high content of silt. Experiments with unplanted soil and pots planted with barley were included. Soil samples were withdrawn during a period of 225 days and analysed for the content of OTA and ZON. The degradation of both toxins consisted of an initial fast degradation followed by a slower transformation step and was described well by a sum of two first-order kinetic equations. The decay first-order rate constants for the first step (k1) were in the range 0.73-2.91 d(-1) for OTA and 0.0612-0.108 d(-1) for ZON, respectively. Half-lives (t0.5) for ZON using data from the first phase were between 6.4 and 11 days, whereas the half-lives for OTA were about 0.2-1 day. The slowest degradation was measured in soil rich in clay. After 225 days, neither OTA nor ZON was detected in any of the soil types. Generally, the degradation of ZON and OTA was faster in planted soil than in unplanted soil, probably due to higher microbial activity. Due to the fast degradation of ZON and OTA in surface soil leaching as soluble substances appears to be limited.     

Speciation of Cd and Zn in contaminated soils assessed by DGT-DIFS, and WHAM/Model VI in relation to uptake by spinach and ryegrass

A pot experiment was carried out to investigate the impact of Cd and Zn extractability in soil and speciation in pore water of industrial contaminated soils, on metal concentration in a metal sensitive species like spinach (Spinacia oleracea) and a more metal tolerant species like Italian ryegrass (Lolium multiflorum). For chemical speciation of Cd and Zn in pore water, WHAM/Model VI version 6.0 was used. The DGT technique was used to determine the effective concentration, C(E), of Cd and Zn in soils. The free ion activity in pore water correlated well with the contents in plants, and there was a linear relationship between the C(E) values and the concentration of Cd and Zn in both spinach and ryegrass in the non-toxic range. However, the C(E) values usually overestimated the plant contents when plants, particularly the spinach plants, were subjected to toxic concentration in the pore water. Metal uptake decreased in plants affected by toxicity, whereas metal binding to the Chelex resin did not. Thus, we found no linear relationship between the C(E) and metal contents in spinach, whereas a linear relationship was found between C(E)-Zn and the Zn concentration in ryegrass (r2=0.96, p<0.001). For Cd in ryegrass this relationship was weak (r2=0.53, p=0.18). This study indicates that the transport of metals from labile metal pools to the DGT-resin is linearly related to plant uptake only when plants are growing well, and that the applicability of DGT as an indicator for plant uptake seems species dependent.     

Outlining a Conception of Animal Welfare for Organic Farming Systems

The concept of animal welfare refersto the animal's quality of life. The choice ofdefinition always reflects some basicvaluation. This makes a particular conceptionof welfare value-dependent. Also, the animalhusbandry system reflects certain values oraims. The values reflected in the chosenconception of animal welfare ought tocorrespond to values aimed for in the husbandrysystem. The IFOAM Basic Standards and otherwritings dealing with organic animal husbandryshould be taken as a departure point for adiscussion of how to interpret the conceptionof welfare in organic farming systems. Theconception of welfare is related to two corevalues in the organic agriculture movement.These core values should be considered in termsof (1) aim for holistic view and (2) aim forsustainability. A third, implicit core value,based on bio- and ecocentric views: (3) respectfor nature is needed as a supplement to thesetwo core values. There are importantimplications of these core values for an``organic' conception of animal welfare and forconfronting two dilemmas due to conflictinginterests. Comparisons among the three commonlyused welfare definitions will show thesuperiority of the third approach, which canprovide an outline for a conception of animalwelfare more suitable for organic farmingsystems. This outline combines a holisticecocentric approach with respect for theindividual animal, and it can be used as thebasis for a complex definition with emphasis onnatural behavior. Such a systemic approachconsiders welfare in relation to differentsystemic levels. The systemic view also offerspossibilities for resolving the dilemmas in newways.     

Validation of FLACS against experimental data sets from the model evaluation database for LNG vapor dispersion

The siting of facilities handling liquefied natural gas (LNG), whether for liquefaction, storage or regasification purposes, requires the hazards from potential releases to be evaluated. One of the consequences of an LNG release is the creation of a flammable vapor cloud, that may be pushed beyond the facility boundaries by the wind and thus present a hazard to the public. Therefore, numerical models are required to determine the footprint that may be covered by a flammable vapor cloud as a result of an LNG release. Several new models have been used in recent years for this type of simulations. This prompted the development of the “Model evaluation protocol for LNG vapor dispersion models” (MEP): a procedure aimed at evaluating quantitatively the ability of a model to accurately predict the dispersion of an LNG vapor cloud.This paper summarizes the MEP requirements and presents the results obtained from the application of the MEP to a computational fluid dynamics (CFD) model – FLACS. The entire set of 33 experiments included in the model validation database were simulated using FLACS. The simulation results are reported and compared with the experimental data. A set of statistical performance measures are calculated based on the FLACS simulation results and compared with the acceptability criteria established in the MEP. The results of the evaluation demonstrate that FLACS can be considered a suitable model to accurately simulate the dispersion of vapor from an LNG release.