Cultivated land – a scarce commodity in a densely populated rural area in South Wollo,Ethiopia

Cultivated and settlement areas were studied in a small area (14 km2) in South Wollo, Ethiopia, by aerial photos, satellite images, field observations and interviews. Areas for cultivation/rural settlement decreased a few per cent between 1958 and 2013. Cultivated land per household slowly decreased in 1958–2003 but in 2003–2013 the annual decrease was 3–4 times higher. New farm buildings are often built on cultivated land, and abandoned buildings areas return to cultivation. Rainwater harvesting ponds have increased the areas with perennial crops that are important as a source of income. Tin roofed buildings are signs of improved livelihood. Very small farm size and rain-dependent agriculture combined with climate variability make food security vulnerable. Land-use inventories including remote sensing and local knowledge would be a valuable approach to assess livelihood needs. Further, it should involve decision makers at different levels, but local agricultural extension officers may play a central role.     

Gas-phase photolytic production of hydroxyl radicals in an ultraviolet purifier for air and surfaces

We have measured the concentration of hydroxyl radicals (OH) produced in the gas phase by a commercially available purifier for air and surfaces, using the time rate of decay of n-heptane added to an environmental chamber. The hydroxyl generator, an Odorox® BOSS? model, produces the OH through 185-nm photolysis of ambient water vapor. The steady-state concentration of OH produced in the 120 m³ chamber is, with 2σ error bars, (3.25 ± 0.80) × 10⁶ cm^?3. The properties of the hydroxyl generator, in particular the output of the ultraviolet lamps and the air throughput, together with an estimation of the water concentration, were used to predict the amount of OH produced by the device, with no fitted parameters. To relate this calculation to a steady-state concentration, we must estimate the OH loss rate within the chamber owing to reaction with the n-heptane and the 7 ppb of background hydrocarbons that are present. The result is a predicted steady-state concentration in excellent agreement with the measured value. This shows we understand well the processes occurring in the gas phase during operation of this hydroxyl radical purifier.

Implications: Hydroxyl radical air purifiers are used for cleaning both gaseous contaminants, such as volatile organic compounds (VOCs) or hazardous gases, and biological pathogens, both airborne and on surfaces. This is the first chemical kinetic study of such a purifier that creates gas-phase OH by ultraviolet light photolysis of H₂O. It shows that the amount of hydroxyls produced agrees well with nonparameterized calculations using the purifier lamp output and device airflow. These results can be used for designing appropriate remediation strategies.     

Costs and consequences of variation in the size of ruff leks

Summary We studied 13 ruff leks in a small region on the island of Gotland (Sweden) to investigate the effect of lek size on the costs and benefits of lekking for individual males. Male ruffs occur in two behaviourally and morphologically distinct forms, independents (residents plus marginals) and satellites, whose costs and benefits we have assessed separately. These ruff leks had from 1–10 resident (territory-holding) males and were visited daily by satellites, marginals and females from 5–25 May, when most copulations occurred. We used the average number of independent males, counted during censuses taken every 5 min during 2-h observation periods at each lek, as an index of mean lek size. Per independent male, the numbers of both satellites and females increased significantly with mean lek size. Female arrival rate and attendance (total female-minutes) also increased significantly with mean lek size as did the average per capita rate of mating success for resident males (that of satellites was not quite significant). Thus, the dispersion of both of these male categories did not appear to fit an ideal free distribution with respect to mating success. In addition, the number of independent-independent fights per independent and the rate of satellite-resident dyad formation per resident increased significantly with mean lek size. These results suggest that ruffs on larger leks enjoy higher mating success than those on smaller leks but also that costs increase with lek size. We suggest that independent males distribute themselves so as to maximize their own net benefits and that this factor can account for both the occurrence of ruff leks and the variation in their size. Correspondence to: J. Höglund     

Polybrominated diphenyl ethers in influents,suspended particulate matter,sediments, sewage treatment plant and effluents and biota from the Netherlands

Polybrominated diphenyl ethers (PBDEs) have been determined in 133 samples of suspended particulate matter (SPM), sediments, sewage treatment plant (STP) influents and effluents, fish and mussels from various locations in The Netherlands, as a part of a large Dutch national study on estrogenic contaminants in the aquatic environment (LOES project). Some PBBs were also analysed but not found in any of the samples at detectable levels. PBDEs and PBBs were included in this study because indications of long term effects on the balance of endocrine systems were found in the literature. High concentrations of decaBDE (up to 4600 g/kg dry weight) were found in SPM from the Western Scheldt. These levels are possibly related to spillage during use of PBDEs in industries upstream the river Scheldt in Belgium. SPM was identified as an important carrier for higher brominated diphenyl ethers in the aquatic environment. DecaBDE was not found at detectable levels in flounder, bream and mussels. The bioaccumulation of decaBDE in these fish and shellfish samples is apparently limited. Lower brominated PBDE congeners (tetra/penta) were also found in the Western Scheldt as well as in the Rhine delta and the river Meuse, but in much lower concentrations than the decaBDE. In contrast with decaBDE, the tetra and pentaBDEs were found in biota. It was concluded that at least a small part of the PBDE can pass STPs.     

Establishing principal soil quality parameters influencing earthworms in urban soils using bioassays

Potential contamination at ex-industrial sites means that, prior to change of use, it will be necessary to quantify the extent of risks to potential receptors. To assess ecological hazards, it is often suggested to use biological assessment to augment chemical analyses. Here we investigate the potential of a commonly recommended bioassay, the earthworm reproduction test, to assess the status of urban contaminated soils. Sample points at all study sites had contaminant concentrations above the Dutch soil criteria Target Values. In some cases, the relevant Intervention Values were exceeded. Earthworm survival at most points was high, but reproduction differed significantly in soil from separate patches on the same site. When the interrelationships between soil parameters and reproduction were studied, it was not possible to create a good model of site soil toxicity based on single or even multiple chemical measurements of the soils. We thus conclude that chemical analysis alone is not sufficient to characterize soil quality and confirms the value of biological assays for risk assessment of potentially contaminated soils.     

Breeding territory quality and agonistic behavior: effects of energy availability and intruder pressure in hummingbirds

Summary The relative importance of food a vailability and intruder pressure on breeding territorial behavior was studied in two experiments with male calliope hummingbirds. In the first experiment, extra food was provided in inconspicuous feeders. Territory owners who fed from the feeders increased their display rates (power-diving and hovering) when on their territories, and spent less time out of sight (mostly off their territories). Food addition by this method had no significant effect on intruder pressure, as measured by number and duration of chases. In the second experiment, intruder pressure was increased by attracting feedertrained males to feeders in territories of individuals who did not feed from feeders. In this experiment, display activity of residents did not change but chasing activity increased. These results suggest that display rates by male calliope hummingbirds depend at least in part on the amount of food available, but are not strongly affected by the number of feeding attempts by male intruders. No attempt was made to determine whether displays can deter competitors, attract mates, or do both. However, since these energetically expensive displays depend at least in part on the energy available to owners, they provide readily available indices of male and/or territory quality which could potentially be used for different purposes by different individuals.     

Desert locust control in ecologically sensitive areas: need for guidelines

Chemical control of desert locust (DL) is carried out over large areas of land, covering a range of different landscapes and ecosystems. There are no real restrictions for spraying in or close to environmentally sensitive areas and awareness of sensitivity is not always obvious to the people involved in control. However, concern about environmental issues in connection with DL control is growing and clear guidelines are needed. The objectives were: to identify and delineate areas particularly sensitive to pesticide contamination in northeastern Africa, e.g. protected areas, wetlands, populated places, oases, and areas with concentrations of migratory birds. These areas were matched with actual DL control during 1986-1998. The conclusion is that chemical control occurred in environmentally sensitive areas especially wetlands, e.g. temporary waters and mangroves; close to human settlements; and, to some extent, in or near protected areas and areas with numerous migratory birds.     

Maternal serum biochemical markers in pregnancies with fetal parvovirus B19 infection

Hydrops fetalis and fetal death caused by fetal parovirus B19 infection have been reported to be associated with elevated maternal serum alpha-fetoprotein (AFP), based on a total of six cases. It has been suggested that the absence of AFP elevation may be reassuring. Maternal serum levels of the Down syndrome screening markers unconjugated oestriol and human chorionic gonadotropin in cases of fetal parvovirus infection have not been previously reported. We report four cases of hydrops fetalis and fetal death caused by fetal parvovirus infection, each with unremarkable second-trimester levels of AFP, unconjugated oestriol, and human chorionic gonadotropin.