The relationship between ecology and the incidence of cooperative breeding in Australian birds

Summary Australia has many cooperatively breeding species of birds. These tend to occur in eucalypt and semi-arid woodlands rather than in rainforests or deserts. They tend to be insectivores that pursue rather than sit and wait for their prey, and tend to forage on the ground rather than above it. We propose that environments where resources do not show marked seasonal fluctuations are those in which cooperative breeding is most likely to evolve. Under these conditions birds might experience difficulty acquiring the extra food necessary to breed, especially if inexperienced. When adult survival was high, young and inexperienced birds could delay breeding. Unpredictable environments may also favor cooperative breeding, but our data do not strongly support this. Groupliving would be favored further if young birds are particularly vulnerable to predators when alone. They should therefore remain in the family group and delay their dispersal unitl a suitable breeding vacancy becomes available. These hypotheses are not mutually exclusive, but are complementary. Both may be required to ensure that at least some year-old birds do not breed and also do not disperse. We believe that they give rise to predictions, which can be tested in future field studies.     

Riverine pollution in some northern and north eastern states of india

Water samples from 30 rivers in northern and north-eastern hilly states of India were analysed for bacteriological and physicochemical parameters along with metals and pesticide residues. It was found that 34% of samples had >50 coliforms/100 ml, while 24% of samples demonstrated >50 thermotolerant (faecal) coliforms/100 ml. Among the metals, iron was found to be above maximum permissible limits in the rivers of all the states, while manganese was found to be above the maximum permissible limit in the rivers of Tripura and some northern states. Zinc, lead, nickel, chromium, copper, cobalt and cadmium plus physicochemical parameters and residual pesticides, however, were within their maximum permissible limits.     

Simulating the Impacts of Irrigation Levels on Soybean Production in Texas High Plains to Manage Diminishing Groundwater Levels

There is an increasing need to strategize and plan irrigation systems under varied climatic conditions to support efficient irrigation practices while maintaining and improving the sustainability of groundwater systems. This study was undertaken to simulate the growth and production of soybean [Glycine max (L.)] under different irrigation scenarios. The objectives of this study were to calibrate and validate the CROPGRO‐Soybean model under Texas High Plains’ (THP) climatic conditions and to apply the calibrated model to simulate the impacts of different irrigation levels and triggers on soybean production. The methodology involved combining short‐term experimental data with long‐term historical weather data (1951–2012), and use of mechanistic crop growth simulation algorithms to determine optimum irrigation management strategies. Irrigation was scheduled based on five different plant extractable water levels (irrigation threshold [ITHR]) set at 20%, 35%, 50%, 65%, and 80%. The calibrated model was able to satisfactorily reproduce measured leaf area index, biomass, and evapotranspiration for soybean, indicating it can be used for investigating different strategies for irrigating soybean in the THP. Calculations of crop water productivity for biomass and yield along with irrigation water use efficiency indicated soybean can be irrigated at ITHR set at 50% or 65% with minimal yield loss as compared to 80% ITHR, thus conserving water and contributing toward lower groundwater withdrawals. Editor's note: This paper is part of the featured series on Optimizing Ogallala Aquifer Water Use to Sustain Food Systems. See the February 2019 issue for the introduction and background to the series.     

Modelling of the contribution of dissolved inorganic nitrogen (DIN) from litterfall of adjacent mangrove forest to Hooghly–Matla estuary,India

Hooghly–Matla estuarine ecosystem of India is very rich in natural resources and receives large amount of nutrients through litterfall from adjacent mangrove forest. Nitrogen as an important nutrient occurs in various forms and plays a crucial role in the regulation of productivity in this estuarine system. Modelling of nitrogen dynamics from mangrove litterfall and particularly the release of dissolved inorganic nitrogen in this estuarine system is important because of its role in augmenting growth of phytoplankton and other higher plants and all other biological components of grazing food chain.     

Effects of SO2 and/or NO2 on Native Plants of the Mojave Desert and Eastern Mojave-Colorado Desert

Ten species of plants, five perennials and five annuals, native to the Mojave desert were grown in pots and fumigated in open top plastic greenhouses, 25 hours/week, with SO₂ and/or NO₂. Three levels of SO₂: 2.0, 0.67, and 0.22 parts per million (ppm); three levels of NO₂: 1.0, 0.33, and 0.11 ppm; three treatments with 2.0 ppm SO₂ + 1.0 ppm NO₂, 0.67 ppm SO₂ + 0.33 ppm NO₂ and 0.22 ppm SO₂ + 0.11 ppm NO₂ plus untreated control plants were used in the fumigations. The perennials were fumigated for 16 weeks in 1977 and 32 weeks in 1978. Three species of annuals were grown and fumigated for 17 weeks, a fourth for 16 weeks, and a fifth for 12 weeks. A second crop of the first three annuals were grown; one for 12 weeks, a second for 8, and a third for 9 weeks.

Individual species differed widely in their particular responses to the fumigants. The fumigations of perennials with 2.0 ppm of SO₂ or NO₂ at 1.0 ppm caused extensive leaf injury, and reduced growth or dry weight of Larrea divaricate Cav., Chilopsls linearis Cav., and Ambrosia dumosa (Gray) Payne. The combined fumigants had additive effects. No suggestion of synergism was noted. These fumigants at lower concentrations stimulated lateral growth of Encelia farinosa Gray ex Torr. and Erodium cicutarium (L.) L’Her., dry weight of Atriplex canescens (Pursh) Nutt. and Plantago insularis Eastw. and increased flowering of Balleya pleniradiata Harv. and Gray, thus indicating beneficial effects.

Annual species were more severely affected by 2.0 ppm SO₂ than the perennials and extensive injury or death of plants occurred in all annuals. At the 0.67 ppm level severe leaf injury occurred. NO₂ at 1.0 ppm was less injurious than SO₂ and addition of NO₂ to SO₂ suggested an antagonistic effect. Plant survival and flowering was increased by adding NO₂ to plants being treated with SO₂

Comparison of perennial species showed Larrea sensitive, Chilopsis, Encella and Ambrosia intermediate, and Atriplex resistant. The annual species showed Erodium cicutarium and Plantago Insularis to be extremely sensitive, Phacelia crenulata Torr very sensitive and Baileya pleniradiata sensitive. Chaenactis carphoclinia Gray grew poorly and no valid rating was possible.     

Seasonal Impact of Blending Oxygenated Organics with Gasoline on Motor Vehicle Tailpipe and Evaporative Emissions

Emissions from a 1988 GM Corsica with adaptive learning closed loop control were measured with 4 fuels at 40, 75, and 90° F. Evaporative and exhaust emissions were examined from each fuel at each test temperature. Test fuels were unleaded summer grade gasoline; a blend of this gasoline containing 8.1 percent ethanol; a refiner’s blend stock; and the blend stock containing 16.2 percent methyl tertiary butyl ether. The ethanol and MTBE blends contained 3.0 percent oxygen by weight. Regulated emissions (total hydrocarbons, carbon monoxide, and oxides of nitrogen), detailed aldehydes, detailed hydrocarbons, ethanol, MTBE, benzene, and 1, 3-butadiene were determined.

The highest levels of regulated emissions were produced at the lower temperature. Blended fuels produced almost twice the evaporative hydrocarbon emissions at high temperatures as did the base fuels. Benzene emissions varied with fuels and operating temperatures, while 1, 3-butadiene emissions decreased slightly with increasing temperatures. Formaldehyde emissions were not sensitive to fuel or temperature changes. Ethanol fuel blend total aldehyde emissions Increased by 40 percent due to increased acetaldehyde emissions.

Fuel blends had approximately a 3 percent economy decrease. The MTBE fuel blend appeared to offer the most reduction in total hydrocarbon, carbon monoxide, and oxides of nitrogen for the fuels and temperatures tested.     

Effects of Wind Direction on Coarse and Fine Particulate Matter Concentrations in Southeast Kansas

Abstract

Field data for coarse particulate matter ([PM] PM₁₀) and fine particulate matter (PM_2.5) were collected at selected sites in Southeast Kansas from March 1999 to October 2000, using portable MiniVol particulate samplers. The purpose was to assess the influence on air quality of four industrial facilities that burn hazardous waste in the area located in the communities of Chanute, Independence, Fredonia, and Coffeyville. Both spatial and temporal variation were observed in the data. Variation because of sampling site was found to be statistically significant for PM₁₀ but not for PM_2.5. PM₁₀ concentrations were typically slightly higher at sites located within the four study communities than at background sites. Sampling sites were located north and south of the four targeted sources to provide upwind and downwind monitoring pairs. No statistically significant differences were found between upwind and downwind samples for either PM₁₀ or PM_2.5, indicating that the targeted sources did not contribute significantly to PM concentrations. Wind direction can frequently contribute to temporal variation in air pollutant concentrations and was investigated in this study. Sampling days were divided into four classifications: predominantly south winds, predominantly north winds, calm/variable winds, and winds from other directions. The effect of wind direction was found to be statistically significant for both PM₁₀ and PM_2.5. For both size ranges, PM concentrations were typically highest on days with predominantly south winds; days with calm/variable winds generally produced higher concentrations than did those with predominantly north winds or those with winds from “other” directions. The significant effect of wind direction suggests that regional sources may exert a large influence on PM concentrations in the area.     

Influence of Oxygenated Fuels on the Emissions from Three Pre-1985 Light-Duty Passenger Vehicles

Tailpipe and evaporative emissions from three pre-1985 passenger motor vehicles operating on an oxygenated blend fuel and on a nonoxygenated base fuel were characterized. Emission data were collected for vehicles operating over the Federal Test Procedure at 40,75, and 90°F to simulate ambient driving conditions. The two fuels tested were a commercial summer grade regular gasoline (the nonoxygenated base fuel) and an oxygenated fuel containing 9.5 percent methyl tert-butyl ether (MTBE), more olefins, and fewer aromatics than the base fuel. The emissions measured were total hydrocarbons (THCs), speciated hydrocarbons, speciated aldehydes, carbon monoxide (CO), oxides of nitrogen (NO_x), benzene, and 1,3-butadiene.

This study showed no pattern of tailpipe regulated emission reduction when oxygenated fuel was used. Tailpipe emissions from the 1984 Buick Century without a catalyst and the 1977 Mustang with catalyst decreased with the MTBE fuel. However, emissions from the 1984 Buick Century and the 1980 Chevrolet Citation, both fitted with catalysts increased. The vehicles emitted more 1,3- butadiene and, in general, more NO_x when operated with the base fuel.

THC, CO, benzene, and 1,3-butadiene emissions from both fuels and all vehicles, in general, decreased with increasing test temperature, whereas NO_x emissions, in general, increased with increasing test temperature. Formaldehyde, acetaldehyde, and total aldehydes also showed a decrease in emissions as test temperature increased. More formaldehyde was emitted when the MTBE fuel was used.

Evaporative, diurnal, and hot soak emissions from the base fuel were greater than those from the MTBE fuel. The evaporated emissions from both fuels increased with increasing test temperatures. Diurnal data indicate that canister conditioning (bringing the evaporative charcoal canister to equilibrium) is required before testing.     

Public Versus Private: Does It Matter for Water Conservation? Insights from California

This article asks three connected questions: First, does the public view private and public utilities differently, and if so, does this affect attitudes to conservation? Second, do public and private utilities differ in their approaches to conservation? Finally, do differences in the approaches of the utilities, if any, relate to differences in public attitudes? We survey public attitudes in California toward (hypothetical but plausible) voluntary and mandated water conservation, as well as to price increases, during a recent period of shortage. We do this by interviewing households in three pairs of adjacent public and private utilities. We also survey managers of public and private urban water utilities to see if they differ in their approaches to conservation and to their customers. On the user side we do not find pronounced differences, though a minority of customers in all private companies would be more willing to conserve or pay higher prices under a public operator. No respondent in public utility said the reverse. Negative attitudes toward private operators were most pronounced in the pair marked by a controversial recent privatization and a price hike. Nonetheless, we find that California’s history of recurrent droughts and the visible role of the state in water supply and drought management undermine the distinction between public and private. Private utilities themselves work to underplay the distinction by stressing the collective ownership of the water source and the collective value of conservation. Overall, California’s public utilities appear more proactive and target-oriented in asking their customers to conserve than their private counterparts and the state continues to be important in legitimating and guiding conservation behavior, whether the utility is in public hands or private.