Linear features and butterflies: the importance of green lanes

Green lanes are unmetalled tracks between fields of variable width, which may be sunk below or raised above field level, and bounded on both sides by ‘grass’ banks, hedgerows or dry-stone walls. In the UK they have no unique planning status and have been overlooked as discrete landscape elements. Green lanes were surveyed for butterflies in 1997 on lowland arable farmland on the Trafford/north Cheshire border (Warburton) and on upland grassland in the Yorkshire Dales (Ribble Valley). At the lowland site the green lanes were bounded by vegetation and were compared with grass banks and single hedgerow field boundaries; at the upland farm, the green lanes were bounded by dry-stone walls and were compared with grass banks and single dry-stone walls. Data from earlier work on a largely arable farm (Manydown) in Hampshire in 1987 and 1988 were re-analysed to make comparisons between a green lane, the rides and glades of two coppiced woodlands, and the grass banks and single hedgerows surrounding arable fields. Green lanes, whether bounded by vegetation or stone were superior to other common farmland biotopes with the exception of woodland, in terms of both butterfly abundance and species richness.Multiple regression of the Warburton data indicated the importance of green lanes, adjacent habitat type, and nectar sources for species richness and butterfly abundance. The interior of green lanes had lower windspeeds, and more bramble nectar sources than hedgerows or grass banks. By their nature they occupy a larger area of uncropped land, and are subject to a reduced disturbance regime and reduced inputs of agrochemicals and fertilisers. Their value as biodiversity reservoirs in intensively managed land is likely to be high.     

The contribution of advective fluxes to net ecosystem exchange in a high-elevation, subalpine forest

The eddy covariance technique, which is used in the determination of net ecosystem CO2 exchange (NEE), is subject to significant errors when advection that carries CO2 in the mean flow is ignored. We measured horizontal and vertical advective CO2 fluxes at the Niwot Ridge AmeriFlux site (Colorado, USA) using a measurement approach consisting of multiple towers. We observed relatively high rates of both horizontal (F(hadv)) and vertical (F(vadv)) advective fluxes at low surface friction velocities (u(*)) which were associated with downslope katabatic flows. We observed that F(hadv) was confined to a relatively thin layer (0-6 m thick) of subcanopy air that flowed beneath the eddy covariance sensors principally at night, carrying with it respired CO2 from the soil and lower parts of the canopy. The observed F(vadv) came from above the canopy and was presumably due to the convergence of drainage flows at the tower site. The magnitudes of both F(hadv) and F(vadv) were similar, of opposite sign, and increased with decreasing u(*), meaning that they most affected estimates of the total CO2 flux on calm nights with low wind speeds. The mathematical sign, temporal variation and dependence on u(*) of both F(hadv) and F(vadv) were determined by the unique terrain of the Niwot Ridge site. Therefore, the patterns we observed may not be broadly applicable to other sites. We evaluated the influence of advection on the cumulative annual and monthly estimates of the total CO2 flux (F(c)), which is often used as an estimate of NEE, over six years using the dependence of F(hadv) and F(vadv) on u(*). When the sum of F(hadv) and F(vadv) was used to correct monthly F(c), we observed values that were different from the monthly F(c) calculated using the traditional u(*)-filter correction by--16 to 20 g C x m(-2) x mo(-1); the mean percentage difference in monthly Fc for these two methods over the six-year period was 10%. When the sum of F(hadv) and F(vadv) was used to correct annual Fc, we observed a 65% difference compared to the traditional u(*)-filter approach. Thus, the errors to the local CO2 budget, when F(hadv) and F(vadv) are ignored, can become large when compounded in cumulative fashion over long time intervals. We conclude that the "micrometeorological" (using observations of F(hadv) and F(vadv)) and "biological" (using the u(*) filter and temperature vs. F(c) relationship) corrections differ on the basis of fundamental mechanistic grounds. The micrometeorological correction is based on aerodynamic mechanisms and shows no correlation to drivers of biological activity. Conversely, the biological correction is based on climatic responses of organisms and has no physical connection to aerodynamic processes. In those cases where they impose corrections of similar magnitude on the cumulative F(c) sum, the result is due to a serendipitous similarity in scale but has no clear mechanistic explanation.     

Enhancing road safety through early detection of outbreaks in the frequency of motor vehicle crashes

Methods for detecting outbreaks in the frequency of particular human-related phenomena have typically monitored daily counts for geographical regions. However, age can also be a significant factor in the frequency distribution of particular phenomena. Using data relating to motor vehicle crashes on public roads, this paper offers a methodology for detecting outbreaks that are age group clustered. The transitional Poisson regression model is used to provide day-ahead forecasts (expected values) for daily crash counts across different age groups. Standardized smoothed count departures from their smoothed day-ahead forecasts across all age groups are used to detect systematic outbreaks. The CUSUM of sequential age group standardized scores is used to signal outbreaks that are age-clustered. Potential applications of the developed methodology include early detection of age-related epidemics and unusual increases in work-related accidents.     

Performance of a Steam-Ejector Scrubber

The results of fractional and overall mass efficiency tests of a steam-ejector scrubber are presented. The tests were performed on one of seven modules of a full scale scrubber used for controlling particulate emissions from an open hearth furnace. Total flue gas particulate mass concentrations were determined at the inlet and outlet of the scrubber by conventional (Method 5) techniques. Inlet and outlet particulate concentrations as functions of diameter were determined on a mass basis using cascade impactors for sizes from about 0.3 μm to 5 μm, and on a number basis for diameters smaller than about 1 μm using optical and diffusional methods. Measurements were made under several scrubber operating conditions. The measured efficiencies based on total particulate mass concentrations with the scrubber operating under near optimum conditions ranged from 99.84 to 99.9%. The measured fractional efficiencies ranged from a maximum of 99.99% for particles having diameters of 1 μm to values of 97 and 99.9% for particles having diameters of 0.1, and 5 μm, respectively.     

FF/C Scrubber Demonstration on a Secondary Metals Recovery Furnace

A flux force/condensation (FF/C) scrubbing system was built to control participate emissions from a secondary metals recovery furnace. Total mass penetration and fractional penetration measurements were made under several different operating modes. The performance of the demonstration scrubber was consistent with the results of previous studies on FF/C scrubbing. The system was generally capable of 90 to 95 % efficiency on particles with a mass median aerodynamic diameter of 0.75 µA. This efficiency was achieved with a 68 cm (27 in.) W.C. gas-phase pressure drop.     

Reducing the Maladaptive Attractiveness of Solar Panels to Polarotactic Insects

Abstract: Human‐made objects (e.g., buildings with glass surfaces) can reflect horizontally polarized light so strongly that they appear to aquatic insects to be bodies of water. Insects that lay eggs in water are especially attracted to such structures because these insects use horizontal polarization of light off bodies of water to find egg‐laying sites. Thus, these sources of polarized light can become ecological traps associated with reproductive failure and mortality in organisms that are attracted to them and by extension with rapid population declines or collapse. Solar panels are a new source of polarized light pollution. Using imaging polarimetry, we measured the reflection–polarization characteristics of different solar panels and in multiple‐choice experiments in the field we tested their attractiveness to mayflies, caddis flies, dolichopodids, and tabanids. At the Brewster angle, solar panels polarized reflected light almost completely (degree of polarization d ≈100%) and substantially exceeded typical polarization values for water (d ≈30–70%). Mayflies (Ephemeroptera), stoneflies (Trichoptera), dolichopodid dipterans, and tabanid flies (Tabanidae) were the most attracted to solar panels and exhibited oviposition behavior above solar panels more often than above surfaces with lower degrees of polarization (including water), but in general they avoided solar cells with nonpolarizing white borders and white grates. The highly and horizontally polarizing surfaces that had nonpolarizing, white cell borders were 10‐ to 26‐fold less attractive to insects than the same panels without white partitions. Although solar panels can act as ecological traps, fragmenting their solar‐active area does lessen their attractiveness to polarotactic insects. The design of solar panels and collectors and their placement relative to aquatic habitats will likely affect populations of aquatic insects that use polarized light as a behavioral cue.     

Predicting community sensitivity to ozone, using Ellenberg Indicator values

This paper develops a regression-based model for predicting changes in biomass of individual species exposed to ozone (RS(p)), based on their Ellenberg Indicator values. The equation (RS(p)=1.805-0.118Light-0.135 square root Salinity) underpredicts observed sensitivity but has the advantage of widespread applicability to almost 3000 European species. The model was applied to grassland communities to develop two further predictive tools. The first tool, percentage change in biomass (ORI%) was tested on data from a field-based ozone exposure experiment and predicted a 27% decrease in biomass over 5 years compared with an observed decrease of 23%. The second tool, an index of community sensitivity to ozone (CORI), was applied to 48 grassland communities and suggests that community sensitivity to ozone is primarily species-driven. A repeat-sampling routine showed that nine species were the minimum requirement to estimate CORI within 5%.     

Options for Controlling Condensation Aerosols to Meet Opacity Standards

The opacity of "detached plumes" formed by condensation of vapors depends upon both the concentration of condensible vapors and the in-stack concentration of fine, submicron, particulate matter. This paper provides an analysis of the condensing aerosol problem and an evaluation of possible control approaches to reduce the downwind detached plume opacity. The opacity of such plumes may be reduced by reducing the concentration of condensible vapors or the in-stack concentration of fine particles or both. The results of the analysis indicate that for low concentrations of condensible vapors the detached plume opacity may be adequately controlled by reducing the in-stack fine particulate concentration alone. For high concentrations of condensible vapors, however, reduction of in-stack fine particulate concentration alone may not be effective, and reduction of vapor concentration may be necessary along with particulate removal for adequate reduction of plume opacity. Different combinations of levels of reduction of vapor concentration and particulate phase concentration are possible to achieve a desired result; and thus may be optimized to obtain a cost-effective combination.