A model for assessing habitat fragmentation caused by new infrastructures in extensive territories – Evaluation of the impact of the Spanish strategic infrastructure and transport plan

The aim of the present work is to design a model for evaluating the impact of planned infrastructures on species survival at the territorial scale by calculating a connectivity index. The method developed involves determining the effective distance of displacement between patches of the same habitat, simplifying earlier models so that there is no dependence on specific variables for each species. A case study is presented in which the model was used to assess the impact of the forthcoming roads and railways included in the Spanish Strategic Infrastructure and Transport Plan (PEIT, in its Spanish initials).This study took into account the habitats of peninsular Spain, which occupies an area of some 500,000 km². In this territory, the areas deemed to provide natural habitats are defined by Directive 92/43/EEC. The impact of new infrastructures on connectivity was assessed by comparing two scenarios, with and without the plan, for the major new road and railway networks. The calculation of the connectivity index (CI) requires the use of a raster methodology based on the Arc/Info geographical information system (GIS). The actual calculation was performed using a program written in Arc/Info Macro Language (AML); this program is available in FragtULs (Mancebo Quintana, 2007), a set of tools for calculating indicators of fragmentation caused by transport infrastructure (http://topografia.montes.upm.es/fragtuls.html).The indicator of connectivity proposed allows the estimation of the connectivity between all the patches of a territory, with no artificial (non-ecologically based) boundaries imposed. The model proposed appears to be a useful tool for the analysis of fragmentation caused by plans for large territories.     

Approaches to assess biocover performance on landfills

Methane emissions from active or closed landfills can be reduced by means of methane oxidation enhanced in properly designed landfill covers, known as “biocovers”. Biocovers usually consist of a coarse gas distribution layer to balance gas fluxes placed beneath an appropriate substrate layer. The application of such covers implies use of measurement methods and evaluation approaches, both during the planning stage and throughout the operation of biocovers in order to demonstrate their efficiency. Principally, various techniques, commonly used to monitor landfill surface emissions, can be applied to control biocovers. However, particularly when using engineered materials such as compost substrates, biocovers often feature several altered, specific properties when compared to conventional covers, e.g., respect to gas permeability, physical parameters including water retention capacity and texture, and methane oxidation activity. Therefore, existing measuring methods should be carefully evaluated or even modified prior to application on biocovers. This paper discusses possible strategies to be applied in monitoring biocover functionality. On the basis of experiences derived from investigations and large-scale field trials with compost biocovers in Austria, an assessment approach has been developed. A conceptual draft for monitoring biocover performance and recommendations for practical application are presented.     

Estimating carbon in savanna ecosystems: rational distribution of effort

Minimising the cost of repeatedly estimating C (C) stocks is crucial to the financial viability of projects that seek to sell C credits. Depending on the price of C, this may imply less or more sampling effort than would be applied for science objectives. In systems with heterogeneous C pools, such as savannas, this translates into a variable-effort sampling strategy that maximises the marginal additional C that can be claimed per incremental unit of effort expended. Analysis of a savanna in north-eastern South Africa indicates relatively modest returns per hectare due to the small C quantities and low sequestration rates. Under these conditions, areas in excess of 1,000 ha and infrequent sampling frequencies of 5–10 years are required to make such projects financially viable. For such projects the sample variance, number of samples, cost per sample and establishment costs have negligible impacts on financial viability. It was also found that the soil-C pool contributes up to three times the net returns of the aboveground C pool and provides a strong argument to monitor soil C for certification and market trading. The financial viability estimates, however, do not include the management or opportunity costs incurred in changing the land use. The economies of scale identified in this study combined with the massive area covered by savannas indicate that these additional costs can be covered. Further research is recommended to quantify these costs and interrogate the feasibility of large scale (in excess of 10,000 ha) C-sink projects in savanna systems.     

Perceptions of air pollution during the work-related commute by adults in Queensland,Australia

BackgroundThis study examines perceived health effect risks from air pollution during the work-related commute by socio-demographic and travel mode variables.MethodsPopulation-representative survey data were collected by telephone from 745 adults from Queensland, Australia. Variables assessed included socio-demographics, usual work travel mode, commute perceptions, and perceived health effects associated with air pollution during the work-related commute.ResultsApproximately 45% of the sample perceived air pollution negatively affected health outcomes when commuting to/from work, yet only 13% recognised air pollution as a major barrier to walking or cycling to/from work. No relationships existed between usual travel mode to/from work and perceived health risks associated with air pollution. Those higher educated or living in major cities were more likely to recognise air pollution harmed their health during their work-related commute when compared to respective referent categories (p ≤ 0.05).ConclusionsRecognition of health risks from air pollution during the work-related commute was high, and awareness did not differ by travel mode. For the majority, air pollution was not a primary barrier for walking or cycling to/from work.     

Prevalence of the Crayfish Plague Pathogen Aphanomyces astaci in Invasive American Crayfishes in the Czech Republic

Abstract:  In Central Europe invasive North American crayfishes are carriers of the oomycete Aphanomyces astaci, which causes crayfish plague. This lethal disease currently represents one of the major threats to native European crayfishes. We used molecular methods—species-specific amplification and sequencing of the pathogen DNA—to investigate the prevalence of individuals latently infected with A. astaci in 28 populations of two invasive American crayfish species (6 of the signal crayfish [ Pacifastacus leniusculus ] and 22 of the spiny-cheek crayfish [ Orconectes limosus ]) in the Czech Republic. The pathogen occurred in 17 investigated populations. We recorded a high variation in positive reactions, ranging from 0% to 100%, in populations of O. limosus . In P. leniusculus, however, only one individual out of 124 tested positive for the pathogen. There was a clear relationship between the water body type and pathogen prevalence in O. limosus . Infection ratios in isolated standing waters were usually low, whereas in running waters, pathogen prevalence often exceeded 50%. Other evaluated characteristics of potential plague pathogen carriers (size, sex, and the presence of melanized spots in the cuticle) seemed to be unrelated to infection. Our data suggest that in contrast to other European countries, O. limosus seems to be the primary reservoir of crayfish plague in the Czech Republic. Although all populations of alien American crayfishes may be potential sources of infections and should be managed as such, knowledge on the prevalence of the plague pathogen at various localities may allow managers to focus conservation efforts on the most directly endangered populations of native crayfishes.     

Development of an analytical method for analysis of flubendiamide,des-iodo flubendiamide and study of their residue persistence in tomato and soil

Flubendiamide is a new insecticide that has been found to give excellent control of lepidopterous pests of tomato. This study has been undertaken to develop an improved method for analysis of flubendiamide and its metabolite des-iodo flubendiamide and determine residue retention in tomato and soil. The analytical method developed involved extraction of flubendiamide and its metabolite des-iodo flubendiamide with acetonitrile, liquid-liquid partitioning into hexane-ethyl acetate mixture (6:4, v v^?1) and cleanup with activated neutral alumina. Finally the residues were dissolved in gradient high pressure liquid chromatography (HPLC) grade acetonitrile for analysis by HPLC. The mobile phase, acetonitrile-water at 60:40 (v v^?1) proportion and the wavelength of 235 nm gave maximum peak resolution. Using the above method and HPLC parameters described, nearly 100 % recovery of both insecticides were obtained. There was no matrix interference and the limit of quantification (LOQ) of the method was 0.01 mg kg^?1. Initial residue deposits of flubendiamide on field-treated tomato from treatments @ 48 and 96 g active ingredient hectare^?1 were 0.83 and 1.68 mg kg^?1,respectively. The residues of flubendiamide dissipated at the half-life of 3.9 and 4.4 days from treatments @ 48 and 96 g a.i. ha^?1, respectively and persisted for 15 days from both the treatments. Des-iodo flubendiamide was not detected in tomato fruits at any time during the study period. Residues of flubendiamide and des-iodo flubendiamide in soil from treatment @ 48 and 96 g a.i. ha^?1 were below detectable level (BDL, < 0.01 mg kg^?1) after 20 days. Flubendiamide completely dissipated from tomato within 20 days when the 480 SC formulation was applied at doses recommended for protection against lepidopterous pests.     

Diffusion mechanism of lindane into wood charcoal

Abstract

The wood charcoal treated by 1N HNO₃ (WCT) was used to remove toxic chlorinated pesticide lindane (y‐HCH) residue from water by the sorption process. Using a simple first order reversible kinetics constants and half time equations, the film and pore diffusion coefficients were determined. Film diffusion was found to be rate limiting step in sorbing lindane by WCT. This was further authenticated by kinetics studies at different initial sorbate concentrations, different sorbent sizes, and different agitation speeds besides interruption test. A pore diffusion model was used to fit the data of kinetics in continuously mixed batch reactors (CMBR), and the tortuosity, external resistance, and surface diffusion effects on lindane sorption by WCT were noticed. The tortuosity values of 15 to 28 were obtained for WCT‐lindane system.     

Aldehyde and Monocyclic Aromatic Hydrocarbon Mixing Ratios at an Urban Site in Las Vegas,Nevada

ABSTRACT

Linhong Jing completed a master's degree in chemistry at UNLV and is currently enrolled in the Ph.D. program at Purdue University. Her address is Department of Chemistry, Purdue University, West Lafayette, IN 47907. Dr. Spencer Steinberg is an associate professor of chemistry at UNLV. His address is UNLV Department of Chemistry, P.O. Box 454003, Las Vegas, NV 89154-4003. Dr. Brian Johnson is an associate professor of chemistry at UNLV. His address is UNLV Department of Chemistry, P.O. Box 454003, Las Vegas, NV 89154-4003.

Oxidation of benzene, toluene, ethylbenzene, and xylenes (BTEX) in air, of significance due to, for example, the potential for O₃ formation, is believed to be initiated by OH attack on the ring (addition) or on the alkyl side chain (H abstraction). A series of ring-breaking reactions follows, with major products predicted to be a-dicarbonyls, simple aldehydes, and organic acids. To test this prediction, ambient air mixing ratios of aldehydes (formaldehyde, ac-etaldehyde, benzaldehyde, glyoxal, and pyruvaldehyde), along with some supporting BTEX data, were measured at an urban site in Las Vegas, NV. Samples were collected on sorbents and determined by chromatographic methods; mixing ratios were compared to ambient levels of CO, O₃, and NO_x. A meteorological analysis (temperature, wind speed, and wind direction) was also included. Statistically significant relationships were noted among the BTEX hydrocarbons (HCs) and among the photochemi-cally derived species (e.g., O₃, NO₂, and some of the aldehydes), although there was seasonal variation. The observations are consistent with a common primary source (i.e., vehicular exhaust or fuel evaporation) for the BTEX compounds and a common secondary source (e.g., OH attack) for glyoxal and pyruvaldehyde.     

Trampling Impacts on Thermotolerant Vegetation of Geothermal Areas in New Zealand

Geothermal features such as geysers, mud pools, sinter terraces, fumaroles, hot springs, and steaming ground are natural attractions often visited by tourists. Visitation rates for such areas in the Taupo Volcanic Zone of New Zealand are in the order of hundreds of thousands annually. These areas are also habitat for rare and specialized plant and microbial communities that live in the steam-heated soils of unusual chemical composition. We evaluated historical and current trampling impacts of tourists on the thermotolerant vegetation of the Waimangu and Waiotapu geothermal areas near Rotorua, and compared the results to experimental trampling at a third site (Taheke) not used by tourists. Historical tourism has removed vegetation and soil from around key features, and remaining subsoil is compacted into an impervious pavement on which vegetation recolonization is unlikely in the short term. Social tracks made by tourists were present at both tourist sites often leading them onto hotter soils than constructed tracks. Vegetation height and cover were lower on and adjacent to social tracks than further from them. Thermotolerant vegetation showed extremely low resistance to experimental trampling. This confirms and extends previous research that also shows that thallophytes and woody shrubs, life forms that dominate in thermotolerant vegetation, are vulnerable to trampling damage. Preservation of these vulnerable ecosystems must ensure that tourist traffic is confined to existing tracks or boardwalks, and active restoration of impacted sites may be warranted.     

Severity of SO2-lnduced Leaf Necrosis on Caribbean,Scots, and Virginia Pine Seedlings

Caribbean pine, an economically important tree of tropical lowlands, is at risk of SO₂ exposure in certain locales. Twenty-week old seedlings of Caribbean, Scots, and Virginia pine were exposed to 0.5, 1.0, and 2.0 ppm SO₂ (1300, 2600, and 5200 μm^?3, respectively) for 1, 2, 4, and 8 h in modified controlled-environment chambers. Severity of SO₂-induced leaf necrosis for each species was related to SO₂ concentration and exposure duration using a regression model. The three dose-response relationships differed in detail, but Caribbean pine seedlings were generally as sensitive to SO₂ as seedlings of the two highly sensitive temperate species. In addition, 173 4-wk-old Caribbean pine seedlings were exposed to 0.5 ppm SO₂ for 4 h. Over one-half of these seedlings exhibited some necrosis and over one-sixth had more than 5 percent of leaf surface necrotic. It is concluded that Caribbean pine seedlings are highly sensitive to acute doses of SO₂.