Quantifying the impact of vegetation-based metrics on species persistence when choosing offsets for habitat destruction

Developers are often required by law to offset environmental impacts through targeted conservation actions. Most offset policies specify metrics for calculating offset requirements, usually by assessing vegetation condition. Despite widespread use, there is little evidence to support the effectiveness of vegetation-based metrics for ensuring biodiversity persistence. We compared long-term impacts of biodiversity offsetting based on area only; vegetation condition only; area × habitat suitability; and condition × habitat suitability in development and restoration simulations for the Hunter Region of New South Wales, Australia. We simulated development and subsequent offsetting through restoration within a virtual landscape, linking simulations to population viability models for 3 species. Habitat gains did not ensure species persistence. No net loss was achieved when performance of offsetting was assessed in terms of amount of habitat restored, but not when outcomes were assessed in terms of persistence. Maintenance of persistence occurred more often when impacts were avoided, giving further support to better enforce the avoidance stage of the mitigation hierarchy. When development affected areas of high habitat quality for species, persistence could not be guaranteed. Therefore, species must be more explicitly accounted for in offsets, rather than just vegetation or habitat alone. Declines due to a failure to account directly for species population dynamics and connectivity overshadowed the benefits delivered by producing large areas of high-quality habitat. Our modeling framework showed that the benefits delivered by offsets are species specific and that simple vegetation-based metrics can give misguided impressions on how well biodiversity offsets achieve no net loss.     

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.     

Effect of tracer dyes on initial deposits and persistence of bacillus thuringiensis subsp. kurstaki toxin after application of two commercial formulations onto spruce trees

Abstract

The effect of two tracer dyes [Erio Acid Red (EAR) and Acid Black 48 (AB‐48)] on initial deposits and persistence of Bacillus thuringiensis subsp. kurstaki (Btk) toxin (delta‐endotoxin) was studied after spraying two commercial formulations, Foray® 48B and Foray® 76B, over potted white spruce [Picea glauca (Moench) Voss] seedlings, at a dosage rate of 30 billion international units (BIU) per ha. Spray was applied using a spinning disc atomizer calibrated to deliver droplet sizes similar to those utilized in ultra‐low‐volume (ULV) treatments in operational insect control programs. The sprayed seedlings were left outdoors at the Sault Ste. Marie laboratory for 18 days under natural conditions of sunlight, wind and rainfall. Initial deposits and persistence of delta‐endotoxin protein in spruce foliage were determined by immunoassay [enzyme linked immunosorbent assay (ELISA)] quantification of the delta‐endotoxin. The total protein (inactive plus active) and delta‐endotoxin (active protein) concentrations in the two formulations were determined by a gravimetric procedure and by ELISA respectively.

The initial deposit levels of the toxin on foliage were not markedly affected by the addition of either of the two tracer dyes, and showed only a narrow range of 1521 to 1625 ng/g foliage (fresh weight) for Foray 48B, and 1789 to 2056 ng/g for Foray 76B. However, the persistence of the toxin was significantly influenced by the presence of the dyes. The toxin persisted in foliage only for 7 d post‐spray When the EAR dye was added to Foray 48B, compared to 10 d when no dye was added. The average half‐life (DT₅₀) of disappearance was 17.4 h for Foray 48B with EAR, and 20.9 h when no dye was present. In contrast, the situation was reversed in Foray 76B, since the duration of persistence was 10 d when EAR was added to Foray 76B, compared to 7 d when no dye was added. The average DT₅₀ was 27.9 h for Foray 76B with EAR, and 22.2 h without the dye. Persistence was the longest (14 d) when the AB‐48 dye was added to Foray 76B, and the DT₅₀ was 44.9 h.     

Phosmet residues in an orchard and adjacent recreational area 1

Abstract

Two cover sprays of phosmet were applied to an orchard adjoining a camping area and a bird sanctuary with a resident goose population. Insecticide residues were monitored on orchard leaves, orchard ground cover, ground cover in the camp‐site and along the adjacent lakeshore. Despite attempts to minimize drift, significant spray residues were found outside the target area. Residues on ground cover and leaves were reduced by sprinkler irrigation subsequent to spray application.     

Speciation and persistence of doxycycline in the aquatic environment: Characterization in terms of steady state kinetics

The aim of the present work was to establish the kinetics for the degradation of doxycycline in the aquatic environment with a view to arriving at a kinetic model that can be used to predict the persistence of antibiotic with confidence. The degradation of doxycycline in both water and sediment phases of aquatic microcosm experiments, as well as in distilled water control experiments, was studied over a period of 90 days. An initial 21% loss due to adsorption by the sediment was observed in the microcosm experiment soon after charging. Biphasic zero-order linear rates of degradation, attributed to microbial degradation of the free and sediment or colloidal particle-adsorbed antibiotic, were observed for both water phase (2.3 × 10^?2 and 4.5 × 10^?3 μgg^?1 day^?1) and sediment phase (7.9 × 10^?3 and 1.5 × 10^?3 μgg^?1 day^?1) of the microcosm experiment. The covered distilled water control experiment exhibited a monophasic zero-order linear rate (1.9 × 10^?3 μgg^?1 day^?1) attributed to hydrolysis, while the distilled water experiment exposed to natural light exhibited biphasic liner rates attributed to a combination of hydrolysis and photolysis (2.9 × 10^?3 μgg^?1 day^?1) and to microbial degradation (9.8 × 10^?3 μgg^?1 day^?1). A kinetic model that takes into account hydrolysis, photolysis, microbial degradation as well as sorption/desorption by colloidal and sediment particles is presented to account for the observed zero-order kinetics. The implications of the observed kinetics on the persistence of doxycycline in the aquatic environment are discussed.     

NONPARAMETRIC TESTS FOR TREND DETECTION IN WATER QUALITY TIME SERIES1

ABSTRACT: A review of nonparametric tests for trend leads to the conclusion that Mann-Whitney, Spearman, and Kendall tests are the best choice for trend detection in water quality time series. Recently these tests have been adapted to account for dependence and seasonality in such series (Lettenmaier, 1976; Hirsch, et al., 1972; Hirsch and Slack, 1984). For monotonic trends, a procedure allowing to select the pertinent tests considering the characteristics of time series is proposed and the practical limitations of the tests are also brought out. This procedure has been applied to identify the appropriate trend detection test for the time series of nine water quality parameters at Lake Laflamme (Québec). When a time series can be tested with the Mann-Whitney, Kendall, Spearman, or Lettenmaier (1976) test, the number of observations required to detect trends of a given magnitude, for selected significance and power levels can be calculated with the power function of the t test. When the test proposed by Hirsch, et al. (1984), Hirsch and Slack (1984), or Farrell (1980) need to be used, the number of observations can only be estimated approximately from the results of empirical power studies.     

Persistence,degradation and leaching of coumaphos in soil

Abstract

Dissipation, degradation and leaching of fresh ¹⁴C coumaphos, alkylated ¹⁴C coumaphos and aged residues of ¹⁴C coumaphos from vats were studied in alkaline sandy loam soil in soil columns in the field under subtropical conditions in Delhi for a year. Dissipation, degradation and bound residue formation was more in case of alkali treated coumaphos than fresh coumaphos. After 365 days total residues of fresh coumaphos accounted for 33.25% while that of alkali treated coumaphos was 19.12%. Bound residue formation was almost double in case of alkali treated coumaphos (18.95%) than fresh coumaphos (9.53%) after 150 days followed by release of bound residue in both the cases. The proportion of metabolites 4 ‐ methylumbelliferone, chlorferon and potasan collectively was 86.05% in fresh coumaphos extractable residues while the same was 91.74% in alkali treated coumaphos after 365 days. Aged residues from vats containing copper sulphate and buffer were found to be more persistent in soil as total residues remained were 95.58% in comparison with 83.09% total residues of aged residues from vats containing only buffer after 150 days of treatment. Copper sulphate seems to inhibit the degradatiion of coumaphos in soil by microorganisms. Chlorferon was the major metabolite in generally all the samples. Coumaphos did not leach below 10 cm in all the cases.     

Festuca arundinacea,glutathione S-transferase and herbicide safeners: A preliminary case study to reduce herbicidal pollution

The expression of glutathione S-transferase (GST) activity in Festuca arundinacea was investigated in response to the following herbicide safeners: benoxacor, cloquintocet-mexyl, fenchlorazol-ethyl, fenclorim, fluxofenim and oxabetrinil. All the above compounds enhanced the GST activity tested towards the “model” substrate 1-chloro-2,4-dinitrobenzene (CDNB). Assays of GST activity towards the herbicides terbuthylazine (N ²-tert-butyl-6-chloro-N ⁴-ethyl-1,3,5-triazine-2,4-diamine) and butachlor (N-butoxymethyl-2-chloro-2′,6′-diethylacetanilide) as substrates also showed the ability of the safeners to enhance the enzyme activity towards both these herbicides, with the exception of cloquintocet-mexyl for the enzyme activity towards butachlor. As a consequence of the above effects at a macro-scale level, decreased herbicide accumulation and persistence were ascertained in response to the addition of the safener benoxacor to both terbuthylazine and butachlor treatments. These results are discussed in terms of capacity of benoxacor to induce herbicide detoxification in Festuca arundinacea with a view to utilizing them in reducing herbicide pollution.     

Artificial neural network based carbon monoxide persistence models for episodic urban air quality management

This paper describes the development of artificial neural network (ANN) based carbon monoxide (CO) persistence (ANNCOP) models to forecast 8-h average CO concentration using 1-h maximum predicted CO data for the critical (winter) period (November–March). The models have been developed for three 8-h groupings of 10 p.m. to 6 a.m., 6 a.m. to 2 p.m. and 2–10 p.m., at two air quality control regions (AQCRs) in Delhi city, representing an urban intersection and an arterial road consisting heterogeneous traffic flows. The result indicates that time grouping of 2–10 pm is dominantly affected by inversion conditions and peak traffic flow. The ANNCOP model corresponding to this grouping predicts the 8-h average CO concentrations within the accuracy range of 68–71%. The CO persistence values derived from ANNCOP model are comparable with the persistence values as suggested by the Environmental Protection Agency (EPA), USA. This work demonstrates that ANN based model is capable of describing winter period CO persistence phenomena.