Stable sulfur isotope ratios as a tool for interpreting ecosystem sulfur dynamics

Water, Air, & Soil Pollution - Stable S isotope ratios (σ34S) were evaluated in soil solution leachates, soluble plus adsorbed soil SO inf4 sup2− , soil organic S, precipitation, and...     

What does IUCN species action planning contribute to the conservation process?

More than 60 Species Action Plans have been published by the Species Survival Commission (SSC) of IUCN—The World Conservation Union. They are designed to assess the status of threatened species and their habitats, and provide prioritised recommendations for action, but there is debate about the effectiveness of such plans in stimulating conservation action and research. We evaluated three Action Plans covering a group of large terrestrial birds, published in 1995. Of 54 projects suggested in these plans, 33 had been initiated in the 5 years since publication, and 35 specific conservation actions were undertaken. Forty-five peer-reviewed papers were published, and at least 88 other outputs in the form of symposium presentations, posters and popular articles were produced. Although it is impossible to demonstrate the effectiveness of species action planning through rigorous scientific assessment, these results indicate a substantial amount of conservation-relevant activity directly attributable to the process. They also highlight the need for a clear definition of the role of Action Plans. We suggest that many of the criticisms directed toward species action plans result from an over-optimistic view of their power to catalyse action, and conclude by presenting a new model describing their niche within the wider context of conservation biology and policy.     

The effect of feeding the leucine metabolite β-hydroxy-β-methylbutyrate (HMB) on cell-mediated immunity and protection against Yersinia ruckeri in pikeperch (Sander lucioperca)

The present study examined the influence of leucine metabolite β‐hydroxy‐β‐methylbutyrate (HMB), a natural product HMB, on nonspecific cell‐mediated defence mechanisms and protection against enteric redmouth disease (ERM) in pikeperch (Sander lucioperca). β‐hydroxy‐β‐methylbutyrate was fed in a pelletted ration at 50 mg kg^?1 of the feed for 8 weeks. The phagocytic ability and potential killing activity of blood and pronephric phagocytes were examined in HMB‐ and control‐fed fish before and after 8 weeks of feeding HMB. Simultaneously, the proliferative response of blood and pronephric lymphocytes stimulated by mitogens concanavaline A and lipopolisaccharide were examined in experimental and control groups. Following 8 weeks of HMB feeding, a challenge test was performed by injecting the fish with live pathogenic bacteria Yersinia ruckeri. β‐hydroxy‐β‐methylbutyrate applied in the diet for 8 weeks prompted a statistically significant (P<0.05) increase in phagocytic ability and potential killing activity of the blood and pronephric phagocytes and the proliferative response of blood and pronephric lymphocytes. The changes in these mechanisms correlated with protection against Y. ruckeri, the ERM pathogen. The results showed that feeding HMB increased the nonspecific cell‐mediated defence mechanisms and protection against ERM by reducing cumulative mortality (30%) following the challenge with pathogenic bacteria. Future studies will include determination of optimal doses and protocols of oral application of HMB to maximize the immunomodulatory effects and protection against viral diseases in intensive pikeperch culture.     

Critical loads for nitrogen deposition for Great Britain

There is currently much interest in mapping critical loads for nitrogen deposition as part of a strategy for controlling nitrogen emissions. While nitrogen deposition may cause acidification and excess nutrient effects, the former were considered previously in studies of sulphur deposition. In the UK, work on developing nutrient nitrogen critical loads maps has used several methods and databases. Two approaches are described here, one a steady state calculation using a nitrogen saturation limit for soil systems, the other an empirical estimate of critical loads set to prevent changes to vegetation communities. The empirical method uses national species records and land cover data derived from satellite imagery. Maps drawn from the available data are dependent upon a number of factors which reflect the approach used. To apply the nutrient critical loads to a strategy for future abatement measures, the nutrient nitrogen values for soils have been incorporated within a “critical loads function” which takes into account both acidity and nutrient effects as related to deposition loads for sulphur and nitrogen. This function may be used with deposition data to identify the need for sulphur and nitrogen emission reductions.     

The efficacy of anticoccidial products against Eimeria spp. in northern bobwhites

To determine whether chemotherapeutic compounds available for use in domestic poultry are effective at controlling coccidiosis in northern bobwhites (Colinus virginianus), we tested 13 chemotherapeutic anticoccidials including amprolium (250 parts per million [ppm]), clopidol (125 ppm), diclazuril (1 ppm and 2 ppm), decoquinate (30 ppm), lasalocid (120 ppm), monensin (90 ppm), narasin/nicarbazin (36/36 ppm), robenidine (33 ppm), roxarsone (50 ppm), sulfadimethoxine/ ormetoprin (125/75 ppm), salinomycin (60 ppm), semduramicin (25 ppm), and zoalene (125 ppm and 150 ppm). Three tests were conducted using two replicates of 10 birds each: Infected, unmedicated controls and medicated birds were challenged with 1 x 10(6) oocysts of a field isolate consisting primarily of Eimeria lettyae. Subsequently, we tested clopidol, lasalocid, salinomycin, diclazuril (1 ppm), and monensin against mixed-species field isolates containing E. lettyae, E. dispersa, E. colini, or all. Weight gain, gross intestinal lesions, severity of diarrhea, and feed conversion ratio (FCR) 6 days postinfection were recorded. Lesion score, as previously reported, was unreliable as a measure of severity of infection in comparison with weight gain, fecal scores, and FCR. Excellent to good efficacy was found in clopidol, decoquinate, diclazuril (1 ppm and 2 ppm), and in lasalocid, narasin and nicarbazin, robenidine, sulfadimethoxine/ormetoprin, and zoalene (150 ppm). Marginal protection was found using monensin, salinomycin, semduramicin, or a roxarsone/semduramicin combination. Amprolium, roxarsone, and zoalene (125 ppm) were ineffective at controlling coccidia. Two of the six isolates tested against diclazuril 1 ppm and clopidol demonstrated a high degree of resistance, but none of the six isolates was resistant to lasalocid. Four of the eight isolates showed mild to moderate, and moderate to high, resistance against monensin and salinomycin, respectively. These findings indicate that several available compounds are effective at controlling coccidiosis in bobwhites.     

Last occurrence and survival during winter of the arbovirus vector Culicoides brevitarsis at the southern limits of its distribution

SUMMARY: Linear regression analysis was used to describe the decline in numbers of Culicoides brevitarsis Kieffer into winter with monthly maximum, average and minimum temperatures at the southern limits to its distribution in New South Wales. From this, low temperature thresholds were derived when C brevitarsis would be absent from the field. The low minimum threshold ± 2 SE (95% Confidence Interval) of 8.1 ± 0.3°C was used with historical temperature data to estimate the last month that the species should occur (March to June) and the mean number of months (2 to 6.5) below the threshold at 17 selected sites. Probability for survival during winter at these sites was estimated from years when the number of consecutive months below the threshold was ≤ 2 months. This varied from zero to 51% depending on the location of the site. Last occurrence was 0.7 months later on average and absolute probabilities for survival ranged from zero to 100% when the temperatures were increased by an arbitrary 2°C.     

An outbreak of Eimeria necatrix coccidiosis in breeder pullets: analysis of immediate and possible long-term effects on performance

Coccidiosis caused by Eimeria necatrix was diagnosed in a flock of 17,640 broiler breeder pullets at 18 weeks of age on a new farm. Mortality and morbidity was excessive in both hens and males, resulting in 10.1% fewer hens capitalized and 15.56% fewer males. Egg production was lower by 4.51% during weeks 30-40 of age in comparison with other flocks of about the same age. Estimates of the cost of replacement of death losses and culls, the direct effect on the cost of the flock, and the increased cost of production amounted to $27,234.