Carbon loads, forms and sequestration potential within ash deposits produced by wildfire: new insights from the 2009 ‘Black Saturday’ fires, Australia

Forest fires release substantial amounts of carbon (C). Much of it is emitted to the atmosphere, but some is deposited within ash on the ground. Little is known about amount and types of C deposited in ash. Here, we quantify total C, and total inorganic, water-soluble and particulate organic fractions deposited in ash during the catastrophic 2009 ‘Black Saturday’ wildfires in Australia. These fires coincided with the highest air temperatures and lowest humidity ever recorded in the local area, which, combined with high fuel loads of mostly long unburnt eucalypt forests, generated extreme burning conditions. In three mixed-species eucalypt forest sites sampled, the canopy, understorey and litter fuels were almost completely consumed, resulting in substantial ash deposition (mean, 81.9 t ha^?1), with 5.9 t ha^?1 of C being transferred from vegetation to the forest floor. In five temperate rainforest sites sampled, the canopy was not burnt and ash deposition was lower (mean, 48.3 t ha^?1) than in the mixed-species eucalypt forest, but overall their higher C content resulted in higher C deposition (8.1 t ha^?1). In all cases, most C contained in ash was organic and its pyrogenic nature infers increased resistance to degradation. Pyrogenic C is viewed by many as an important C sink, which could contribute to long-term C sequestration when incorporated into soils or sediments. Our results highlight the potential importance of the pyrogenic C pool in freshly deposited ash and, therefore, the necessity of a systematic and detailed analysis of ash deposition and C forms in ash to improve our understanding of C fluxes by forest fires.     

Comment on "Productivity is a poor predictor of plant species richness"

Adler et al. (Reports, 23 September 2011, p. 1750) analyzed the standardized sampling data from 48 herbaceous-dominated plant communities and concluded that "Productivity is a poor predictor of plant species richness" at fine-scale. However, their method was biased toward site-number-dominated plant communities. They also failed to provide enough data for regional analysis and detailed information for within-site analysis.     

The effect of rehabilitation of northern elephant seals (Mirounga angustirostris) on antimicrobial resistance of commensal Escherichia coli

The aim of this study was to determine if antimicrobial drug use increases resistance of commensal gastrointensinal Escherichia coli of wild northern elephant seals (Mirounga angustirostris) treated in rehabilitation, and, if so, identify the risk factors involved. Minimum inhibitory concentration (MIC) levels of twelve antimicrobial drugs were determined for 289 E. coli isolates from 99 seals sampled at admission and 277 isolates obtained at release from rehabilitation using broth microdilution. Prevalence of E. coli antimicrobial resistance, MIC(50), MIC(90), and clustering of MIC values were determined for seals and the data were analyzed using Fisher's exact test, ordinal logistic regression and negative binomial regression. At release from rehabilitation 77.8% of the seals had antimicrobial resistant E. coli compared to 38.4% of the seals at admission. The MIC(90) for amoxicillin-clavulanic acid, chloramphenicol, enrofloxacin, ticarcillin-clavulanic acid, and trimethoprim-saulfamethoxazole were at levels considered to be sensitive at admission but they increased to levels of resistance at release. E. coli were grouped into four clusters by their MIC values, with increasing levels of resistance going from Cluster 1 to 4. A primary risk factor associated with the probability of a seal having E. coli in Clusters 3 and 4 was time in rehabilitation, regardless of whether the animal received treatment with antimicrobial drugs, suggesting nosocomial infection. The results of this study provide evidence that increased levels of hygiene and appropriate use of antimicrobial therapy might be important in the rehabilitation of wild animals to prevent rise in the prevalence of antimicrobial resistant bacteria.     

Life-history and ecological correlates of population change in Dutch breeding birds

Predicting relative extinction risks of animals has become a major challenge in conservation biology. Identifying life-history and ecological traits related to the decline of species helps understand what causes population decreases and sets priorities for conservation action. Here, we use Dutch breeding bird data to correlate species characteristics with national population changes. We modelled population changes between 1990 and 2005 of all 170 breeding bird species using 25 life-history, ecological and behavioural traits as explanatory variables. We used multiple regression and multi-model inference to account for intercorrelated variables, to assess the relative importance of traits that best explain interspecific differences in population trend, and to identify the environmental changes most likely responsible. We found that more breeding birds have increased than decreased in number. The most parsimonious models suggest that ground-nesting and late arrival at the breeding grounds in migratory birds are most strongly correlated with decline. Increasing populations are mainly found among herbivores, sedentary and short-distance migrants, herb- and shrub-nesting birds and large species with a small European range. Declines in ground-nesting and late arriving migrant birds suggest that agricultural intensification, eutrophication and climate change are most likely responsible for changes in Dutch breeding bird diversity. We illustrate that management strategies should primarily focus on the traits and causes responsible for the population changes, in order to be effective and sustainable.     

Hereditary spectrin deficiency in Golden Retriever dogs

Spectrin deficiency with increased erythrocyte osmotic fragility (OF) is a hallmark of hereditary spherocytosis, which is the most common congenital hemolytic anemia in humans of northern European ancestry. A radioimmunoassay revealed that erythrocyte spectrin concentration was 50-65% of normal in 5 adult Golden Retriever dogs, which had recovered from hemolytic anemia but whose OF had persistently remained increased. OF also was increased and spectrin concentration was decreased (60-73%) in 10 dogs of an apparently healthy family of 19 Golden Retrievers related to a proband. Pedigree analysis revealed autosomal dominant inheritance. In addition, OF was increased in 23 (17%) of 134 randomly chosen Golden Retrievers with nonhematologic diseases. In these Golden Retrievers, the spectrin concentration was decreased in 5 dogs with increased OF and within the reference range in 6 dogs with normal OF, indicating that in this population spectrin deficiency and increased OF are highly associated (P < .002). Considering these patients a representative sample of the Golden Retriever population in the Netherlands, spectrin deficiency may occur in 11.2-24.6% of Dutch Golden Retrievers (confidence level = 0.95). In blood smears, spherocytes were recognized only in dogs with immune-mediated anemia. At scanning electron microscopy, blood from spectrin-deficient Golden Retrievers showed slight crenation when fixed freshly but abundant echinospherocytes after 24 hours of incubation. We conclude that occult autosomal dominant spectrin deficiency occurs in dogs and is frequent in Dutch Golden Retrievers. It is not clear whether spectrin deficiency in Golden Retrievers may result in hemolytic anemia, as in humans.     

Infectious bovine rhinotracheitis outbreak on a mostly BHV-1 free farm can result in great damage

In a suckler herd with 110 cows (without young stock born in 2003) 5 cows died within 10 days, 6 calves were born dead prematurely and 5 calves were born alive but prematurely. The diagnosis BHV1-infection was based on clinical symptoms and confirmed with PCR. The clinical signs, diagnostic methods, therapy, risk-analysis and prevention are discussed.