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A methodological approach to the identification of biodiversity indicators in commercial forest stands is illustrated by analysis of the relationships between syrphid (hoverflies) and carabid (ground beetles) community composition and diversity, and stand structure and fieldlayer vegetation. Data were collected from 12 commercial forest sites encompassing a range of climatic conditions and different crop types (Scots pine, Sitka spruce, Norway spruce and Corsican pine) across the UK. Comparisons were also made between unmanaged semi-natural Scots pine woods and Scots pine plantations. For both syrphids and carabids, no differences in species richness and diversity were recorded between semi-natural stands and plantations; one rare syrphid considered to be restricted to semi-natural pine stands was also found in spruce. Syrphid species diversity and richness was higher in southern spruce sites than in the northern sites. Northern sites had distinctivecarabid communities, as did sites in the New Forest, a large ancientwoodland in southern England. Of the measured habitat variables, vertical stand structure showed the best correlation with species richness and diversity of both carabids and syrphids. Richness and diversity were less in stands with high vertical cover values for canopy layers. Stands with higher field layer cover supported greater syrphid divemity, but lower carabid diversity. Measures of stand structure could be used as potential indicators of syrphid and carabid diversity, but additional habitat parameters also need to be tested. (c) 1999 Published by Elsevier Science B.V. [ABSTRACT FROM AUTHOR]

Abstract Piscirickettsiosis caused by Piscirickettsia salmonis constitutes one of the main problems in farmed salmonid and marine fishes. The objective of this study was to evaluate the modulation of genes involved in the oxidative stress in the liver and muscle of Salmo salar challenge with low dosage of P. salmonis. The treatment (in duplicate) were as follows: Control injection (culture medium) and P. salmonis injection (1 × 102 PFU/mL) with sampling (liver and muscle) at several time-points during the 42-days experimental period (dpi). In liver, the gene expression of superoxide dismutase (SOD) and acetylcholinesterase (AChE) had differences with the control group only at 7 dpi, compared with glutathione-S-transferase (GST) and heat shock protein 70 (HSP70) that presented increases at 7 and 21 dpi. The glutathione peroxidase (GPx) and catalase (CAT) mRNAs were elevated at 13 and 21 dpi, respectively. While glutathione reductase (GR) and cytochrome P450 (P450) did not show variations in their expression during the experimental course. In muscle, the expression of CAT and AChE was higher than in the control condition at 2 and 42 dpi, respectively. While the number of transcripts SOD, GPx, GR, GST, P450 and HSP70 showed increases at 7- and 42-days post injection. The results suggest a transcriptional activation of genes involved in oxidative stress in both liver and muscle, with expression profiles that were tissue-specific and dependent on the time. This is the first study that reveals the transcriptional participation of all these genes associated with oxidative stress in response to the injection of P. salmonis. Graphical abstract Unlabelled Image Highlights • Piscirickettsiosis caused by Piscirickettsia salmonis constitutes one of the main problems in farmed salmonid and marine fishes. • The objective of this study was to evaluate the modulation of genes involved in the oxidative stress in the liver and muscle of Salmo salar challenge with low dose of P. salmonis. • The results suggest a transcriptional activation of genes involved in oxidative stress in both liver and muscle. • The gene expression changes in liver and muscle of infected fish suggested that P. salmonis produced a modulation of the expression of genes involved in the oxidative stress response. • The responses to oxidative stress were specific to each tissue analyzed, suggesting that antioxidant defense in liver is more effective to eliminate free radicals than in muscle. [ABSTRACT FROM AUTHOR]