Polymerisation of added coniferyl alcohol by inherent xylem peroxidases and its effect on fungal decay resistance of Norway spruce

It is known that active peroxidase isozymes exist in mature wood of Norway spruce (Picea abies L. Karst.) and that they remain active for years and are found even in the heartwood (in Scots pine), where all cellular activity has ceased. This peroxidase activity was utilised in the impregnation of wood blocks with a natural monolignol, coniferyl alcohol and hydrogen peroxide. The hypothesis was that the internal wood peroxidases would oxidise the added monolignol and bind it stably into the cell wall matrix, which could hinder fungal decay. Since coniferyl alcohol is not very soluble in water, the impregnation was done under vacuum with an acetone–water solution containing 10% coniferyl alcohol and 0.4 mM H₂O₂ at room temperature (ca. 0.02 g of coniferyl alcohol was added to 1 g of wood). After impregnation, dimers of coniferyl alcohol and free coniferyl alcohol were found in acetone extracts with GC–MS analysis. Penetration of coniferyl alcohol and non-extractable reaction products were studied from the wood blocks with FTIR PAS technique. The wood samples treated were also subjected to a fungal decay test with Coriolus versicolor. This treatment hindered fungal decay in a 60-day experiment and led to a dry weight loss of 8.8% in comparison with 19.9% in the control. The reactions of coniferyl alcohol and H₂O₂ in the presence of peroxidases are discussed as well as the use of monolignols to increase wood decay resistance.     

Responses of small mammals to land restoration after mining

Context

Land degradation from mining influences biodiversity and ecosystem functioning. However, comparative studies using small mammal functional groups within rehabilitated mining sites are missing, despite their significant ecological contributions.

Objectives

We investigated the recovery of small mammals according to their trophic guild and terrestriality in restored mining sites and analyzed whether they were influenced by restoration scheme (active or passive), restoration time, mineral type, body mass and invasive species. We were especially interested in whether functional groups showed different recovery patterns across time.

Methods

We classified small mammals into functional groups according to trophic levels distinguishing carnivores, herbivores and omnivores, and according to their terrestriality categorized as above ground-dwelling (AGD) and fossorial and/or ground-dwelling individuals (FGD). We studied small mammal recovery globally following restoration of mining sites based on a meta-analysis using effect sizes. Influences of environmental variables were investigated with linear mixed models using effect sizes as response variable.

Results

We did not find significant differences for restoration scheme and time but we did for mineral type, body mass and invasive species in terms of population (abundance) recovery. Trajectories of functional group recoveries differed: FGD and herbivores quickly recovered after mining activities stopped, but declined later, whereas AGD, carnivores and omnivores recovered within the first few years or decades.

Conclusions

Our results highlight the different vulnerability of functional groups, and the importance of considering this in conservation interventions.