1. Resource availability and habitat heterogeneity are principle drivers of biodiversity, but their individual roles often remain unclear since both factors are usually correlated. The biodiversity of species dependent on dead wood could be driven by either resource availability represented by dead-wood amount or habitat heterogeneity characterized by dead-wood diversity or both. Understanding their roles is crucial for improving evidence-based conservation strategies for saproxylic species in managed forests. 2. To disentangle the effects of dead-wood amount and dead-wood diversity on biodiversity relative to canopy openness (microclimate), we experimentally exposed different amounts of logs and branches of two different tree species representing a gradient of dead-wood diversity in 190 sunny and shady forest plots. During the 3 years after exposing dead wood, we sampled saproxylic beetles, which are together with fungi the most diverse and important taxonomic group involved in decomposition of wood. 3. The composition of saproxylic beetle assemblages differed clearly between shady and sunny forest plots, with higher richness in sunny plots. Both dead-wood amount and deadwood diversity positively and independently affected species richness of saproxylic beetles, but these effects were mediated by canopy openness. In sunny forest, species richness increased with increasing amount of dead wood, whereas in shady forest, dead-wood diversity was the prevailing factor. 4. The stepwise analysis of abundance and species richness, however, indicated that effects of both factors supported only the habitat-heterogeneity hypothesis, as the positive effect of high amounts of dead wood could be explained by cryptic variability of dead-wood quality within single objects. 5. Synthesis and applications. As canopy openness and habitat heterogeneity seem to be the major drivers of saproxylic beetle diversity in temperate forests, we recommend that managers aim to increase the heterogeneity of dead-wood substrates under both sunny and shady forest conditions. Intentional opening of the canopy should be considered in anthropogenically homogenized, dense forests. Specifically in temperate mixed montane forests, dead wood should be provided in the form of large logs in sunny habitats and a high diversity of different dead-wood substrates should be retained or created in shady forests.

Two phosphorus-containing heterocyclic flame retardants -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and 2,8-dimethyl-phenoxaphosphin-10-oxide (DPPO) -and their derivatives were characterized and incorporated in the backbone of epoxy novolac to obtain flame-retardant epoxy resins. The structures and spectroscopic data including high-resolution mass spectroscopy of these flame retardants were determined. Flameretardant epoxy resins with a phosphorus content of up to 2% based on heterocyclic DOPO and DPPO were cured with 4,4 0 -diaminodiphenylmethane (DDM), and their features were examined by UL 94, LOI, and DSC. In this manner, high-performance polymers with glass transition temperatures around 1908C and the UL 94 rating V0 were obtained. These polymers were compared with epoxy resins incorporating diphenyl phosphite and diphenyl phosphate, which are nonheterocyclic and do not pass the UL 94 test up to 2% phosphorus. DPPO has a similar flame retardancy like the commercially available DOPO. Furthermore, to explain the difference in the efficiency of the tested flame retardants, key experiments for the determination of the active species during the flame-retarding process were performed and the PO radical was identified 2007 Wiley Periodicals, Inc. J Appl Polym Sci 105: [685][686][687][688][689][690][691][692][693][694][695][696] 2007

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