Summary1 Utilization of carbon sources by culturable soil bacteria can be assessed with BIOLOG microtiter plates (contain 31 C sources). We used this technique to investigate bacterial community structure at various levels of plant diversity. Plant diversity levels were replicated and we investigated the in¯uence of three plant functional groups, grasses, legumes and non-leguminous herbs, as well as the in¯u-ence of individual plant species. 2 Catabolic activity and catabolic diversity of culturable soil bacteria were used to estimate their density (abundance) and functional diversity, respectively. Both increased linearly with the logarithm of plant species number and with the number of plant functional groups in experimental grassland ecosystems. These eects may have been caused by an increased diversity and quantity of material and energȳ ows to the soil. They may also have been mediated by increased diversity of soil microhabitats via a stimulation of the soil fauna. 3 The presence of particular plant species or functional groups in the dierent experimental communities stimulated the activity and functional diversity of the culturable soil bacteria in addition to their contribution via plant diversity. The legume Trifolium repens had the strongest eect and may be regarded as a keystone species with regard to plant±microbial interactions in the systems studied.

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A variety of methods can be used to compile a life cycle inventory (LCI) as part of a life cycle assessment (LCA) study. Hybrid LCI methods attempt to address the limitations inherent in more traditional process and input-output (IO) LCI methods. This paper provides an overview of the different hybrid LCI methods currently in use in an attempt to provide greater clarity around how each method is applied and their specific strengths and weaknesses. A search of publications quoting the use of hybrid LCI was undertaken for the period from 2010 to 2015, identifying 97 peer-reviewed publications referencing the use of a hybrid LCI. In over one third of the literature analysed, authors only refer to their analysis as a hybrid LCI, without naming the actual method used, making it difficult to fully understand the method used and any potential limitations. Based on the way in which the various hybrid methods are applied and their existing use, the authors propose a set of clear definitions for existing hybrid LCI methods. This assists in creating a better understanding of, 2 and confidence in applying hybrid LCI methods amongst LCA practitioners, potentially leading to a greater uptake of hybrid LCI. KeywordsLife cycle assessment; life cycle inventory analysis; input-output analysis; process analysis; hybrid analysis.