Daniel Tyteca

An activity analysis model of the environmental performance of firms - Application to fossil-fuel-fired electric utilities

The productivity of firms when some outputs (pollution) are undesirable has been studied in the literature for some time. In this paper we introduce an environmental performance indicator based on the decomposition of overall factor productivity into a pollution index and an input-output efficiency index. This indicator is compared to the more conventional Jaggi and Freedman (1992) model. Results are given for illustrative purposes, using data from U.S. fossil-fuel-fired electric utilities. The rankings of the utilities obtained with the two models show significant divergence, which is due to the different ways in which the undesirable outputs are dealt with, as well as due to the different possible tradeoffs between the pollutants released into the atmosphere and the resources used as inputs.

Linear Programming Models for the Measurement of Environmental Performance of Firms—Concepts and Empirical Results

I use linear programming models to define standardised, aggregate environmental performance indicators for firms. The best practice frontier obtained corresponds to decision making units showing the best environmental behaviour. Results are obtained with data from U.S. fossil fuel-fired electric utilities, starting from four alternative models, among which are three linear programming models that differ in the way they account for undesirable outputs (pollutants) and resources used as inputs. The results indicate important discrepancies in the rankings obtained by the four models. Rather than contradictory, these results are interpreted as giving different, complementary kinds of information, that should all be taken into account by public decision-makers.

Environmental indicators for business: a review of the literature and standardisation methods

Abstract This paper reviews the existing literature on environmental performance indicators as they relate to private sector organisations, followed by a basic classification of ways in which environmental data are being standardised for use in indicators. It was found that the majority of standardisation schemes for environmental information fall into one of five categories, namely standardised using economic criteria, physical impact categories (such as global warming potential), linear programming methods (such as productive efficiency), economic valuation methods or as part of business management review processes. The paper concludes that environmental data, once normalised, should be used in a diversity of indicators that are tailored to the information needs of the data users and that, as long as normalisation of data is kept separate from aggregation and standardisation, many different indicators can be developed based on a comparatively small dataset.

Analysis of network architecture reveals phylogenetic constraints on mycorrhizal specificity in the genus Orchis (Orchidaceae)

The specificity of orchids for their fungi can vary substantially, from highly specialist interactions to more generalist interactions, but little is known about the evolutionary history of the mycorrhizal specificity of orchids. Here, we used a network analysis approach to investigate orchid mycorrhizal associations in 16 species of the genus Orchis sampled across 11 different regions in Europe. We first examined in detail the structure of the network of associations and then tested for a phylogenetic signal in mycorrhizal specificity and identified the fungi with which the orchids associated. We found 20 different fungal lineages that associated with species of the genus Orchis, most of them being related to members of the Tulasnellaceae (84.33% of all identified associations) and a smaller proportion being related to members of the Ceratobasidiaceae (9.97%). Species associations formed a nested network that is built on asymmetric links among species. Evolution of mycorrhizal specificity in Orchis closely resembles a Brownian motion process, and the interaction between Orchis and Tulasnellaceae fungi is significantly influenced by the phylogenetic relationships between the Orchis species. Our results provide evidence of the presence of phylogenetic conservatism in mycorrhizal specificity in orchids and demonstrate that evolutionary processes may be an important factor in generating patterns of mycorrhizal associations.

Are EMS environmentally effective? The link between environmental management systems and environmental performance in European companies

Based on the analysis of a large dataset on the environmental performance of European companies in five industrial sectors, this paper examines the question of whether the presence of an environmental management system (EMS) has a positive impact on the eco-efficiency of companies. It begins with a review of evidence about the link between EMS and environmental performance in business organisations, finding that, despite much research, there is still little quantitative evidence. The second part of the paper uses three independent statistical methods (simple correlations, Jaggi-Freedman indices and a ‘trend differences’ approach) to assess whether companies and production sites with EMS perform better than those without and whether performance improves after an EMS has been introduced. The paper shows that there is currently no evidence that EMS have a consistent and significant positive impact on environmental performance. Policy action based on the simple assumption that companies with an EMS perform better than those without therefore seems inappropriate.

Patterns of chloroplast diversity among western European Dactylorhiza species (Orchidaceae)

In Europe, the genus Dactylorhiza comprises a bewildering variety of forms that are difficult to sort into discrete species. Most Dactylorhiza species are diploid or tetraploid and contrasting hypotheses have been proposed to explain the complex variation within this group. Using PCR-RFLP analysis in eight putative species, we could identify four highly differentiated chloroplast DNA lineages. The first lineage (clade A) included the unique haplotype found in D. sambucina. Clade B grouped four haplotypes belonging mostly to D. incarnata. Clades C and D included 27 haplotypes detected in diploid D. fuchsii and in all tetraploid species investigated. Eighty percent of the chloroplast variation were consistent with currently accepted species boundaries. The imperfect agreement between chloroplast variation and species boundaries may be ascribed to incomplete lineage sorting and/or reticulation. Our cpDNA results provide strong evidence that the allotetrapolyploids have been formed through asymmetric hybridization with a member of the D. fuchsii / maculata group as the maternal parent.

Microbial diversity in the floral nectar of seven Epipactis (Orchidaceae) species

Floral nectar of animal‐pollinated plants is commonly infested with microorganisms, yet little is known about the microorganisms inhabiting the floral nectar of orchids. In this study, we investigated microbial communities occurring in the floral nectar of seven Epipactis (Orchidaceae) species. Culturable bacteria and yeasts were isolated and identified by partially sequencing the small subunit (SSU) ribosomal RNA (rRNA) gene and the D1/D2 domains of the large subunit (LSU) rRNA gene, respectively. Using three different culture media, we found that bacteria were common inhabitants of the floral nectar of Epipactis. The most widely distributed bacterial operational taxonomic units (OTUs) in nectar of Epipactis were representatives of the family of Enterobacteriaceae, with an unspecified Enterobacteriaceae bacterium as the most common. In contrast to previous studies investigating microbial communities in floral nectar, very few yeast species (mainly of the genus Cryptococcus) were observed, and most of them occurred in very low densities. Total OTU richness (i.e., the number of bacterial and yeast OTUs per orchid species) varied between 4 and 20. Cluster analysis revealed that microbial communities of allogamous species differed from those of autogamous and facultatively autogamous species. This study extends previous efforts to identify microbial communities in floral nectar and indicates that the floral nectar of the orchids investigated mainly contained bacterial communities with moderate phylogenetic diversity.

Biostatistical studies on western European Dactylorhiza (Orchidaceae)-the D. maculata group

Multivariate analysis tools are exploited on a data set composed of quantitative characteristics collected on 35 populations of plants of theDactylorhiza maculata (L.)Soó group from Western-Europe. These samples lead to four well-defined clusters; this, together with qualitative, cytological and ecological arguments, allows for the recognition of four specific entities:D. maculata s.str.,D. fuchsii (Druce)Soó,D. saccifera (Brongn.)Soó andD. caramulensis (Vermeulen)Tyteca. It is concluded that the floral characters play an essential role in the taxonomical distinction. It also appears that the set of characters measured, as well as the methods exploited, are especially well-suited and valuable tools for the morphological study of the genusDactylorhiza.

Biostatistical Studies of Western-european Allogamous Populations of the Epipactis-helleborine (l) Crantz Species Group (orchidaceae)

Multivariate methods using morphological characteristics were applied to the study of 23 western European allogamous Epipactis populations belonging to five taxa in the E. helleborine group and two taxa in the E. atrorubens group. The study concentrated on four recently described, not yet widely accepted, taxonomic entities of the former group and on the identification of discriminant characters. Several vegetative and floral differences allow proper discrimination of E. helleborine s. str., E. distans, E. neerlandica, and a subgroup composed of E. tremolsii and E. lusitanica. A more detailed analysis was needed for the latter two, for which the differences are chiefly vegetative. The five taxa also possess distinctive ecological characteristics and, considering the respective geographical ranges and sympatries, can be regarded as independent species.

Measuring environmental performance for industry: from legitimacy to sustainability and biodiversity?

In this paper, we argue that environmental business performance indicators are substantially and qualitatively different to sustainable development indicators and thus require different approaches in terms of public consultation, scope of measurement, time scale and range of issues covered. It does so by first reviewing some developments within environmental performance indicators for industry and, after providing a definition of sustainable development, it argues for the necessity of including SDIs in business in a way that reflects the fundamentally different nature of SDIs in comparison to environmental performance indicators for industry. It exemplifies the differences by focusing on one often-missing aspect - Biological Diversity.