The adverse consequences of pollution impact on terrestrial ecosystems have been under careful investigation since the beginning of the twentieth century. Several thousand case studies have documented the biotic effects occurring in contaminated areas. However, after more than a century of research, ecologists are still far from understanding the effects of pollution on biota. Only a few generalisations have been made on the basis of extensive monitoring programs and numerous expe- ments with industrial contaminants. The need to reveal general patterns in the responses of terrestrial biota to ind- trial pollution and to identify the sources of variation in these responses became obvious more than a decade ago. At about that time, our team initiated a quanti- tive research synthesis of the biotic effects caused by industrial pollution, based on 1 a meta-analysis of published data. All meta-analyses conducted so far (covering diversity and abundance of soil microfungi, diversity of vascular plants, diversity and abundance of terrestrial arthropods, and plant growth and reproduction) c- sistently showed high heterogeneity in the responses of terrestrial biota to industrial pollution. At the same time, they demonstrated an unexpected shortage of infor- tion suitable for meta-analyses, as well as a considerable influence of methodology of primary studies on the outcome of the research syntheses. To overcome the identified problems, we designed a comparative study, the results of which are reported in this book.

Mikhail Kozlov got his Ph.D. in entomology in 1986 at the Institute of Biology in Novosibirsk, Russia. Since 1991 he works in the Section of Ecology of the University of Turku, Finland. Mikhail has been working on the impact of aerial pollution on terrestrial ecosystems over the past 25 years. He has been doing fieldwork in several polluted regions of Eurasia, but his principal study area is the Kola Peninsula in Russia. Other research interests include: global change impact on terrestrial ecosystems; evolutionary ecology, mostly in relation to plant adaptations to polluted environments; herbivore population dynamics; biogeography, with particular interest to urban biota and landscape fragmentation; taxonomy, morphology, and phylogeny of moths and butterflies. Mikhail has published two books, 168 articles in journals and 59 book chapters. Elena Zvereva got her Ph.D in Entomology in 1985 at the Zoological Institute in Leningrad, Russia. Since 1994 she is working in the Section of Ecology of the University of Turku, Finland. Elena has been working on different ecological problems, with an emphasis on three-trophic-level interactions in herbivorous insects, in particular in polluted environments. At present Elena is leading a research project exploring pollution impact on the relationships between basic structural and functional properties of terrestrial ecosystems, and is also involved in the project exploring effects of endemic herbivory on growth of forest trees in relation to climate. Other research interests include: ecological and evolutionary consequences of global change impact on insect-plant relationships, factors regulating herbivore population dynamics, and positive plant-plant interactions in stressful environment. Elena has published 59 articles in journals and 27 book chapters. Vitali Zverev is now working on his Ph.D. thesis in the Section of Ecology of the University of Turku, Finland. He started working as a field ecologist in 1991, and has since then participated in many research projects that have addressed effects of pollution and global change on terrestrial biota. He is an excellent photographer. Vitali has published 5 research papers and 3 reports in conference proceedings.