Soil and Sediments: Linkages to New Research

The SCOPE Committee on Soil and Sediment Biodiversity and Eco system Functioning, chaired by Diana Wall Freckman, Colorado State Uni versity, USA and aided by co-chairs Margaret Palmer, University of Maryland, USA (Freshwater Sedi ments), Lijbert Brussaard, Agricul tural University, The Netherlands (Soils), and T. Henry Blackburn, Aarhus University, Denmark (Marine Sediments), met for the first work shop in late April 1997 in Wageningen, Holland. The 40 experts from 15 countries, representing tax onomists, ecologists, and biogeo chemists working in the domains of soils, freshwater sediments, and ma rine sediments, spent almost a week summarizing the status of knowledge on biodiversity in relation to func tioning in "their" ecosystems, and identifying similarities in taxa and functions and gaps in knowledge pre venting a synthesis across these do mains. SCOPE was the first integra tive workshop bringing together sci entists from these three domains and the first to emphasize the functional significance of specific organisms and taxa to ecosystem processes and the ecosystem services they repre sent. A common basis of the meeting was our collective scientific knowl edge of the organisms that supply many of the critical ecosystem ser vices such as clean water, soil fertil ity, biocontrol for crops, and decay of organic matter. A recent study showed that these services contribute to global value for natural services of U.S.$33-48 trillion a year. The biota are affected by changes in land use practices, pollution of soils with con necting effects on streams and oceans, groundwater contamination, and their activities impact food sup ply (fisheries, agricultural crops) and ecosystem health. Many of these hu man-induced effects on our environ ment are studied in isolation (as black boxes in models, or as research topics such as groundwater and watershed biogeochemistry) from the diversity of organisms that provide the essen tial ecosystem services upon which society depends. In addition, there are few research projects linking soil freshwater-marine biodiversity and ecosystem functioning. Participants quickly realized that: a) Soil, freshwater, and marine sediments are interconnected by simi larities in ecosystem processes, bio geochemistry, and the types of func tions performed by the diversity of biota, many of which occur across all three domains. b) Though many of the processes were similar, important terminology used by the participants differed among the domains. For example, soil ecosystem engineers share many functional characteristics with bio turbators in aquatic and marine sedi ments. c) Similar methods are lacking for sampling biota across the three do mains, or even within a domain. It is also unclear how spatial scaling is sues will differ across the domains, a critical issue in linking biota to large scale processes and global change. d) Most of the taxonomic descrip tions of organisms in these domains have been from developed countries or in nearshore shallow waters of oceans, leaving our knowledge of global biodiversity and ecosystem functioning poorly known. e) Linkages of knowledge across the three domains would increase our understanding of how disturbances affect subsurface biodiversity and functioning, and, in turn, how these impacts of disturbance influence above-surface ecosystem function. The implications for sustainable agri culture and forestry are large. f) A major effort is recommended to improve our communication and understanding of the biodiversity of soils and sediments. The linkage of the soil and sediments as a research and synthesis effort will provide more information and a broader un derstanding of our planet on a global scale than traditional studies of each domain alone. Here are a few topics that were among the priorities: Training.-(1) Systematics and taxonomic expertise on biodiversity within and across domains should be expanded globally and organized through a biodiversity informatics ap proach, and user-friendly identifica tion aids for key taxa should be de veloped to facilitate global bio diversity assessments. Research.-(2) A multidisci plinary approach to research should be encouraged between systematists and ecologists to provide information on: (a) feedback mechanisms con necting aboveand belowsurface spe cies, (b) important taxa in bio remediation of pollutants within and across domains, (c) which organisms are pests that, with disturbance, could affect soil and sediment functioning, and (d) the role of these species in global processes, such as atmospheric trace gas production and consump tion. Syntheses.-(3) Data on subsur face herbivory across domains has not been synthesized. We need to de termine how disturbance and/or dis persal of these biota can impact pri mary productivity and organic matter decomposition. (4) Biogeochemical and food web models are needed across domains to examine the simi larities and differences in functions and the roles of the taxa in controlling these functions, and to predict con sequences of disturbance to the habitat.