BOOK TITLE: Foundations for Ecological Research West of the Antarctic Peninsula EDITORS: Robin M. Ross, Eileen Hofmann, Langdon B. Quetin BOOK SERIES: Antarctic Research Series Vol.70 DATE: 1996 SECTION: Preface xiii-xv TITLE: THE WESTERN ANTARCTIC PENINSULA REGION: PREFACE The Long-Term Ecological Research (LTER) Program was established in 1981 by the United States National Science Foundation in recognition of the need to study ecological processes over time spans longer than those of most research grants. The LTER Net- work now consists of 18 sites that span a variety of ecosystem types in the continental United States, Alaska, Puerto Rico, and Antarctica. The addition of the Palmer LTER at Palmer Station, Antarctica in October 1990 extended the geographical and ecologi- cal range of the LTER Network and provided the opportunity to link physical and ecological processes in the northern and south- ern hemispheres. One criterion for establishment of a LTER site is the existence of historical data and observations that can provide a basis for guiding research programs. Thus, the intent of this volume is to bring together meteorological, hydrographical, biological and ecological observations made in the general area west of the An- tarctic Peninsula and to discuss the processes underlying the ob- servations. This compilation of available data and observations in conjunction with the present understanding of processes pro- vides the foundation for long-term studies of the ecosystem in the western Antarctic Peninsula region. The central hypothesis of the Palmer LTER is that interannual variability in the annual extent of pack ice has major impacts on all levels of the marine ecosystem. One of the objectives of the Palmer LTER is to assess the impact of this variability on representative species of the marine pelagic ecosystem in the re- gion west of the Antarctic Peninsula. The LTER study region is bounded by the southern end of Bransfield Strait and extends alongshore to south of Marguerite Bay and offshore from the An- tarctic Peninsula for 200 km (see map in Figure 1 of Hofmann et al., this volume). The northern end of the study region is at the southern edge of a gap in Adelie penguin (Pygoscelis adeliae) populations, which is believed to result from the dependence of this species on sea ice. The offshore limit of the region is near the seaward limit of Antarctic krill (Euphausia superba) distributions, and the nearshore portion of the region includes probable spawning grounds for Antarctic silverfish (Pleuragramma antarcticum). The interactions of regional climatology and hy- drography and sea ice, and the resulting impact on all trophic levels of the ecosystem west of the Antarctic Peninsula, make this region unique and appropriate for long-term studies. The primarily marine focus of this volume reflects differences in habitat area and species richness between the marine and terres- trial ecosystems in Antarctica. The geographical breadth of the volume is restricted to the western Antarctic Peninsula region, but the emphasis on synthesis extends the depth and multidisci- plinary nature of the coverage. Thus, geographically restricted observations of patterns and distributions are placed in the con- text of present knowledge of the underlying processes that affect them, and this knowledge comes from many regions in the Southern Ocean. The first paper in this volume provides a historical perspective of expeditions, international and individual research programs, and non-sponsored programs. These programs have contributed to the development of the current understanding of the structure and functioning of the ecosystem of the Southern Ocean west of the Antarctic Peninsula. The next section includes descriptions of environmental features of the terrestrial and marine habitats west of the Antarctic Peninsula, including the glacial marine sediments in fjords and their use as paleoenvironmental indica- tors. The paper on the terrestrial and freshwater ecosystems in- cludes a review of their biota and functional processes in addi- tion to habitat description. In this section, the emphasis is on the effect of environmental features on the plant and animal com- munities. The abundances and patterns associated with the verti- cal and horizontal distributions of biological populations west of the Antarctic Peninsula are the focus of the next group of pa- pers. These cover distributions and the processes controlling populations of fish, penguins, and marine mammals. Other papers in this section provide the basis for the process-oriented focus in the following section, in which the current state of knowledge of the factors controlling biological distributions and abun- dances is evaluated. The papers on human disturbance consider human impacts in the region west of the Antarctic Peninsula, both terrestrial and marine. An understanding of human-induced dis- turbances, such as activities around penguin rookeries, commer- cial fishing, and oil spills, is an important aspect of any long-term ecological research program. A concluding paper pro- vides a summary intended to place the Palmer LTER within the con- text of the various ecosystems and programs described throughout the volume. One primary objective of each site within the LTER Program is to collect and archive its core measurements for use in collabora- tion with other LTER sites and national and international research programs. The Palmer LTER site is unusual among the LTER Program sites since it is located in an area that histori- cally has been the focus of both individual and cooperative international research efforts. In future years the region west of the Antarctic Peninsula promises to be one of increasingly ac- tive ecosystem research. In addition to the Palmer LTER and on going national research programs, renewed interest in ecological and physical processes in this region is underscored by shifts in geographical emphasis and initiatives being planned as part of national and international programs, for example, British Antarc- tic Survey (BAS), Global Ocean Ecosystems Dynamics (GLOBEC), and various initiatives associated with the International Long-Term Ecological Research (ILTER) Program. The initiation of the Palmer LTER has clearly identified the need to compile and synthesize historical data and observations and to provide a foundation and departure point for future ecological research west of the Antarctic Peninsula. This volume has been an international effort toward that need. The authors have in- troduced new data and have drawn upon material from research out- side the limited geographical region of the Palmer LTER in order to discuss the current understanding of the processes at work in the western Antarctic Peninsula region. This collective effort will have achieved its objectives if research on the linkages and integration of biological and physical dynamics of ecosystems over broader spatial and longer time scales is stimulated, if the volume serves to foster and broaden scientific collaboration im- portant to the region of the Palmer LTER, and if the need to ac- quire and maintain long-term data sets on both the physical and biological processes in the region has been reemphasized.