Monday, August 6, 2007: 1:30 PM-5:00 PM
A1&8, San Jose McEnery Convention Center
Organizer:
Carla D'Antonio, University of California Santa Barbara
Co-organizers:
Paula Schiffman, Calif State University, Northridge;
Jeffrey Corbin, Union College; and
Mark Stromberg, University of California Berkeley
Moderator:
Carla D'Antonio, University of California Santa Barbara
Grass-dominated habitats occupy close to one fifth of California and are a valued ecological and economic resource. Largely dominated by annual species, these grasslands have been considered non-equilibrium ecosystems where compositional dynamics are driven by climate and not by competition or grazing regime. Ecological processes in California grasslands are now being more mechanistically studied because of widespread interest in manipulating grassland composition to increase dominance of native species, particularly perennials, and in improving wildlife values gained from these habitats. This symposium will bring together scientists and managers studying pattern and process in California grasslands to apply emerging knowledge and concepts to the ecological restoration of these systems. We will begin the symposium with an overview of competing hypotheses regarding the pre-European state of these systems and the forces caused widespread conversion to dominance by European species. These ideas, while controversial, may be important in selecting target communities and identifing possible constraints on restoring systems to desired composition. We will move on to evaluate some current research into soil and plant processes that might constrain restoration of native species into California grasslands. Presentations address (1) the role of plant pathogens in limiting native species recruitment and interaction of pathogens with invasive species to affect restoration efforts, (2) legacies of historic land use in the soil microbial communities, (3) the interaction of plant competition and seed limitation in limiting establishment of native species in exotic-dominated sites and (4) influence of global environmental changes, such as N deposition and changing climate, on composition. Finally, we will evaluate experimental evidence concering the uses of livestock and fire as tools for restoration in nature reserve or public lands settings. The symposium will conclude with a panel summary and general discussion including a question/answer session focused on unanswered questions in grassland restoration. While the symposium focuses on California grasslands, individual talks will be presented within the broader conceptual framework of how ecological theory can be applied to restoration and whether lessons learned so far in California grasslands are consistent with or bring insight to restoration challenges in grasslands elsewhere.