Grasslands are often regarded as transient, early successional ecosystems with lower ecological value than forests. This perception has been particularly strong for grasslands maintained by human activities, which are often dismissed as merely "secondary" or "degraded" nature. By contrast, recent studies recognize the existence of old-growth grasslands that have persisted for many centuries, or even millennia, under natural and anthropogenic disturbance regimes, even in regions climatically suitable for forests. Old-growth grasslands can harbor high levels of biodiversity comparable to those of primary forests and offer important ecosystem services to society. In our previous symposia, “Hidden Environmental Values of Old-Growth Grasslands" (held over the past two years), studies conducted mainly in Nagano Prefecture, Japan, demonstrated that the diversity of plants, herbivores, pollinators, and symbiotic microorganisms is higher in old-growth grasslands than in recently established grasslands or forests. Moreover, these long-established grasslands appear to provide superior ecosystem services, including aesthetic appeal, carbon storage, disaster prevention, and genetic resources.
Building on these findings and discussions, the present symposium aims to reassess the biodiversity and environmental values of ecosystems maintained by long-term anthropogenic disturbances, challenging the perspective that human-managed ecosystems are inherently secondary and thus of lower conservation value. Our discussion will extend beyond grasslands to encompass a broader range of disturbed or managed landscapes that have developed stable ecological structures and functions through long-term persistence.
To deepen this discussion, we will invite Dr. Joseph W. Veldman, who has played a leading role in extending the concept of “old-growth" to savannas and grasslands in recognition that many of Earth's grassy ecosystems are ancient. His research has highlighted the long-overlooked conservation value of grasslands and demonstrated that they can be as ecologically complex and irreplaceable as old-growth forests. By integrating Dr. Veldman's insights with the results of our ongoing grassland project, as well as with studies from other semi-natural ecosystems, we will identify approaches to maintain long-standing human-ecosystem relationships and reposition semi-natural ecosystems as mature and valuable components of the biosphere—not as degraded or secondary nature—that represent both ecological history and cultural heritage. Through discussions among speakers and participants, we aim to foster a broader understanding of the ecological significance of ecosystems maintained by long-term human stewardship.