Bioregionalism claims that interaction between the biophysical and human components of a region generates place-based environmental and social understanding and concern, which lead to locally shared power and responsibility in cooperative land management and governance. The Man and the Biosphere Programme's Seville Strategy calls for local community participation in a multi-stakeholder ecosystem-based approach to conservation, but it is unclear if tenets of bioregionalism play a role in its implementation. Bookmark Biosphere Reserve (BBR) in Australia has substantially succeeded in scientific research and monitoring, conservation, environmental education and sustainable land-use initiatives. Aspects of bioregionalism (for example recognition of the region's unique identity, local community sense of responsibility, integration of local knowledge, presence of motivated local leaders and cooperative community-based management through a network of groups) have contributed to success. Other crucial factors were funding, technical and scientific information and support from government agencies, leadership from members of state and federal government and from private philanthropic foundations, community capacity-building for sustainable land management and availability of volunteers from outside the region. Nevertheless, conflict arose in relation to governance, originating from the recognized difficulties of reconciling a diversity of allegiances, motivations, management styles and personalities, and resulted in division of BBR into two, one section being managed largely through the private sector and community volunteers, the other (renamed Riverland Biosphere Reserve) coordinated by a committee with more diverse affiliations. Bioregionalism can play a role in biosphere reserves but motivations and resources of external public and private organizations are also vital. Avoiding weaknesses of bioregional approaches requires greater attention to social aspects of environmental management. Governance structures and processes need to be inclusive, flexible and equitable in decision making and access to funds. They should support both agency and community-initiated activities and include conflict resolution mechanisms.