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As a multi-jurisdictional, non-fire-adapted region, the Sonoran Desert Ecoregion is a complex, social-ecological system faced increasingly with no-analogue conditions. A diversity of management objectives and activities form the socioecological landscape of fire management. Different managers have different objectives, resources, and constraints, and each therefore applies different activities. As a result, it can be difficult to predict the regional consequences of changing fire regimes. We interviewed and surveyed managers of 53 million acres of government-managed lands across the Sonoran Desert Ecoregion of Arizona, asking them to describe their management objectives and activities as well as expected changes in the face of projected fire regime change across the region. If current activities were deemed unlikely to meet objectives into the future, this represents a likely adaptation turning point, where new activities are required in order to meet objectives. If no potential activity will meet an objective, it may be necessary to select a new objective, indicating an adaptation tipping point. Here, we report which current objectives and activities are deemed by managers most likely and least likely to succeed. We also discuss constraints reported by managers from different jurisdictions. We find that agriculture, military, and resource extraction objectives are perceived by managers as most likely to be met, whereas conservation of natural and cultural resources is considered least likely to be achieved. Federal land managers reported higher likelihood of both achieving current objectives and adopting new activities than did non-federal land managers. This study illustrates how rapid global change is affecting the ability of land managers differing in missions, mandates, and resources to achieve their central objectives, as well as the constraints and opportunities they face. Our results indicate that changing environmental conditions are unlikely to affect all management entities equally and for some jurisdictions may result in adaptation turning points or tipping points in natural and cultural resource conservation.

Changes in fire frequency, size, and severity are driving ecological transformations in many systems. In arid and semi-arid regions that are adapted to fire, long-term fire exclusion by managers leads to declines in fire frequency, altered fire size distribution, and increased proportion of high severity fires. In arid and semi-arid systems where fire was historically rare, factors such as invasion by highly combustible non-native plants elevate fire frequency and size, elevating mortality of native species. Altered temperature and precipitation regimes may exacerbate these changes by increasing biomass and flammability. Current transformation in fire dynamics carry social as well as ecological consequences. Human cultures, livelihoods, values, and management behaviors are attuned to fire dynamics. Changes can make it costly or impossible to maintain traditional landscape use and economic activities. We review the ecological and social science literature to examine drivers of altered fire dynamics in arid and semi-arid systems worldwide and the conditions representing fire dynamics thresholds—points at which altered conditions may make it difficult or impossible to achieve management objectives, even via traditional adaptive management focusing on alternative management activities to achieve objectives. Such thresholds could force a wholesale shift in management objectives and practices and a new approach to adaptive management that redefines objectives when no viable adaptive action can be undertaken.