10 - Central Concepts

Summary

New information and evidence challenge equilibrium models. Fluctuations among livestock in African rangelands and northern fur seals in the Pacific Ocean do not conform to models of competition for resources maintaining populations in equilibrium. Rather than the self-interested competition for resources predicted by the tragedy of the commons, many societies regulate resource use through cooperative arrangements. Evidence from several disciplines undermines the concept of a stable climax association that perpetuates itself indefinitely. Some so-called climax communities depend on disturbances, including natural or anthropogenic burning. Some ecosystems have multiple stable states, and some reach irreversible tipping points, which are becoming more likely because of climate change. Viewing nature as in flux rather than in balance addresses these issues, while the current scale of environmental change infuses a sense of urgency into these discussions.