Energy hierarchy and landscape sustainability

The study of ecosystems suggests principles by which energy flows generate hierarchies in all systems. All ecosystems in the landscapes are associated with energy transformation and the convergence of transformed products toward higher hierarchical levels, the recycling of materials to dispersed backgrounds, and feedbacks to reinforce the supporting environment. A hierarchy can be seen as an organized pattern with many small units at one level contributing to fewer units at the next higher level. Due to spatial variability in the natural environment, different types and amounts of energy received on the earth are not homogeneous; this in turn generates a heterogeneous pattern on the landscape. Energy from life-support and production systems of a heterogeneous landscape is transformed and converged spatially toward consumption centers. All energy transformation can be arranged in a series. The concept of transformity is used in this paper to indicate the position of an energy flow in the series. A hierarchical system can help to explain how energy and matter can be produced and recycled through each level of energy transfer. Building on the brief reviews of the concept of hierarchy in the landscape and the theoretical development of the concept of an ecological energetic hierarchy, this paper proposes two principles of energetic hierarchy for landscape sustainability. First, the landscape must be arranged spatially according to its energy hierarchy. Evaluation of normalized energy flows (emergy) can help identify zones of different spatial hierarchies, which will help establish the strategies needed for the landscapes to be sustainable. Second, a sustainable landscape must comprise a hierarchy of self-organizing ecosystems that can enable the systems to maximize useful power at all levels of the energy hierarchy.