Optimality as a Concept to Understand and Model Vegetation at Different Scales

Observations made at different scales are often incomparable, because they reveal different patterns within the same entity. The change in observed pattern with the change in scale of observation is often abrupt, a phenomenon referred to as 'break in scale'. Linking patterns with different scales of observation has become a major challenge in all sciences; however, it appears that the better our ability to observe patterns becomes, the more 'breaks in scales' we find. This article links breaks in scales to hierarchical levels of organisation. It is argued that organisation is linked with optimality and that optimality is predictable to a certain degree. It is further argued that in some cases heterogeneity within a level of organisation can be neglected if this heterogeneity is assumed to be a result of optimisation; hence, the implementation of vegetation optimality in models can lead to a new degree of predictability in ecohydrology.