Towards a taxonomy of spatial scale‐dependence

Spatial scale‐dependence is a ubiquitous feature of ecological systems. This presents a challenge for ecologists who seek to discern general principles. A solution is to search for generalities in patterns of scale‐dependence – that is, what kinds of things are scale‐dependent, in what ways, and why? I argue that this is likely to be a productive way forward for ecology, but that progress in this direction is currently hindered by the conflation of a set of distinct concepts under the category of ‘scale‐dependence’. Here, I propose a taxonomy of spatial scale‐dependence that categorizes its major types in hopes of moving towards a more formal and unambiguous vocabulary. I argue that three major distinctions are necessary and sufficient for this goal: that between grain size and extent (the scale component), between data and models (the subject), and between true and perceived scale‐dependence (the class). I illustrate the need for these distinctions with a set of examples demonstrating causes of different types of scale‐dependence. I then describe how this taxonomy relates to an array of scale‐related concepts from other fields. Finally, I discuss the generalization that biotic interactions are most important at small scales in light of this taxonomy.