Botany blog post on Defining heterogeneity as a second level of variation:

On the 19th of June 2015, Web Ecology published a research paper by B. B. Hanberry titled Defining heterogeneity as a second level of variation. The paper evaluates the use of the word heterogeneity in modern literature for the purpose of scientific research. While currently it appears heterogeneity is generally seen as a superior description to homogeneity in many situations, the paper attempts to initiate a discussion on a few logical fallacies which exist in this methodology. Initially this is addressed on terms of grounds of terminology and from a logical perspective the author draws an important distinction in the actual hierarchy of terminology: that in fact heterogeneity is not, as frequently claimed, an existential quantifier, but actually closer to a universal quantifier. While I did not find it clear that heterogeneity was therefore claimed as a definite universal quantifier, use of challenging the grounds of actual use was quite helpful in discovering what this actually meant: because many botanical papers use heterogeneity synonymously with variability, this can create confusion because in fact variability is only one part of multiple different aspects upon which the inclusive term heterogeneity must touch upon. To illustrate this point, a forest fire is used as an example. While heterogeneity is a spatial measurement, abiotic conditions tend to represent variability within the context of the premises provided in the example, that is variation independent of other variables, with a few exceptions such as soil or water. For conditions to be described as homogenous or heterogenous, it follows, the variability or lack thereof must be accessible across spatial, time, or other physical description (which can be extrapolated through a reduction of a given paradigm, as is done in the article with a forest fire).

Hanberry, B. B. "Defining heterogeneity as a second level of variation." Web Ecology 15.1 (2015): 25-28.