Calcium carbonate (CaCO3) content is one of several ecological settings variables that collectively characterize the biophysical setting of each 30 m cell at a given point in time (McGarigal et al 2017). CaCO3 buffers acidity in soil and water, increasing nutrient uptake by plants, and providing a ready source of calcium for organisms such as aquatic insects. CaCO3 content (Fig. 1), affects the composition of natural communities both directly and indirectly, such that areas with high calcium have increased species richness and support a number of unique species.