Figure 1.

Schematic representation of the conceptual framework underlying the modeling approach. Hypervolumes of temporal environmental conditions are represented describing the relationship between the relative phenological niche of a hypothetical phenomenon of interest (a), a subset of this niche that is represented by available presence-only observation records (b), and the full set of temporal environmental variation that is available in locations where the phenomenon occurs (c). Delineation of hypervolumes is made along a simplified two-dimensional space defined by the timing of two hypothetical environmental drivers.