“…However, an expanding literature by ecologists, geographers, geologists, and climatologists addresses yield variability in association with environmental heterogeneity beyond the plant scale (Day et al, 2003; Hutchings and John, 2004; Si and Farrell, 2004; Waltman et al, 2004; Williams et al, 2008). From this literature, spatially explicit predictive (versus explanatory) modeling (e.g., Legendre et al, 2002; Lobell and Ortiz‐Monasterio, 2006; Miller et al, 2007; Popp et al, 2005; Williams et al, 2008), and concepts of the association of different potential limiting factors with different spatial patterns of yield variability (Lobell and Ortiz‐Monasterio, 2006) have emerged. Applied to regional scales, these approaches offer opportunities for identifying longer‐term spatial patterns of yield variability in association with environmental heterogeneity and thus, a vital first step in developing hypotheses about causes of their formation (Begon et al, 1990).…”