Short- versus long-term environmental variation
We first explore how the temporal scale of variation and mean temperature influence species coexistence under scenarios of (1) continuous short-term variation with discrete long-term variation and (2) discrete short-term variation with continuous long-term variation. When short-term variation is continuous and long-term variation discrete, there is a uniform trend such that the proportion of species coexisting increases with an increase in short-term variation, regardless of the magnitude of the long-term variation (Fig. 2a-d). Similarly, when that the range of continuous long-term variation is constant, the area of high coexistence also increases with increasing short-term variation (Fig. 2e-h). In contrast, we observe the opposite effect of long-term variation, which mainly promote exclusion (Fig. 2a-d and 2e-h). Together, these results suggest that greater short-term environmental variation promotes coexistence, whereas greater long-term environmental variation leads to a reduction in species coexistence.