Figure 2.

Hypothetical example illustrating why an apparent trade-off may arise between temperature and precipitation niche breadths (TNB and PNB) in a broadly distributed clade. In temperate regions, species are expected to have broad TNB and narrow PNB, whereas in species in tropical regions are expected to have narrow TNB and broad PNB. Note that this relationship between different climatic niche widths is expected given observed patterns of within-locality seasonality in tropical regions versus temperate regions [15,17,27–29], but has not been tested directly with climatic data among species.