Leaf morphology shift is not linked to climate change

In a recent study, Guerin et al. [1] (Guerin, Wen and Lowe, hereafter GWL) used leaf width measurements from herbarium specimens of Dodonaea viscosa subsp. angustissima collected in South Australia to document two patterns. First, mean leaf width declined with increasing latitude. Latitude in their study region was strongly correlated with mean maximum temperature of the warmest month, such that leaf width declined as mean maximum temperature increased. This pattern is consistent with other studies that have documented predictable spatial variation in leaf morphology along gradients of temperature and moisture [2], implying that climate may exert a strong selection pressure on leaf morphology