Dew and fog as possible evolutionary drivers? The expansion of crustose and fruticose lichens in the Negev is respectively mainly dictated by dew and fog.

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conclusionThe expansion of crustose lichens in the Negev is principally determined by dew and that of fruticose lichens by fog. Crustose and fruticose lichens are largely adapted to dew and fog, respectively. Although crustose and fruticosea lichens were shown to efficiently use dew and fog, the link between their expansion and the occurrence of dew and fog has never been shown experimentally. This is also the case for the Negev Desert Highlands, where (i) dewless habitats were not inhabited by lichens and (ii) an increase in fruticose lichens with high-altitude fog-prone areas was noted, leading us to hypothesize that the expansion of crustose and fruticose lichens is mainly linked to dew and fog, respectively. Experiments aiming to compare the non-rainfall water (NRW) were conducted. We used cloths attached to 7 cm-high cobbles to mimic crustose lichens (MCL), cloths placed horizontally aboveground to evaluate the amount of NRW without the presence of the cobble (CoP), cloths attached to a wire scaffold mimicking fruticose lichens (MFL), and cloths attached to glass plates (CPM) that served as a reference. Substrate temperatures were compared to the dew point temperature. In addition, sprinkling experiments, which mimicked fog under variable wind speeds (0.9, 1.4, 3.3 and 5.7 m s