Dominant plants alter the microclimate along a fog gradient in the Atacama Desert
We assessed the impact of fog on microclimate in a poorly understood fog desert under two common nurse plant species, at three sites: (1) foggy coast, (2) intermediate, and (3) above the main fog belt in the Atacama Desert (Peru). We quantify nurse plant modification of their understory that creates favorable microsites for other species. Dataloggers collected temperature, relative humidity (RH) and dew point temperature under Randia armata, Caesalpinia spinosa and in the open at the three sites. The Relative Interaction Index (RII), Friedman’s two-way ANOVA, and correlation were used to compare conditions across microsites and field sites. At noon, the understory was cooler and RH was higher than in the open, consistent with non-fog deserts. Early morning temperatures were warmer in the open at the more fog-influenced sites, unlike non-fog deserts. The temperature gap (cooler in the understory) is smallest at the coast and largest in the interior. Temperature and moisture generally fluctuate less at the most fog-influenced sites, while understory conditions at the interior (least-fog influenced) site was most similar to those found in non-fog deserts. Because fog reduces weather extremes, amelioration by vegetation becomes less on foggy days as extremes are already dampened by the fog, and facilitation by nurse plants is greatest when conditions are most like traditional deserts (e.g., clear skies, hot). These results provide mechanistic support for the effects of nurse plants through stress amelioration in fog deserts.
KeywordsAtacama Desert Facilitation Fog deserts Microclimate Plant–fog interactions
We thank C. Lortie for equipment and York University Faculty of Graduate Studies for salary support during field work. We thank the community of Atiquipa for allowing us entrance to their private reserve.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Brako L, Zarucchi JL (1993) Catalogue of the flowering plants and gymnosperms of Peru. Monographs in Systematic Botany Vol. 45. Missouri Botanical Garden, St. Louis.Google Scholar
- Dobson RT (2005) Thermal modelling of a night sky radiation cooling system. J Energy in Southern Africa 16:20–31Google Scholar
- Drezner TD (2004) Saguaros and their nurses in the Sonoran Desert: a review. Desert Plants 20:3–10Google Scholar
- Kerfoot O (1968) Mist precipitation on vegetation. Forestry Abstracts 29:8–20Google Scholar
- Sotomayor DA, Lortie CJ (2015) Indirect interactions in terrestrial plant communities: emerging patterns and research gaps. Ecosphere 6: art 103.Google Scholar