Revista Chilena de Historia Natural 76 (2): 235-254, 2003
RESEARCH ARTICLE
Multi-annual climate in Parque Nacional Pan de Azúcar, Atacama Desert,
Chile
The lomas formations of the Peruvian and Atacama deserts are characterized by both
climatic and floristic spatial heterogeneity, as well as non-contiguous pockets of relatively distinct flora. We examined two distinct types
of communities in Parque Nacional Pan de Azúcar in Chile, the low-elevation arroyo and bajada community, and the high-elevation
fog-zone community. We determined the distribution with elevation of the dominant perennial plant species in a single arroyo
community, as well as the distribution of associated climatic characteristics. Climatic conditions (including air temperature, relative
humidity, and wind speed and direction) were recorded from June, 1999, to March, 2001, for the arroyo, as well as for a medium-
elevation inland site with little vegetation, and a high-elevation fog-zone site with copious vegetation. The fog layer, or camanchaca,
derived from the marine inversion layer ubiquitous to the Peruvian and Atacama deserts was found to be more persistent, though
weaker, during the summer months and somewhat more condensed and shallower in the winter months, with uncharacteristically dry
air and high temperatures occurring at and above 400 m elevation during the late fall and early winter of 2000. The reduction or
increase in the maximum elevation of the camanchaca or a change in the rainfall regime of the park may have broad implications for
the distribution or even presence of certain species in Parque Nacional Pan de Azúcar. Vegetation patterns appear to be strongly
dependent on inversion layer development, and perhaps on its subsidence during the winter. A number of species prevalent at low
elevation sites may have little advantage at a high-elevation foggy site, whereas the consistently high humidity at low elevations would
be a boon to any desert plant accustomed to low precipitation. If we are to successfully assess the effects of changes in southern
Pacific weather patterns, it will become necessary to more closely examine the local variation in climate and plant distribution in these
regions, on sets of species with known distributions and in environments whose climatic conditions are particularly well
characterized.
Key words:
Pan de Azúcar,
meteorology, plant, distribution
