Azorella compacta conservation and demography in Parque Nacional Lauca, Chile

Background/Question/Methods Our objective was to study the world's largest cushion plant, llareta (Azorella compacta), in Parque Nacional Lauca.  Mining and degazettement of this park threaten llareta habitat.  Local peoples have been recorded to harvest the plant for cooking and home heating.  Very little is known about the range and distribution of this plant, particularly the highest altitudes where it is found and the germination rate.   We measured all A. compactawithin 30 different 100 meter transects around the park and determined growth rate using previously marked plants.

Results/Conclusions The highest elevation for llareta was 5,250 meters.   Llareta is only harvested in the dry season; thus, we saw no active harvesting, though there was some evidence of previous harvesting.  We reevaluated 9 plants that were permanently tagged in 1999 to determine A. compacta growth rate to be 0.11 cm yr^-1.   We measured 406 A. compacta plants, and on average, 100 meter transects contained about 13 +/- 3 plants.  Sizes of plants ranged from 1 cm², for a plant 1 cm by 1 cm up to 515,025 cm² for a plant 545 cm by 945 cm.  We found no correlation with amount of A. compacta encountered in a transect and elevation via simple linear regression (F = 2.240, p = 0.136), though mean area of all plants in the transect did increase with elevation (F = 9.582, p =0.002).  A histogram of A. compacta also showed that young size classes (< 20 cm) were most abundant and older size classes were evenly distributed.  Our work indicates that conservation efforts with A. compacta are working.