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Abstract
The Andes are known as a hotspot for biodiversity and high species endemism for both plants and animals. Two important tropical, high-elevation ecosystems in the Andes are the puna in Peru, Bolivia and Chile between 7° and 27° South, and the páramo in Colombia, Venezuela and Ecuador between 11° North and 8° South; both are found at elevations above 3500 meters. The genus Puya (Bromeliaceae) is found throughout the puna and the páramo, and is relatively under-studied. Life history of most Puya species is largely unknown, with the notable exception of entirely semelparous Puya raimondii, which flowers once right before dying and does not reproduce clonally. Other species in the genus do reproduce clonally to varying degrees; their life history strategies have not been defined. Decreased cloning ability in Puya may be evolving convergently as in other plant groups endemic to high-elevation, tropical ecosystems. We studied three species of Puya (P. raimondii, P. cryptantha and P. goudotiana) across the two ecosystems in Bolivia and Colombia, and collected data on threshold size at flowering and clonal reproduction. Data were also analyzed in conjunction with life history theory to hypothesize each species' life history strategy. All three species were found to have a consistent and predictable minimum size at flowering, while P. cryptantha was found to also have a minimum size for clonal reproduction. No such evidence was found for P. goudotiana. Our data supported that P. raimondii is fully semelparous, and indicated that P. goudotiana and P. cryptantha may be semi-semelparous.