Quezada 2015 (Conference Paper) Puya

Morphological variability in Chilean Puya species: preliminary results and implications for future climatic scenarios

Author(s):—I. Quezada in Benko-Iseppon, A.M.; Alves, M. & Louzada, R. (2015) An overview and abstracts of the First World Congress on Bromeliaceae Evolution. Rodriguésia 66(2): A1-A66.

Publication:— (2015).

Abstract:—Mediterranean climate regions will be under heavy pressure in the forthcoming years due to global climate change. In this context, the ability of plant species to tolerate climatic variations will be of key importance for the maintenance or expansion of their distribution ranges under the new climatic scenario. The Mediterranean climate zone of central Chile spans approximately from 29° to 37°S. In this region precipitation increases and temperature decreases towards south. This zone is recognized as a biodiversity hotspot and is of key importance as home to significant endemic species and as the probable center of origin of important taxa. Six of the seven Chilean Puya species are distributed within this area. All of these species are adapted to face arid and semiarid conditions, permanent or seasonal, and have different latitudinal ranges, with some spanning along a few degrees of latitude and others through the entire Mediterranean region. Future climate projections show an increase in mean temperatures and a decrease in precipitation rates in this area. This will directly affect the distribution of plant species, with those better suited to respond to the new conditions probably maintaining or expanding their ranges. An important feature to counter environmental changes is the flexibility in the expression of key traits. In this work I evaluated morphological variability in 4 chilean Puya species: P. gilmartiniae, P. venusta, P. chilensis and P. alpestris subsp. zoellneri, aiming to correlate morphological variability -or the lack of it- with the extension of the geographic range of each species and, by extension, with the climatic variability these species face within those ranges and the flexibility they might show under possible future climatic scenarios. I measured and compared a small set of leaf and whole plant attributes between populations distributed along the geographic range of each species. For all traits, variability was significantly higher in the species with broader latitudinal ranges (P. chilensis and P. alpestris subsp. zoellneri). Lack of variability could, on the other hand, explain the reduced geographical range of P. gilmartiniae and P. venusta, and predict a reduced response to climate change, leading to catastrophic consequences for both. These results, however, are preliminary and should be taken cautiously. It would be advisable to increase the number of populations per species to account for any environmental variation within geographic ranges, especially for the species with small distribution areas. Lack of morphological variation could also be explained by phenomena such as countergradient variation, which should be evaluated. Furthermore, the detected variation, if any, might not be heritable, thus losing any potential influence over selection. Nonetheless, these preliminary results give valuable insight on intraspecific variation for Puya species, and are important as a starting point for future research.

Keywords:—Mediterranean Climate; Puya; Variability.