Are populations of Polylepis australis locally adapted along their elevation gradient?

FERRERO, MARÍA CECILIA; FUNES, GUILLERMO; CÁCERES, YOLANDA; TECCO, PAULA A; ZEBALLOS, SEBASTIÁN RODOLFO; ARIAS, GONZALO.; MARCORA, PAULA INÉS; FERRERAS, ANA ELISA; GURVICH, DIEGO EZEQUIEL; HENSEN, ISABELL

Neotropical Biodiversity

Taylor and Francis

Lugar: Londres; Año: 2021 vol. 7 p. 246 - 256

2376-6808

Mountain ecosystems are characterized by steep environmental gradients. Species with broadelevation distribution are exposed to contrasting climatic conditions along their gradients. Inresponse to those changes, species might develop ecotypes adapted to the local climate. Earlyregeneration is the most critical stage for plant populations and, therefore, withstands strongselection pressures. Previous studies showed a unimodal pattern of intraspecific variability in fitnesscomponents among Polylepis australis populations along their elevation gradient in the mountainsof central Argentina. Whether this variability is the result of local populations? adjustments to theirrespective site remains unknown. We tested the hypothesis that P. australis populations fromdifferent elevations would be locally adapted to their local environments, where they wouldperform better than populations from other elevations (origins). We applied an experimentalapproach by establishing common gardens at three contrasting elevations. Seeds and saplingsof P. australis populations from the low, mid- and high elevation belts of the species distributiongradient (i.e. three origins) were reciprocally sown and transplanted in three elevation sites (low,mid- and high). Seed germination success, sapling growth and mortality were monitored for threeyears. Our main results show that the origin of populations influenced germination success andsapling growth, whereas sapling mortality was marginally affected. Populations of both elevationextremes seem to be more adjusted to local conditions than the population from the intermediateelevation, probably due to the harsher environmental conditions for plant regeneration typical ofthe lower and upper elevation belts of semiarid mountains. Finally, our results strongly suggest thattemperature rise due to climate change in this mountain area might have negative effects on theregeneration of P. australis populations.