Fases reproductivas de Araucaria angustifolia en dos regiones de Argentina con clima diferente: Efecto del clima en la reproducción de Araucaria angustifolia

Abstract

Araucaria angustifolia is a critically endangered species due to the reduction of its original environment and the lack of natural regeneration. The scarcity of seeds in its distribution area makes it difficult to use reforestation as a restorative measure. This work analyses climate influence on pollen and seed production. Aerobiological monitoring and seed collection were performed in two regions of Argentina: San Antonio (SA), Misiones, a subtropical site; and 25 de Mayo (25M), Buenos Aires, a temperate area. The seasonality of pollination was similar between sites (spring). However, pollen amount was four times higher in 25M, with high hourly values throughout the day, and a shorter duration of about half the number of days in relation to SA. Seed production was also higher in 25M (six fold). Reproduction proved to be favoured by temperate climate because of higher summer temperatures prior to pollination (period of strobili initiation), lower winter temperatures (during the pollen grain formation), and lower rainfall during pollen transport. Management guidelines involving ex-situ conservation of this native forest species are proposed.