Annual variation in precipitation due to El Nino affects growth of a tropical cactus, Lemaireocereus aragonii

We measured annual growth increments on 77 individuals of Lemaireocereus aragonii, a columnar cactus growing at Palo Verde. Most of the height growth of this cactus occurs during the dry season when most of the canopy trees are leafless. Relative growth rates of L. aragonii varied considerably among years. The variation in growth was directly related to the total precipitation of the previous year and inversely related to the amount of precipitation that occurred during the dry season. El Nino years produce conditions unfavorable to the growth of L. aragonii: low total rainfall may inhibit moisture recharge following the previous dry season, and high dry season precipitation may result in increased leaf retention in canopy trees (resulting in lower light levels).



Waxy bands deposited yearly make it possible to measure the annual height growth of L. aragonii


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