Root contraction does not increase long-term population growth in <i>Pediocactus bradyi</i>, an endangered cactus of Northern Arizona.

ABSTRACT: Pediocactus bradyi, a semi-globose cactus endemic to northern Arizona, displays a root-contraction mechanism to survive extreme drought: its roots contract, pulling the stem below ground during dry periods, re-emerging once rains return. To quantify how root contraction shapes population dynamics, we developed an integral projection model based on 31 years of demographic data from a P. bradyi population on the Navajo Nation Off-Reservation Trust Land. We explored two scenarios: one including root contraction and one excluding it. We found that, being ∼10% of the individuals and mostly confined to smaller individuals, root contraction did not have an effect on the long-term population growth [λ = 1.041 (1.039, 1.303) with contraction vs. λ = 1.044 (1.035, 1.289) without]. Also

SUBMITTER: Rojas-Pimentel J 

PROVIDER: S-EPMC12797314 | biostudies-literature | 2026 Feb

REPOSITORIES: biostudies-literature