Population dynamics of Zea diploperennis , an endangered perennial herb: effect of slash and burn practice

Summary1 Zea diploperennis is a wild relative of maize that is endemic to the Sierra de Manantlán Biosphere Reserve in Mexico. Because this species is a priority for conservation in the reserve, the effects on its populations of the most common types of anthropogenic disturbance – slash‐and‐burn, and slash without subsequent burning – were investigated in three populations for 5 years. 2 The patterns of establishment and mortality were similar in all populations studied. Numbers of ears and fruits produced were significantly higher when disturbances were applied. 3 Because permanence is the most important stage in contributing to λ, the results suggest that the first genets to become established have an advantage over newly recruited plants. 4 When the two disturbance types were applied, λ was close to 1 or > 1. After the first disturbance, λ increased by almost 100%. In almost all situations, with or without disturbance, the persistence loops of Z. diploperennis are the most important life history pathways in the relative contribution to λ. In general, when λ increases, sexual growth loops also increase in importance, and persistence loops decrease. Changes in λ are not related to changes in vegetative growth loops. 5 If populations of Z. diploperennis are not disturbed at least once every 5 years, then species will go locally extinct in the wild.