Analysis of Reproduction and Natural Regeneration of Psidium cattleianum Afzel., an Invasive Species in Eastern Madagascar

Abstract

Psidium cattleianum Afzel. ex-Sabine (Myrtaceae) is an invasive alien species occurring in the Betampona Nature Reserve in eastern Madagascar, where it disrupts native vegetation. This study aimed to analyse its phenology and evaluate its natural regeneration capacity. A phenological assessment was carried out, combined with the setting up of sampling plots for floristic inventories in savoka ecosystems dominated by P. cattleianum. Field observations enabled the identification of dispersal agents, while three plots were used to quantify natural regeneration. Phenological results indicate a vegetative phase from May to October, flowering from November to March, and fruiting from November to May. The main dispersal vectors include runoff water, Eulemur fulvus albifrons, Potamochoerus larvatus, Alectroenas madagascariensis, and human activities. The density of P. cattleianum ranges from 4 to 11 individuals per square metre, with strong natural regeneration. Compared to Harungana madagascariensis and Treculia africana, the species develops a more vigorous root system from the seedling stage onward. Following ANOVA testing, cutting and artificial wounding produced a significantly higher number of sprouts than girdling. No significant difference was observed between girdling and natural wounds. Significant differences were found among classes 1, 2, 3 and 4 (p). The applied treatments showed an increase in bud production with increasing stem diameter. A wound of 4 cm² healed within approximately eight months. These results have important implications for the practical management of the reserve. Accordingly, control of this species can be achieved through manual uprooting, cutting, girdling (ringbarking), and active ecological restoration.