Geographical Expansion and Native Species Displacement: The Invasion of Cecropia peltata L. (Urticaceae) in Cameroon

ABSTRACT

Plant invasions pose a global ecological concern, yet their study in continental tropical Africa is limited. Cecropia (Urticaceae) is a genus of fast‐growing Neotropical tree species, some of which have been introduced and become invasive in the paleotropics. In this study, we examined the invasion process of the C. peltata introduction in Cameroon, focusing on its geographical distribution, temporal dynamics, and potential impacts on the closely related native species Musanga cecropioides . After surveying 837 km of roads in 2018, we found that C. peltata was widely distributed across the Littoral and South‐West regions, extending over an area of ca. 15,000 km ² (ca. 3% of the total terrestrial area of Cameroon), where it often occupies recently disturbed vegetation. Its abundance decays with distance from the town of Limbe, supporting the hypothesis that the Limbe Botanical Garden was the point of introduction. This invasion represents an expansion of ca. 143 km eastwards and 110 km northwards over approximately 100 years, a mean rate of progression of ca. 1–3 km per year. Cecropia peltata seems to be replacing M. cecropioides , which showed a five‐fold decrease in abundance between 1986 and 2018 along two road sections 20–60 km away from Limbe. Considering that environmental degradation can promote C. peltata establishment, ongoing human population growth and land use change in Cameroon may exacerbate the C. peltata invasion in the future. Consequently, further investigation is necessary to assess the ecological and socio‐economic impacts of this invasion as part of considering management priorities.