Unveiling management suggestions for the invasive tree Senna spectabilis through literature review, species distribution models and ecological knowledge

Abstract

Senna spectabilis (D.C.) H.S. Irwin & Barneby (Fabaceae) is a medium to large tree native to the American Tropics, introduced in 25 countries around the world. Its human introduction to biodiversity hotspots, including tropical island ecosystems, has made it an invasive species of global concern. In this study, we aim to provide management suggestions through a systematic review of its ecology, distribution, human uses and the mechanisms driving its invasion, combined with an analysis of field-based observations in India's Western Ghats. We also developed species distribution models (SDMs) at a global scale under four projected climate change scenarios using 22 general circulation models (GCMs) to assess the current and future potential suitable habitats. Inferences from our integrative approach reveal that S. spectabilis exhibits broad habitat compatibility across continents. Biodiversity-rich and low-income countries of tropical and subtropical regions in Africa and Southeast Asia are considered suitable for its likely future spread. At the regional scale, we found a decline in native species richness and grass cover with an increasing abundance of S. spectabilis. Based on our findings, we propose six practical management strategies for effectively controlling S. spectabilis and outline future research directions to manage this highly invasive tree species.