Double agents: invasive Burmese pythons (Python bivittatus) and Argentine black and white tegus (Salvator merianae) as potential seed dispersers in South Florida

Abstract

Invasive species can reshape ecological processes, including seed dispersal, through both direct and indirect pathways. In this study, we explore how invasive reptiles influence seed dispersal dynamics in the Greater Everglades ecosystem using two case studies: the Burmese python (Python bivittatus) and the Argentine black and white tegu (Salvator merianae). Guided by a conceptual framework, we investigate three primary mechanisms through which invasive species may alter seed outcomes: direct seed consumption, predation on seed dispersers before seed ingestion, and secondary seed dispersal via predation on animals that have already consumed seeds. Burmese pythons, as apex predators, may contribute to seed dispersal through diploendozoochory while simultaneously driving trophic cascades that restructure the seed disperser community. Tegus, as omnivorous frugivores, directly consume and disperse a wide diversity of plant seeds. We documented 25 seed morphotypes in python diets and 73 in tegu diets, spanning a broad 38 families and including native, endangered, and invasive plant species. Using a binary interaction network, we found that these reptiles exhibit high generalization, nestedness, and connectance—suggesting they are becoming functionally integrated into Everglades seed dispersal networks. These findings reveal that invasive reptiles not only disrupt native plant–animal interactions but may also reshape them, with implications for ecosystem stability, restoration, and management.