A Social-Ecological perspective on the invasive creeper Coralita (Antigonon leptopus) on St. Eustatius, Dutch Caribbean: a review
Invasive species and habitat destruction are seen as the biggest threats to biodiversity worldwide, especially on small islands. The Caribbean islands are a hotspot for biodiversity, harboring 2.3% of the world’s endemic plant species on a tiny area. Due to habitat degradation invasive species are considered a major environmental problem in the Caribbean. The invasive vine Antigonon leptopus Hook. & Arn., colloquially known as coralita, is the most abundant invasive species on the Dutch Caribbean island of St. Eustatius. Forming thick, monospecific carpets, the species is seen by many as a threat to biodiversity. Insight is needed in the ecological and social factors that cause A. leptopus-dominated ecological regimesto be so abundant on the island.
Materials and methods:
We used the Social-Ecological Systems framework to search for literature that provides information on factors affecting the invasion status of A. leptopus on St. Eustatius. We reviewed 40 documents, ranging from technical reports and theses to peer-reviewed scientific articles. Based on the information contained in these documents, we built a conceptual model to assess the social and ecological factors that influence the invasibility of the island’s ecosystem. We assessed the level of empirical support for the relationships, and determined research priorities for those factors whose influence has not yet been proven experimentally.
We found three major factors responsible for the A. leptopus-dominated regimes on St. Eustatius: overgrazing by feral animals, anthropogenic disturbance and climate change. These relationships where supported by 16, 13 and six publications, respectively. None of the authors identifying climate change as a factor provided empirical evidence, while the influence of anthropogenic disturbance and overgrazing were supported by three papers that provided quantitative data to back up their claim. Less than half of the papers that reported factors influencing A. leptopusinvasion were published in peer-reviewed scientific journals
Our results indicate that the abundance of A. leptopuson St. Eustatius is more of a symptom than a cause in itself. We therefore conclude that efforts to manage A. leptopus infestations by chemically or manually removing the plant are futile if not combined with active reforestation and grazer exclusion. Empirical evidence for the relation between invasibility and social and ecological factors is scarce, as most authors quote the same sources and do not provide empirical evidence for their claims. More experimental research is needed to inform policy and management decisions. We recommend new research to focus on the effects of feral grazer exclusion on the recovery of the vegetation.