What distribution models of alligator weed in its native and invaded ranges tell us about its invasion story and biological control

• Published in: Entomologia experimentalis et applicata 2023-12, Vol.171 (12), p.1009-1018
• Main Authors: Sánchez‐Restrepo, Andrés F., Reche, Vanina A., Cabrera, Nora, Pan, Xiaoyun, Pratt, Paul, Sosa, Alejandro J.
• Format: Article
• Language: English
• Subjects: Agasicles hygrophila; Alternanthera philoxeroides; Amaranthaceae; Aquatic plants; Aquatic reptiles; Beetles; Biological control; Chrysomelidae; Climate change; Coleoptera; Control programs; Disonycha; Ecological niches; Floating plants; Geographical distribution; Global warming; Niches; Range extension; Risk reduction; Systena; Weeds
• ISSN: 0013-8703; 1570-7458
• DOI: 10.1111/eea.13353

Ecological niche models of species occurrence have gained interest in biological control programs to improve efficiency, reduce risks, and to inform when and how control agents may be released and/or surveyed. Alligator weed, Alternanthera philoxeroides (Mart.) Griseb. (Amaranthaceae), is an amphibious aquatic plant native to southern South America that has invaded several countries around the world. In this study, our aim was to quantify the current and to model the future alligator weed geographical distributions in its native range in South America, and in its introduced range (USA, the country where biological control of the weed was first implemented). Additionally, we modelled the current and potential distribution of its biocontrol agent Agasicles hygrophila Selman & Vogt (Coleoptera: Chrysomelidae), released in the USA in 1964, and other potential biocontrol agents, including the flea beetles Disonycha argentinensis Jacoby and Systena sp. In total, 19438 occurrence records of alligator weed, 253 of A. hygrophila , 48 of D. argentinesis , and 19 of Systena sp. were compiled. Niche models predicted expanded distributions of alligator weed, particularly in northern regions of South America. However, the models of the flea beetles A. hygrophila , D. argentinensis, and Systena sp. did not predict geographic range expansion and the future scenarios are similar to current distributions. Our study predicts an increase in the suitable areas for alligator weed in South America in future scenarios of global warming, whereas these new areas would not be as favourable for the biocontrol agents historically used. Los modelos de nichos ecológicos de ocurrencia de especies han ganado interés en los programas de control biológico para mejorar la eficiencia, reducir los riesgos e informar cuándo y cómo se pueden liberar y/o inspeccionar los agentes de control. La lagunilla, Alternanthera philoxeroides (Mart.) Griseb. (Amaranthaceae), es una planta acuática anfibia originaria del sur de América del Sur que ha invadido varios países del mundo. En este estudio, nuestro objetivo fue cuantificar las distribuciones geográficas actuales y futuras de la maleza en su área de distribución introducida (EE. UU., el país donde se implementó por primera vez el control biológico de esta planta) y su área de distribución nativa en América del Sur. Además, modelamos la distribución actual y potencial de su agente de control biológico Agasicles hygrophila Selman & Vogt (Coleoptera: C