Contrasting responses of native ant communities to invasion by an ant invader, Linepithema humile

• Published in: Biological invasions Vol. 23; no. 8; pp. 2553 - 2571
• Main Authors: Devenish, Adam J. M., Newton, Rosemary J., Bridle, Jon R., Gomez, Crisanto, Midgley, Jeremy J., Sumner, Seirian
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01-08-2021; Springer Nature B.V
• Subjects: Biomedical and Life Sciences; Community structure; Developmental Biology; Ecology; Freshwater & Marine Ecology; Herbivores; Indigenous species; Introduced species; Invasive species; Life Sciences; Linepithema humile; Native species; Nature reserves; Original Paper; Plant Sciences; Sampling; Sampling methods; Species extinction; Species richness; Community structure; Competitive displacement; Cape floristic region; Argentine ant; Formicidae; Iberian peninsula; Biological invasions; Field experiment
• ISSN: 1387-3547; 1573-1464
• DOI: 10.1007/s10530-021-02522-7

Invasive alien species pose a serious threat to the integrity and function of natural ecosystems. Understanding how these invaders alter natural communities is therefore an important aspect in predicting the likely future outcomes of biological invasions. Many studies have documented the consequences of invasive alien species on native community structure, through the displacement and local extinction of native species. However, sampling methods and intensities are rarely standardised across such studies, meaning that it is not clear whether differences in response among native communities to the same invader species are due to biological differences between the invaded regions, or differences in the methodologies used. Here we use a matched sampling methodology to compare the effects of the Argentine ant (
Linepithema humile
Mayr) on native ant community assemblages in two distinct biogeographical regions that share similar ecologies: Girona (Spain) and Jonkershoek Nature Reserve (South Africa). We found a strong negative association between
L. humile
presence and native ant species richness within both geographic regions. However, the effects differed between the two study regions: in Girona, a single native ant species (
Plagiolepis pygmaea
) persisted in invaded sites; by contrast, substantially more native ant species persisted at invaded sites in Jonkershoek Nature Reserve. In addition, in Jonkershoek Nature Reserve, the abundance of certain native species appeared to increase in the presence of
L. humile
. This study therefore demonstrates the potential variable effects of an invasive species in contrasting locations within different biogeographical regions. Future work should explore the causes of this differential resistance among communities and expand standardised sampling approaches to more invaded zones to further explore how local biotic or abiotic conditions of a region determine the nature and extent of impact of
L. humile
invasion on native ant communities.