Spatial and temporal variation of the Formicidae assemblage in different forest types of the Chaco Seco ecoregion, Argentina

Abstract

Ants have been widely used as bioindicators of natural and disturbed environments. In Argentine Chaco Seco, ants represent an important part of the total biodiversity and fulfil various functions in forest ecosystems. With the aim of evaluating β diversity and identifying indicator ants, surveys were carried out in three types of implanted forests: Neltuma alba (mesquite), Eucalyptus tereticornis (eucalyptus) and mixed forests without intervention for 50 years, mainly composed of Ceiba speciosa and Phoenix canariensis, located at the Fernández Experimental Station of the Catholic University of Santiago del Estero. The samplings were carried out in spring, summer and autumn, between 2019 and 2022, using pitfall traps that remained active for 24 h. The abundance and composition of Formicidae at each site and season were evaluated using the Jaccard similarity index and generalized linear mixed models. A total of 7366 individuals grouped into 28 species belonging to 6 Formicidae subfamilies were identified. Some species were present at all sites and seasons, with Solenopsis saevissima, Camponotus mus and Pheidole bergii being the most abundant in the mesquite, eucalyptus and mixed stands, respectively. In addition, three exclusive species of N. alba, two of E. tereticornis and one of the mixed stand were identified. Furthermore, it was observed that the myrmecological composition varied seasonally, mainly during autumn. These results demonstrate that due to the characteristics of each site, representative groups of ants can be found for each that could be used as indicators of each type of environment and that the temporal variation of the communities is favored by the diversification of the habitats, which offer different resources during each season of the year, increasing the turnover rate.