Nest refuse of Atta opaciceps (Hymenoptera: Formicidae) increases plant biomass and diversity during the regrowth of herbaceous species

Abstract

The time interval in which a community plant recovers after a disturbance is strongly associated with the availability of nutrients and soil organic matter, factors that are widely known as limiting for the establishment of pioneer species. The nest refuse (NR) produced by leaf cutting ants may act to favour herbaceous regeneration in newly disturbed areas, but little is known about its effects in this process. In the present study, we experimentally verified the effect of NR on plant regeneration in a newly deforested area, testing the hypothesis that plots with NR act as hot spots for plant establishment, promoting greater aboveground biomass and altering the vegetation structure in comparison to control sites. Thirty plots of 30 × 30 cm were installed, where half of the plots received a layer of 3 cm of soil from the same site (control) while the other plots received a layer of 3 cm of a mixture of control soil + NR, in a 3:1 ratio (25% organic refuse). After 150 days of natural regeneration, we evaluated the diversity of herbaceous species that colonised each plot and the aboveground dry biomass. The species composition differed between treatments and the aboveground biomass was 45% higher in the plots with NR than control soil. In this way, refuse dumps can act as regeneration sites, favouring pioneer species in newly deforested areas.