Ants represent a widespread and functionally diverse taxonomic group that are both sensitive to land
management and serve as important regulators of key soil processes. Building upon this idea, we sought
to understand the impacts of agricultural management on ant communities in the Orinoco River Basin of
eastern Colombia and to identify species that could be used as indicators of soil-based ecosystem
services. Ants were collected and identified from the soil and litter layer within 75
fields (nine TSBF subsamples
along a transect in each
field) divided among
five common agricultural land uses in the region: 1)
annual crops (maize, soy and rice), 2) rubber plantations, 3) oil palm plantations, 4) improved pastures
(based on Brachiaria spp.), and 5) semi-natural savannas. As expected, land management was found to
greatly influence ant communities. Improved pastures showed the highest species richness (6.9 species
per transect) and semi-natural savanna the greatest abundance of ants (145 individuals per transect).
Within each of these
fields a suite of soil and agroecosystem characteristics were measured and
combined into synthetic indicators of
five soil-based ecosystem services: 1) nutrient provision, 2) water
storage and regulation, 3) maintenance of soil structure, 4) climate regulation services and 5) soil
biodiversity and biological activity. Ant species were then associated with these synthetic indicators
using the IndVal method to identify indicator species for each of the
five consolidated ecosystem services
measured. In total, 14 indicator species were identified and found to be significantly associated with
either the high or low provision of each of the
five services. The development of such bioindicators offers
a rapid and relatively inexpensive tool to facilitate land management and policy decisions in this
biologically diverse and rapidly changing region of Colombia.