The impact of ants on mineral soil properties and processes at different spatial scales E. L. H. Cammeraat 1 & A. C. Risch 2 1 Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Nieuwe Achtergracht, Amsterdam, The Netherlands 2 Swiss Federal Institute for Forest, Snow and Landscape Research, Research Unit Community Ecology, Zuercherstrasse, Birmensdorf, Switzerland Introduction Ants belong to the periodic endopedonic fauna (Hole 1981) and are present in almost all terrestrial ecosys- tems (Ho ¨ lldobler and Wilson 1990; Bolton 1994). They have an important impact on soil physical, chemical and biological properties by creating macro-voids, galleries, chambers, organo-mineral soil aggregates and by changing the composition of carbon, nutrients and soil microbes within their nests (Lavelle 1997; Lobry de Bruin 1999; Seybold et al. 1999; Karlen et al. 2003). The ancient Greeks were well aware of the importance of soil digging by ants as elucidated by the myth of the giant gold digging ants (Herodotus 2007). Ants are perceived as ecosystem engineers (Jones et al. 1994; Folgarait 1998; Lavelle and Spain 2001), but their importance in contributing to soil turnover Keywords ecosystem engineers, infiltration, nutrient cycling, overland flow, scale, soil quality Correspondence E. L. H. Cammeraat (corresponding author), Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands. E-mail: lcammera@science.uva.nl Received: June 18, 2007; accepted: January 17, 2008. doi: 10.1111/j.1439-0418.2008.01281.x Abstract Soil dwelling ants are important soil engineers that have a large impact on the soil ecosystem. This is reflected in the alteration of soil properties by ants due to burrowing activities, the accumulation of organic matter and other nutrients in the soil, which, in turn, alters soil physical, chemical and (micro) biological processes. A review of recent literature on these fine scale soil changes resulting from ant activity is presented in this paper. However, ants do not only affect soil properties at the fine scale but also have effects at the hillslope and catchment scales with respect to surface hydrological processes and ecosystem functioning. At the finest scale, most studies showed changed soil textures, lowered bulk densities and increased infiltration where ant burrows or mineral mounds are prominent. Only a few studies investigated the effects of ants on soil properties such as soil structure and aggregate stability, which were improved by ant activity. Nutrients were generally consid- ered to be concentrated in nests, and increased nutrient cycling involv- ing microbial processes were reported. On a broader scale, the information on nest densities and patterns is crucial to understand the impacts of ants, but this information is scarcely available. It has been reported that the activity of ants increases the heterogeneity of soil infil- tration rates and nutrient concentrations at the landscape scale, which in turn has consequences for the redistribution of sediments and nutri- ents by geomorphological and biotic processes. A hierarchical descrip- tive model focusing on dry land ecosystems is presented to incorporate small-scale ant activity into broader scale hillslope and catchment pro- cesses. However, this model has to be tested and more research is needed, especially on these broader scale aspects, to be able to fully understand the role of ants on the ecosystem and landscape scale. J. Appl. Entomol. J. Appl. Entomol. 132 (2008) 285–294 ª 2008 The Authors Journal compilation ª 2008 Blackwell Verlag, Berlin 285