Original article The effect of two ant species Lasius niger and Lasius flavus on soil properties in two contrasting habitats M. Holec a,b,c , J. Frouz a, * a Institute of Soil Biology, Academy of Sciences of the Czech Republic, Na Sádkách 7, České Budějovice, CZ 337005, Czech Republic b Faculty of Environmental Sciences, University of J.E. Purkyně in Ústí nad Labem, Králova výšina 7, 40096, Ústí nad Labem, Czech Republic c Faculty of Biological Sciences, University of South Bohemia in České Budějovice, Na sádkách 7, 370005, České Budějovice, Czech Republic Available online 08 August 2006 Abstract Ants significantly change the soil environment within the nest. The aim of this study is to contribute to ecology and thus the importance of two ant species Lasius niger and Lasius flavus in a post-mining landscape near the town of Sokolov in northwest Bohemia where both species are common. Chemical (total C, N, and available P) and microbiological parameters (respiration, cellulose decomposition and direct counts of bacteria) were investigated in both ant species in two different habitats: a tertiary clay heap after brown coal mining with a weakly developed organic layer and semi natural meadows with well developed organic horizons. Total C and N in the L. flavus mound was lower than in the surrounding soil in both stands, the same was true for total N in L. niger on the heaps. L. niger nests in both sites were significantly enriched by available P. A litter bag test with cellulose indicated lower decomposition in the ant nest in comparison with the surrounding soil. Respiration seems to be limited by lower soil moisture in the nest. However, microbial respiration, even in suitable moisture conditions, did not differ between the nest and soil (on heaps) or nest respiration was significantly lower (in L. flavus nests in the meadow). In meadow soil both species had a lower bacteria count than the surrounding soil, but the L. niger nest on the heap had higher bacterial numbers. Both species significantly alter soil conditions, although the effect on selected parameters is variable. Moreover, the result with lower nest moisture and lower decomposition rate in ant mounds indicates that soil moisture should be the next important factor limiting soil processes inside ant mounds. © 2006 Elsevier Masson SAS. All rights reserved. Keywords: Ants; Soil chemistry; Soil microbiology; Coal mining; Ecosystem restoration 1. Introduction Ants significantly alter the physical, chemical and biological properties of the soil environment [4,5,8,13, 18,19]. They are often mentioned as an example of eco- system engineers [12]. Higher values of nutrients and the intensive microbial life in anthills, in comparison to the surrounding soil have been mentioned by many authors. Nest soil enrichment is easily explainable as the result of food and excreta storage in the anthill [1, 7,15]. On the other hand lower values of nutrient were found inside the nest mound also. For example in a case study carried out by Petal and Kusinska [20] lower total carbon and humic acids content were found in compar- ison to the adjacent soil. The authors explained this http://france.elsevier.com/direct/ejsobi European Journal of Soil Biology 42 (2006) S213–S217 * Corresponding author. Tel.: +420 38 7775 769; fax: +420 38 5300 133. E-mail address: frouz@upb.cas.cz (J. Frouz). 1164-5563/$ - see front matter © 2006 Elsevier Masson SAS. All rights reserved. doi:10.1016/j.ejsobi.2006.07.033