Quatorze types de structures physiques produites par des ingenieurs ecologiques ont ete echantillonnees a la surface du sol d'une savane colombienne. Les invertebres impliques dans leur production ont ete identifies. Une selection de proprietes physiques (taille et stabilite des agregats, densite apparente) et chimiques (teneur en C, N, P, etc) de ces structures ont ete evaluees. Trois groupes de structures sont identifies<space>: a) turricules de vers de terre compacts (1,3-1,4<space>g.cm - 3 ), constitues d'agregats de grande taille (7-10<space>mm), riches en C organique (3-4<space>%) et en elements assimilables<space>; b) termitieres peu compactes (0,6-0,9<space>g.cm - 3 ), constitues d'agregats de grande taille (8-9<space>mm), riches en C organique (3,5-10<space>%) et en elements assimilables<space>; et c) placages de termites et fourmilieres peu compacts (0,4-0,7<space>g.cm - 3 ), granulaires (agregats <<space>1,5<space>mm) pauvres en C organique (moins de 1,5<space>%) et en elements assimilables. Ces resultats mettent en avant la grande diversite des structures biogeniques produites a la surface du sol, et laissent entrevoir la possibilite d'une classification fonctionnelle des organismes ingenieurs tenant compte de facon simultanee des differents attributs fonctionnels refletes par ces structures.
Fourteen types of physical structures produced by ecosystem engineers were sampled at the surface of a savanna soil of Colombia. Invertebrates implicated in the creation of these structures were identified. Some physical (aggregate size and stability, bulk density) and chemical (C, N, P contents, pH, etc) properties of structures were assessed. Three large groups of structures were identified: (i) earthworm casts characterised by a high bulk density (1.3-1.4<space>g.cm - 3 ), constituted of aggregates (7-10<space>mm), high in organic C (3-4<space>%) and assimilable nutrients; (ii) termite mounds with low bulk density (0.6-0.9<space>g.cm - 3 ), constituted of aggregates (8-9<space>mm), high in organic C (3.5-10<space>%) and assimilable nutrients; and (iii) slightly compact (0.4-0.7<space>g.cm - 3 ) and granular (aggregate size <<space>1.5<space>mm) termite superficial channels and ant mounds low in organic C (less than 1.5<space>%) and assimilable nutrients. These results underline the large diversity of the biogenic structures produced at the surface of the studied soil. They suggest the feasibility of a functional classification of engineer organisms that would take into account simultaneously the different functional attributes reflected by these structures.