[Structure of the Collembolan community (Hexapoda: Collembola) in bark mosses along an altitudinal gradient of a subhumid forest in Mexico].

The structure of the community of moss springtails on oak and fir bark in the forests at the NW slope of Iztaccihuatl Volcano, State of Mexico, is analyzed. The study included four samplings (November 2003, March-June-August 2004), carried out in three altitudes I: 2750 m, II: 2 930 and 3 250 m a.s.l. Calculated indexes were: species richness (S), Shannon's diversity index (H'), Pielou's evenness index (J') and Simpson dominance (lamda). An ANOVA of two way test was used to evaluate the effect of altitude and sampling date on the total density of the springtails. The total number of species was 24 (altitude I=17, altitude II=14, altitude III=13). The greatest density was at altitude III and the highest species richness at altitude I. Americabrya arida and Willowsia mexicana were dominant. There is a positive significant effect of altitude on their density. The highest Sörensen similarity between communities was 59% (altitudes II and III).