03947naa a2200145 a 450000100080000000500110000800800410001910000240006024501870008426000090027152031550028070000240343570000210345977303210348013149092008-09-23       2008    bl uuuu     u00u1 u    #d1 aHERNÁNDEZ-RUIZ, P.  aComparison of composition and functional groups of epiedaphic ants (HymenopterabFormicidae) between agroecosystems and nonagricultural areas in Valley of Mezquital, Hidalgo, Mexico.  c2008  aAs indicators of environmental conditions, ants are very useful organisms. This study focused on determining the composition and the functional groups of epiedaphic ants in non-agricultural systems and agroecosystems with varying qualities of irrigation water, as well as seasonal variations. This work is being carried out in Valley of Mezquital, a semi-arid ecosystem located in Central Mexico, with a very important agricultural activity. Thirty nine plots with various irrigation types were studied from 2005 to 2006 [nine non-agricultural plots (NA), nine temporal plots (T), six plots irrigated with well water (P), and 15 plots irrigated with waste water (W)]. Twelve pitfall traps were used in each plot. A total of 52,223 organisms were collected, belonging to six subfamilies (Dolichoderinae, Ecitoninae, Formicinae, Myrmicinae, Ponerinae and Pseudomyrmicinae), corresponding to 22 genera and 34 species. The highest abundances were recorded in NA and T plots. The average of ants by trap varied from 65.3±d.e.9.39 in NA plots, 36.31±6.77 in T, 9.49±1.36 in W, and 7.25±0.79 in P plots. The NA plots showed the highest richness of species (30), followed by T (29), P (23), and W plots (24). The highest similarity value among communities was recorded between the NA and T plots, with 91.5% (similarity Sörensen index) and the lowest between NA and P, with 79.2%. The groups with highest abundance and richness of species in all plots were Opportunists and Generalized Myrmicinae (sensu Andersen, 1995) (with 6-8 spp). In particular, Hot Climate Specialists showed more abundance and richness of species (5) in NA and T plots than in P and W plots. Generalized Myrmicinae recorded the highest abundance in P and W plots, Opportunists in NA and Dominant Dolichoderinae in T plots. Not irrigated plots (NA + T) are characterized by registering high relative abundance of genera Liometopum, Forelius, Camponotus, Pogonomyrmex, Atta, Dorymyrmex and Odontomachus, while irrigated plots (P+W) recorded a high relative abundance of Tapinoma. It is possible to infer that the constant irrigation (with waste water or well water) has a negative effect on the structure of the community of edaphic ants. Two communities are clearly distinguishable: that of non-irrigated areas and the other of irrigated areas. In accordance with the composition and abundance of species, areas may be characterized based on functional groups, with emphasis on stress and disturbance. The functional groups characteristic of not irrigated areas were Dominant Dolichoderinae (Liometopum and Forelius), Subordinate Camponotini (Camponotus), Hot Climate Specialists (Pogonomyrmex), Tropical Climate Specialists (Atta) and Opportunists (Dorymyrmex and Odontomachus); while the functional group characteristic of irrigated areas was Opportunists (represented by Tapinoma). The decrease of Dominant Dolichoderinae and Hot Climate Specialists, characteristic of conserved and natural arid areas, respectively, as well as high abundance of Generalized Myrmicinae and Opportunists, suggests that there are habitats with a certain degree of disturbance in the whole region.1 aCASTANO-MENESES, G.1 aCANO-SANTANA, Z.  tIn: INTERNATIONAL COLLOQUIUM ON SOIL ZOOLOGY, 15; INTERNATIONAL COLLOQUIUM ON APTERYGOTA, 12., 2008, Curitiba. Biodiversity, conservation and sustainabele management of soil animal: abstracts. Colombo: Embrapa Florestas. Editors: George Gardner Brown; Klaus Dieter Sautter; Renato Marques; Amarildo Pasini. 1 CD-ROM.