03596naa a2200169 a 450000100080000000500110000800800410001910000180006024501970007826000090027552027510028470000210303570000160305670000160307270000170308877303210310513150062008-10-02       2008    bl uuuu     u00u1 u    #d1 aMENDES, S. M.  aBioindicators and biological indexes of soil quality. Improving the application of IBQS index in assessing effects of management practices on Mediterranean areas using soil epigeal macrofauna.  c2008  aMonitoring soil quality can be done using several approaches, namely through the use of soil quality indices based on biological indicators. Among these, the ?Indice Biotique de la Qualité du Sol? (IBQS) uses the concept of indicator species associated to a typology of sites/treatments under assessment to rank their soil quality. In order to evaluate the application of IBQS methodology to Mediterranean landscapes, its resolution power and applicability to soil epigeal macrofauna data, a case-study, implemented in a Portuguese cork-oak forest (?Montado?) was analysed. Five areas were established following a chronosequence of a disturbance regime (time since understory clearing), comprising a non disturbed control area plus four areas with different times since shrub was cut (1 year, 2 years, 3-4 years and 4-5 years); in the same farm, three more areas were defined: an area with cattle grazing and two areas where the understory cut residues were incorprated into soil at different times, implying a strong soil mobilization. At each area, nine pitfall traps were settled, following a nested design. Sampling took place in Autumn 2003. Biological material was identified to family/order and to species level; when this was not possible, morphospecies was used. Over 240 species/morphospecies were identified. When using the traditional IBQS formula, areas where shrub is incorporated into the soil (the more disturbed areas) presented the highest IBQS values, followed by areas with traditional ?Montado? use; the lowest value was obtained for grazing. However, using a correction factor (indicator species contribution for explaining the variability observed on a PCA) to the formula, developed under this study, IBQS values for areas representing the traditional and sustainable use of ?Montados? are higher than the ones obtained for other areas. Regarding the taxonomical discriminatory power of IBQS when calculated based on data at different taxonomic level, the shift from species to higher taxonomical levels suggested a loss of resolution, with values calculated at species level allowing a better discrimination between the different areas. Overall analysis showed that IBQS is sensitive to the abundance of specific taxa, especially of opportunistic species, able to reach high abundances in disturbed areas, and originating a biased ranking of soil quality values. This is a common phenomenon when evaluating pitfall trap data, what could lead to a strong bias in IBQS values. The application of the developed correction factor to IBQS formula originates a more ecologically relevant ranking, suggesting that its application could be useful in bypassing questions arisen from using pitfall data in calculating IBQS values.1 aRUIZ-CAMACHO, N.1 aFREITAS, H.1 aLAVELLE, P.1 aSOUSA, J. P.  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.