03690naa a2200157 a 450000100080000000500110000800800410001910000210006024501430008126000090022452029290023370000190316270000180318170000120319977303210321113148182008-09-16       2008    bl uuuu     u00u1 u    #d1 aPODGAISKI, L. R.  aInfluence of artificial shelters on distribution and abundance of Neotropical terrestrial isopods (Crustacea, Oniscidea) in a forest soil.  c2008  aBesides the litter layer, natural microhabitats on the soil surface like rocks and coarse wood debris are important elements that determine habitat heterogeneity. Knowledge about how invertebrate communities relate to these elements is fundamental to the conservation of species and ecosystems. We investigate the colonization pattern of artificial shelters by terrestrial isopods in relation to seasonality and presence of other invertebrates. The importance of sheltering to isopods was investigated taking into account reproduction, life strategies and susceptibility to desiccation of two Neotropical species: Atlantoscia floridana (Philosciidae) and Balloniscus glaber (Balloniscidae). These species are commonly syntopic and often show a high species association (Quadros & Araujo, 2008). We predict that (1) Shelter use should be more important to A. floridana - which is a typical surface-litter dwelling isopod - than to B. glaber, which shows an increased burrowing ability; (2) Intensity of sheltering should increase in summer, specially in the case of A. floridana which is more susceptible to desiccation, (3) Abundance of reproductive females should be higher under shelters than in the adjacent litter and (4) Distribution of isopods under shelters is not random and may be influenced by other invertebrates. The experiments were conducted during one year in a secondary forest fragment (Triunfo city, RS, Brazil). Clay roofing tiles of 24x40 cm served as artificial shelters. The experiment was set in a block design, with shelter and leaf litter samples. Samplings occurred in the end of each season, with 10 replicates per season (Podgaiski et al., 2007). We captured 731 individuals, 77% being A. floridana and 23% being B. glaber. ANOVA revealed a significant interaction between treatments and seasons for A. floridana (P=0.045) and its ovigerous females (P=0.012), but not for B. glaber (P=0.513). As expected, in summer the abundance of A. floridana under the shelters increased and decreased in the litter. Abundance of ovigerous females was higher under the shelters in all seasons with exception of spring. The distribution of isopods was aggregated. Indexes of species association revealed a negative association of B. glaber with Hymenoptera and Opiliones (shelters) and with Chilopoda (litter). A. floridana presented a strong negative association with Opiliones in shelters and a positive association with other detritivorous in both shelters and litter. We conclude that rocky elements on the soil surface are important shelters for terrestrial isopods and that their colonization differs markedly between isopod species and seasons. Life strategies, resistance to desiccation and interaction with invertebrate taxa can explain the patterns of shelter occupation. Availability of soil microhabitats may influence community?s fitness and maintenance of the services they provide to ecosystems.1 aQUADROS, A. F.1 aARAUJO, P. B.1 aOTT, R.  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.