Soil nematode community structure as affected by temperature and moisture in a temperate semiarid shrubland Ga ´ bor Bakonyi a, *, Pe ´ter Nagy a , Edit Kova ´ cs-La ´ ng b , Eszter Kova ´ cs b , Sa ´ ndor Baraba ´s b , Vikto ´ria Re ´pa ´ si a , Aniko ´ Seres a a Department of Zoology and Ecology, Szent Istva ´n University, 2103 Go ¨do ¨llo, Pa ´ ter K.u.1., Hungary b Institute of Ecology and Botany, Hungarian Academy of Sciences, 2163 Va ´ cra ´ to ´ t, Alkotma ´ ny u. 2-4., Hungary 1. Introduction Moderate, but continuous warming and/or drying in some areas of the Earth is a common phenomenon whose occurrence is supposed currently being enhanced (IPCC, 2001). This will have effects on community structure of different groups of organisms, including soil animals (Adams and Wall, 2000; Shaver et al., 2000) and as a result on different soil processes like nitrogen cycling (Swift et al., 1998). Soil temperature and moisture content are usually the main abiotic factors to determine nematode distribution and abundance. The effects may be direct and/or indirect and these two factors are strongly interdependent. Local climate, soil type and plant community, all modify temperature and applied soil ecology 37 (2007) 31–40 article info Article history: Received 11 April 2006 Received in revised form 16 March 2007 Accepted 20 March 2007 Keywords: Soil warming Soil drying Nematode community Global change abstract Nematodes are key agents in important soil processes, such as decomposition, mineraliza- tion and nutrient cycling. Therefore, alterations of the nematode community structure induced by global change may have a considerable influence on ecosystem functioning. However, it is not clear whether minor changes in soil temperature and/or moisture have any significant effect on nematode community structure. A field experiment was performed in a mosaic of open sand grassland and Juniper–Poplar woodland (VULCAN Project). Soil temperature and moisture were modified to the extent expected for the near future due to global changes. Community diversity and multivariate structure of the nematode commu- nity proved to be more sensitive to minute changes in soil temperature and moisture than different indices, such as specific richness (SR), maturity index (MI), plant parasite index (PPI), enrichment index (EI), channel index (CI), fungal feeder to bacterial feeder ratio (F/B) and nematode channel ratio (NCR). Nematode genera with high densities (>0.1 individual g À1 soil) were better indicators of the temperature and moisture changes than those of low density (<0.1 individual g À1 soil) in this sandy soil. Both drying and warming had significant influence on low density (Wilk’s lambda: 0.02) and high density (Wilk’s lambda: 0.002) genera according to canonical variate analysis. Cephalobus and Plectus were associated with the dried plots, while Cervidellus, Ditylenchus, Eudorylaimus, Seinura and Thonus were favoured by warming. Drying induced the development of a more structured nematode community in the bare soil compared to the control. Drying and warming effects on the soil nematode community were most pronounced in bare soil, less so in soil under poplar, while no significant effect was found in the fescue grass soil. # 2007 Elsevier B.V. All rights reserved. * Corresponding author. Tel.: +36 28 522 085; fax: +36 28 410 804. E-mail address: bakonyi.gabor@mkk.szie.hu (G. Bakonyi). available at www.sciencedirect.com journal homepage: www.elsevier.com/locate/apsoil 0929-1393/$ – see front matter # 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.apsoil.2007.03.008