Abstract
Human impact on structure and functioning of ecosystems is rapidly increasing. Virtually all European forests are managed with major implications for diversity and structure of food webs. Centipedes (Chilopoda: Lithobiidae) are abundant arthropod predators in European temperate forest soils with a generalistic feeding behaviour. However, little is known on the variability in the prey spectrum of centipedes with land use and the responsible factors. Combining fatty acid (FA) analysis, which allows determination of the relative contribution of different prey to predator nutrition, and stable isotope analysis, providing insight into the trophic structure of decomposer food webs, we investigated variations in trophic niches of two dominant centipede species,Lithobius mutabilisandLithobius crassipes, in differently aged beech and spruce forests. FA composition of the two centipede species differed significantly with bacterial marker FAs being more abundant inL. crassipesas compared toL. mutabilis. Differences were most pronounced in spruce as compared to beech forests. The results suggest that dense needle litter in coniferous forests may restrict prey availability to the largerL. mutabilisand confine foraging to the litter surface whereas the smallerL. crassipesis able to also exploit prey of deeper litter layers.Lithobius crassipeswas significantly more enriched in15N and13C compared toL. mutabilissuggesting that, compared toL. mutabilis, the smallerL. crassipesoccupies higher trophic levels and relies more on root derived carbon. The results indicate that trophic niches of centipedes vary in a species specific way between forest types with body size and habitat structure being major determinants of the variations in the prey spectrum. Combining techniques for delineating predator–prey interactions allowed insights into variations in trophic interrelationships and their driving forces in temperate forest soil food webs.
Published Version
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