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Summary The soil seed bank functions to escape unfavourable environmental conditions and seed predation. Anecic earthworms are increasingly recognised as important dispersers and predators of plant seeds. In contrast, the role of the usually more abundant endogeic earthworms which live and feed in the soil on plant seeds is largely unknown. We tested whether (A) endogeic earthworms ( Aporrectodea rosea , Allolobophora chlorotica , Octolasion tyrtaeum , Aporrectodea caliginosa ) ingest and digest grassland plant seeds ( Phleum pratense , Bellis perennis , Trifolium repens , Poa trivialis , Plantago lanceolata , Medicago varia ), (B) the passage of seeds through the gut of endogeic earthworms modifies seed germination, and (C) excreta (mucus and casts) of endogeic earthworms modify seed germination. As a reference effects of the well-studied anecic species Lumbricus terrestris were determined. Endogeic earthworms ingested and digested all of the studied plant seeds; however, both ingestion and digestion were earthworm and plant species specific. Moreover, passage through the gut of endogeic earthworms and their excreta modified plant seed germination (gut passage: B. perennis ; excreta: Ph. pratense and Pl. lanceolata ). The results indicate that endogeic earthworms may strongly impact the composition of the soil seed bank and, consequently, plant community assembly via direct and indirect effects on plant seeds. Since post-dispersal seed predation is a key factor for the structure of plant communities, with the effect on seed survival potentially exceeding that of pre-dispersal predation, seed predation and changes in germination of seeds by endogeic earthworm species is likely to drive plant community composition.

Summary On four differently managed and abandoned alpine meadows and pastures densities, biomasses and 15 N signatures of the macrofauna were assessed to evaluate the structural and functional changes of the decomposer food webs. The composition of the macrofauna decomposer community changes remarkably after the abandonment of alpine meadows and pastures. Lumbricus rubellus functions as key primary decomposer on alpine meadows and pastures whereas on abandoned sites other primary decomposers including Dendrobaena octaedra , Cylindroiulus meinerti , C. fulviceps and diptera larvae become more important. Decomposer species, such as Enantiulus nanus, presumably function as both primary and secondary decomposers and endogeic earthworms, such as Octolasion lacteum and Aporrectodea rosea , uniformly function as secondary decomposers. Abandonment of pasturing causes a shift in the composition of the macrofauna and the newly established fauna is unable to process and translocate the litter materials produced by the plants of the abondoned sites.

Summary A mixed stand of red oak (Quercus rubra) and common beech (Fagus sylvatica) on a compacted and acidified sandy loam soil was harvested and reforested with ash (Fraxinus excelsior) in 1992. The ecosystem restoration trial in this newly established ash plantation included 180 trees and was set up in a block design with 4 blocks, 3 experimental groups per block and 15 trees per experimental group. Experimental groups were: (1) application of P, K, Ca and Mg fertiliser to the planting pit; (2) combined application of fertiliser and earthworms to the planting pit; and (3) a control without additional restoration measures. Fertiliser application consisted of 500g dolomite, 100g Thomas slags and 100g kieserite; earthworm introduction consisted of 40 individuals, being 20 anecics (Lumbricus terrestris L. and Nicodrilus longus Ude) and 20 endogeics (Aporrectodea caliginosa Sav., Aporrectodea rosea Sav. and Allolobophora limicola Michaelsen). Tree growth was monitored annually. The control trees failed to grow and died after two years. Excellent growth was found for treated trees, and treatment-related growth patterns were observed: fertilised trees grew faster than fertilised trees with earthworms during the first two years, with the trend reversed from year 4 onwards. Although this trend suggested that introduced earthworms provided a more sustained response to fertiliser, this was not conclusively confirmed by an evaluation of 24 trees 10 years after planting (based on nutrient concentration in above-ground biomass and soil, litter biomass, earthworm biomass, and aggregate stability of organic particles in the soil); although statistically significant differences were found between treated and untreated plots, differences between fertilised plots with and without earthworms were not significant. Endogeic earthworms recolonised most fertilised plots, with or without earthworm introduction. Anecic earthworms did not colonize any plots. Although our findings suggest that earthworm introduction might contribute to a sustained fertiliser response in ash trees, more experiments are needed to demonstrate the precise role of earthworm introduction as part of integrated forest soil restoration.

A mixed stand of red oak (Quercus rubra) and common beech (Fagus sylvatica) on a compacted and acidified sandy loam soil was harvested and reforested with ash (Fraxinus excelsior in 1992. The ecosystem restoration trial in this newly established ash plantation included 180 trees and was set up in a block design with 4 blocks, 3 experimental groups per block and 15 trees per experimental group. Experimental groups were: (1) application of P, K, Ca and Mg fertiliser to the planting pit; (2) combined application of fertiliser and earthworms to the planting pit; and (3) a control without additional restoration measures. Fertiliser application consisted of 500 g dolomite, 100g Thomas slags and 100g kieserite; earthworm introduction consisted of 40 individuals, being 20 anecics (Lumbricus terrestris L. and Nicodrilus longus Ude) and 20 endogeics (Aporrectodea caliginosa Sav., Aporrectodea rosea Sav. and Allolobophora limicola Michaelsen). Tree growth was monitored annually. The control trees failed to grow and died after two years. Excellent growth was found for treated trees, and treatment-related growth patterns were observed: fertilised trees grew faster than fertilised trees with earthworms during the first two years, with the trend reversed from year 4 onwards. Although this trend suggested that introduced earthworms provided a more sustained response to fertiliser, this was not conclusively confirmed by an evaluation of 24 trees 10 years after planting (based on nutrient concentration in above-ground biomass and soil, litter biomass, earthworm biomass, and aggregate stability of organic particles in the soil); although statistically significant differences were found between treated and untreated plots, differences between fertilised plots with and without earthworms were not significant. Endogeic earthworms recolonised most fertilised plots, with or without earthworm introduction. Anecic earthworms did not colonize any plots. Although our findings suggest that earthworm introduction might contribute to a sustained fertiliser response in ash trees, more experiments are needed to demonstrate the precise role of earthworm introduction as part of integrated forest soil restoration.

The earthworms, Aporrectodea rosea and A. trapezoides (Lumbricidae), occur commonly in soils used for grain production in south-eastern Australia, but their distributions are patchy and their abundance low. In a field experiment, inoculations of A. trapezoides, but not A. rosea, increased the growth of oats at early tillering and oat straw and grain yield at harvest. Neither earthworm species influenced the growth and yield of lupins. At early tillering of the oats and concurrent flowering of the lupins, the amounts of 1 5 N (from fertiliser applied the year before) taken up by both oats and lupins were greater in the presence of A. trapezoides, but not A. rosea. However, there were no differences in the % N in lupin and oat plants between the earthworm treatments. At harvest, there were no differences in the amounts of 1 5 N taken up by the lupin straw, nor were there in the % N in straw or grain for either lupins or oats between earthworm treatments. The 1 5 N contents of the oat straw and the lupin and oat grain were higher in the presence of both earthworm species when compared with controls. More than 90 % of the N in the lupins was fixed symbiotically. The proportion of fixed N was reduced slightly by A. trapezoides. Inorganic N was analysed at various depths in the soil profile at sowing and early tillering and flowering. An earthworm effect on soil inorganic N was recorded in only one instance - at early tillering / flowering, when soil inorganic N was slightly higher at 0.6-1 m depth in the presence of A. trapezoides. Management practices, which improve earthworm abundance, in particular that of A. trapezoides, in cropping soils in southern Australia may enhance productivity of some, but not all, crops.