Decomposers (Lumbricidae, Collembola) Affect Plant Performance in Model Grasslands of Different Diversity

Abstract

Decomposer invertebrates influence soil structure and nutrient mineralization as well as the activity and composition of the microbial community in soil and therefore likely affect plant performance and plant competition. We established model grassland communities in a greenhouse to study the interrelationship between two different functional groups of decomposer invertebrates, Lumbricidae and Collembola, and their effect on plant performance and plant nitrogen uptake in a plant diversity gradient. Common plant species of Central European Arrhenatherion grasslands were transplanted into microcosms with numbers of plant species varying from one to eight and plant functional groups varying from one to four. Separate and combined treatments with earthworms and collembolans were set up. Microcosms contained 15N labeled litter to track N fluxes into plant shoots. Presence of decomposers strongly increased total plant and plant shoot biomass. Root biomass decreased in the presence of collembolans and even more in the presence of earthworms. However, it increased when both animal groups were present. Also, presence of decomposers increased total N concentration and 15N enrichment of grasses, legumes, and small herbs. Small herbs were at a maximum in the combined treatment with earthworms and collembolans. The impact of earthworms and collembolans on plant performance strongly varied with plant functional group identity and plant species diversity and was modified when both decomposers were present. Both decomposer groups generally increased aboveground plant productivity through effects on litter decomposition and nutrient mineralization leading to an increased plant nutrient acquisition. The non-uniform effects of earthworms and collembolans suggest that functional diversity of soil decomposer animals matters and that the interactions between soil animal functional groups affect the structure of plant communities.

Earthworms, Collembola and residue management change wheat (Triticum aestivum) and herbivore pest performance (Aphidina: Rhophalosiphum padi)

“…This suggests that the eVects of earthworms on plant performance were caused by an earthworm-mediated increase in the mineralization of N from both soil and litter as has been observed previously (Scheu 2003;Partsch et al 2006). In contrast to the amount of N from litter in the plants, earthworms reduced plant atom% 15 N in seeds, shoots and roots, supporting the conclusion that earthworms predominantly increase the mineralization and plant uptake of soil N Partsch et al 2006).…”

“…Due to changes in resource distribution and other mechanisms earthworms have been shown to aVect the bacterialfungal ratio (McLean et al 2006;Butenschoen et al 2007), aggregate formation (Mummey et al 2006;Fonte et al 2007), and plant growth (Scheu 2003;Kreuzer et al 2004;Partsch et al 2006). Particularly in arable systems their eVect on plant growth is likely to depend on the distribution of resources in soil; however, this has been hardly studied.…”

“…Indeed, Kreuzer et al (2004) found the eVect of Collembola on plant growth to vary with litter distribution. Notably, Collembola and earthworms appear to synergistically aVect plant nutrient acquisition, suggesting that the mechanisms involved complement each other (Kreuzer et al 2004;Partsch et al 2006).…”

Effects of epigeic earthworm (Eisenia fetida) and arbuscular mycorrhizal fungus (Glomus intraradices) on enzyme activities of a sterilized soil–sand mixture and nutrient uptake by maize

“…Lumbricus terrestris) (Römbke et al 2005). Studies of AM fungi and earthworm interaction have been focused on anecic species (such as L. terrestris L.) (Scheu 2003) or endogeic species (such as Aporrectodea caliginosa S.) (Partsch et al 2006;Tuffen et al 2002;Wurst et al 2004), and little is known about the interaction of epigeic species and AM fungi and their effects on soil properties and plant growth. The objective of this study was to investigate the effects of epigeic species (E. fetida) and AM fungi (Glomus intraradices) on soil enzyme activities and nutrient uptake by maize, which was grown on a mixture of sterilized soil and sand.…”

Agroenergy Crops Influence the Diversity, Biomass, and Guild Structure of Terrestrial Arthropod Communities

“…Herbivorous arthropods will act as pests of biomass crops, capable of reducing the quantity or quality of biomass harvested [17]. Conversely, other arthropod groups such as decomposers, pollinators, predators, and parasitoids will enhance nutrient mineralization and plant performance in biomass crops [18,19], enhance pollination services [20], and assist in the control of herbivorous crop pests [17,21], respectively. Insomuch as expansion of biomass production can shape arthropod communities and influence arthropod biodiversity, selection of biomass crops can change the ways arthropod-mediated ecosystem services such as pollination and pest suppression are distributed in agricultural landscapes [14,17].…”