Belowground responses by AM fungi and animal trophic groups to repeated defoliation in an experimental grassland community

Mikola, Juha; Nieminen, Mervi; Ilmarinen, Katja; Vestberg, Mauritz

doi:10.1016/j.soilbio.2005.01.027

Cited by 35 publications

(16 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For instance, H. lanatus and P. lanceolata plants decreased soil microbial biomass, L. corniculatus and P. lanceolata plants decreased the numbers of fungal-feeding Aphelenchoides and each of the live plant species decreased the abundance of omnivorous nematodes and the abundance of bacterial-feeding Acrobeloides and Eucephalobus. Such negative effects of live plants on decomposer growth have also been reported earlier Guitian and Bardgett 2000;Mikola et al 2005), and the explanation is likely to relate to soil fertility. Innes et al (2004) investigated the effect of six plant species (including grasses, herbs and one legume) on soil bacterial and fungal biomass and found that the effects were on average positive in an improved fertile soil, but on average negative in unimproved low fertility soil.…”

Section: Litter Effects On Decomposers and Plant N Uptakesupporting

confidence: 70%

“…The reason for this is that these organisms are abundant in the rhizosphere and thus are directly affected by plant roots (Clarholm 1985;Griffiths 1994). They also have high turnover rates and can respond to changes in resource availability within a few days (Bazot et al 2005;Mikola et al 2005;Saj et al 2008), which allows examination of plant-soil feedbacks in a short temporal scale (Hamilton and Frank 2001). It is, however, possible that the effects of changes in micro-food web structure on litter-N availability were outweighed by the effects of changes in the abundance of bigger organisms, such as enchytraeids and microarthropods, although populations of these animals should be less able to respond to changes in resource availability in the time scale of our study.…”

Section: Litter Effects On Decomposers and Plant N Uptakementioning

confidence: 99%

See 1 more Smart Citation

Species-specific effects of live roots and shoot litter on soil decomposer abundances do not forecast plant litter-nitrogen uptake

Saj

Mikola

2009

Oecologia

Self Cite

View full text Add to dashboard Cite

Plant species produce litter of varying quality and differ in the quality and quantity of compounds they release from live roots, which both can induce different decomposer growth in the soil. To test whether differences in decomposer growth can forecast the amount of N species acquire from plant litter, as suggested by theory, we grew individuals of three grassland plants-Holcus lanatus, Plantago lanceolata and Lotus corniculatus-in soils into which (15)N-labelled litter of either Holcus, Plantago or Lotus was added. We measured the effects of live roots and litter of each species on soil microbes and their protozoan and nematode feeders, and to link decomposer growth and plant nutrient uptake, we measured the amount of N taken up by plants from the added litter. We hypothesised that those species that induce the highest growth of microbes, and especially that of microbial feeders, will also take up the highest amount of N from the litter. We found, however, that although numbers of bacterial-feeding Protozoa and nematodes were on average lower after addition of Holcus than Plantago or Lotus litter, N uptake was higher from Holcus litter. Further, although the effects on Protozoa and bacterial- and fungal-feeding nematodes did not differ between the live plants, litter-N uptake differed, with Holcus being the most efficient compared to Plantago and Lotus. Hence, although microbes and their feeders unquestionably control N mineralization in the soil, and their growth differs among plant species, these differences cannot predict differences in litter-N uptake among plant species. A likely reason is that for nutrient uptake, other species-specific plant traits, such as litter chemistry, root proliferation ability and competitiveness for soil N, override in significance the species-specific ability of plants to induce decomposer growth.

show abstract

Section: Litter Effects On Decomposers and Plant N Uptakesupporting

confidence: 70%

Section: Litter Effects On Decomposers and Plant N Uptakementioning

confidence: 99%

Species-specific effects of live roots and shoot litter on soil decomposer abundances do not forecast plant litter-nitrogen uptake

Saj

Mikola

2009

Oecologia

Self Cite

View full text Add to dashboard Cite

show abstract

“…Nematodes and enchytraeids are highly representative of the soil animal community, since they comprise all soil animal trophic groups, i.e., herbivores, bacterivores, fungivores, omnivores, detritivores and predators (Mikola et al 2005). In the current study, nematodes and enchytraeids were not aVected by the UV treatments, nor were there diVerences in their numbers between the tree species.…”

Section: Discussionmentioning

confidence: 99%

Solar ultraviolet radiation alters alder and birch litter chemistry that in turn affects decomposers and soil respiration

et al. 2009

View full text Add to dashboard Cite

Solar ultraviolet (UV)-A and UV-B radiation were excluded from branches of grey alder (Alnus incana) and white birch (Betula pubescens) trees in a field experiment. Leaf litter collected from these trees was used in microcosm experiments under laboratory conditions. The aim was to evaluate the effects of the different UV treatments on litter chemical quality (phenolic compounds, C, N and lignin) and the subsequent effects of these changes on soil fauna and decomposition processes. We measured the decomposition rate of litter, growth of woodlice (Porcellio scaber), soil microbial respiration and abundance of nematodes and enchytraeid worms. In addition, the chemical quality of woodlice feces was analyzed. The exclusion of both UV-A and UV-B had several effects on litter chemistry. Exclusion of UV-B radiation decreased the C content in litter in both tree species. In alder litter, UV exclusion affected concentration of phenolic groups variably, whereas in birch litter there were no significant differences in phenolic compounds. Moreover, further effects on microbial respiration and chemical quality of woodlice feces were apparent. In both tree species, microbial CO(2) evolution was lower in soil with litter produced under exclusion of both UV-A and UV-B radiation when compared to soil with control litter. The N content was higher in the feces of woodlice eating alder litter produced under exclusion of both UV-A and UV-B compared to the control. In addition, there were small changes in the concentration of individual phenolic compounds analyzed from woodlice feces. Our results demonstrate that both UV-A and UV-B alter litter chemistry which in turn affects decomposition processes.

show abstract

“…Nematodes were counted live and later, using preserved samples, up to 150 nematodes per sample were identified to genus and allocated into trophic groups according to Yeates et al (1993). Nematode data were analyzed both at the trophic group and genus level since different genera of a trophic group may not always respond to defoliation in parallel ways (Mikola et al 2005). For the analyses at the genus level, 11 most numerous genera, representing 91% of all identified individuals, were selected.…”

Section: Experimental Set-upmentioning

confidence: 99%

Legume defoliation affects rhizosphere decomposers, but not the uptake of organic matter N by a neighbouring grass

Saj

Mikola

2008

Plant Soil

View full text Add to dashboard Cite

Legume-grass interactions have a great influence on grassland primary production and it was recently shown how defoliation of a legume can increase the transfer of fixed N to a neighbouring grass. It has also been shown that defoliation of a plant can increase soil microbial activity and lead to better soil N availability in the rhizosphere of the defoliated plant. We combined these two perspectives and tested whether defoliation of a legume (Lotus corniculatus) can enhance N nutrition of the neighbouring grass (Holcus lanatus) by increasing growth of soil decomposer biota and the availability of soil organic matter N for grass uptake. We grew mixtures of L. corniculatus and H. lanatus in grassland soil that included 15 N-labelled L. corniculatus litter. In half of the systems, we subjected L. corniculatus to a defoliation treatment mimicking insect larvae feeding. At destructive harvests 1, 3, 9 and 30 days after the last defoliation event, we determined how L. corniculatus defoliation affected decomposer microbes, protozoa and nematodes and whether these changes among decomposers created a feedback on the growth and 15 N uptake of the neighbouring H. lanatus. Defoliation reduced the growth and litter-N uptake, but increased shoot N concentration of L. corniculatus. Of the soil variables measured, defoliation doubled the number of bacterial-feeding protozoa, but did not affect the abundance of decomposer microbes and bacterial-and fungal-feeding nematodes. Defoliation did not have statistically significant effects on H. lanatus shoot growth, shoot N concentration or litter-N uptake. Our results demonstrate how defoliation-induced changes in legume ecophysiology can affect the growth of decomposers in soil. However, these effects did not appear to lead to a significant change in the availability of soil organic N to the neighbouring grass. It seems that when positive effects of legume defoliation on grass N nutrition are found in grassland ecosystems, these are more likely to be explained by direct transfer of fixed N rather than changes in the availability of soil organic matter N.

show abstract

Belowground responses by AM fungi and animal trophic groups to repeated defoliation in an experimental grassland community

Cited by 35 publications

References 39 publications

Species-specific effects of live roots and shoot litter on soil decomposer abundances do not forecast plant litter-nitrogen uptake

Species-specific effects of live roots and shoot litter on soil decomposer abundances do not forecast plant litter-nitrogen uptake

Solar ultraviolet radiation alters alder and birch litter chemistry that in turn affects decomposers and soil respiration

Legume defoliation affects rhizosphere decomposers, but not the uptake of organic matter N by a neighbouring grass

Contact Info

Product

Resources

About