Short-term and long-term effects of bacterivorous nematodes and nematophagous fungi on carbon and nitrogen mineralization in microcosms

Bouwman, Lex; Bloem, J.; Boogert, P.H.J.F. van den; Bremer, F.; Hoenderboom, G. H. J.; Ruiter, Peter C. de

doi:10.1007/bf00383977

Cited by 79 publications

(21 citation statements)

References 17 publications

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“…In the absence of the latter group the way in which the predators may have in¯u-enced nutrient and energy¯uxes in the current experiment was by reducing the biomass of microbivores that are known to increase mineralisation of N. Although we found that concentration of mineral N in the soil was slightly reduced in the presence of predators (see also e.g. Bouwman et al 1994;Mikola and SetaÈ laÈ 1998b), cumulative plant N uptake (a large pool of N compared to that of mineral N in the soil) was not concomitantly reduced. Thus, the generally weak control of ecosystem functioning by the food web structure corresponds to our observation that the strength of top-down in¯uences at the population level decrease towards the bottom of the food web (Laakso and SetaÈ laÈ 1999).…”

Section: Eect Of Trophic Structure On Biomasses and Respiration Of MImentioning

confidence: 79%

Population- and ecosystem-level effects of predation on microbial-feeding nematodes

Laakso¹,

Setälä²

1999

Oecologia

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We studied the role of nematode predation in the functioning of detrital food webs assembled in microcosms. The microcosms contained defaunated humus and litter materials, a diverse microbial community with bacteria, fungi and protozoa, and a birch (Betula pendula) seedling infected with mycorrhizal fungi. Different levels of top-down control upon microbivorous nematodes were set up by assembling food webs either without predators, or in combinations with a specialist and a non-specialist predatory mite (Mesostigmata). The nematode community was composed of either (1) three species of bacterivorous, or (2) three species of fungivorous nematodes or (3) both groups together. After two growing periods for the birch (38 weeks), the microcosms were destructively sampled for animal and microbial biomasses, concentration of mineral N in the soil, plant biomass and plant N concentration. The specialist predator reduced biomasses of both bacterial- and fungal-feeding nematodes by more than 50%, whereas the non-specialist predator weakly increased the biomass of fungivorous nematodes. Thus, under high predation pressure, the biomass of microbivores changed as predicted by trophic dynamic models assuming strong top-down control and uniformly behaving trophic levels. Despite this, microbial biomass was unaffected by the predators. However, microbial respiration increased slightly in the presence of predators. Assuming that microbial respiration correlates with microbial productivity, the increase in microbial respiration indicates a cascading productivity regulation. The composition of the microbivore community had only a minor effect on the outcome of the top-down control on microbes. The >50% reduction in nematode biomass and respiration coincided with <16% increase in microbial respiration and did not affect microbial biomass. Presence of the specialist predator slightly reduced soil NH concentration in communities with fungivore nematodes but plant growth and N uptake remained unchanged. Thus, the structure of the community only weakly controlled nutrient mineralisation.

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Section: Eect Of Trophic Structure On Biomasses and Respiration Of MImentioning

confidence: 79%

Population- and ecosystem-level effects of predation on microbial-feeding nematodes

Laakso¹,

Setälä²

1999

Oecologia

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“…The combined effect of standard tillage and continuous cropping significantly enhanced the abundance of nematodes at the entry level of the soil food web. Bacterial-feeding nematodes influence C-and Nmineralisation by feeding on bacteria, excreting NH + 4 and by spreading bacteria through the soil (Bouwman et al, 1994, Fu et al, 2005. Mesorhabditis and Acrobeloides, two of the most abundant bacterial-feeders in our plots, were positively associated with NH + 4 , a reasonable expec- tation for the group associated with increased N mineralisation (Ferris et al, 1997(Ferris et al, , 2004.…”

Section: Ntfmentioning

confidence: 81%

Linking soil properties and nematode community composition: effects of soil management on soil food webs

Sánchez‐Moreno¹,

Minoshima²,

Ferris³

et al. 2006

Nematol

116

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The purported benefits of conservation tillage and continuous cropping in agricultural systems include enhancement of soil ecosystem functions to improve nutrient availability to crops and soil C storage. Studies relating soil management to community structure allow the development of bioindicators and the assessment of the consequences of management practices on the soil food web. During one year (December 2003-December 2004), we studied the influence of continuous cropping (CC), intermittent fallow (F), standard tillage (ST) and no tillage (NT) on the nematode assemblage and the soil food web in a legume-vegetable rotation system in California. The most intensive systems included four crops during the study period. Tillage practices and cropping pattern strongly influenced nematode faunal composition, and the soil food web, at different soil depths. Management effects on nematode taxa depended on their position along the coloniser-persister (cp) scale and on their trophic roles. At the last sampling date (December 2004), Mesorhabditis and Acrobeloides were positively associated with NH + 4 , while Panagrolaimus and Plectus were negatively correlated with certain phospholipid fatty acids (PLFA). Microbial-feeders were in general associated with both bacterial and fungal PLFA, microbial biomass C (MBC) by chloroform fumigation-extraction, total C and N, NH + 4 and NO − 3 , and were most abundant in the surface soil of the NTCC treatment. Fungal-feeders were more closely related to PLFA markers of fungi than to ergosterol, a purported fungal sterol. Discolaimus, Prionchulus, Mylonchulus and Aporcelaimidae, in contrast, were associated with intermittent fallow and deeper soil layers. The organisms in the higher levels of the soil food web did not respond to the continuous input of C in the soil and a long recovery period may be required for appropriate taxa to be reintroduced and to increase. At the end of the experiment, each treatment supported quite different nematode assemblages and soil food webs.

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“…In a study of the effects of bacterivorous nematodes and the nematophagous fungi on carbon and nitrogen mineralization, Bouwman et al (27) found that the presence of nematodes enhanced carbon mineralization during the first month, then followed a decline. N mineralization was increased during the first two months and then also diminished.…”

Section: Food Webs and Nutrient Cyclingmentioning

confidence: 98%

“…Questions regarding sustainability of crop-production systems and related demands for alternative options for nematode management have impelled researchers into a more holistic approach to fundamental research on plant parasites (21,27,57,62,87,108,186). Research now ranges from characterizing the general diversity of nematode species in given habitats and cropping systems, the role of nematodes in nutrient cycling, to the genetic diversity of different species of plant-parasitic nematodes and other organisms on specific crops.…”

Section: Food Webs and Nutrient Cyclingmentioning

confidence: 99%

“…N mineralization was increased during the first two months and then also diminished. Nematodes affect carbon mineralization indirectly by their effect on bacterial activity, whereas N mineralization is apparently determined by nematodes mineralizing bacterial biomass (27). Because of different temperature optima, certain nematode species within a nematode community may be adapted to predominance at different times and/or soil depths.…”

Section: Food Webs and Nutrient Cyclingmentioning

confidence: 99%

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Developing Sustainable Systems for Nematode Management

Barker

Koenning

1998

Annu. Rev. Phytopathol.

176

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Early researchers identified key concepts and developed tactics for multiple-option management of nematodes. Although the emphasis on integrated pest management over the past three decades has promoted strategies and tactics for nematode management, comprehensive studies on the related soil biology-ecology are relatively recent. Traditional management tactics include host resistance (where available), cultural tactics such as rotation with nonhosts, sanitation and avoidance, and destruction of residual crop roots, and the judicious use of nematicides. There have been advances in biological control of nematodes, but field-scale exploitation of this tactic remains to be realized. New technologies and resources are currently becoming central to the development of sustainable systems for nematode-pest-crop management: molecular diagnostics for nematode identification, genetic engineering for host resistance, and the elucidation and application of soil biology for general integrated cropping systems. The latter strategy includes the use of nematode-pest antagonistic cover crops, animal wastes, and limited tillage practices that favor growth-promoting rhizobacteria, earthworms, predatory mites, and other beneficial organisms while suppressing parasitic nematodes and other plant pathogens. Certain rhizobacteria may induce systemic host resistance to nematodes and, in some instances, to foliage pathogens. The systems focusing on soil biology hold great promise for sustainable crop-nematode management, but only a few research programs are currently involved in this labor-intensive endeavor.

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Short-term and long-term effects of bacterivorous nematodes and nematophagous fungi on carbon and nitrogen mineralization in microcosms

Cited by 79 publications

References 17 publications

Population- and ecosystem-level effects of predation on microbial-feeding nematodes

Population- and ecosystem-level effects of predation on microbial-feeding nematodes

Linking soil properties and nematode community composition: effects of soil management on soil food webs

Developing Sustainable Systems for Nematode Management

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