Facilitation and predation structure a grassland detrital food web: the responses of soil nematodes to isopod processing of litter

Small woodland streams make the majority of water courses in most watersheds. Litter decomposition is a key ecosystem process in these shaded streams, and its response to warming can have profound consequences for food webs and the carbon (C) cycle. However, these responses can be modulated by litter identity and the structure of the detrital food web. Here we report on a manipulative study aiming at evaluating the effects of warming (+2.8 °C), litter identity (chestnut (Castanea sativa) or oak (Quercus robur) litter), and the structure of the detrital food web (presence or absence of macroinvertebrates) on litter decomposition and decomposers in a small, temperate woodland stream. Warming significantly stimulated overall (microbial- + macroinvertebrate-driven) decomposition of oak and microbial-driven decomposition of chestnut. The similar shredder densities at elevated and ambient temperatures suggest that stimulated overall decomposition of oak resulted from increased activity of macroinvertebrate individuals. Stimulated microbial-driven decomposition of chestnut resulted from higher fungal activity with warming. Stimulation of litter decomposition by warming can lead to increases in the amount of C returned to the atmosphere and to a faster disappearance of litter from the benthos, with consequences to the C cycle and aquatic food webs.

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Peer Review #2 of "Long-term resource addition to a detrital food web yields a pattern of responses more complex than pervasive bottom-up control (v0.1)"

10.7287/peerj.3572v0.1/reviews/2 ◽

2017 ◽

Keyword(s):

Food Web ◽

Peer Review ◽

Bottom Up ◽

Detrital Food Web

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THE DETRITAL FOOD WEB AND SURFACE MINE RECLAMATION

Journal American Society of Mining and Reclamation ◽

10.21000/jasmr85010319 ◽

1985 ◽

Vol 1985 (1) ◽

pp. 319-321 ◽

Cited By ~ 1

Author(s):

Lawrence W. Parker ◽

Walter G. Whitford

Keyword(s):

Food Web ◽

Mine Reclamation ◽

Surface Mine ◽

Detrital Food Web ◽

Surface Mine Reclamation

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Spatial variability in nursery functions along a temperate estuarine gradient: role of detrital versus algal trophic pathways

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f06-086 ◽

2006 ◽

Vol 63 (8) ◽

pp. 1848-1864 ◽

Cited By ~ 22

Author(s):

Md. Shahidul Islam ◽

Masaru Tanaka

Keyword(s):

Spatial Variability ◽

Food Web ◽

Condition Factor ◽

River Estuary ◽

Sea Bass ◽

Gut Content ◽

Feeding Intensity ◽

Trophic Pathways ◽

Detrital Food Web ◽

Copepod Biomass

We aimed to identify spatial variability in estuarine trophic pathways and to elucidate their role as a nursery for juvenile fishes along Chikugo River estuary, Japan. First, we investigated distribution of larval and juvenile fishes and their diets. Using estuarine-dependent species as a model, we analyzed diets of Japanese sea bass (Lateolabrax japonicus) and conducted copepod distribution and gut fluorescence studies. To evaluate the nursery functions of spatially variable food webs, we used several indices: copepod biomass, feeding intensity, gut content biomass, growth rates, RNA/DNA ratio, condition factor, and starvation status of sea bass larvae and juveniles. We identified four different spatial distribution patterns of fishes: oligohaline, mesohaline, euryhaline, and polyhaline. Copepod assemblages and diets of fishes were completely different among the regions. Gut chlorophyll a and phaeopigment indicated that copepods in the oligohaline region depend on a detrital food web, while in the euryhaline region they depend on an algal food web. The oligohaline region had maximum turbidity, nutrients, chlorophyll pigments, and copepod biomass, and sea bass juveniles had higher feeding intensity, gut content biomass, RNA/DNA ratio, growth rate, and condition factor and lower starvation rates. This suggests that the oligohaline region, supported by a detrital food web, is an important nursery that positively influences fish growth and condition.

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Peer Review #1 of "Long-term resource addition to a detrital food web yields a pattern of responses more complex than pervasive bottom-up control (v0.1)"

10.7287/peerj.3572v0.1/reviews/1 ◽

2017 ◽

Author(s):

S Turney

Keyword(s):

Food Web ◽

Peer Review ◽

Bottom Up ◽

Detrital Food Web

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Effect of transgenic insect-resistant maize to the community structure of soil nematodes in two field trials

Helminthologia ◽

10.1515/helmin-2015-0001 ◽

2015 ◽

Vol 52 (1) ◽

pp. 41-49

Author(s):

A. Čerevková ◽

L Cagáň

Keyword(s):

Community Structure ◽

Food Web ◽

Field Trials ◽

Soil Nematode ◽

Soil Nematodes ◽

Soil Food Web ◽

Bt Maize ◽

Maize Hybrid ◽

Nematode Communities ◽

Soil Nematode Communities

Summary The aim of this study was to determine the effects of Bt maize hybrid cultivation on soil nematode communities in two field trials, as well as to analyse other factors (fertilisation and moisture) responsible for the community structure of soil nematodes. Nematode communities were studied in maize plots at the locality of Borovce in western Slovakia. During 2012 and 2013, hybrids DK440 and DKC3871 (conventional) or DKC4442YG and DKC3872YG (Bt maize, event MON810) were sown in 10 repetitions each. Nematodes were extracted from soil samples collected at the maize flowering (July 11, 2012 and July 30, 2013). Altogether, 39 nematode species belonged to 35 genera were identified in two maize variants. The dominant taxa in both variants were Acrobeloides nanus, Ce-phalobus persegnis, Aphelenchoides composticola, Aphelenchus avenae, Eudorylaimus carteri and Filenchus vulgaris. Calculation of the maturity index, plant parasitic index, enrichment index and structure index did not confirm any clear influence of year or hybrid type on soil nematode communities. The proportional representation of cp-1, cp-2 and cp-3-5 groups of nematode fauna indicated conditions of low stability and high stress. Faunal profiles representing the structure and enrichment conditions of the soil food web showed an environment with a high C:N ratio and high levels of fungal feeders. Based on the calculation of the metabolic footprint of nematodes in the soil food web, a difference between the isoline maize variant and Bt maize variant in 2012 was found, but this difference was not readily apparent in 2013. The occurrence of nematodes, their abundance, proportion of feeding types and selected ecological indices did not depend on the type of maize hybrid (Bt or non-Bt). Thus, the cultivation of genetically modified maize did not directly influence nematode populations. The application of fertiliser at certain periods does not influence the nematode community. The observed significant higher abundance of nematodes was correlated with soil moisture.

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