Food Webs and Nutrient Cycling in Soils: Interactions and Positive Feedbacks

Bengtsson, Janne; Setälä, Heikki; Zheng, David W.

doi:10.1007/978-1-4615-7007-3_3

Cited by 56 publications

(49 citation statements)

References 40 publications

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“…Detritivore enhancement may have positive feedbacks on growth of the invasive Spartina, through greater regeneration of nutrients by detritus breakdown within the sediments (Bengstton et al 1996). Loss of key secondary producers, in this case the surface feeders most preferred by foraging birds and fishes, may have cascading effects upward with negative implications for threatened and endangered species (Simenstad and Thom 1995).…”

Section: Implications For San Francisco Bay and Other Ecosystemsmentioning

confidence: 99%

Invasive Cordgrass Modifies Wetland Trophic Function

Levin¹,

Neira²,

Grosholz³

2006

Ecology

220

144

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Abstract. Vascular plants strongly control belowground environments in most ecosystems. Invasion by vascular plants in coastal wetlands, and by cordgrasses (Spartina spp.) in particular, are increasing in incidence globally, with dramatic ecosystem-level consequences. We examined the trophic consequences of invasion by a Spartina hybrid (S. alterniflora ϫ S. foliosa) in San Francisco Bay (USA) by documenting differences in biomass and trophic structure of benthic communities between sediments invaded by Spartina and uninvaded sediments. We found the invaded system shifted from an algae-based to a detritus-based food web. We then tested for a relationship between diet and tolerance to invasion, hypothesizing that species that consume Spartina detritus are more likely to inhabit invaded sediments than those that consume surface algae. Infaunal diets were initially examined with natural abundance stable isotope analyses and application of mixing models, but these yielded an ambiguous picture of food sources. Therefore, we conducted isotopic enrichment experiments by providing 15 N-labeled Spartina detritus both on and below the sediment surface in areas that either contained Spartina or were unvegetated. Capitellid and nereid polychaetes, and oligochaetes, groups shown to persist following Spartina invasion of San Francisco Bay tidal flats, took up 15 N from labeled native and invasive Spartina detritus. In contrast, we found that amphipods, bivalves, and other taxa less tolerant to invasion consumed primarily surficial algae, based on 13 C enrichment experiments. Habitat (Spartina vs. unvegetated patches) and location of detritus (on or within sediments) did not affect 15 N uptake from detritus. Our investigations support a ''trophic shift'' model for ecosystem response to wetland plant invasion and preview loss of key trophic support for fishes and migratory birds by shifting dominance to species not widely consumed by species at higher trophic levels.

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Section: Implications For San Francisco Bay and Other Ecosystemsmentioning

confidence: 99%

Invasive Cordgrass Modifies Wetland Trophic Function

Levin¹,

Neira²,

Grosholz³

2006

Ecology

220

144

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“…Bergstrom et al (1998a) determined that implementation of no-till and previous cropping to forages increased activity of six enzymes (dehydrogenase, urease, glutaminase, phosphatase, arylsulfatase and β-glucoidase). Bergstrom and Monreal (1998) observed an effect on soil enzyme measurements of crop and row position; that is, greater activity was found in the plant row than in the between-row positions. However linkages were not clear due to the nature of the variable itself including or being representative of numerous biological components other than soil organisms and being the end result of many chemical interactions.…”

Section: Extent Of Influence Of Soil Biota On Soil Organic Matter Dynmentioning

confidence: 91%

“…The authors linked humification and adsorption of microbial products as functions of soil clay content such that predicted C mineralization was consistent with recorded data. Coleman et al (1983), Parton et al (1996), Bengtsson et al (1996), and Huston (1993) have presented models and concepts to evaluate soil organic matter dynamics and the functional role of soil biodiversity. Andrén et al (1990) presented an overview of available models and concepts for characterizing C and N flows from primary production and plant nutrient uptake through to litter decomposition and nutrient mineralization.…”

Section: Issues Concerning Modeling Efforts Related To Functional Rolmentioning

confidence: 99%

Characterizing soil biota in Canadian agroecosystems: State of knowledge in relation to soil organic matter

Fox¹

2003

Can. J. Soil. Sci.

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Organic residues resulting from crop and animal production either become incorporated in the soil or remain on the surface and, thus, provide much of the nutrient and energy sources for many soil organisms. Characterizing the response of soil biota to these organic materials is a challenging undertaking due to the complexity of the soil ecosystem with respect to the magnitude of biodiversity involved, the possibilities for interrelationships with biochemical and biophysical processes, and the immense range of scale of observation from particle, through to aggregate, field, landscape and regional levels. The objectives of this paper were to review the available research pertaining to Canadian agroecosystems, which characterize the response of soil biota to soil organic matter dynamics, and to identify the issues, challenges and knowledge gaps. The response by soil organisms is discussed from two approaches: (1) their state of occurrence in terms of population response to soil organic matter as a nutrient and carbon/energy source, and (2) the extent of their influence in contributing to organic matter dynamics, that is, assessing their functional role. For the most part, Canadian research has emphasized comparative studies based on population responses by broad soil biota groups to soil organic matter additions or losses as an outcome of undertaking various agronomic practices. Studies that evaluate the extent of contributions by soil biota to soil organic matter dynamics are few, and rare at the species level. For Canadian agroecosystems, there is currently a great need for research initiatives that address the immense knowledge gaps that exist in relation to (a) identifying the specific contributions to soil organic matter processes and interactions of soil biota both at species and community level, (b) predicting outcomes of the contributions of soil biota groups in regulating or controlling soil organic matter processes both spatially and temporally across landscapes, and (c) assessing the risk to soil biodiversity in various agroecosystems in being able to sustain these functional roles. Key words: Soil biota, functional role, soil organic matter, agroecosystems, ecosystem services

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“…Pre, P > 0.1) in forest soil Regulation of oribatid mite density by top-down control seems unlikely (Schneider and Maraun, 2009) Supported (Ori ! Pre, P > 0.1) Low predation pressure for oribatid mites could drive the numerical dominance of this group (predatory mites have weak effects on oribatid mites, P > 0.1) Detritus-based soil food webs are thought to be bottom-up controlled (Bengtsson et al, 1996) Supported (most correlations between the soil microbes and microbivores, microbivores and predators are positive)…”

Section: Established Hypothesesmentioning

confidence: 99%