Does plant growth phase determine the response of plants and soil organisms to defoliation?

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

doi:10.1016/j.soilbio.2004.07.034

Cited by 26 publications

(24 citation statements)

References 46 publications

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“…Several studies have shown that soil and litter invertebrates, and the processes that they drive, can be influenced by vertebrate herbivores (Ilmarinen et al 2005;Mikola et al 2009) and their predators (e.g., Dunham 2008;Towns et al 2009). One group of vertebrate predators that can have important effects on soil and litter invertebrates are seabirds (Fukami et al 2006;Towns et al 2009;Kolb et al 2012Kolb et al , 2015.…”

Section: Introductionmentioning

confidence: 99%

Burrowing seabird effects on invertebrate communities in soil and litter are dominated by ecosystem engineering rather than nutrient addition

et al. 2015

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Vertebrate consumers can be important drivers of the structure and functioning of ecosystems, including the soil and litter invertebrate communities that drive many ecosystem processes. Burrowing seabirds, as prevalent vertebrate consumers, have the potential to impact consumptive effects via adding marine nutrients to soil (i.e. resource subsidies) and non-consumptive effects via soil disturbance associated with excavating burrows (i.e. ecosystem engineering). However, the exact mechanisms by which they influence invertebrates are poorly understood. We examined how soil chemistry and plant and invertebrate communities changed across a gradient of seabird burrow density on two islands in northern New Zealand. Increasing seabird burrow density was associated with increased soil nutrient availability and changes in plant community structure and the abundance of nearly all the measured invertebrate groups. Increasing seabird densities had a negative effect on invertebrates that were strongly influenced by soil-surface litter, a positive effect on fungal-feeding invertebrates, and variable effects on invertebrate groups with diverse feeding strategies. Gastropoda and Araneae species richness and composition were also influenced by seabird activity. Generalized multilevel path analysis revealed that invertebrate responses were strongly driven by seabird engineering effects, via increased soil disturbance, reduced soil-surface litter, and changes in trophic interactions. Almost no significant effects of resource subsidies were detected. Our results show that seabirds, and in particular their non-consumptive effects, were significant drivers of invertebrate food web structure. Reductions in seabird populations, due to predation and human activity, may therefore have far-reaching consequences for the functioning of these ecosystems.

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Section: Introductionmentioning

confidence: 99%

Burrowing seabird effects on invertebrate communities in soil and litter are dominated by ecosystem engineering rather than nutrient addition

et al. 2015

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“…It has been argued that plants can allocate more resources to roots after defoliation (Hokka et al 2004;Ilmarinen et al 2005). However, in our study we did not observe an increase of root biomass in response to defoliation.…”

Section: Responses Of Root Biomasscontrasting

confidence: 87%

“…Nevertheless, we did observe an increase in the density of one of the two nematode species, P. penetrans, which only occurred following early defoliation, suggesting a dependence of defoliation effects on plant development stage. We hypothesized that effects of the timing of defoliation should be caused by growth stage-specific changes in plant quality following defoliation as suggested by Ilmarinen et al (2005). Unexpectedly, overall root quality, as indicated by N concentration was not influenced by the timing of defoliation in our study, suggesting that root quality did not change with time at which defoliations occurred.…”

Section: Responses Of Root-feeding Nematodes To Timing Of Defoliationmentioning

confidence: 51%

“…The impact of defoliation on plant-associated belowground processes and subsequently on belowground organisms can also depend on timing (Richards 1984;Hester et al 2004;Ilmarinen et al 2005). So far, the majority of studies on effects of timing of defoliation on plant responses have predominantly focused on aboveground plant responses (Maschinski and Whitham 1989;Obeso and Grubb 1994;García and Ehrlén 2002;Akiyama and Ågren 2012), whereas information on the responses of plant roots is scarce.…”

Section: Introductionmentioning

confidence: 99%

“…For example, Ilmarinen et al (2005) reported that defoliation reduced the root C/N ratio when plants were defoliated at an early growth stage, but increased the root C/N ratio when defoliation occurred at a later stage of plant development. In the same study, late defoliation promoted the abundance of herbivorous and predacious nematodes, whereas there was no such response by other trophic groups of nematodes .…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Arriving at the right time : a temporal perspective on above-belowground herbivore interactions

Wang

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Defoliation reduces soil biota – and modifies stimulating effects of elevated CO₂

Dam

Christensen

2015

Ecology and Evolution

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To understand the responses to external disturbance such as defoliation and possible feedback mechanisms at global change in terrestrial ecosystems, it is necessary to examine the extent and nature of effects on aboveground–belowground interactions. We studied a temperate heathland system subjected to experimental climate and atmospheric factors based on prognoses for year 2075 and further exposed to defoliation. By defoliating plants, we were able to study how global change modifies the interactions of the plant–soil system. Shoot production, root biomass, microbial biomass, and nematode abundance were assessed in the rhizosphere of manually defoliated patches of Deschampsia flexuosa in June in a full‐factorial FACE experiment with the treatments: increased atmospheric CO 2, increased nighttime temperatures, summer droughts, and all of their combinations. We found a negative effect of defoliation on microbial biomass that was not apparently affected by global change. The negative effect of defoliation cascades through to soil nematodes as dependent on CO 2 and drought. At ambient CO 2, drought and defoliation each reduced nematodes. In contrast, at elevated CO 2, a combination of drought and defoliation was needed to reduce nematodes. We found positive effects of CO 2 on root density and microbial biomass. Defoliation affected soil biota negatively, whereas elevated CO 2 stimulated the plant–soil system. This effect seen in June is contrasted by the effects seen in September at the same site. Late season defoliation increased activity and biomass of soil biota and more so at elevated CO 2. Based on soil biota responses, plants defoliated in active growth therefore conserve resources, whereas defoliation after termination of growth results in release of resources. This result challenges the idea that plants via exudation of organic carbon stimulate their rhizosphere biota when in apparent need of nutrients for growth.

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Does plant growth phase determine the response of plants and soil organisms to defoliation?

Cited by 26 publications

References 46 publications

Burrowing seabird effects on invertebrate communities in soil and litter are dominated by ecosystem engineering rather than nutrient addition

Burrowing seabird effects on invertebrate communities in soil and litter are dominated by ecosystem engineering rather than nutrient addition

Arriving at the right time : a temporal perspective on above-belowground herbivore interactions

Defoliation reduces soil biota – and modifies stimulating effects of elevated CO₂

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Does plant growth phase determine the response of plants and soil organisms to defoliation?

Cited by 26 publications

References 46 publications

Burrowing seabird effects on invertebrate communities in soil and litter are dominated by ecosystem engineering rather than nutrient addition

Burrowing seabird effects on invertebrate communities in soil and litter are dominated by ecosystem engineering rather than nutrient addition

Arriving at the right time : a temporal perspective on above-belowground herbivore interactions

Defoliation reduces soil biota – and modifies stimulating effects of elevated CO2

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Defoliation reduces soil biota – and modifies stimulating effects of elevated CO₂