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Published on: November 21, 2015
Multitrophic effects of nutrient addition in upland grassland
M T Fountain1, V K Brown, A C Gange
1East Malling Research, Kent, UK. michelle.fountain@emr.ac.uk
Bulletin of Entomological Research
|February 9, 2008
Summary
Nutrient addition to soil increased juvenile Collembola and altered spider communities, demonstrating a moderate bottom-up effect on soil food webs. This study distinguished nutrient effects from physical habitat changes, highlighting impacts on soil biodiversity.
Area of Science:
- Soil ecology
- Trophic dynamics
- Nutrient cycling
Background:
- Effects of nutrient enhancement on aquatic systems are known, but soil food web responses are poorly understood.
- Previous research on bottom-up effects in soil is conflicting, often failing to separate nutrient enrichment from physical organic matter addition.
- Understanding soil management impacts on biodiversity is crucial due to land development and food production pressures.
Purpose of the Study:
- To investigate the hypothesis that nitrogen addition to soil would trigger a trophic cascade from detritivores (Collembola) to predators (spiders).
- To assess the impact of nutrient enrichment on invertebrate numbers and diversity in an upland grassland soil food web.
- To differentiate the effects of nutrient addition from physical habitat structure changes.
Main Methods:
- Field study involving nitrogen and lime addition to randomized grassland plots.
- Sampling of Collembola and spider populations using pitfall traps.
- Identification of species to assess changes in assemblage, diversity, richness, evenness, and total numbers.
Main Results:
- Nitrogen and lime addition did not affect overall Collembola species assemblage, diversity, richness, evenness, or total numbers.
- Increased numbers of Isotomidae juveniles and Parisotoma anglicana were observed in nutrient-amended plots.
- Spider community composition showed changes on specific sampling dates, with Oedothorax retusus being less abundant in nutrient-amended plots.
Conclusions:
- Nutrient inputs caused a bottom-up effect, increasing juvenile Collembola and altering spider community composition.
- While soil moisture reduction is a potential confounding factor, the study minimized physical habitat structure effects.
- Provides evidence for moderate bottom-up influences in epigeic soil food webs and highlights the importance of soil management on biodiversity.
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