Land use effects on soil food webs and ecosystem functioning (KB-14-003-021)
Summary: The structure and functioning of the soil food web governs soil ecosystem processes, such as the
decomposition of soil organic matter, the emission of CO2 and the mineralization of nitrogen. These processes
are major components in the global cycling of matter, energy and nutrients. On-going changes in land use,
climate and environmental processes may have profound effects on the structure and stability of the soil
community and hence on the soil processes. This project aims to link land use change to soil biodiversity and
ecosystem functioning.
In the present project, a large data-set of soil food webs (from the National Soil Survey-LMB) over various
types of land use and soil types will be analysed. In this way, we investigate mechanisms underlying food web
structure and stability and ecosystem processes that are the direct consequences of food web interactions,
especially carbon sequestration (in relation to climate change) and nutrient cycling (in relation to sustainable
agricultural practices). The project aims to provide clarity in science and policy, in the role of soil biodiversity
in relation to important ecosystem services. These services relate to current societal issues like climate change,
but also to farmers in terms of economically and environmentally sustainable management practices.
Scientific relevance: The project builds further on two well received modelling approaches in community and
system ecology. The energy flow model is a classical functional group approach to determine carbon emission
and nitrogen production (Hunt et al., 1987, de Ruiter et al., 1993b). Allometric modelling is another modelling
approach where scaling relationships are investigated (Brown et al., 2004) between e.g. body size and
abundance (Mulder and Elser, 2009). Especially body size is an important characteristic, because it determines
many physiological processes; e.g. how much energy is required for maintenance, prey preference. This will
have an ultimate impact on food web stability and diversity.
These two approaches are developed relatively independent of each other. Yet they focus on the same issue, i.e.
that of community structure and stability, and the role of belowground food webs in ecosystem functioning. As
both approaches aim to clarify the relationship between biodiversity and ecosystem functioning and services,
the project will look at the differences and similarities in the result via the two approaches. This is of strategic
importance, as it may show the best way to analyse the biodiversity-ecosystem functioning relationships.
References
Brown, J.H., Gillooly, J.F., Allen, A.P., Savage, V.M. & West, G.B. (2004) Toward a metabolic theory of
ecology. Ecology, 85, 1771-1789.
de Ruiter, P.C., Van Veen, J.A., Moore, J.C., Brussaard, L. & Hunt, H.W. (1993) Calculation of nitrogen
mineralization in soil food webs. Plant and Soil, 157, 263-273.
Hunt, H.W., Coleman, D.C., Ingham, E.R., Ingham, R.E., Elliott, E.T., Moore, J.C., Rose, S.L., Reid, C.P.P.
& Morley, C.R. (1987) The detrital food web in a shortgrass prairie. Biology and Fertility of Soils, 3,
57-68.
Mulder, C. & Elser, J.J. (2009) Soil acidity, ecological stoichiometry and allometric scaling in grassland food
webs. Global Change Biology, 15, 2730-2738.
Micro-arthropod feeding
mites
Plant-feeding nematodes
Plant-feeding mites
Roots
Plant-feeding collembolans
Omnivore diplurans
Fungivore nematodes
Generalist predatory mites
Fungi
Fungivore mites
Fungivore collembolans
Omnivore mites
Enchytraeids
Detritus
Nematode-feeding mites
Earthworms
Nematode-feeding
nematodes
Bacteria
Bacterivore nematodes
Omnivore nematodes
Bacterivore mites
Figure 1: The most-detailed soil food web (i.e. “master food web”) constructed from 170 soil
samplings on sand. Arrows indicate who is eaten by whom. Each of the 170 food webs is
contained in the web represented above.