ISSN:
1365-2486
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
,
Energy, Environment Protection, Nuclear Power Engineering
,
Geography
Notes:
Global change may affect the structure and functioning of decomposer food webs through qualitative changes in freshly fallen litter. We analyzed the predicted effects of a changing environment on a dynamic model of a donor-controlled natural decomposer ecosystem near Wekerom, the Netherlands. This system consists of fungi, bacteria, fungivores, bacterivores and omnivores feeding on microbiota and litter as well. The model concentrates on carbon and nitrogen flows through the trophic niches that define this decomposer system, and is designed to predict litter masses and abundances of soil biota. For modeling purposes, the quality of freshly fallen leaf litter is defined in terms of nitrogenous and non-nitrogenous components, of which refractory and labile forms are present. The environmental impacts of elevated CO2, enhanced UV-B and eutrophication, each with their own influence on leaf litter quality, are studied. The model predicts steady-state dynamics exclusively, for all three scenarios. Environmental changes impact most demonstratively on the highest trophic niches, and affect microbiotic abundances and litter decomposition rates to a lesser extent. We conclude that the absence of trophic cascade effects may be attributed to weak trophic links, and that non-equilibrium dynamics occurring in the system are generally because of encounter rates based on fractional substrate densities in the litter. We set out a number of experimentally testable hypotheses that may improve understanding of ecosystem dynamics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-2486.2005.00898.x
