Integrating the Effects of Earthworms on Nutrient Cycling across Spatial and Temporal Scales - Earthworm Ecology - page 153

9

Integrating the Effects of
Earthworms on Nutrient
Cycling across Spatial and
Temporal Scales

Patrick J. Bohlen

Archbold Biological Station, Lake Placid, Florida, U.S.A.

Robert W. Parmelee

Yucca Valley, California, U.S.A.

John M. Blair

Division of Biology, Kansas State University, Manhattan, Kansas, U.S.A.

CONTENTS

Overview........................................................................................................................................162
Conceptual Models........................................................................................................................165
Mechanistic Models................................................................................................................165
Ecosystem Budget Models.....................................................................................................168
Future Experiments.................................................................................................................170
A Hierarchical Approach...............................................................................................................171
Individual Earthworms............................................................................................................171
Earthworm Populations...........................................................................................................173
Earthworm Communities........................................................................................................174
Earthworms in Ecosystems.....................................................................................................174
Earthworms in Landscapes.....................................................................................................175
Conclusions....................................................................................................................................176
Acknowledgments..........................................................................................................................176
References......................................................................................................................................176

There has been an exponential increase in research publications addressing the impact of earth-
worms on terrestrial nutrient cycling processes. This research has demonstrated that earthworms
significantly affect key soil properties and processes such as microbial biomass and activity,
organic matter dynamics, nutrient availability, plant uptake and production, and soil structure.
There is sufficient evidence to conclude that earthworms are central to regulating nutrient cycling
processes in many ecosystems. Earthworms may alter the balance between conservation and loss
of nutrients in ecosystems, and their net influence at large scales defines their role in ecosystem
processes. Many investigations have focused on small-scale phenomena, such as nutrient dynamics

161