Belowground experimental approaches for exploring aboveground-belowground patterns

Abstract

Experiments involving aboveground and belowground components are now commonplace in community ecology but they remain challenging compared to those that focus solely on either component. Challenges are manifold but mainly stem from the difficulty in observing and manipulating belowground components. Overcoming these challenges relies, in part, on techniques and approaches used by soil scientists whose interest in the aboveground compartment was traditionally confined to plant growth and health. This is even illustrated in the title of the excellent Soil Conditions and Plant Growth edited by Gregory and Nortcliff (2013) which is the twelfth incarnation of Soil Conditions and Plant Growth, first published in 1912 (Russell 1912). Contributors to these volumes rarely considered plant-mediated interactions between organisms beyond those interactions between microbial communities. Similarly, community ecologists were either largely unaware of techniques used in soil science or unclear of how they could be incorporated experimentally. With growing emphasis on multidisciplinary research, these barriers have broken down and researchers have incorporated techniques from different disciplines when designing and executing experiments.

In this chapter, we consider a range of experimental approaches which have helped characterise the belowground component of aboveground–belowground interactions. These experimental approaches have helped advance the field of aboveground–belowground community ecology. The enormous diversity of interactions between microbes, plants and animals described in the 15 chapters in this volume prevents us from covering all experimental approaches. Instead, we focus on particular experimental approaches that may allow researchers to better characterise and manipulate belowground components of their experiments. Facilitating this aspect, in particular, should enable researchers to answer key questions in aboveground–belowground community ecology. We provide examples of each experimental approach which we readily acknowledge focus on study systems familiar to the authors (e.g. root herbivores) rather than comprehensive coverage of all groups that comprise soil communities. Nonetheless, many of the approaches we discuss are applicable to organisms we don't specifically mention and we encourage readers to keep this in mind.