Are we underestimating the potential role of soil fauna in global sustainabiliy?
Soils are extremely rich in species, but our knowledge of the functional role of organisms inhabiting soils remains limited. Microbes are directly responsible for carrying out a multitude of essential soil processes, such as the decomposition of organic material and thus carbon and nutrient cycling, but the presence of larger soil fauna can greatly stimulate the rates at which these processes occur. Moreover, many groups of soil fauna (i.e. the earthworms and termites) are known to be ecosystem engineers that have substantial impacts on ecosystem properties and functioning. The loss of such species may lead to substantial changes in the provision of ecosystem services. Given ongoing global changes we are likely losing species of soil fauna before their ecological roles have been quantified. Yet, rarely are the consequences of belowground biodiversity losses given much attention. Consequently, a synthesis of the current literature was used to develop a conceptual framework that outlines what we know about the role soil fauna play in the provision of ecosystem services, and whether we are underestimating the role soil faunal communities could play in global sustainability.
It is evident that healthy soil faunal communities can promote a wide range of ecosystem services in both managed and natural ecosystems, but rarely are these explicitly incorporated into management practices, and there are no concerted efforts to preserved belowground biodiversity. For example, while the sustainable management of soils in agriculture and horticulture has become more fashionable, there is still plenty of room for improvement: the negative impacts of certain organisms belowground are well known but the benefits of soil fauna are still largely ignored in agricultural and horticultural settings. It may be difficult to attain functionally complex communities of soil fauna in high intensity/annual cropping systems, but there is great scope for increased sustainability of perennial cropping systems through better management of soil fauna communities. Similar effects could be reached in other managed ecosystems. In conclusion, evidence of the importance of soil fauna for global sustainability is growing rapidly and the role of these organisms should not be shorthanded. However, the synthesis presented here highlights that there is a need to further explore how soil fauna biodiversity can be used to promote, or restore, the provision of ecosystem services in both natural and managed ecosystems including agriculture and horticulture.