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Soil Health
The Issue
Soil macroinvertebrates (eg termites, earthworms) recycle nutrients and carbon in soils, and their activities increase soil porosity critical to the infiltration of water. These processes are vital to sustaining production and biodiversity in tropical savannas. Grazing by cattle and fire can significantly alter macroinvertebrate activity and consequently change landscape processes and therefore the health of the environment. Understanding the effect of land management on the relationship between soil macroinvertebrates and landscape processes will help develop ways to improve the resilience of healthy systems and hasten the recovery of degraded systems.
CSIRO Research
Our research addresses the following key questions:- How does land condition affect the functional role of macroinvertebrates in forming soil pores and improving water infiltration?
- How does grazing intensity affect soil function through changes in the diversity, activity and functional roles of macroinvertebrates in savannas?
- Can macroinvertebrate activity be manipulated to hasten the recovery of soil function in degraded landscapes?
- How does fire frequency and seasonal timing affect the activity, diversity and functional role of key soil macroinvertebrates and what are the consequences for soil health?
Preliminary results suggest that- in poor land condition sites or under intensive grazing, overall macroinvertebrate diversity and abundance is reduced and water infiltration rates decline;
- particular suites of termite species are able tolerate poor condition sites;
- mulching of degraded sites increases invertebrate activity and diversity, which leads to the creation of macropores in soils, increased water infiltration and increased litter decomposition rates.
The consequences of these changes for soil processes and landscape health are being investigated.
| International Collaboration |
Termites and other soil macroinvertebrates play a major role in key soil processes and are known to respond negatively to disturbances (e.g. grazing) worldwide. Soil macrofauna are therefore potential indicators of landscape health, but only if the structure of macrofaunal assemblages can be reliably assessed. In collaboration with researchers from the Natural History Museum, London, we are testing the application of an international macroinverterbrate sampling protocol developed for tropical forests, to the savanna ecosystems of northern Australia.
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Collaborators
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