Details of Award
NERC Reference : NE/T004258/1
The African Savanna Cyclone Experiment (CyclEx)
Grant Award
- Principal Investigator:
- Dr CM Ryan, University of Edinburgh, Sch of Geosciences
- Grant held at:
- University of Edinburgh, Sch of Geosciences
- Science Area:
- Terrestrial
- Overall Classification:
- Panel C
- ENRIs:
- Biodiversity
- Global Change
- Science Topics:
- Terrestrial ecosystems
- Tropical ecosystems
- Vegetation change
- Ecosystem Scale Processes
- Ecosystem monitoring
- Environmental Informatics
- Synthetic aperture radar
- Technol. for Environ. Appl.
- Abstract:
- CyclEx will test the theory that savannas and dry forests are alternative stable states by examining the long term impacts of Cyclone Idai. The concept of ecosystems having alternative stable states is crucial to how we manage and predict the future of the biosphere. Savannas are the largest land cover in the tropics and support the livelihoods of 100s of millions of the world's poorest people. They also harbour an ancient, unique, charismatic flora and fauna - the "safari" landscape. However, the regions of the world where most savannas are found are widely considered to be bistable - that is they can support either savannas (a stable state with few trees that burns regularly and can support many grazing animals), or forests (another stable state with a closed tree canopy, high carbon storage, less grass and few fires). Many scientists believe that these two states can both exist given the same environmental conditions, and that for example dry forests may "flip" to become savannas due to shocks to the system, such as cyclones. These ideas are widely used to guide savanna management and to predict how savannas will respond to climate and other global change. However, whilst the concept of bistability in the dry tropics is easy to hypothesise, it is very hard to prove and has remained controversial. The evidence for it comes from mathematical models, and observations of static spatial patterns of tree cover and tree height, which show distinct "peaks" in their frequency distributions, which many have interpreted as the different stable states. Recent modelling work suggests however that these peaks are not reliable evidence of bistability - they are consistent with the idea, but other mechanisms associated with non-bistable ecosystems can generate these observations. Cyclone Idai provides a unique opportunity to test these theories. The cyclone is reported to have toppled or damaged large numbers of trees, in areas where theory suggests alternative stable states are likely. Our field site, Gorongosa National Park, was subjected to some of the highest windspeeds during the cyclone and provides an excellent place to carry out long term observations of the impacts and recovery. We believe that, if alternative stable states do exist, we are very likely to observe them here. CyclEx will first map the impact of the cyclone using radar remote sensing to examine the structure of the savannas and dry forest pre- and post-cyclone. We will then establish long term plots where we can understand how the vegetation recovers after the cyclone and see if areas where lots of trees were knocked over or damaged get "stuck" in a stable open savanna state, or if forest areas eventually recover their pre-cyclone structure and mix of species. This will tell us if switches between savanna and forests are possible, and whether the theory of alternative stable states is supported. The results of CyclEx are important both as a test of the key ecological theory of alternative stable states, and on a more practical level. Intense cyclones are predicted to become more common in East Africa due to climate change, and to affect a wider area than at present. We need to know what their impacts will be on an ecosystem that is important for biodiversity and for local livelihoods, and CyclEx will be the first ever analysis of the impacts of cyclones in African savannas.
- NERC Reference:
- NE/T004258/1
- Grant Stage:
- Completed
- Scheme:
- Standard Grant FEC
- Grant Status:
- Closed
- Programme:
- Urgent Grant
This grant award has a total value of £52,412
FDAB - Financial Details (Award breakdown by headings)
| DI - Other Costs | Indirect - Indirect Costs | DA - Investigators | DI - Staff | DA - Estate Costs | DA - Other Directly Allocated | DI - T&S |
|---|---|---|---|---|---|---|
| £3,968 | £15,024 | £1,316 | £15,797 | £7,101 | £497 | £8,710 |
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