1. AB Davies 1, SR Levick 2, GP Asner 2, MP Robertson 1, BJ van Rensburg 1 & CL Parr 3 1 Centre for Invasion Biology, Department of Zoology and Entomology, University of Pretoria 2 Department of Global Ecology, Carnegie Institution, Stanford, USA 3 Department of Ecology, University of Liverpool, UK SR Levick

2. Highly variable environments WC Oosthuizen

3. Highly variable environments Spatial heterogeneity important – Ecological functioning – Biodiversity – Ecosystem resilience WC Oosthuizen

4. Induced by several factors – Fire – Climatic events (variable rainfall) – Herbivory

5. Create heterogeneity

6. Alter soil properties

7. Nutrient hotspots – Support richer, more nutritious vegetation – Focal feeding sites

8. Understanding their spatial patterns – Densities – Spatial patterning

9. Understanding their spatial patterns – Densities – Spatial patterning Enable better understanding of heterogeneity and savanna functioning

10. Carnegie Airborne Observatory (CAO) – Remote sensing system designed to study the 3D structure and function of ecosystems – Integration of light detection and ranging (LiDAR) and hyperspectral imagery

13. Map mound dynamics across space – Densities – Mound structure – Spatial patterning

14. Map mound dynamics across space – Densities – Mound structure – Spatial patterning Mapped mounds across an entire river catchment – the N’waswitshaka

15. 5 km

17. 60 m

20. 5 km

21. Decreasing clay content

22. Mounds are on crests – Where matrix vegetation is of poor quality WC Oosthuizen

23. Mounds are on crests – Where matrix vegetation is of poor quality – Evenly spaced on these crests WC Oosthuizen

24. Spatial distribution – High densities of large colonies in nutrient rich (dry) savanna WC Oosthuizen

25. Spatial distribution – High densities of large colonies in nutrient rich (dry) savanna – Associated with high levels of woody cover WC Oosthuizen

26. Spatial distribution – High densities of large colonies in nutrient rich (dry) savanna – Associated with high levels of woody cover Induce positive feedback loops – Maintaining nutrient rich savanna WC Oosthuizen

27.  DST/NRF Centre of Excellence for Invasion Biology  Carnegie Institution for Science  Andrew Mellon Foundation  South African National Parks