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

Highly variable environments WC Oosthuizen

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

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

Create heterogeneity

Alter soil properties

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

Understanding their spatial patterns – Densities – Spatial patterning

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

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

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

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

5 km

60 m

5 km

Decreasing clay content

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

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

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

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

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

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