Paper No. 15-9
Presentation Time: 11:40 AM
ZOOGEOMORPHIC IMPACT OF AFRICAN ELEPHANTS IN HWANGE NATIONAL PARK, ZIMBABWE: INSIGHTS FROM SATELLITE-BASED ANALYSIS
Large mobile terrestrial animals produce massive impact on landforms, sediments, and vegetation, often initiating and maintaining smaller-scale geomorphic cascades. This study focused on satellite image-aided (GoogleEarth ProTM) analysis of locomotion traces and geomorphic impact of African bush elephant (Loxodonta africana) in Hwange National Park, Zimbabwe. Morphometric assessment included temporally persistent trails, tramplegrounds, and waterholes produced by super-herds, where the number of individuals can exceed 300. Major trails radiated from larger waterholes and ranged in length from 2.03-9.69 km. For the waterholes (n=26), the average area was 308 m2, with surrounding trampled zones typically 6-7 times greater in extent. Calculations based on a published set of metrics show that a herd of 250 elephants can affect (compact/remove) >0.18 km3 of sediment per year, which is consistent with 0.3-1.7 km3 values estimated from long-term zoogeomorphic features. A normalized difference vegetation index (NDVI) was used to assess the overall impact on local vegetation over a 30-year period. Our study demonstrates the utility of spatial analysis for identification, mapping, and quantification of the impact of large mammals on vegetation and landforms.