Evaluation of low‐cost consumer‐grade UAVs for conducting comprehensive high‐frequency population censuses of hippopotamus populations

Abstract

AbstractThe hippopotamus Hippopotamus amphibious (hereafter referred to as hippo) is classified as vulnerable according to the IUCN Red data list. They play a significant role in aquatic systems as allochthonous nutrient providers, and as facilitators and competitors in grasslands. Traditional census methodologies for hippo are difficult and costly to repeat. Previous research has been conducted on the use of unmanned aerial systems (UASs) to conduct hippo population estimates; however, findings either needed justification through additional field testing or used high‐cost UASs that may be unaffordable for management authorities in developing countries in Africa. Therefore, using a low‐cost, consumer‐grade, DJI Phantom 3 Advanced multi‐rotor unmanned aerial vehicle (UAV), 47 surveys were conducted of the hippo population at Ndumo Game Reserve (NGR), South Africa, between August 2016 and July 2017. In addition, comparisons were drawn between the results of and the logistical requirements and costs of the respective helicopter and UAV surveys conducted on the same day of the same hippo population. The use of a consumer‐grade UAV permitted frequent, accurate, and comparatively low‐cost surveys to identify temporal changes in the number of hippos present in NGR and at different locations within NGR. Hippos are a data deficient species, particularly in remote developing countries. UAVs surveys of hippo will allow accurate, highly repeatable, and comparatively low‐cost data collection for management of hippos and the ecosystems within which they occur.