Events

PhD Defence Festus Ihwagi

Living in a risky landscape: Elephant movement in response to poaching. 

Festus Ihwagi is a PhD student in the Natural Resources (NRS) department, his supervisor is prof.dr. A.K. Skidmore fromt the faculty ITC. 

The illegal killing of elephants, i.e. poaching and human-elephant related mortality, is the greatest immediate threats to elephants. They have led to declining of many populations of elephants in Africa. The Monitoring of Illegal Killing of Elephants (MIKE) program of the Convention on International Trade in Endangered Species (CITES) was set up in the year 2002 as a framework of monitoring trends in illegal killing in 57 African sites. MIKE program seeks to establish the relationships between the levels of illegal killing of elephants and various possible explanatory variables within and beyond the monitoring sites. The effort in implementing MIKE program vary from site to site, and to make the results comparable; a metric referred to as the Proportion of Illegally Killed Elephants (PIKE) out of all recorded deaths in a site has been adopted as the standard measure of severity of illegal killing.

Loss of habitat due to the expansion of agriculture and infrastructural developments are the largest long-term threats to elephants. The migratory corridors of elephants and other wildlife in many landscapes have been cut off.  The majority of wildlife resides outside formally protected areas on  private and community lands. In the landscapes shared by wildlife and humans, competition for resources influences the spatial-temporal distributions of wildlife. Efforts to win the goodwill of private and community landowners regarding hosting of wildlife on their lands are ongoing in many sites across the elephant range. Despite the numerous studies on the nature of risk faced by elephants, fewer studies have focused on the behavioural adaptations of elephants living in those risky landscapes.

This thesis sought to understand the site level drivers of illegal killing and how elephants adapt to the threat in Africa’s most intensively monitored site, the Laikipia-Samburu MIKE in northern Kenya. Using field verified records of causes of elephant mortality, the distribution of live elephants, and, the cadastral attributes of land parcels in the ecosystem, the thesis established that land use type is the most important correlate of levels of illegal killing and not its ownership. The study analyses the movement of elephants at hourly, day and night, and overall 24 hr activity cycle in relation to the spatial and temporal variation of the levels of illegal killing. Past studies have given a lot of attention to movement behaviour along corridors. The research in this thesis focusses on movement within core areas. At the hourly time interval, the research showed that elephants walk with lower tortuosity when they are in core areas with higher levels of illegal killing, i.e., higher risk. The study found that elephants move more at night when they are in core areas with higher risk, than when they are in safer core areas. Based on this finding, the research presents a new metric for inferring the levels of risk, i.e., night-day sped ratio. When elephants move from a core area to another one with a different level of risk, they alter their daily activity pattern to include a longer resting phase during the mid-day hours, and this is even more pronounced in core areas closest to permanent human settlements. The study found that as a result of the alteration of activity cycle within 24-hour periods, elephants loose approximately one hour of activity time.

The results have the potential use as a remote means of assessing the spatial and temporal variation of risk by analysing elephant movement behaviour remotely thus complimenting patrol based anti-poaching efforts. The study provides new insight into the ecology of elephants living in fear. The confirmed increase of night-time movement potentially predisposes calves to the savannah predators, who are more active at night.