Using elephants’ speed of travel to assess poaching levels

Ihwagi, F. W., Thouless, C., Wang, T., Skidmore, A. K., Omondi, P., & Douglas-Hamilton, I. (2018). Night-day speed ratio of elephants as indicator of poaching levels. Ecological indicators, 84, 38-44.

This study investigated the utility of data on African elephants’ speed of travel during the day and night as an indicator of poaching activity

Elephants continue to be at risk of poaching to the extent that their survival in the wild remains under serious threat.  Prior research has indicated that one of the ways elephants respond to perceived human threat in their environment is by altering their speed of travel. Elephants avoid potential human conflict and predation during daytime and increase the speed of movement through potentially dangerous areas, and do the same at night.  The aim of this study was to investigate the utility of data on a night/day ratio of elephants’ speed of travel as an indicator of poaching activity. 

Data were collected over ten years (from 2002 to 2012) from 28 female and 32 male elephants for 72 and 118 months respectively in the Laikipia-Samburu area of Kenya. This area is estimated to accommodate approximately 6000 African elephants during the study period.  One elephant per family unit was tracked with GPS collars transmitting their location every hour.  Data from a severe drought period in 2009 and areas within 2.5km of roads and fences were excluded due to confounding behavioural effects.  Data on elephant mortality was also collected in conjunction with other stakeholders working on the ground, including cause of death when determinable.  A poaching surge occurred between 2010-2012, therefore subjects’ speed of travel before and during this period were compared in the analyses. 

Elephants adapted to increased poaching by travelling significantly more at night than during the day. 

Results indicated that when poaching levels were high, elephants of both sexes moved significantly more during the night than during the day.  This was observed to a greater extent in females than males, although the potential reasons for this were not discussed.  It was not feasible to include a ‘non-poaching’ baseline period or control group due to the extent of poaching throughout the study period and ecosystem. However, data from one area with declining poaching levels showed a night/day speed ratio proportionately lower than all other areas where poaching levels were increasing. The study findings confirm observational evidence that elephants in low risk areas of poaching demonstrate greater activity during the day than at night. 

Due to the severe risks to wild elephant populations, cost-effective methods to monitor poaching activities are important to support efforts to conserve the species.  The authors suggest that when GPS data is available, there are benefits in utilising these to complement and inform existing resource-intensive ground-based anti-poaching and monitoring strategies, on account of offering near real-time information and facilitating remote monitoring.

 

World Animal Protection’s view

The plight of African elephants remains a significant concern for World Animal Protection, as rates of illegal killing continue to outstrip birth rates, leading to declining in wildlife populations.  We welcome new and non-invasive methodologies to assess poaching activity, with the aim of informing anti-poaching strategy.