Poaching’s Threat To Rhino Populations

Rhino poaching is a significant wildlife conservation threat that needs to be addressed through scientific, political, and policing measures. In Kruger National Park, southern white and south-eastern black rhino populations are in danger of significant declines as a result of poaching. With that being said, data to estimate population growth rates has been needed, so that the severity of the issue can be determined. In this study, southern white and south-eastern black rhino population declines were estimated in combination with rhino poaching trends from 2008 through 2013.

In order to determine the extent to which decreases in rhino populations could be explained by increases in poaching behaviors, several data sources were required. Data were collected through observation to estimate rhino birth and death rates, while poaching rates were based on identified rhino carcasses, as well as density and rainfall. These data points were used to estimate rhino populations, so that changes in rhino growth rates over time could be estimated and projected into the future.  

Data for generating these estimations were obtained from aerial surveys with two observers and one note recorder, using statistical population estimation methods that are known to minimize estimation bias.  Poaching rates were determined based on carcass detection with the use of field ranger patrols and aerial patrols. For the field ranger patrols, 22 Sections of Kruger National Park were scanned by 18-25 rangers per section. Aerial patrols included two helicopter pilots in Skukuza and two micro-light aircraft pilots located in the southern and northern region of Kruger National Park.  

Once all of the required data were collected, statistical analyses were conducted to determine the extent to which rates changed over time as well as to predict future trends from 2013 through 2018. Based on the predicted results, 0.06 black rhinos per day and 2.69 white rhinos per day would be killed by poachers. When comparing those predictions to what has actually been observed and reported since the predictions were made in 2013, the poaching rates were found to be lower than what was predicted for both white and black rhinos. The results of this study also shed light on additional factors that impacted mortality rates for white rhinos specifically. For example, female mortality rates increased with population size, while male mortality rates decreased with rainfall.

While poaching rates were not found to be as high as predicted for 2014 and 2015, poaching remains a significant threat to black and white rhino survival. For example, the estimated white rhino annual growth rates from 1998 to 2008 were high while more recent growth rate estimates indicate that white rhinos may be growing at a slower rate. Furthermore, the significant decline in white rhino growth rates is assumed to be a consequence of substantial increases in illegal poaching since 2009. Intentional and strategic measures will need to be taken in order to reduce the threat of poaching on Africa’s rhino survival.