Research Article: Range Analysis and Terrain Preference of Adult Southern White Rhinoceros (Ceratotherium simum) in a South African Private Game Reserve: Insights into Carrying Capacity and Future Management

Date Published: September 13, 2016

Publisher: Public Library of Science

Author(s): S. Thompson, T. Avent, L. S. Doughty, Mathew S. Crowther.

http://doi.org/10.1371/journal.pone.0161724

Abstract

The Southern white rhinoceros (Ceratotherium simum) is a threatened species, central to the tourism appeal of private game reserves in South Africa. Privately owned reserves in South Africa tend to be smaller than government run reserves such as Kruger National Park. Because of their relatively small size and the often heterogeneous nature of the landscape private game reserve managers benefit from detailed knowledge of white rhinoceros terrain selection preferences, which can be assessed from their ranging behaviours. We collected adult and sub-adult white rhinoceros distribution data over a 15 month period, calculating individual range size using kernel density estimation analysis within a GIS. From this, terrain selectivity was calculated using 50% and 95% kernels to extract terrain composition values. Jacob’s correction of the Ivlev’s selectivity index was subsequently applied to the terrain composition of each individual to identify trends in selectivity. Results reveal that adult males hold exclusive territories considerably smaller than those found in previous work conducted in “open” or large reserves. Similarly, results for the size of male versus female territories were also not in keeping with those from previous field studies, with males, rather than females, having the larger territory requirement. Terrain selection for both genders and age classes (adult and sub-adult) showed a strong preference for open grassland and avoidance of hill slope and riparian terrains. This research reveals white rhinoceros terrain selection preferences and how they influence range requirements in small, closed reserves. We conclude that this knowledge will be valuable in future white rhinoceros conservation management in small private game reserves, particularly in decisions surrounding removal of surplus individuals or augmentation of existing populations, calculation of reserve carrying capacity and future private reserve acquisition.

Partial Text

Private game reserves in South Africa are becoming increasingly integral to the maintenance and enhancement of its biodiversity. These reserves are fenced (closed) and often small in comparison to those managed by the State Authority (South Africa National Parks). Among the largest state run reserves are the Kruger National Park and the Kgalagadi Transfrontier National Park which cover 19,485 km2 9,591 km2 respectively [1], while 123km2 is stated by Sims-Castley et al., [2] as the average size for private game reserves in the Eastern Cape. As such small private games reserves require intensive land and livestock management, to both maximize their “game” carrying capacity for wildlife tourism purposes, and to minimise problems linked to over-grazing, poor nutrient status and imbalance between predator and prey numbers [3].

The primary objective of this research was to explore the relationship, both between and within, gender of adult and sub-adult white rhinoceros in a small contained (fenced) game reserve, in terms of range analysis and terrain preference. This we considered important as small private game reserves are increasingly becoming the stronghold of white rhinoceros distribution, as they are estimated to hold up to 25% of rhinoceros in South Africa [41], given the considerable poaching pressures experienced in the larger, open game reserves. Recent data [42] on poaching of rhinoceros supports this assertion, indicating that 1,215 rhinoceros are known to have been poached in 2014 and 1,175 in 2015 in South Africa alone, with the majority of these incidents taking place in the larger reserves [4]. In response, wildlife managers are taking steps to translocate individuals from poaching hotspots such as Kruger National Park to smaller private game reserves in to order fo better ensure their protection [43].

 

Source:

http://doi.org/10.1371/journal.pone.0161724