The foremost reason for monitoring is to “audit” rhino populations and to check that none of their members, being valuable biological assets, are missing because of illegal offtakes or other demographic impacts. The knowledge that a rhino population is being kept under close demographic surveillance, so that any poaching will be detected, serves to deter would-be poachers including corrupt elements within that area’s protection/management force. The need to be able to undertake “auditing” fully justifies the costs and (relatively small) risks of immobilizing rhinos in order to cut ear notches as identification features.
A second major reason for rhino monitoring is because the adaptive management that is required to maximize metapopulation growth rates for rhinos is not possible without reasonably accurate annual population estimates, measures of demographic performance, and information on mortality patterns, behaviour and translocations.
The sharing and synthesis of this information at a national and regional level (for example, the routine annual black rhino status reporting and periodic analysis of data within the SADC RMG) serves to provide:
- measures of progress towards meeting metapopulation goals (in the form of underlying metapopulation growth rates, and the consequent estimates of how long it will take to reach target metapopulation sizes);
- estimates of population sizes and densities which can be used to derive recommended offtake levels (either using set-percentage harvesting or by keeping numbers at or below 75% of estimated ECC);
- data on the comparative performance of the different populations in a metapopulation, which encourages each park manager to put that park’s rhino population performance into context, and to consider how that population can help contribute to attain metapopulation goals;
- additional insights into factors affecting rhino population performance;
- an effective way to share lessons learned from both experience in the field and the results of research;
a consolidated record of movements of rhinos within and in and out of a metapopulation.
Raoul du Toit
from the "Guidelines for implementing SADC rhino conservation strategies," published by the SADC Regional Program for Rhino Conservation