Illegal exploitation of black rhinoceros and elephant populations : patterns of decline, law enforcement and patrol effort in Luangwa Valley, Zambia

(1) At the start of the 1980s, conservationists in Africa gave a high priority to protecting the largest remaining populations of black rhinos and elephants from illegal exploitation. This study documents the demise of both species in the Luangwa Valley, Zambia. (2) Sightings and captures by law enforcement patrols were used to monitor (i) changes in rhino and elephant numbers during 1947-69 and 1979-85; (ii) their motivation and success at capturing offenders involved in illegal activity during 1979-85; and (iii) the distribution of illegal activity in relation to patrol effort and the abundance of rhinos and elephants during 1979-85. Sightings were analysed with log-linear models and population trends for elephants and rhinos so derived compared favourably with accurate methods of counting both species. (3) Elephants increased at an instantaneous annual rate of +0 06 from 1947 to 1969, causing the 'elephant problem' of the 1960s and 1970s. Sightings of rhinos and elephants were negatively correlated in different areas of Luangwa Valley during this period. (4) The overall rates of decline of rhinos and elephants were-0 63 and -0 12 during 1979-85, following rapid increases in the price of rhino horn and ivory on world markets. These declines arose from illegal activity as most skulls had their trophies removed. (5) Sightings of rhinos and elephants changed at different rates in each area of Luangwa Valley. Rhinos declined in all areas at rates ranging from -0 99 to -0 24, but elephants increased in some areas due to local immigration. By 1985 there was a positive correlation between sighting rates of rhinos and elephants. (6) Despite these large declines in rhino and elephant numbers, law enforcement units were motivated and successful at capturing offenders involved in illegal activity in Luangwa Valley during 1979-85. (7) Most staff in law enforcement units spent about half each month patrolling on foot under remote and difficult conditions. Offenders caught on foot patrols provided information for making arrests more successfully on vehicle patrols. Arrests were made cost-effectively and about 40% of operating costs were recovered from found and seized ivory. (8) Offenders involved in less serious illegal activity originated from most areas of Luangwa Valley. In contrast, well-organized armed gangs exploited rhinos and elephants and originated from areas outside Luangwa Valley. Offenders who exploited rhinos and elephants were delivered sentences that did not uphold wildlife laws. (9) Signs of illegal activity, such as poachers, their camps and fresh carcasses, were encountered throughout the year. Encounters of illegal activity generally showed consistent trends across years within different areas, but most trends in illegal activity were complex rather than exponential across time. (10) Increased patrol effort affected levels of illegal activity. Poachers and camps tended to be seen less often in more heavily patrolled areas even though these held a relative abundance of quarry. Finds of fresh carcasses declined with rhino and elephant numbers, but also were found less frequently in areas of heavier patrol effort. (11) Differences in patrol effort were related directly to rates of change in rhino and elephant abundance, and were sufficient to create areas of relative safety which