WCS has been supporting the training of Uganda Wildlife Authority (UWA) staff to undertake ground surveys of elephants and other large mammals in forests in Uganda as well as aerial surveys of savannas. We have supported the development of an aerial survey training manual (see publications) to improve surveys by UWA and ICCN in DRC.
In 2006 we radio-collared eight elephants in the Greater Virunga Landscape to assess their movements between the various protected areas in the landscape, particularly between Queen Elizabeth Park and Virunga Park. The results showed that the elephants knew where the international boundary was and spent most of their time in Uganda, only venturing for short distances over the border into Virunga Park where armed groups regularly shoot elephants for meat and ivory. Aerial surveys of the elephants in the savannas of the Greater Virunga Landscape show that most of the population (about 2500-3000 animals) resides in Uganda with only about 300-400 in Virunga Park. Elephant numbers declined from about 3000 in Queen Elizabeth Park in the 1960s to 150 in 1980 and have since increased back to 2500-3000. This could not have occurred by birth alone and is mostly due to transboundary movements of elephants between Virunga Park and Queen Elizabeth Park. In the 1970s it is likely elephants fled to DRC and more recently they have fled to Uganda. As a result numbers have remained more stable than in areas which were totally enclosed within Uganda such as Murchison Falls National park, where elephant numbers dropped from 14,000 to only 250 individuals during the 1970s and early 1980s.
The large changes in elephant numbers has led to changes in the vegetation of the savannas in the Greater Virunga Landscape. Because vegetation takes time to grow back after elephants have been at high density there is a lag time in the response to changes in elephant numbers. WCS made a study to compare species of plant in Queen Elizabeth Park that were measured in plots established in 1990 and subsequently re-measured in 2010. These showed that in areas where elephant density was high acacia gerradii increased in cover but that most other plant species did not show any relationship with elephants. This implies that elephants are fairly unselective in their impacts and while removing woody cover for the most part when at high density they don’t affect understorey plants in any consistent way. However hippos had a much greater impact on the vegetation around water bodies and specific plant species are affected by them. We have also compared aerial photos from the 1950s and 2006 and shown that the reduction of elephants has led to a general increase in woody cover in the park, but they don't seem to determine which species come back.
We are supporting coordinated patrols along the international border as well as antipoaching efforts within Virunga Park to reduce the killing of this species. We also are continuing to support monitoring of elephants in the Greater Virunga Landscape.