Recent surveys for hippos in Virunga National Park -- the oldest protected area in Africa -- have found that the beleaguered behemoths are finally recovering from decades of poaching and habitat loss in the eastern Democratic Republic of Congo, according to researchers from the Institut Congolais pour la Conservation de la Nature (ICCN) and WCS (Wildlife Conservation Society) who conducted the research.
The published research titled "Conservation of the common hippopotamus in Virunga National Park, eastern Democratic Republic of Congo" appears in the most recent addition of Suiform Soundings, a newsletter published by the IUCN's Pigs, Peccaries, and Hippos Specialist Group. The authors of the study are: Deo Kujirakwinja, P. Shamavu, Andrew Plumptre, and E. Muhindo of WCS; and J.D. Wathaut and E. de Merode of the ICCN (Institut Congolais pour la Conservation de la Nature).
"The hippo is one of Africa's iconic species, one that is becoming increasingly threatened by hunting and other factors," said WCS Scientist Deo Kujirakwinja, the lead author of the paper. "Our findings that hippos are on the increase is encouraging and evidence that efforts to protect hippos and other species are working. "
The researchers estimate that the current population of hippos in the park represents only 11 percent of the original population and only 8.2 percent of the peak population estimate of about 30,000 individuals made in the 1970s.
The increase in hippos is likely the result of increased enforcement in Virunga National Park's portion of Lake Edward and nearby river systems and collaboration between fishermen and park authorities in both the Democratic Republic of Congo and Uganda.
Virunga National Park used to contain Africa's largest known hippo population in the 1970s, with especially large groups found in both the Rwindi and Rutshuru rivers. Later surveys revealed a steep decrease in hippo numbers as a result of hunting, human development and agriculture, as is the case with declines in other large mammals in the eastern Democratic Republic of Congo. "This recent surveys have shown that the Ishasha River on the border with Uganda is now very important for their conservation and shows that transboundary conservation efforts are succeeding there," stated Andrew Plumptre, WCS senior scientist and co-author of the report.
Scientists noted that, while past surveys have relied partly on aerial surveys, more recent efforts entailed more ground surveys than before (plane-based counts were avoided in many areas due to the presence of militias in many survey areas). The ground counts resulted in more hippos being recorded and improved population estimates, in part because aerial surveys often miss submerged animals in lakes and rivers.
Growing up to 13 feet in length and weighing up to 4,400 pounds, the common hippo is one of the largest mammals in Africa. It often congregates in pools, rivers, and lakes and can stay submerged for up to six minutes. They are herbivorous animals and feed almost exclusively at night. The common hippo is listed as "Vulnerable" on the IUCN's Red List.