Diet of the common warthog (Phacochoerus africanus) on former cattle grounds in a Tanzanian savanna
Publication Type: |
Journal Article |
Year of Publication: |
2006 |
Authors: |
Anna C. Treydte, Stefano M. Bernasconi, Michael Kreuzer, Peter J. Edwards |
Publication/Journal: |
Journal of Mammalogy |
Keywords: |
african savanna, isotopic analyses, livestock, medium-sized grazer, nitrogen, phosphorus |
Abstract:
In otherwise nutrient-poor savannas, fertile vegetation patches are particularly attractive to ungulates because of the higher-quality food they provide. We investigated forage plants and diet of the common warthog (Phacochoerus africanus) on an abandoned cattle ranch in coastal Tanzania. The forage grasses of highest nutritional quality occurred in former paddock enclosures (bomas) where cattle had been herded at night. In the dry season, grass samples from bomas contained approximately 4 times as much nitrogen and phosphorus as those of the surrounding vegetation. δ15N values of soil and plants also were highest in bomas and decreased significantly with distance, and high δ15N values in feces suggest that warthogs preferentially fed in the vicinity of the former bomas. $delta^{13}N$ values of warthog feces indicate that warthogs ingested on average 83% (77-98%) C4 grasses, with this proportion varying regionally but not seasonally. We conclude that, for medium-sized selective grazers such as warthogs, bomas represent attractive feeding grounds. We also hypothesize that by promoting nutrient turnover in these patchily distributed areas, grazing animals help to maintain them as sources of high-quality forage.