Fire history and management as determinant of patch selection by foraging herbivores in western Serengeti, Tanzania

摘要

Although the use of fire as a management tool has increased during the past decades in East African savannas, there is insufficient knowledge about herbivores' utilization of areas with different fire history. We therefore examined large mammal herbivores' preference for patches that differed in fire history to test whether herbivores would non-randomly select patches according to availability. Our study area was the East African Serengeti ecosystem. Animals were recorded along transects at monthly intervals from May 2001 to April 2006, and data on the burnt and non-burnt areas along transects were extracted from existing fire maps. The prediction was tested using chi-square goodness-of-fit test, and selection ratio as a preference index for patch types. Our results show that African buffalo persistently occurred in non-burnt patches, whereas browsers (Giraffe and Kirk's dik-dik) and mixed feeders (Grant's gazelle and impala) were often seen in non-burnt patches but also used burnt patches. Grazer species (Thompson's gazelle, topi, wildebeest and Burchell's zebra) favoured patches burnt in the current year compared to non-burnt patches. For all species together, patches burnt repeatedly were least selected compared to those that were burnt only once in 3 years. The outcome of this study suggests that annual burning of the same patches is not optimal for biodiversity maintenance and ecosystem functioning.