Use this URL to cite or link to this record in EThOS:
Title: Fire and herbivory in the Serengeti-Mara
Author: Probert, J. R.
ISNI:       0000 0004 7970 363X
Awarding Body: University of Liverpool
Current Institution: University of Liverpool
Date of Award: 2018
Availability of Full Text:
Access from EThOS:
Access from Institution:
Savannahs are consumer controlled systems where fire and herbivory maintain plant biomass below the level that is predicted by rainfall and temperature. Savannahs are globally important biomes, covering around 20% of our planet's terrestrial surface and providing economic and cultural value, carbon sequestration, ecosystem services, and habitat for many unique species. Whilst both fire and herbivory consume plant biomass they vary in their mechanism, timing, geographic extent, frequency, and selectivity. Studying fire, herbivory and their effects can be challenging because both are multifaceted phenomena. They also interact and capable of both facilitating and inhibiting one another. However, understanding the patterns in fire and herbivory and the differences in how flora and fauna respond is vital to the successful management of savannah systems. Here we use both satellite data and field experiments to quantify the fire regime of the Serengeti-Mara ecosystem of southern Kenya and northern Tanzania and compare the effects of fire and herbivory on the ecology of the system. We describe the spatiotemporal patterns in the components of the Serengeti-Mara's fire regime and show that rainfall is the primary driver of the variability we observe. We also observe a striking decline in the area burnt and the number of fires and attribute this to increasing livestock density. We use the high intensity and short duration of grazing by the wildebeest migration as an analogue to fire and compare the effects of the two disturbances on vegetation, resident mammalian herbivores, and invertebrates. We show that there are similar effects on grass structure but only fire increased grass quality and there were contrasting effects on forb communities. These differences in vegetation cascade to affect the distribution of resident mammalian herbivores. Long grass areas attracted bulk grazers such as zebra and buffalo whilst short grass areas were attractive to selective grazers such as wildebeest and Thompson's gazelle. Not all of the species that were more abundant in short grass areas were attracted to high quality grazing, indicating that some species may select short grass areas for anti-predator rather than resource benefits. Finally, we show that fire and herbivory have contrasting direct and indirect effects on invertebrates, with responses varying based on taxa and ecological niche. Our results have important implications for the management of the Serengeti-Mara and our understanding of savannahs.
Supervisor: Parr, Kate ; Beale, Colin Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral