Humans have a relatively negative impact on the savanna biome through desertification and tourism. However, the increased tourism has had some positive impacts, such as increased conservation efforts, according to the BBC.
Desertification means that the land is increasingly dry, losing much of its plant life and water. Humans speed this process by letting farm animals graze on the area, gathering wood for fires or building, removing vegetation and farming in an unsustainable way. These can be easily remedied by controlling how humans use the land and doing it in a sustainable way, such as moving animals to different areas before they cause damage through overgrazing.
Tourism increases human traffic through the area, which impacts the water cycle and environment. Accommodating tourists requires building roads and allowing vehicles on the savanna, leading to the erosion of vegetation and an increase in the removal of trees to make room for roads. Changing where water goes affects the plant and animal life, since water has to be diverted from natural sources to hydrate tourist sites, such as hotels.
The increased income from tourism does improve some aspects, most notably increased conservation funding. These conservation efforts help save animals and plants from being entirely overrun by tourism.