Vegetation and fire history of Bwabwata National Park, Namibia

The relationships between woody vegetation cover and fire, climate, herbivory, and human activities in African savanna ecosystems are complex. Fire has been managed by humans for thousands of years, but post 1800, fire suppression was implemented in many areas. The impact of these policies are largely unknown, due to a lack of long-term records extending from before, during and after their implementation.Here, we present two similar to 1000-year pollen, dung fungal spore and charcoal records from a savanna ecosystem in Bwabwata National Park, in north-east Namibia, an area that had a fire suppression policy in place from 1888 to 2005. Proxies from both cores (Jackalberry and Mukolo) show similar trends. Both records show higher tree abundance during a wetter period early in the record. No evidence of fire suppression or enhanced tree recruitment is seen in the charcoal and pollen data from the period post 1888. The results imply that the policy of fire suppression was ineffective, and did not lead to noticeable decreases in fire and associated enhancement of tree recruitment. The results are consistent with the knowledge that fire is an integral component of this ecosystem, and that fire occurrence in savanna ecosystems is more closely linked to climate than management. Therefore, fire management should adapt to rainfall variability as well as integrating customs of early dry season burning that benefit both biodiversity and livelihoods. Our results show how long-term datasets can be used to assess the impacts of fire suppression and inform present-day management decisions.

Automated summary

The relationships between woody vegetation cover and fire, climate, herbivory, and human activities in African savanna ecosystems are complex. Fire suppression policies implemented in a national park in northeast Namibia from 1888 to 2005 did not lead to noticeable decreases in fire or enhanced tree recruitment, suggesting that fire occurrence in savanna ecosystems is more closely linked to climate than management. Fire management should adapt to rainfall variability and integrate customs of early dry season burning.