PATTERNS OF RIVER VISITATION BY LARGE HERBIVORES IN RELATION TO RAINFALL AND SEASON: Makgadikgadi Pans National Park

Abstract

Climate change poses a major threat to African ecosystems. Climate change will affect southern Africa by changing rainfall patterns, reducing the amount of annual rainfall, and making droughts more frequent and intense. Therefore, knowledge about how the behaviour of different species is linked to rainfall and season is important for conservation. This study investigates patterns of river visitations by large herbivores in relation to rainfall and season. This was done using approximately three years of data from camera traps that were set up along eight different elephant highways near the Boteti River in Makgadikgadi Pans National Park in Botswana. The herbivores included in the study were african savannah elephant (Loxodonta africana), south african giraffe (Giraffa camelopardalis giraffa), greater kudu (Tragelaphus strepsiceros), and impala (Aepyceros melampus). Data was analysed using generalized additive models (GAMs), controlling for day of year and moving average of rain. Two moving averages of rain were used, one 2-day moving average to investigate the effect of the rain itself on river visitations and one 30-day moving average to investigate the effect of more long-term rainfall. Results showed that river visitations by the herbivores were associated with day of year. Giraffe and kudu had quite clear seasonal patterns with more visits during the dry season and fewer visits during the wet season. Results also showed that river visitations by the herbivores were associated with rainfall. River visits from elephants and giraffes had a negative association with rainfall and decreased with increased rainfall. River visits by greater kudu showed no association with 2-day moving average of rain, but a strong positive association with 30-day moving average. Impala showed a positive association with rainfall, and visits increased with increased rainfall. However, further studies need to be done to investigate exactly how and why patterns of river visitations by large herbivores shows association with both day of year and rainfall.