Baobab (Adansonia digitata) trees are iconic symbols of the arid lands of continental Africa, and aside from some populations in Southern Africa are largely dependent on fruit bats for pollination. However, the bats visit a diversity of plant species to meet their energetic and nutritional needs, so the pollination service they provide the baobabs may be influenced by the landscape context of individual trees. In collaboration with Dr Paul Webala, Macy Krishnamoorthy set out to determine the relative contribution of individual plant traits, namely tree height and girth, and landscape features and context (e.g., the distance of baobab trees to conspecifics, distances to resources that might attract or distract bats, land use) to baobab reproductive success. Very ably assisted by Mr Michael Bartonjo, she mapped more than 700 baobab trees in ~10 km2 area in Kenya, measured them, and derived a number of landscape variables for each tree. She counted the number of fruit per baobab as a measure of reproductive success.
So what did she find? Perhaps not surprisingly, larger trees were more likely to produce fruit and produce more fruit, but landscape variables also played a role, but in a complex and scale-dependent way. The importance of distance to and density of alternate food resources changed with scale, but generally, pawpaws tended to act as attractants whereas figs distracted bats from their role as pollinators.
You can read the full story here:
Krishnamoorthy, M.A., Webala, P.W. & Kingston, T. Baobab fruiting is driven by scale-dependent mediation of plant size and landscape features. Landsc Ecol (2022).
Fieldwork was fun but arduous and there are many people in Kenya to thank! A special thank you to Macy’s local host Daniel Ngei and his family, the local chief Joseph Kavui and all the landowners in the villages of Kaai, Kalesi, Kaluku South, Kandundu, Katithini, Kavui, Kawula, Kiwaani, Mutoleka, Ngieni East, Ngieni West and Yungamaduu who generously allowed us to sample baobabs or others fruiting trees on their lands. Funding for the project came from Bat Conservation Internationa, the Association of Biologists at Texas Tech University, and the Department of Biological Sciences at TTU.