#04 2022

Friend or foe? New Ndlovu Node postdoc investigates the ecological benefits of parasitic mistletoes

By Dr Tsitsi S. Maponga, Postdoctoral Researcher, NRF-SAEON Ndlovu Node

Dr Tsitsi Maponga is a new NRF-funded postdoctoral researcher at the Ndlovu Node (Fig. 1). She has a PhD in Plant Ecology (2021) from the University of the Witwatersrand under the supervision of Professor Ed Witkowski and Professor Hilton Ndagurwa. During her PhD studies, she was also the full-time curator of mammals at the Natural History Museum of Zimbabwe. 

For her earlier studies (Fig. 2), Tsitsi attained her MSc in Sustainability (Environment and Development) at the University of Leeds in the UK, funded by the Canon Collins Trust. She previously obtained her BSc (Hons) in Forest Resources and Wildlife Management from the National University of Science and Technology (NUST) in Zimbabwe and completed an internship under Professor Herve Fritz at Hwange National Park through the Centre of Scientific Research.  

Tsitsi’s postdoctoral research at the Ndlovu Node is an extension of her PhD study, which showed that mistletoes – parasitic plants which obtain all or part of their nutrition from a plant host – are keystone species that increase understory plant and environmental heterogeneity in the semi-arid savannas of Zimbabwe (Fig. 3). Her current project has shifted in focus and locality and aims to investigate mistletoe effects on the physio-morphological structures (functional traits, nutrient composition and regeneration capacity) of their hosts and to analyse the spatial patterns of mistletoe-infected trees across a human-impact gradient in Bushbuckridge in the South African lowveld.

Furthermore, her study will investigate whether the socio-economic value of mistletoes (such as woodroses) has changed over time. No local studies have investigated the impacts of mistletoe parasitism on host plant ecophysiology (water and nutrient balance, leaf traits, etc.). Yet, like termite mounds which offer critical nutrient-enriched soils and diverse plant communities in savannas, Tsitsi’s earlier work showed that mistletoes can also positively impact the heterogeneity of substrates and plant communities around host trees.

The new focus on the hosts rather than the mistletoes themselves is because large trees are important sources of food and shelter for many domestic and wild animals, and they provide both timber and non-timber forest products (NTFPs) to communities living around these savannas. Moreover, woodrose-forming mistletoes are in themselves NTFPs that can be traded (Fig 4).

Overly high mistletoe densities may kill the host and jeopardise the economic and ecological enrichment benefit. Paradoxically, the excessive removal of mistletoes, for NFTP for example, may reduce positive ecological benefits. Thus, management of mistletoe densities can and should be balanced to maximise both ecological and economic benefits.

“I am mainly interested in understanding savanna ecosystems and how we can sustainably use their ecosystem services,” Tsitsi explains. “This has been one of my passions for several years. Therefore, working with NRF-SAEON, particularly with my mentor Dr Dave Thompson who is involved in many other savanna landscape projects, is a major boost for my career.

“Moreover, my project has a multidisciplinary design, ensuring added mentorship from Prof Ed Witkowksi, Prof Wayne Twine and Dr Justice Muvengwi (WITS University) and Prof Hilton Ndagurwa (NUST, Zimbabwe) over the next two years. With all these mentors, I am very excited and looking forward to getting significant hands-on experience in data collection and analysis, critical writing and science communication skills.”

Apart from mistletoes, Tsitsi loves the English Premier League. “I am an avid supporter of both Manchester United and Manchester City, a weird red and blue combination,” she says, “but what’s life without a little weirdness.”

Links to published papers 

  1. Maponga, T.S., Ndagurwa, H.G., Muvengwi, J., Sebele, L. and Nzuma, T.M., 2022. The influence of African elephants on litter and soil nitrogen attributes in mopane woodland in Hwange National Park, northwest Zimbabwe. Journal of Arid Environments204, p.104790. https://doi.org/10.1016/j.jaridenv.2022.104790
  2. Maponga, T.S., Ndagurwa, H.G.T. and Witkowski, E.T.F., 2021. Functional and species composition of understory plants varies with mistletoe-infection on Vachellia karroo trees in a semi-arid African savanna. Global Ecology and Conservation, p.e01897. https://doi.org/10.1016/j.gecco.2021.e01897
  3. Ndagurwa, H.G.T., Maponga, T.S. and Muvengwi, J., 2020. Mistletoe litter accelerates the decomposition of recalcitrant host litter in a semi‐arid savanna, southwest Zimbabwe. Austral Ecology45(8):1080-1092. https://doi.org/10.1111/aec.12935
  4. Maponga T.S., Mkhwananzi K., Sibanda M. and Rukuni P., 2019. Mobilizing specimen data on bats and rodents from Zimbabwe. Version 1.9. Natural History Museum of Zimbabwe. Checklist dataset https://doi.org/10.15468/12foms
  5. Ndagurwa, H.G.T., Maponga, T.S., Dube, B., Nzuma, T.M. and Muvengwi, J., 2018. Termitaria vs. mistletoe: Effects on soil properties and plant structure in a semi-arid savanna. Acta Oecologica91:35-42. https://doi.org/10.1016/j.actao.2018.06.002
  6. Maponga T.S., Mkhwananzi K., Sibanda M. and Rukuni P., 2018. Making the zoology collection at the Natural History Museum of Zimbabwe accessible through GBIF by end of 2017 (BID-AF2015-0117-SMA). Version 1.11. Natural History Museum of Zimbabwe. Occurrence dataset https://doi.org/10.15468/mmhmlb 
  7. Ndagurwa, H.G.T., Ndarevani, P., Muvengwi, J. and Maponga, T.S., 2016. Mistletoes via input of nutrient-rich litter increases nutrient supply and enhance plant species composition and growth in a semi-arid savanna, southwest Zimbabwe. Plant ecology, 217(9):1095-1104. https://doi.org/10.1007/s11258-016-0635-4

Figure 1. Dr Tsitsi Maponga brings a wealth of plant ecology expertise to the Ndlovu Node (Photo: Zinhle Manqele)

Figure 2. Tsitsi is familiar with the challenges that sometimes accompany fieldwork in remote locations (Photo: Nalie Moyo)

Figure 3. At high densities, parasitic mistletoes may kill their tree host. However, at lower densities mistletoes can bring positive ecological benefits to the local environment surrounding their hosts (Photo: T. Maponga)

Figure 4. Woodroses, which form at the point of attachment between mistletoe and host, are traded as natural products (Image: https://mountainfolkcraft.com/)