Photo: Pieter Botha

© 2016 biological interactions

Former Member

Department of Botany and Zoology


biological interactions

Pieter Botha

I have been fascinated by nature since I can remember. This enchantment, along with a deep concern for the well-being of the planet and its inhabitants, lead me to study Biodiversity and Ecology at Stellenbosch University (SU). During my undergraduate years, a friend and I founded EcoMaties, a student society that promotes sustainability on campus. I obtained a BSc Honours in Botany at SU in 2011. My honours research project at the DST/NRF Centre of Excellence for Invasion Biology looked at the distributions, seed banks and management of French Broom and Spanish Broom, two emerging invasive alien plant species in South Africa. In 2012 I travelled in South America, where I volunteered as research assistant with a sea turtle conservation program and with the NGO ProAves at the El Dorado Bird Reserve in Colombia.

My research interests are quite broad. My ideal: answering fundamental ecological questions that also have direct conservation applications. I am particularly interested in pollination ecology and biological invasions. Other interests include conservation biology in general, ethnobotany, science communication, environmental ethics, environmental education, the value of wilderness and environmentalism.

I love travelling, hiking and mountain biking and adore language and literature.


Many plant species in the hyper-diverse Cape Floral Kingdom are pollinated by nectar-feeding sugarbirds and sunbirds. Pollination studies typically focus on pairs or small groups of interacting species, and that has been the case for the Cape flora especially. As a result little is known about the networks of interactions between plants and pollinators in fynbos communities. Increasing the scale of enquiry to the community level allows one to answer important new questions. How are such plant-pollinator networks structured? What are the ecological consequences when a key group of pollinators such as birds is lost from a community? The goal of my research has been to answer these questions by conducting an unprecedented experiment – excluding birds from entire fynbos communities.

We erected 20 x 20 m cages to exclude birds from six communities in the Jonkershoek Nature Reserve close to Stellenbosch. Communities without birds were compared to neighbouring communities with birds. I characterised the pollination networks of communities and recorded the seed set of various bird-pollinated plant species. I conducted seed germination trials to test for seed quality differences. During my fieldwork I also discovered that destructive feeding on inflorescences by rodents and baboons significantly reduce the fecundity of a dominant plant species, Protea neriifolia.


My research has been featured in the following media:

Researchers go to the birds, Sunday Argus, 17 August 2014

Simulating a “world without birds” in major field experiment. Stellenbosch University website, 18 August 2014

Voëls se effek op fynbos bekyk. Die Burger, 21 Augustus 2014

As die laaste suikerbekkies verdwyn. Die Burger, 26 Augustus 2014

Current Research

Botha, P.W. and Pauw, A., (2016) Rodents and baboons reduce seed cone production of Protea neriifolia. South African Journal of Botany. DOI: 10.1016/j.sajb.2016.07.020

de Jager, M., Newman, E., Theron, G., Botha, P., Barton, M. & Anderson, B. (2016) Pollinators can prefer rewarding models to mimics: consequences for the assumptions of Batesian floral mimicry. Plant Systematics and Evolution. DOI 10.1007/s00606-015-1276-0

Geerts, S., Botha, P.W., Visser, V., Richardson, D.M., & Wilson, J.R. (2013). Montpellier broom (Genista monspessulana) and Spanish broom (Spartium junceum) in South Africa: An assessment of invasiveness and options for management. South African Journal of Botany, 87, 134-145.