After habitat alteration, invasive species are considered to be the second-leading factor contributing to the loss of biodiversity worldwide. The Buffelgrass Project provides the scientific basis for biological control and integrative management of introduced grass species in regions where they have become invasive. The team studies Buffelgrass in its native range (Kenya) to better understand what makes it so successful when introduced into foreign rangelands.
This study showcases how our long-term buffelgrass exclosure project provides data that is broadly relevant to our knowledge of grass-insect interactions and community ecology. The buffelgrass study has six sites across the rainfall gradient at Mpala, with each site containing a fenced and unfenced plot in which the team tracks ecological responses of Buffelgrass to various treatments, including insect herbivores of grasses. The specific purpose of the long-term exclosures is to test how buffelgrass responds when released from ecological stressors such as wildlife, insects, fungi, and plant competition to understand more about buffelgrass, which is a very important pasture resource in Africa but has become aggressively invasive when it has been introduced overseas.
This study provides scientific training to Kenyan researchers based at Mpala Research Centre. The Kenyan team at Mpala currently includes of Lab Coordinator Aimee Gaitho and Research Technicians Godfrey Gitimu, George Koech, and Godfrey Amoni. Former team members include Ivy Ng’iru (now a PhD student at Cardiff), Katero Kamukunji, and Kennedy Saitoti (now a PhD student at Princeton).
The establishment of buffelgrass in regions like Australia and Arizona has resulted in a transformation of fire regimes, leading to the domination of invasive species in native desert communities and a consequent reduction in the cultural and ecological value of these regions. The presence of invasive grasses can have unintended environmental implications, such as an increase in the frequency of fires due to the accumulation of dense and flammable biomass, as seen in Hawaii.
Interactions between native plants and their herbivores stabilize food webs and keep grass populations from becoming overly dominant. This study has characterized over 30 insect herbivores that eat buffelgrass at Mpala. Two of these insects are new species of gall-forming midges that appear to be highly specialized on eating buffelgrass. These species attack different grass tissues and have potential to be impactful biological control agents of buffelgrass where it has become invasive.
This study elevates the project’s capacity to document the interactions between plants, herbivores, and their natural enemies that revolve around grass host plants on a global scale. The team currently uses lessons learned throughout this project to document grass-insect associates of over 75 grass species across Kenya (Mpala Research Centre and Arabuko-Sokoke), South Africa, and Texas USA.
So far, the project has produced three publications [i][ii][iii] that share findings. Dr. Dino Martins is the primary Kenyan contributor. The project works with Nature Kenya, and received funding from the Lee and Ramona Bass foundation through the University of Texas at Austin.
Universities and Organizations: University of Texas, Mpala Research Centre, Turkana Basin Institute
Primary Investigators: Dr. Dino J Martins, ceo@turkanabasin.org, Dr. Rob Plowes, robplowes@utexas.edu, Dr. Aaron Rhodes, aaronrhodes@utexas.edu
[i] Morrison C, Plowes R, Ng’iru I, Rhodes A, Martins D, Gilbert L. Arthropod associates of Kenyan buffelgrass (Cenchrus ciliaris): a field survey for biological control candidates of a globally important invasive grass. Afr. Entomol. [Internet]. 2023 Nov. 24 [cited 2024 May 17];31. Available from: https://www.africanentomology.com/article/view/16178
[ii] Rhodes, A. C., Plowes, R. M., Bowman, E. A., Gaitho, A., Ng’Iru, I., Martins, D. J., & Gilbert, L. E. (2024). Systematic reduction of natural enemies and competition across variable precipitation approximates buffelgrass invasiveness (Cenchrus ciliaris) in its native range. Ecology and Evolution, 14, e11350. https://doi.org/10.1002/ece3.11350
[iii] Rhodes AC, Plowes RM, Martins DJ, Ng’Iru I, Gilbert LE (2022) The invasiveness of Guinea grass
(Megathyrsus maximus) is characterized by habitat and differing herbivore assemblages in its native and invaded range.
NeoBiota 78: 25–44. https://doi.org/10.3897/neobiota.78.87069